Note: Descriptions are shown in the official language in which they were submitted.
~2207~7
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This is a division of Application Serial No. 453,063,
file~r April 27, 1984,
TECHNICAL FIELD
This invention relates to the recovery of oil
using mining techniques
.~ore specifically, the invention relates to a
novel method and apparatus for the recovery of oil contained
in oil bearing fields which are either virgin (untapped
previously by known oil well drilling and pumping techniques)
currently producing fields, or are classified as depleted
and incapable of further oil production using existing
surface oil well drilling, pumping and secondary treatment
techniques. The recovery of oil from such fields is
achieved by the application of novel`underground mining
methods and apparatus used in combination with oil well
technology.
15 BACKGROUND PROBL~1 AND PRIOR ART
The petroleum industry beaan in 1859 in
~enns~lvania when the Drake well was drilled purposely
to find liauid petroleum. The petroleum industry
grew very slowly. It was not until 1~01, with the
discovery of the Spindletop field in Texas, that the
world was convinced there was more petroleum than could
ever be consumed. The birth of the automobile industry
created a growing demand for petroleum products and an
accelerated growth in the petroleum industry.
As the world had more petroleum than it could
consume, the oil reservoirs found prior to 1940 were
produced utilizina only the natural energies of the
petroleum accumulation. In the late 30's wa~erflooding
and gas injection were initiated in some petroleum
reservoirs that had been depleted of their natural
energies. These reservoirs were usually at pressures
of less than 100 psi and were waterflooded at pressures
of 400 to 800 psi.
After ~orld War II the petroleum industry began
utilizing more engineering in the development o petroleum
reservoirs. This resulted in initiation o~ pressure
maintenance by water injection and gas injection much
earlier in the produ~:tive life o~ tha reser~oir~ Th~s~
` q-'
~2~07g7
injection projects were carried out at pressures usually
in excess of 500 psi and often at pressures as hig~ as
4000 psi. Oil remaining in these reser~oirs contains
considerable gas in solution.
In the late '50's it was already evident that
finding new petroleum was becoming more difficult and
more expensive. The world demand for petroleum had
grown at an unpredicted rate. It became evident that
the world would soon be short of petroleum. As a result,
new processes were initiated in an attempt to recover
more of the pëtroleum that had alreadv been found.
These new processes, fire-flooding, steam stimulation,
steam flooding and misciable flooding, were initiated in
an effort to increase the recovery from existing reser-
voirs. Most of these techniques were verv expensive
and in most cases did not achieve the desired degree of
success. At present, the only process still being util-
ized is steam stimulation and steam flooding, in reser-
voirs with low gravity and viscosity oil.
In the mid '60's the industry began to investi-
gate possibilities of tertiary recovery in reservoirs
that had been water flooded in the mid '40's. Tertiary
projects utilizing caustics, surfactants, special
emulsions and polymers were initiated on an experimental
basis. At the present time the Federal government,
through ERDA, and the petroleum industry are continuing
to investigate the tertiary recovery processes. None
of these techniques have been classified an economic
success with a great futu`re potential of recovering large
quantities of additional petroleum.
In the late 1960's the first large scale commer-
cial mining of an oil sand was initiated in Alberta,
Canada. This project is strip mining a "tar" sand and
processing the sand to recover the hydrocarbon. The
project was uneconomic at world oil prices prior to 1973.
The project became economical after petroleum prices were
~220~97
. -3-
increased. As of this writing other projects scheduled
in the area have still not been placed on a production
status because of economics.
Oil reservoirs which: may be candidates for a
mining recovery process can be classified into two
general categories, depleted or virgin. The depleted
reservoirs were estimated to contain some 3Q0 billion
barre~s of unrecovered oil in a 1976 study by the
National Petroleum Council and are estimated to comprise
between 60 and 80 percent of the oil originally present
in these fields. The depleted reservoirs can be classi~
fied into two general categories; those which have under.
gone some type of secondary recovery process and those
which have onlv been primarily depleted. The former
category ~!ould probably be classified as containing the
greatest amount of remaining petroleum because they
represent the greatest number of petroleum reservoirs.
A considerable'number of primary depleted reservoirs
exist in the viscous crude oil category. Some of these
reservoirs have undergone steam s~imulation but not a
secondary recovery process. The volume of oil in this
category is probably in excess of 150 billion barrels.
The depleted systems which have undergone second-
ary recovery processes are the ones flooded in the late
'30's and early '40's. These were at relatively shallow
depths and which were at very low pressures. Some of
these reservoirs were placed on a vacuum during ~orld
~ar II and hence would contain very small amounts of
gas in solution'in the oil. The low gas in solution
results in very small amounts of any gas in the reser-
voir to be utilized as a displacing fluid.
The other type of reservoirs which have undergone
secondary recovery will have been flooded at pressures
, in excess of 500 psi and will have considerable gas in
solution and possibly free gas to assist in the removal
of fluids from the formation.
~Z~079 7
These depleted reservoirs will probably contain
oil having the following properties.
Viscosity - 1 to 10 centiposes
Gravity - greater than 25 API
Gas in Solution - between 10 and 800 std. cu. ft.
per reservoir barrel
Oil Saturation - between 10 and 40 percent of
the pore space
Porosity - between 15 and 30 percent
Whether these reservoirs will be feasible for a
mining process will be a function of the product of the
formation thickness, formation porosity and residual oil
saturation.
Oil in Place = Area x Thickness x Porosity x Oil
Saturation. Factors o~ depth ~nd mineability of forma-
tions above or below the oil zone itself will be major
factors in the economics or feasibility of any such pro-
cess.
The reservoirs which have undergone primary
depletion only, with or without steam stimulation, will
normally contain a much higher percentage of inplace oil
at the time any mining process may be initiated.
These reservoirs will normally contain a more
viscous oil, be at relative low pressures, and at
relatively shallow depths. These reservoirs are repre-
sented by the higher viscosity oil reservoirs in
California, Venezuela, and in Canada. They are presently
being produced but with great difficulty. There is
probably over 500 billion barrels of oil in this class
of reservoir in the world.
Virgin reservoirs which might be susceptible to
underground mining are represented by the known tar sands
and the very viscous or high pour point oil deposits
throughout the world. It is known that very extensive
3~ reserves of petroleum exist in these type of deposits in
the United States, Canada and South America. The
1220797
--5--
es~imated reserve is 1,000 billion barrels. These
virgin deposits are susceptible to both strip mining
and to some types of underground recovery.
The "tar" sands which are being produced in
Canada by means of strip mining have been drilled and
tested by conventional petroleum recovery mechanisms
with very little success. The petroleum content of
these "tar" sands change into a very viscous oil with
depth. They have not been treated with combinations of
known recovery technology in order to make them produc-
tive. They have been overlooked as a potential source
of petroleum production primarily because of the
quality of the petroleum and their location. In many
cases these reservoirs represent a petroleum deposit
which is directly mineable by surface methods. As the
depth of these deposits increase, the contained petro-
leum is very highl~ viscous and has gas in solution so
that removal of the petroleum containing formation is not
possible because of gaS release to the atmosphere in
the pit and the resultant ventilation and fire-explosion
hazard.
It is believed that using available mining
technology it is possible to develop mine working
preferably beneath the oil-water contact of certain
oil fields in selected areas. By being below the oil-
water contact, it should be possible to hold the greatest
hazard to mining, the inflow of any of the gasses normally
associated with oil production, to an acceptable minimum.
The other important limiting criteria include the
30 : following items:
- (1) Rock Characteristics for Mine Workings
If mine workings are to be developed below an
oil-water contact, it is likely that the workings must
be in a formation which is highly competent with very
low permeability such as a shale or dense limestone,
~22~791'7
-- 6
or at least with such a stratigraphic unit acting as a
seal against uncontrolled inflow of fluids from the producing
reservoir. At least in the early stages of oil recovery by
mining, fields with minimum faulting should be developed,
again, to aid in control or elimination of unexpected gas
and water inflows.
Since shales are relatively incompetent and often
tend to "flow" or "squeeze" to fill mine workings, thus
causing expensive support problems, it is estimated that
development in shales should be limited to depths of 1200
feet or less. However circumstances may exist where a much
greater depth can be worked.
Limestones are more competent. It is estimated that
in general, with acceptable levels of support requirements,
it should be possible to develop mine workings, under oil,
reservoirs, in limestones or dolomites to depths of at least
4000 feet. Again circumstances may exist where a much
greater depth can be worked.
Probably mine development within a salt unit would
be the ideal. In this case, the salt would be an excellent
seal against water inflow, it is easily cut by conventional
mining equipment, and it is possible that the salt produced
in the development of mine workings coula be marketed. The
flow characteristics of salt would limit the depth of working
possible without excessive support problems.
Sandstones may or may not be a desirable medium for
mine development. Such things as permeability and porosity,
gas, oil or water content, and strength of the formation
would be major limiting factors, as well as stratigraphic
features of the formations above and below the sandstone.
(2) Reservoir Temperature
In general, men can work in mine workings in rocks
with temperatures up to about 125F. At temperatures above
this, cooling is possible but may or may not be economical.
(3) Quality of Crude
Two important considerations suggest that reser-
voirs with higher quality crude, roughly defined here as
--7--
- higher than 30 API, shouId be the target for oil mining.
The lower gravity crudes, 8-12 API, are worth less than
a barrel of 50 API crude. This indicates the payout for
high quality crude will likely come much earlier than for
the lower quality crudes. The only reason for any
question in this regard is the needed estimate of size
or reserve versus mining cost. This will have to be
developed for each individual case. Higher quality
crudes, with contained lighter fractions, are likely to
be more mobil in a reservoir than are the low gravity
crudes.
(4) Pour Point
The reservoirs planned for mining of oil should
contain crudes with low pour points although this is not
a limiting factor. There are systems available, one
in particular that has recently been publicly announced,
that will permit in-place controlled heating of a reser-
voir. It will be possible to heat the reservoir uniformly
in blocks extending for several hundreds of feet. The
temperature can be raised several hundreds of degrees,
if necessary, within a few weeks time. Such heating
would fluidize high pour point crudes, or in other cases,
could be used to increase gas pressures within a reser-
voir, thus tending to re-establish a natural gas drive
within the reservoir. In the few cases of higher gravity
oil, lower rock temperature and higher pour point,
heating of reservoir, with development and production
through mine workings could be an excellent solution to
an otherwise non-producible field.
(5) Thickness of Pay Section
The thickness of pay section should be as great
as possible. This would simply allow more reservoir
development per foot of mine workings, thus reducing
the development cost per barrel of oil produced.
07Y7
--8--
(6) Depth of Pay Section
It is hoped that the first oil mines can be
developed in reasonably shallow fields, that is at depths
of 1000 feet or less, to hold down development costs
and to permit more easily handled rock conditions for
mine development. The reservoir should be deep enough
that natural water and/or gas drives, to the extent
possible in a depleted field, could still be utilized.
(7) Porosit~
Target reservoirs must have sufficient oil-
saturated porosity, with enough oil remaining after
production by surface well methods, to make the reservoir a
potentially economic target. Data for this determina-
tion should be available for any developed field, in
lS varying degrees of completeness. Probably this type of
data will be less complete or useable for the earlier
discovered field, which may also be the best targets
for initial oil mining.
Limestones may range in porosity from zero to
cavernous. In more cavernous limestones, porosity at
the well may be essentially zero ~hile à short distance
away a large untapped oil resèrve may exist. Limestone
reservoirs, overlain and underlain by competent forma-
tions are fairly prevalent in the Appalachian states,
~est Texas and New Mexico. Many of these reservoirs
contain large ~uantities o~ hydrocarbon material, but
the recovery, either by primary or secondary methods, is
usually extremely small. These formations have not
behaved as existing petroleum engineering theory pre-
dicted, hence it is believed that a tremendous amountof oil is still present in most of these limestone
formations. More complete opening of the reservoir by
mining techniques may provide the "permeability" that
appears to be lacking in the porosity.
12;~07~7
g
-(8~ Permeability
In normal well production, permeability, the
interconnection between points of oil-containing porosity~
is essential. For oil mining, higher permeability reser-
voirs would be desireable in sandstone reservoirs.
Within limestone reservoirs, particularly those that
tend to be cavernous, more complete development of the
reservoir, mav permit much more complete recovery from
these reservoirs.
(9~ Other Characteristics
Other oil and reservoir characteristics, such as
viscosity, pressures, gas in solution, sulfur content of
the oil and H2S percentage in gas, uniformity of reser-
voir vertically and horizontally to name but a few,
will all be important characteristics, but are not
thought to be as important as those listed separately
above.
Advantages of Oil Mining
There are several advantages offered by oil mining
which are as follows:
1. This is a possible way of placing "wells" on
approximately one acre spacing or less, providing a much
greater possibility that oil entrained in the reservoir will
move to the well.
2. Natural gas and/or water drives can be
utilized.
3. By drawing from the bottom, gravity can be
used to the maximum effect.
4. Drill holes for each well are much shorter
than those drilled from the surface and hence less
expensive per well while the cost of the access shaft
and tunnels can be amortized over a large number of wells.
5. No pumping equipment at each well would be
needed but ~nly at the bottom of the shaft for all wells.
~Z20~
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6. Currently, depending upon the company,
discovery of new oil costs from $4 to $7 per barrel.
Since the mining development would be within known fields
there would be no cost of discovery. It is thought that
the saving from this cost alone could pay most if not
all of the development and production costs.
7. Landowners would already be familiar with
oil production and its benefits. Perhaps they would ~e
reasona~ly receptive to oil mines being developed in
their area.
8. If there has been production from the field,
perhaps useable surface pipelines to refineries might
be reasonably close.
The concept of applying mining techniques to
the production of oil from oil bearing sands, both virgin
and depleted, is both old and well known as described in
a United States Bureau of Mines Bulletin No. 351 entitled
"Mining Petroleum By Underground Methods" by George S.
Rice published by the U. S. Government Printing Office
in Washington, D. C. in i932. Methods for the under-
ground mining of oil were further investigated and
reported in a bulletin entitled "Mining For Petroleum:
Feasibility Study" prepared for the U. S. Department of
the Interior - Bureau of Mines under contract No. JO275002
July, 1978. These prior art publications while informa-
tive, do not include sufficient specific details of how
to go about overcoming the many practical problems
encountered in the underground mining of petroleum.
To overcome this deficiency the present invention was
devised.
SUMMARY OF INVENTION
It is therefore a primary object of the invention
to provide new and improved techniques and equipment for
t~e practical underground mining of petroleum from both
virgin and depleted oil fields under certain geological
conditions where such mining of oil is feasible.
12Z0797
-~In practicing the invention, a method of drilling
a relatively small diameter drainage-type mine oil well
using a fluid and cutting control assembly,is provided.
The fluid and cutting control assembly comprises a stop
valve mounted on a pipe casement for securement to a firmly
anchored collar pipe providing the outer liner for an
access opening to a drainage-type mine oil well. The
drainage-type mine oil well is drilled into the overlying
roof of a tunnel cut into a competent rock zone below
oil well sands containing unrecovered oil. The gate valve
and pipe casement have an inside diameter opening with
the gate valve in the open condition which is sufficient
to accommodate the outside diameter of a drainage-type
mine oil well produc~ion conductor pipe and/or a drill
bit and drill string together with appended stop valve,
coupling and the like required to support the drill string
or production conductor pipe. Upper and lower blow-out
preventers are secured to the casement below the stop
valve and have internal diameters sufficient to accommo-`
date the external diameter of the drainage-type mine oil
well production conductor pipe and!or the drill string
fitting for the drill bit. An upper drain vent control
valve is connected to a first drain vent branch pipeline
and to the casement between the stop valve and the upper
blow-out preventer. A lower drain vent control valve is
connected to a second drain vent branch pipeline and to
the casement intermediate to the upper and lower blow-out
preventers. ~ith the fluid and cutting control assembly
in place mounted on the annular collar, a drill bit and
supporting drill string is inserted through the opened
lower and upper blow-out preventers and through the opened
stop valve. The small diameter gravity-type oil drain
well is then drilled upwardly through the overlying com-
petent rock roof of the tunnel and into the oil bearing
sand zone to a desired depth while supplying cutting fluid~
to the drill bit under pressure upwardly through the drill
~220797
-12-
string.- During drilling, the upper and lower blow-out
preventers are maintained tightened down on the exterior
of the drill string to only a slide fit and cutting fluid
and entrained cuttings are drawn off through the upper
and lower drain vent control valve and the connected
branch drain pipeline for supply through a piping syste~
installed in the tunnel and to a pump for pumping to the
surface and disposal.
Another feature of the invention is the provision
of a method for installing oil well production conductor
pipe in the relatively small diameter drainage-type mined
oil wells a~ter drilling in the above-described manner.
The method comprises loosening the upper and lower
blow-out preventers while withdrawing the drill string
to the point where the drill bit is just below the stop
valve while drawing off any fluid cutting oil and gas
and water entrained in the fluid through the upper and
lower drain vent control valve for removal to the surface
in the above-described manner. The stop valve is then
closed and the drill bit completely withdrawn from the
fluid and cutting control assembly. A production conductor
pipe is then inserted within the casement thraugh the
loosened upper and lower blow-out preventers to a point
where the upper end of the conductor pipe is just below
the stop valve. The blow-out preventers are then tightened
to the point of providing only a slide fit for the exterior
surface of the production conductor pipe while maintaining
the upper and lower drain vent control valve open and
under suction to drain off any leakage of fluid past the
upper blow-out preventers. The stop valve is then opened and
the-production conductor pipe driven upwardly through the
drilled opening into the oil bearing sand strata to a
desirea depth.
Another feature of the invention is the provision
of a closure over the upper end of the relatively small
i220~797
-13-
diameter drainage-type oil mine well production conductor
pipe during the emplacement thereof in the preceeding
described manner together with selectively opening the
upper end of the production conductor pipe after it is
secured in place to a desired depth into the oil sand
strata in order to place the well into production. To
facilitate placement of the production conductor pipe
with its upper end closed, the pipe is vented during
emplacement and subseauent cementing into place. For
this purpose, it is necessary to vent the space inter-
mediate the drilled hole and the conductor pipe as it
is being emplaced and cemented. To accomplish the venting,
a small diameter flexible fluid impervious venting tube
is supported through the interior of the conductor pipe
while it is being emplaced and at the upper tip end
thereof extends through a small port in the upper end of
the conductor pipe. A control valve is secured in the
venting tube at a lower accessible end of the tube so
that it can be controllably opened and closed to control
the venting through the tube. The discharge end of the
vent tube is led through the tunnel back up through the
access shaft to the surface in order that the mine at-
mosphere is not contaminated with gases vented through
the venting tube.
Still another feature of the invention is the
provision of a method for permanently cementing the pro-
duction conductor pipe into place by first tightening
do~n the upper and lower blow-out preventers to the
greatest possible extend to prevent movement of the con-
ductor pipe during cementing. Cement under pressure is
then forced from a cement pump connected through the
upper drain vent control valve and its interconnected
first branch pipeline to the space surrounding the con-
ductor pipe. During cementing the stop valve is in its
fully opened condition so that it is not cemented into
~220797
~-14 ~
place and subsequently can be removed along with the fluid
and cutting control assembly. To facilitate this oper-
ation, the space between the upper and lower blow-out
preventers preerably is flooded with water during the
cementing stage. Arter setting of the cement, the fluid
and control assembly casement including the stop valve
is removed and a new stop valve coupled to the end of the
cemented in place production conductor pipe along with
any additional lengths of production conductor pipe
reauired to lead away the oil produced by the well to a
suitable collection point within-the mine tunnel system.
A still further feature of the invention is the
provision of a method for opening the upper end of the
production conductor pipe after it has been cemented into
place. A preferred method is to attach a small charge
of explosive to the closed upper end of the production
conductor pipe and thereafter selectively detonating the
charge to blow open the top of the conductor pipe and
place it into production. An alternative method is to
employ a Johnson Screen together with a suitable closure
element such as a one way check valve disposed in the
conductor pipe below the screen. A small charge of
explosive should be attached to the closure element and
a small remotely operated detonator secured to the charge
for selectively detonating the charge and blowing open
the closure element to place the oil well into production
through the Johnson Screen. In the case of the Johnson
Screen care must be exercised to assure that the cement
is not allowed to rise sufficiently high to close the
Johnson Screen. A further method is to employ a
~ Schlumberger type perforating gun secured to the interior
of the closed end of the production conductor pipe while
it is inserted into place and thereafter remotely fired
to perforate the upper end and upper sides of the pro-
duction pipe in order to place the well into production.,
- 14A
12Z0757
The present divisional application is directed
to A gravity-type drain oil well production oil conductor
pipe assembly having a closed upper end together with fluid
impervious vent tube means having controllable stop valve
means therein for controllably venting space above the
closed upper end of the conductor pipe assembly, and remote
control means for selectively producing liquid passageway
openings in the closed upper end of the conductor pipe
assembly after installation, said conductor pipe assembly
being proportionally shaped and designed to be inserted
in a gravity drainage-type oil well opening formed in the
roof or wall of an oil well mine facility by means of a
fluid and cuttings control assembly.
122~797
BRIEF DESCRIPTION OF DE~AWINGS
Other objects, features and many of the attendant
advantages of this invention will become better under-
stood upon a reading of the following detailed description
when considered in connection with the accompanying draw-
ings; wherein, like parts in each of the several figures
are identified by the same reference character, and
wherein:
Figure 1 is a schematic drawing illustrating the
positioning of two access mine shafts through an oil
bearing sand strata in such a manner that the shaft pene-
trates from an upper competent rock shelf, through a
gas cap! through an oil bearing zone and down into a
lower competent rock zone where access tunnels are pro-
15 vided for mining development of drainage-type oil
wells within the tunnel system;
Figure 2 is a more detailed schematic drawing
of an oil field being mined according to the invention but
which has no gas cap and illustrates the manner in which
drainage-type procudtion oil wells are connerted to col-
lection lines leading to a vertical access shaft where the
oil is pumped to the surface for storage;
Figure 2A is similar to Figure 2 except that it
depicts an oil field wherein a gas cap is present in the
strata;
Figure 3 is a schematic drawing illustrating a
preferred way of driving an enlarged diameter shaft of
sufficient size to accommodate men and equipment through
a competent rock zone to near the oil and gas bearing
horizon, then providing an annular chamber by means of
which small driftholes are drilled-in an annular array
around the intended path of the extended large diameter
access shaft to permit freezing, grouting or otherwise
. stabilizing the oil-producing zone to permit sinking of
the large diameter access shaft through it to a second
lower competent rock zone into which access tunnels
beneath the oil field can be drilled. Figure 3 also
12;~0'7Yq
-16- ,
illustrates the provision of a fluid impervious casing
around the large diameter access shaft for the portion
of the len~th thereof which extends through the oil
bearing sand strata;
S Figure 4 is a schematic illustration of the
manner in which a relatively smalt diameter drainage-
ty~ mine oil well is initailly drilled through the
r of cf a tunnel formed in the underlving lower or
second competent rock zone by initially placing a
cemented in place enlarged diameter collar pipe in a
larger diameter hole drilled upwardly through the roof
of the tunnel so as to provide a solid anchor for a well
hole collar pipe;
Figure 5 is a schematic/ side sectional view of
a fluid and cutting control assembly employed in prac-
ticing the invention and shows the same installed in
place on a drainage-type mine oil well being drilled
in the roof of one of the access tunnels to permit the
drilling of such wells within the mine without contam-
inating the mine workings atmosphere;
Figure 6 is a schematic elongated side sectionalview similar to Figure 5 illustrating the manner in
which a production conductor o~l pipe for a drainage-
type mine oil well is cemented into place employing
the fluid cutting and control assembly;
Figure 7 is a partial elongated sectional view
of a cemented-in-place production conductor pipe for a
drainage-type mine oil wellsafter it has been processed
according to Figures 5 and 6 and showing different types
of stop valyes, screens~ detonator control circuits, flow
control valves as well as other measuring instruments,
and the connection of the cemented-in-place oil well
conauctor pipe to an oil collection piping system that
runs through the mine tunnel for accumulating oil drained
from a multiplicity of different drainage type oil
wells placed ~long the length of the tunnel;
1220~
. . -17- ~
Figure 8A illustrates a modification of the
installation shown in Figure 2 wherein certain of the
relatively small diameter drainage-type oil well production
conductor pipes are connected to a supply line for
supplying secondary treatment fluids such as steam,
compressed air, water or other fluid for pressurizing
particular points.along the length of a tunnel to im-
prove collection at different points within the tunnel
or within the depth of the field having another tunnel
or tunnels beyond the pressurization point in the same
plane;
Figure 8B is a schematic, elongated sectional
view of.a somewhat different form of drainage-type oil
well emplaced in a mine according to the invention which
uses a Johnson Screen and also incidentally shows a
geological installation where there is a gas cap over an
oil bearing sand strata which in turn has an oil/water
interface below the oil bearing sand;
Figure 9 illustrates still another al~ernative
arrangement for perforating a production conductor pipe
which has been sealed closed during its installation
and emplaced within the oil bearing sand strata using a
Schlumberger gun;
Figure 10 is a schematic functional diagram of
a suitable production fluids sensing and control system
useable in conjunction with a main control computer
located remotely from the mine workings and which allows
oil production within the mine workings to be completely
automated, semi-automated or manually controlled as
operating conditions permit;
Figure ll is-a schematic side view of a motor
actuated valve used in the control system of Figure 10
and showing the manner in which limit switches can be
employed to telegraph to a main control compute~ or
- control console the operating condition of such valves;
~220'797
-17A-~ -
~Figure 12 is a schematic functional diagram of
a li~e support and safety system designed for use in
petroleum mines according to the invention and which
provide ventilation air, gas detection and protection,
fire detection and protection, flooding detection and
protection and monitors operation of vital equipment
needed in the safe operation of an underground petroleum
mine.
Figure 13 is a detailed, schematic side sectional
view of sub-groupsof underground drainage-type mine
oil wellsconstructed according to the invention and
filled with necessary sensors and equipment to allow
completely automated control over oil product~on from
the wells pursuant to the control system shown in
Figure 10;
Fi~ure 14 is a detailed, schematic side sectional
view of an alterative form of installation similar to
that of Figure 13 but which allows introduction in a
controlled manner of secondary treatment agents into
selected ones of the drainage-type underground mine
oil wells for use in conducting re-pressurization and/or
other secondary treatment.processes in connection with
selected portions of the oil field;
Figure 15 is a partial, detailed, schematic
diagram showing the Fire Detection and Protection
System portion of the life support system shown
generally in Figure 12; and
Figure 16 is a pa_tial, detailed, schematic
diagram showing the Gas Detection and Control System
comprising a part of the overall life support system
of Figure 12.
DETAILED DESCRIPTION OF BEST MODE FOR CARRYING OUT THE
INVENTION
Figure 1 is a schematic illustration of a typical
12Z~79~
. . -17B-
layout for a mine development for the recovery of oil by
mining. In Figure 1, two relatively large diameter ver-
tical shafts 11 and 12 which are of sufficient size to
accommodate both men and equipment for mining beneath
the ground have been driven through an overlying upper
competent rock strata 13, through an oil bearing sand zone
14 and into a lower competent rock zone 15. The two verti-
cal shafts 11 and 12 terminate in a horizontal tunnel indi-
cated at 16 which likewise is of sufficient size to accomo-
date workmen and the equipment required for driving upwardlythrough the roof of the tunnel 16 a number of relatively
small diameter, drainage-tupe oil production wells
indicated at 19, 19~ and 19" with the drainage-type oil
~220~97
-18-
proauc~ion wells being placed at predetermined intervals
along the length of the tunnel 16. It is anticipated
that the tunnel 16 will interconnect with other horizon-
tally extending tunnels (not shown) so that substantially
a criss cross network of tunnels will be provided beneath
the oil field depicted at 14. The drawing is illustrative
of a typical geological condition wherein the oil field
is capped by a gas cap indicated at 17 which at least at
some time in the past pressurized the oil within the oil
sands 14 as well as a layer of water indicated at 18
trapped between the lower competent rock strata 15 and
the oil bearing sands 14. This results in the formation
of an oil-water interface as shown at 21.
From Figure 1 it will be seen that the vertical
access shafts 11 and 12 for mine access must pass through
the oil and/or gas bearing productive zone or zones all
of which may be under pressure. The sinking of the verti-
cal shafts under such conditions requires a system
whereby all possible inflow of gas and/or oil will be
completely controlled without danger to men and equipment
working on and in the mine. The mine workings are to
provide access preferably under an oil-water interface for
drilling operations and the placing of the piping,
for the removal of drill cuttings, any oil and/or gas
encountered during the drilling of production wells in
addition to providing for a piping system for transporting
produced gas and oil from the wells. This ~is in addition
to the normal mine drainage, ventilation, power and waste
removal system~required in any mine workings. Preferably
the development should be such that oil and gas produc-
tion can be carried out even while mine development
workings are going on to drive additional drainage-type
oil wells as will be described hereina~ter.
~zzo~s7
--19--
The mine shaft configuration shown in Figure 1
employs two vertical access shafts since safety rules
and regulations require two entryways to a mine. Thus
the drilling cuttings removal and oil production system
and piping can be placed in one of the vertical sha~ts
for access to the surface and the other vertical shaft
can be employed for personnel access and egress. It is
desirable that the two vertical shafts be rotary drilled
or sunk at a pre-set distance apart and the shafts securely
sealed by fluid impervious liners through at least the
oil and gas zones 14, and.the two shafts extended down
into the lower competent rock zone 15 where the ends of
the shaft are interconnected through the tunnel 16.
Shaft 11 can then be used for ventilation exhaust,
removal of production drill hole cuttings, produced gas
and oil and removal of mine wastewater as well as to
provide an escapeway if necessary. Shaft 12 can be the
main mine development shaft carrying the ventilation
inflow, any electrical systems for supply of electricity
to equipment required below as well as all other services
needed for developing the mine.
Figure 2 illustrates an-installation quite similar
to that depicted in Figure 1 but shows in greater detail
the fluid impervious liners 22 and 23, respectively, for
the vertical access shafts 11 and 12 which extend through
the oil and gas bearing zone 14. Figure 2 further illus-
trates thecollection piping system 24 laid through the
horizontal tunnel 16 which interconnects the production
conductor pipes 19, 19' and 19" at the plurality of
`30 drainage-type mine oil well sites to a pump 25 at the base
~ of vertical access shat 11 which pumps the collected oil
and gas to an oil storage tank 26 on the surface. The
installation shown in Figure 2 does not include a gas
cap but does include an oil-water interface shown at 21.
For this reason, the lengths of the small diameter gravity-
~2~0~97
-20-
type drain oil well pipes 19, 19' and 19" are extended
above the oil-water interface. Because of the height
of the oil-water interface it is possible that there may
have been existing surface oil wells such as the one
indicated at 27 driven into the field which are no longer
sufficient]y productive to justify further working. In
such instances the abandoned surface oil wells could be
capped as indicated or alternatively could be used as
a means for introducing secondary treatment agents such
as hot steam, compressed gas water, etc., to increase
working pressure within tne oil sand strata. In
addition to such measures, one or more of the individual
gravity type oil production conductor pipes 19 at
different locations along the length of the access tunnel
could be disconnected from the main collection pipe 24
and instead connected to a secondary treatment agent
supply pipe 23 such as shown in Figure 8A of the drawings
in order to introduce such secondary treatment agents
into the oil bearing sand strata at different selected
sites along the length of the access tunnels.
Figure 2A is a view similar to that shown in
Figure 2 but illustrates instçad a geological installa-
tion wherein there is a gas cap 17 interposed between
the upper cap rock 13 and the oil bearing sand strata 14.
In such installations it may be desireable to provide
drain oil well production conductor pipes such as 19' of
sufficient length to reach into the gas cap 17 for the
purpose of controlling pressure induced by the existence
of the cap. For this purpose, the extended lengths of
production conductor pipes such as 19' could be used
to bleed off certain of the gas pressure in the gas cap
to maintain it below certain predetermined levels or
alternatively, such extended lengths of pipe could be
connected to pressurized ~s sources for increasing the
i2207g7
- 21 -
pressure within the gas cap for improving production from
the other adjacent drainage-type oil mine production
conductor pipes such as 19 and 19" or those located
further along tunnel 16.
The existence of a gas cap such as shown at 17
in Figure 1 and in Figure 2A would tend to complicate the
process of driving a large diameter access shaft such as
11 or 12 down through the upper cap rock 13 into and
through the oil bear-ng sand strata and thence down into
the lower cap rock 15. The gas cap zone would be
relatively free of water or oil and thus would probably
not respond to freezing techniques and may not react
satisfactorily to grout. If such conditions are indicated
by prior exploration and evaluation, it is likely that
rotary drilling of the shaft, using conventional oil well
drilling needs and techniques, would be indicated. Shaft
casing can be floated on the mud, down into position,
and cemented, perhaps using the same technique as was
used in lining the U.S. Bureau of Mines deep shaft
through oil shale near Rio Blanco, Colorado.
Where gas cap danger is not indicated but it
will be necessary to sink the shaft through an oil and/
or water saturated formation, the shaft can be sunk by
any conventional sinking procedure to a safe depth above
the oil-bearing zone 14.
lZ20~
- 22 -
At this particular level, an annular chamber shown at 28
is mined in the upper competent cap rock 13 so as to
completely surround the shaft location 11. From the floor
of the annular chamber 28, a number of very small diameter
drill holes are drilled completely around the circumfer-
ence of the path of the pro~ected vertical access shaft
11 as shown at 29. The vertical drill holes 29 are then
supplied with a suiiable solidifying agent such as grout,
cement, silicon fluoride or the like or alternatively
may be supplied with a suitable refrigerant for freezing
the oil sands 14 within the region of the projected path
of the vertical access shaft. The vertical access shaft
is then drilled through the solidified gas and oil bearing
sand region and sides of the shaft in this region are
lined with a suitable fluid impervious liner 23 or 24
as described earlier with respect to Figures 2 and 2A
of the drawings. The drill holes 29 must be positioned
so that the temperature of the oil and gas zones 14
can be lowered below the freezing point of water and
pour point temperature of the contained oil. As noted
above, freezing may be replaced by the use of any of
the several possible grouts including but not limited
to AM-9 manufactured and sold by American Cyanamide,
silicon fluoride or cement grouting. In the event that
the oil and gas region 14 is quite shallow and close to
the surface of the earth, the drill holes 29 could be
drilled from the surface in a similar manner in order to
solidify the projected path through which the vertical
access shaft must be driven. After the oil and gas
bearing zone 14 has been frozen or otherwise stabilized,
the shaft 11 can be driven, using gassy mine techniques
through the oil and gas bearing zone 14 down to and
1220~
-23-
through a portion of the lower competent cap rock region
15. If desired, a suitable sump such as shown at 31 can
be provided at the base of the vertical access shaft.
The development of the mine workin~susing verti-
cal access shafts 11 and 12 drilled in the above briefly
described manner, can be on whatever pattern appears
appropriate as dictated by cost analysis of the geology
of the particular oil deposit being mined. The mine
workings are solely for the purpose of providing access
for drill site locations for the relatively small diameter
drainaqe-type oil wells to be drilled upwardly into the
overlying competent cap rock roof of the access tunnel 16.
The location of the drainage-type oil well sites along the
lengths of the access tunnel will be deter~ined primarily
by the following basic factors:
a) Competence and impermeability characteristics
of the host rocks in which the access ~unnel
16's have been bored.
b) The location of needed drill sites as deter-
mined by the nature of the oil deposit.
c) Ventilation requirements.
d) Optimum scheduling permiting simultaneous
continued mine development, drilling of pro-
duction wells and completion and production
from producing wells.
e) Accomplishing the above with the least possible
complexity of the mine workings.
Since each oil field is different from all others,
the above analysis undoubtedly will result in different
mine layouts for each field. As previously noted, the
mine workings simply are to provide continuous access to
the producinq drain oil wells, a way of removing waste
during mine development and any that may develop later
and to provide passageways for the positioning of produc-
tion pipelines for removal of produced oil and gas. Themine workings in the form of the access tunnels can be
driven by known underground mining drilling-blasting-
~220'797
. -24-
muck removal techniques and by the utilization of hori-
zontal tunnel boring systems with or-without hydraulic
jet assist. Whatever system is used, it will be advan-
tageous in the environment noted to keep fracture of the
raw rock around the tunnels to a minimum in order to
assist in prevention of undesired leakage from the over-
lying oil and gas horizon. Also it is anticipated that
all of the small diameter drainage-type mine oil wells
such as 19, 19' and 19" within the mine workings would
be tied into central piping systems designed to optimize
both manual and automatic production control of oil and
gas through the well head.
Referring to Figure 4 of the drawings, a cross
section of one of the access tunnels 16 is illustrated
with the cross section being taken through a drainage-type
oil mine well site. At the well site, a hole shown at
32 is drilled upwardly through the overlying roof 15
of access tunnel 16 at any angle upward through only a
portion of the competent rock cap surrounding access
tunnel 16. The hole 32 is drilled to a depth great
enough to permit solid cementing into place of a collar
pipe 33. The collar pipe, for example, may have a diameter
from about 6 to 8 inchesmore or less depending u~sn the desired
diameter for the gravity-type drain oil wells to be in-
stalled at the site. A shoe flange shown at 34 isthreaded over the lower threaded en~ 38 of collar pipe
33 in order to close the space between the outer surface
of collar pipe 33 and the inside of the drilled hole 32.
Cement is then supplied under pressure to this space via
cement ports 35 formed in the end of the collar pipe
above the threaded end 38 and a cement gun nozzle shown
at 36. After cementing, the cement gun 36 is removed
and the ports 35 closed with suitable stoppers while
the cement 37 sets. After the cement 37 has set, so as
to`firmly seal collar pipe 33 into place in the drilled
122079q
-25-
hole 32, the shoe flange 34 can be unscrewed and removed.
With reference now to Figure 5 of the drawings,
the cemented into place collar pipe 33 has a coupling 39
screwed onto its lower threaded end 38 for coupling to
the collar pipe 33 a fluid cutting and control zssembly
shown generally at 40. The fluid cutting and control
assembly 40 is comprised by an outer casement 41 which
in fact may be made up of different segments which include a
manually operated stop valve a2 which may be of the well known,
commercially available gate valve type, an upper blow-out
preventer 43, a lower blow-out preventer 44, an upper
drain vent control valve 45 connected to the casement 41
intermediate stop valve 42 and the upper blow-out pre-
venter 43 and a lower drain vent control valve 47
connected to casement 41 in the space between upper and
lower blow-out preventers 43 and 44. The upper and
lower drain vent control valves 45 and 47 are connected
through respective branch pipelines 46 and 48 to a
suitable trunk pipeline that carries fluids used during
drilling, any entrained oil, gas, rubble and the like
away through a suitable mud pump (not shown) for trans-
port through a conduit laid down through the access
tunnels and vertical access shaft up-to the surface and
discharged to a suitable collection point. Where it is
desired to use the fluid and cutting control assembly 40
repeatedly at different well sites, a third drain vent
control valve 49 is provided together with an inter-
connected branch pipeline for connection to the same
discharge conduit system. The purpose of the third drain
vent control valve 49 will be described more fully here-
aft~r with relation to Figure 6 of the drawings.
The drain vent control valves ~, 47 and 49 are
entirely conventionàl and available commercially, and
hence need no further description. Likewise, the pipin~,
collar pipe! casement segment, couplings, flanges and
the likè are believed to be entirely conventional and
1220'797
- 26 -
commercially available and require no further description.
The stop valve 42 and upper and lower blow-out preventers
43 and 44 similarly are conventionally available items
obtainable from oil field equipment supply firms such as
the Hydril Co. of Los Angeles, California, the Gardner
Denver Corp., the Grinnell Valve Co. and the Jamesbury Corp.
These items must be of sufficient size so that their inside
diameters will accommodate passage through the centers of
the equipment and valves of the outside diameter of a drill
bit 51 and its associated supporting drill string 52, coup-
lings between segments of the drill string and a one-way
flap or check valve 54 which is mounted at the top of the
drill string 52 immediately under the drill bit 51. The flap
valve 54 which is set in the first section of the drill
string or drill pipe 52 supporting drill bit 51 permits
drilling fluid such as water under pressure to flow upward
around the drill bit 51 to facilitate drilling but will check
or stop any back pressure to the drill string 52 and prevents
any backflow of such fluid down through the inside of drill
pipe 52 when the drilling fluid input is discontinued.
With a drilling rig, such as manufactured by Joy
Mfg. Co. or Boyles Bros., set up in the manner shown in
Figure 5, the drill bit and its supporting string is inserted
through the fluid and cutting control assembly 40 by
loosening the blow-out preventers 43 and 44 and opening the
stop valve 42 to allow passage of the drill bit 51 and its
supporting string up through the casement 41 to the end of
the hole in which the firmly anchored collar pipe 33 is
cemented. The blow-out preventers 43 and 44 are then
tightened down to just a slide fit, drilling fluid is sup-
plied to the inside of the drill pipe 52 and the drain vent
valves 45 and 47 opened to drain off the drilling fluids and
any entrained solid matter contained in such drilling
fluids. If desired, a suction can be placed on the drain
conduit connected to the branch pipelines 46 and 48 via
a suitable mud pump of the type sold by Ideco or Envirotech
(not shown) connected to the conduit for pumping the
i220'79'7
-27-
fluids back up to the surface and discharged. During
drilling in a conventional fashion, the check valve 54
will prevent any backflow of fluids, gas, or other matter
due to encountering a high pressure pocket as drilling
proceeds. The drilled oil well drainage hole 53 then is
drilled upwardly through the roof of the overlying com-
petent rock shelf lS out into the oil bearing sand strata
as described previously with respect to Figures 1, 2 and
2A of the drawings.
After drilling of the oil well hole 53 at a
particular site has been completed to a desired depth,
the drill rig is then withdrawn from the hole. To
facilitate this operation, as well as the drilling
operation, it is anticipated that the drill string $2
will be coupled to drill bit 51 in segments which would
allow its handling within the confines of access tunnel
16. For this purpose, the drill string is withdrawn
until the drill bit 51 is just below the stop valve 42.
At this point in the withdrawal of the drill string ,
the stop valve 42 is closed so as to hold off any back
pressure that otherwise might force gas, oil, water, or
other rubble down into the access tunnel 16. The drill
string is then withdrawn completely by loosening the blow-
out preventers 43 and 44 and from this point on further
withdrawal of fluids through the drain vent valves 45
and 47 and their interconnected branch pipeline would
cease. An oil production conductor pipe 61 shown in
Fig~lre 6 of the drawings is then mounted for emplacement
in the previously drilled oil well hole 53. The oil
production conductor pipe 61 likewise will be inserted
into the hole in suitable length segments so that it can
be handled within the confines of the access tunnel 16.
As best shown in Figure 6, the topmost segment of the
conductor pip~ 61 has its end 62 completely closed so
that after it is inserted in place in hole 53 and
i2~20~97
-28-
cemented as shown at 69 in a manner.to be described
more fully hereafter, it will prevent the passage of
any oil, gas, water or other fluid down through the
conductor pipe until it is desirea to commence produc-
-5 tion from the oil well site.
In order to inser~ the oil production conductor
pipe 61 into place, the blow~out preventers 43 and 44
are loosened and the topmost segment of the conductor
pipe 61 inserted in the fluid and control assembly 40
to a point where the closed end 62 of the topmost seg-
ment of conductor pipe 61 is just below stop valve 42.
At this point the hlow-out preventers 4.3 and 44 are
tightened down to just a slide fit so that the conductor
' pipe 61 can be lifted upwardly through hole ~ segment
15 by segment until it reache¢ the desired depth into the
oil bearing sand zone 14 as shown in Figure 6. At
this point, the blow-out preventers 43 and 44 are tight-.
ed down to a firm grip and water under pressure is
supplied from a water pump 67 which may be somewhere
- 20 in the tunnel system or possibl~ even on the surface
through the branch pipe 48 and vent control valve 47
to the space intermediate conductor pipe 61andcasement 41.
The space between the outside surface of the oil con-
ductor pipe 61 and the inside of casement 41 is then
flooded with water under pressure hetween upper and
lower blow-out preventers 43 and 44. During this
flooding, the air in the space is vented through the
third vent and control valve 49 until water passes
through the valve and then the valve is closed so that
: 30 the space can be pressurized with water. As a backup,
~ a retainer collar 50 may be threaded into the end of the
casement 41 be~low the lower blow-out preventer 44 so
as to completely seal off the possibility of water seep-
. ing past the lo~er blow-out preventer and down into the
tunnel space 16. Alternativelv, it may be desired to
also flood this space by slackening the lower blow-out
122079~7
preventer 44 until the space is filled and pressurized to
the same extent as the upper space and then re-tightening
the lower blow-out preventer. By this means, cement will
not be allowed to enter into the fluid and coupling assembly
so that it can be removed and reused at different oil well
sites in the tunnel.
With the production conductor pipe 61 in place
and the fluid and control assembly 40 flooded in the above-
described manner, a cement pump 68 is coupled through the
branch pipeline 46 and drain vent control valve 45 to the
space between the entire extent of the production conduc-
tor pipe 61 and the inside of the oil well hole 53 above the
stopped down upper blow-out preventer 43. At this point
the stop valve 42 is in the fully opened condition so that
cement provided through the upper fluid vent control.valve
45 is allowed to pass upwardly into;.the space. During
cementing, gas or fluids in the space above the cement level
as it rises in the space intermediate the sides of hole
53 and the exterior surfaces of conductor pipe 61 is
vented if necessary through a suitable fluid impervious
vent pipe shown at 65 which extends out of a port in the
closed upper end of the upper production conductor pipe
segment 61. This fluid impervious vent tube 65 e*tends
down through the interior of the conductor pipe 61
along with suitable detonator wire 64 for detonating a
charge of explosive 63 attached to the upper closed
end 62 of conductor pipe 61. The vent tube 65 leads
down through a vent tube control valve 66 which may be
located remotely on the surface or at some other accessible
point in the mine working system where it is safe to
locate the valve and may be even right at the base of the
oil well site being worked upon as shown in Figure 6.
As cementing takes place and cement rises upwardly around
the production conductor pipe 61, venting of the space
in this manner will facilitate the cementing process.
lZ2079'7
, , -30-
After c-ementing has been completed, the upper drain vent
control valve 45 may be closed down and the cement allowed
to set so as to assure firm anchoring in place of the oil
well production conductor pipe 61.
Figure 7 of the drawings shows the final produc-
tion conductor oil piping installation after the cement
69 has set and firmly anchored the segments of the con-
ductor pipes 61 extending through the tunnel 16 roof.
After cement 69 has set, the water within the casement
41 between the upper and lower blow-out preventers 43 and
44 is drained out via the lower drain vent control valve
47 and pump 67 which may be a reversible pump or alter-
natively connected through a branch pipeline to a single
acting pump used to reverse flow of water through the
casement section and branch pipeline 48. Following this,
the entire fluid and cutting control assemblv 40 is
removed including the interconnected branch pipelines
46 and 48 and the stop valve 42. Following this step,
a new segment of conductor pipe indicated at 70 is coupled
to the end of the cemented-conductor pipe 61 protruding
beyond the end of the cemented section 69 by means of a
coupling (not shown) which may be of the type indicated
at 73. In this additional segment of production conduc-
tor piping a stop valve 71 is provided which may be of
- 25 the conventional gate valve type available from any oil
field equipment manufacturer or supply wa~ehouse. Also
included in the additional condutor pipe segment at this
point is a detonator control assembly shown at 72 which
is connected via the wires 64 to the detonator for`the
explosive charge 63 in the capped end of cemented conduc-
tor segment 61. This portion of the installation will
be removed following the blowing open of the top end or
head of conductor pipe segment 61 as desc,ribed hereafter.
Below the detonator control assembly 72 a fairly strong
screen shown at 74 is inserted in the pipe segment 70
12Z0797
-31-
by means of coupler 73 so that it can catch blasting
wires 64, the venting tube 65 and other any assorted
rubble that may result from the blast of the detonator
charge 63 which places the oil well into production.
Similar to the detonator control assembly 72 the screen
- 74 and any assorted rubble caught in the screen is re-
moved after the capped end of conductor pipe segment 61
has been blasted open by closing down the stop valve 71
and unscrewing the coupler segments 73. In its place
a sand screen also indicated at 74 is inserted for use
in screening sand out of any oil and gas production flow
through the well during operation.
Below the sand screen 74 is a unit 75 which may con-
stitute a coupling for coupling to the production con-
ductor pipe segment 70 an input branch pipeline 77 forsupplying to the production conductor pipe 70 and 61
input secondary treatment agents such as high pressure
steam, pressurized gas~ water, or other sllitable treat-
ment agents for increasing flow and production thru~
either the well in question or for increasing production
at adjacent well sites in the field. A suitable pressure
guage 76 is attached at the input coupling 75 in order
to assure that the input secondary treatment pressure
is within presecribed values. If desired, additional
metering instruments for temperature, flow rate, etc.,
in mûnitoring the input of the secondary treatment agents
can be installed at this point or the sensors for such
parameters can be installed here for leading back to a
central control room whereby a master controller can be
employed to control these parameters for all the well
sites where it is desired to introduce such secondary
treatment agents. During normal production from the oil
well site, however, the coupling 75 would constitu~e a
straight-through coupling for oil so that it passes down
through the lower end of the pipe segment 70 through a
1220797
. -32-
second stop valve 78 and any other desired measuring
instrument sensor heads indicated generally at 79 for
sensing such parameters as the oil and gas pressure,
temperature, flow rate, viscosity, or other aesired
characteristics to be employed in controlling production
- from the well site. Finally, the conductor pipe segment
70 is coupled to and supplies the collector trunk pipeline
24 for leading the produced oil or gas back out through
the tunnel system to the pump 25 at the base of the access
shaft 11 for pumping back up to the surface as shown in
Figures 2 and~2A of the drawings.
With the conductor pipe segment 61 cemented in
place and capped at the top, there is no leakage of
fluids through the conductor pipe segment 61 until its
upper capped end is blasted open. After the conductor
pipe segment 70 is in place together with its appended
upper stop valve 71, the detonator blast control unit 72,
screen 74, coupler 75, the lower stop and flow control
valve 78 and appended instrument sensors 79, the lower
stop valve 78 is closed and coupler 75 placed in the
position such that the supply input branch line 77 is
closed and upper stop valve 71 is maintained open. The
detonator wires 64 are then connected to a suitable
detonating signal generator for detonating the small
explosive charge 63 attached to the capped upper end of
the cemented conductor pipe segment 61 as shown in
Figure 6. Upon detonating this charge, the wires 64,
venting tube 65 together with other assorted rubble will
fall down through the conductor pipe segment and be re-
tained by screen 74. The stop valve 71 tXen is immedi-
ately closea to minimize any flow of gas or oil or other
fluids through the conductor pipe and allows the lower
portion of pipe segment 70 to be opened up, the screen
74 removed together with the collected rubble and a
sand screen inserted in its place and the blasting
1220'797
-33-
control assembly 72 removed entirely.
While a wired system for detonating the charge 63
and upper capped end of the conductor pipe 61 has been in-
dicated, it should be appreciated bv one of ordinary skill
in the art that a radio controlled detonator could be
employed in place of the wired detonator described with
relation to Figure 6. With such an arrangement, the
control assembly 72 would comprise an input transmitter
end for a microwave signal generator for emitting a micro-
wave signal up through the cemented conductor pipe 61which would serve as a suitable waveguide to transmit the
control mlcrowave signal to the radio wave'controlled
detonator thereby eliminating the wires 64 from the
~ubble,that will be collected by the screen 74. Col-
lS lector screen 74 still would be required however forany rubble that might initially drop down through con-
ductor pipe 61 after blasting open the upper capped end
of the pipe. A similar radio wave control venting valve
could be installed at the capped end of conductor pipe
61 whereby the valve could be opened during cementing
and eliminate the need for the fluid impervi~us venting
pipeline 65 together with its exhaust system, but in
such eventuality, the end of the production conductor
pipe 61 during cementing would have to be connected to
a suitable exhaust conduit temporarily provided during
the,cementing process for exhaus~ing out any vented gas
from the mine workings atmosphere. Further, in place of
a combined flow control and stop valve 78, it may be
desireable to use single valves for each of these purposes
wherein in place of a combined valve there would be a
separate lower stop ~alve such as shown at 78 and below
that a flow control valve which could be either manually
or automatically controlled from a remote located control
room. The operating parameter sensor units 79 would then
of course have sùitable leads out to the master control
i~20 7g7
-34-
room to allow an operator of the well to monitor oil and
gas flow out of each well site from the master control
room location. Such remotely controlled instrumentation
and flow control valves as well as the stop and flow control
valves including the upper master stop valve 71 could be
designed for remote operation and tied in with a suitable
computer system to allow computer control of the oil and
gas production from all of the well sites as will be des-
cribed hereinafter with relation to Figurè 10. Other
variations and changes will occur to those skilled in the
art of oil well production control for use in place of or
in conjunction with the instrumentation and.control valve
system described above without departing rom the spirit
of the invention.
In addition to the above-described characteristics,
the flow coupler/diverter 75 similarly could be designed
to be automatically operated from a remote master control
location together with the lower stop valve 78 whereby
the production conductor pipe segment 61 of any individual
well could be isolated and that well site coupled through
the ~ranch pipeline 77 to a supply line 28 for secondary
treatment agents extending through the network of horizontal
tunnels 16 as shown in Figure 8A of the drawings. In this
manner any individual well site can be either manuallv or
automatically controlled from a remote master control loca-
tion to convert from a producing well to a well which can be
used for injecting secondary treatment agents into the oil
bearing sand strata 14 or into an upper gas cap region 17
or a water containing region, etc. as will be described with
relation to Figure 14.
Should alternate systems and techniques for open-
ing the capped end of the production conductor pipe 61
to production be desired, Figure 8B of the drawings
illustrates one possible alternate system. In the
arrangement of Figure 8B, a Johnson type screen is
shown at 81 secured to, the upper top end of the ~jl ~
conductor pipe segment 61.
~2Z0797
-35-
.
Below t~e Johnson type screen 81 is inserted a suitable
flap valve 82 which will prevent any back pressurizing
of the conductor pipe 61 until it is desired to place
the oil well into production. Here again, a small ex-
plosive charge will have to be provided to remove theflap valve 82 together with its remotely actuated
detonator charge. Similarly, a small vent opening
should be provided throu~h the inclusion of a
fluid impervious vent tu~e together with associated
stop valve as described with relation to Figure 6 to
facilitate cementing. The detonator for detonating the
flap valve 82 and its attendant connected wires and
vent tube may be either a wired detonator or radio wave
controlled detonator as described above. If the cost is
not prohibitive, the flap valve 82 could be designed to
permit a slide opening for a sufficient distance to
allow venting of the space to be cemented,during the
cementing process,to the interior of the production
conductor pipe 61. In this eventuality, some suitàble
conduit system for exhaus~ing the conductor pipe must be
provided to prevent any vent gases from escaping into
the mine workings atmosphere. In other respects, the
installation and procedure for placing the gravity-type
oil drain well into production would be entirely similar
to that described earlier with respect to Figures 6 and 7.
Particular care should be taken, however, during the
cementing process to assure that cement does not rise
to and clog the openings of the Johnson type screen 81.
An alternative arrangement using a Schlumberger
: 30 type perforating gun to perforate the upper capped opening
~ of the oil production conductor pipe 61 is illustrated in
Figure 9 of the drawings. The Schlumberger type perfor-
ating guns are shown at 85.
In utilizing this system a closed conductor pipe,
as indicated in F gure 6 would be cemented into the drill
12Z~79~7
- 36 -
hole. The explosive charge 63 and detonation wires 64
would not be needed nor would the blasting control assembly,
item 72 of Figures 7 and 8B.
After the conductor pipe 61 is cemented in place
and the collar end finished to its final form, the stop
valve 71 can be attached and the fluid and control assembly
40 can be reattached. The conventional Schlumberger
perforation gun could then be modified into segments to
permit raising through this unit. The Schlumberger unit
would have to be redesigned so that the firing circuitry
could be plugged through successive pipe segments that
would be needed to raise the perforation gun into firing
position.
After the conductor pipe had been perforated as
desired, the gun could then be lowered through stop valve
71. Then the fluid control assembly 40 could be removed.
The blowout preventors 43 and 44 would prevent fluid and
gas leakage into the atmosphere during perforating gun
withdrawal. Any fluids produced at this stage would be
drained off through valves 45 and 47 as indicated in
Figure 6.
~220797
The drainage type oil wells drilled in the above-
described mannef may bP drilled at whatever angle or
direction is deemed most feasible for maximization o~
oil production from a given oil field. The mine workings
for access should be designed for each individual oil
field but should provide adequate room for collector
piping systems, secondary treatment agent piping systems,
automated well control systems, ventilation, drainage of
the mine workings, and easy access to all ~ell sites for
routine inspection and maintenance. During drilling sp~cial
measures to supply ~entilation air and to withdraw any leakage
gases around the drilling site by a suitable air and gas
- exhaust system should be undertaken. This may include
jacketing and exhausting the drilling rig. Each oil well
site should have its own flow meter to measure production of
gas, oil and water, pressure gauge, temperature gauge and any
other oil well operating characteristic measurement device
needed to provide the required measurement to report
1 220797
-38-
continuously to a central control station conditions at
each well site within the field being mined. As noted
earlier, all well sites can be constructed for either
automatic or manual changes in well management or pro-
duction, or both, depending upon the economics of anygiven oil field being mined.
In addition to the oil well site reporting,
production control and management systems described above,
the mine workings should be provided with suitable hydro-
carbon gas, sulphur gas, carbon dioxide gas, oxygendeficiency and other ~imilar detectors for safety pur-
poses. Further, fire warning systems should be placed
at key positions throughout the mine workings with con-
tinuous reporting to the central control station. Built-
in immediate warning systems should be provided throughoutthe mine workings to signal personnel should any of the
above-noted factors become abnormal and signal the ex-
istence of problems or the possibility of such problems
developing. These warning systems should be designed to
warn all persons within the mine workings and alert crews
both in the mine workings and on the surface as to the
potential for a problem developing.
If the mine workings are monitored in the above-
described manner, there should be no fire or explosion
hazard provided timely action is taken with respect to
any of the advance warning systems output alarms. How-
ever, to guard against the unexpected, it is recommended
that the mine workings include pipelines carrying
carbon dioxide gas, together with valves that can be
opened either manually or by remote control. These
valves should be so located that any portion of the mine
workings can be quickly flooded with carbon dioxide gas
thus denying any fire or potential explosion the required
- oxygen and reducing the potential for a disaster. The
same system should be designed to stop normal mine
1220'797
-39-
ventilation to an affected area within the mine workings
but of course should be tied in with very stringent
alarm systems to indicate to personnel within any par-
ticular section of the mine that it is about to be C02
flooded and a safetv stop accessible to possible per-
sonnel in the affected sector who could countermand tne
proposed action immediately until excape from the
affected section is accomplished.
~lINE WORXINGS SURPERVISORY CONTROL SYSTEM
10 Figures 10 and 12 of the drawings compris~
schematic, functional illustrations of a suitable super-
visory control system for the mine workings which
embodies the above-listed desirable characteristics
and which when used in conjunction with the sensing
instruments, pumps, air blowers, motGr driven valves,
motor driven airtight sealing doors and other devices
illustrated schematically in Figures 11 and 13-16
together with a main control computer (not shown),
provide for safe and productive operation of the
petroleum mine from a central control room by super-
visory personnel. The control room can be located
remotely from the mine workings and above surface so
that during continuous operation of the mine only minimum
exposure of personnel to hazards inherent in the opera-
tion of such a mine will occur. A sui.able main controlcomputer for use in suchsupervisory control system is the
Hewlett Packard 2250 Data Acquisition and Control System -
Processor and Series Control Computer 9800. While the
main control computer itself has not been illustrated,
input and output terminals to and from the computer have
been shown in the control system schematic diagrams by
hexagon-shaped terminals C~, .
Figure 10 is a schematic illustration of the mine
workings drainage oil collection piping system constructed
~2~q97
-40-
according to the invention, taken in plan looking down
on a typical mine workings without illustrating the
interconnecting access tunnels or access shafts, for
simplicity in illustration. The various drainage-type
oil well sites are sho~ at 19, 19' and 19" and would
correspond to similarly numbered elements described
earlier in the specification. The drainage-type oil
well sites are interconnected through a mine workings
collection piping system shown at 24. Included in the
piping system 24 intermediate each interconnected
group of drainage-type oil well sites 19, 19', 19" are
system flow control valves 101, the construction of
which is shown in Figure 11 of the drawings. The main
control computer, the access terminals of which are
indicated by the hexagon-shaped terminal 102 is con-
nected to each of the flow control valves 101 through a
remote monitoring and signal transmission system 103
such as the Cutler Hammer "DIRECTROL" manufactured and
sold by the Cutler Hammer Corporation~ As shown in
Figure 11, the ~low control valves 101 includes suitable
sensors such as limit switches 104 for sensing the con-
dition of the flow control valve 101 whether it is
open orclo~d and if open the degree to which it is open
and sending a signal back to the main control computer
which is indicative of the operating condition of the
flow control valve. By suitably monitoring with a control
console the condition of these flo~ control valves, the
mine workings supervisor can control total flow o~
collected fluids out of the mine workings which then are
supplied through suitable booster pumps such as the one
indicated at 105 for pumping the collected fluids to the
surface for treatment and disposition as will be described
further on. As is true in all vital equipment used in
the mine workings, the booster pump 105 is driven by a -
hermetically sealed electric motor 106 whose operatingcondition is monitored by a temperature sensor TE2-107
whose output is supplied back through the remote monitoring
and signal transmission system 103 to the main control
computer through terminals 102.
~220~97
-41-
, .
Figure 13 of the ~rawings is a schematic illus-
tration of a preferred form of drainage well site monitoring
and production control system according to the invention
for a sub-group of three wells 19, 19' and 19" wherein `
each well in the sub-group as well as all sub-groups in
the collection system are constructed in substantially
the same mannerlexcept as to possible modification to
include the introduction of secondary treatment agents
as will be described with relation to Figure 14 of the
drawings. It is anticipated that the drainage well opera-
tion monitoring and control system shown in Figure 13
would be installed in back of the main, manually and/or
automatically operated cutoff valve installed during
drilling of the well s~ch as valve 71 shown in Figures 7
and 8B of the drawings but would,replace other flow
control valves, etc., shown in those figures.
As shown in Figure 13, the output from each
individual drainage-type well site 19 is supplied first
through a conductivity analyzer device CE-CT - 111 such
as the Bec~man Model,CELR ~55-160 manufactured and sold
by the Beckman Instrument Company. The conductivity
analyzer device senses and analyzes the type of fluid
being produced by the individual well in question,
whether oil, gas or water and transmits a corresponding
electrical signal thrutheremote monitoring and signal
transmission system 103 and computer terminal input 102
to the main control computer indicative of the nature of
the fluid being produced by that well site at any given
instance. The pressure of the fluid in the well site at
the corresponding point in time is sensed by a pressure :
sensor such as a VITRAN Model 701 pressure sensor 112 which -
supplies an' electrical signal back thru the data trans-
mission system 103 and computer terminal 102 to the main
control computer which is indicative of the pressure in
1220797
-42-
the fluid at the well head at any yiven time. Similarlyr
a temperature sensor TEl-113 which may be of the type
manufactured and sold by H-Cal Engineering their ~odel
ULTRA-7, senses the temperature of the fluids in the well
head and supplies an electrical signal through the data
t~ansmission system 103 and main computer input terminal
102 back to the main control computer which is indicative
of the temperature o~ the fluids being delivered at the
well head. These parameters, i.e~ type of fluid, pressure
of fluid, and temperature of fluid may ~e displayed on
a suitable display console upon call-up or during
periodic checks by the supervisor in charge of the mine.,
Control of the fluids discharged from each
drainage-type oil well drill hole 19 in the system is
accomplished by supplying the discharge after passing
sensors 111~ 112 and 113 into a holding tank 114 which
has a pressure sensor connected thereto for'sensing the
build-up of pressure in the holding tank 114. Pressure
sensor 115 has its electrical output supplied to control
operation of a motor operated valve 116 connected in the
discharge line 117 from holding tank 114 into th,e mine
workings drainage oil well collection piping system 24,,
through a conventional check valve 118., Check valve 118 -
prevents ,any backup of fluids from the collection system
piping,24 in the event the pressure in piping 24 ex'ceeds
the pressure in any of the holding tanks 114. The
motor operated valve 116 includes operating condition
sensor switches 119 and 121 which sense the operating
condition of the motor-operated valve 116 whether open
or closed and if open to what extent the valve is open
and supplies signals back through the data transmission
system 103 and terminals 102 to the main control computer
for use in monitoring conditions at the well siteS
1220797
-43-
-- The flow rate of fluids supplied from each well
site via holding tank 114 to collection piping system 24
is measured by a ~low rate sensor FTl-122 whose output
signal is supplied through the data transmission system
103 and terminals 102 back to the main control computer.
Based on data supplied fro~ the flow rate sensor 122,
the main control computer can compute the true flow rate
for given perioas of time which together with the
identity of the flowing fluid medium as determined by
the inputs from a conductivity analyzer 111, provides
the mine supervisor with information concerning the
totalized flow of fluid through the well head as well
as the nature and type of the fluid. The computer of
course can integrate the flow rate being sensed by
flow rate sensor 122 over particular operating inter-
.. vals to provide the superyisor with an indication ofthe total amount and.type of fluid being produced over a
given period of time.
As noted earlier, control of the discharge of
fluids from each oil well site drill hole is accomplished
by sensing the hydrostatic head of fluid pressure built-
up in the holding tanks 114. ~hen the level of the fluid
pressure in holding tank 114 reaches a value indicating
-a full condition, pressure switch 115 causes motor-
operated valve 116 to open thereby emptying the holdingtank content into the collection piping system 24~ When
the pressure sensor switch 115 senses that the tank 114
is substantially empty, the valve 116 is reclosed~ The
limit switches ll9 and 121 on motor-operated valve 116
provide electrical signals to the main control computer
which are indicative of the operating condition of the
motor-operated valve 116. The piping system motor-
operated valves 101 shown in Figure 10 of the drawings
. which are located throughout the collection piping
-~ 44 -
system 24 are set to automatically close when flow in excess
of a predesigned maximum flow rate occurs, or in the event
of a reverse flow. Closure of the valves 101 under such
operating conditions, isolates any particular section of
5 the collection piping system 24 that may have ruptured and
thus prevents or at least limits spillage that might occur
as a result of such rupture. Suitable limit switches on
the valves 101 supply information back to the data
transmission system 103 and terminals 102 to the main
control computer indicating the operating condition of each
of the flow control valve 101 including the information
that the valve is open and operating normally.
As described previously, oil bearing fluids
collected at each of the drainage-type well sitesin the
above-briefly described manner is ~pplied through the
mine workings collection system 24 via booster pumps such
as 105 shown in Figure 10 which are located throughout
the collection piping system 24 at strategic points. The
fluids are pumped to a suitable collection point (which may
be above ground) for treatment and storage. At this point,
the fluids are supplied to a separator 123 which may be of
the type manufactured and sold by CE-NATCO under model
VFH. CE-NATCO is the name of the company formed by the
merger of Combustion Engineering with National Tank Co.
The separator 123 separates the fluids into their con-
stitutent parts oil, gas and water and supplies each
constitutent part through a respective discharge line
124 for the oil, 125 for the gas and 126 for the water.
The oil flow rate supplied through oil line 124 to an
oil collection tank 128 is measured by a flow sensor 127
which supplies its output signal back through the
transmission line 103 to the main control computer via
input terminal 102. The gas being produced by the system
is measured by a flow sensor 129 installed in the gas out-
let line 125 which supplies its output signal back through
the transmission line 103 and terminal 102 to the main
1220797 .
-45-
control computer. Similarly, water being produced by
the system and supplied through outlet line 126 is
measured by a flow sensor 131 whose sensed signal is
supplied back to the main control computer via trans-
mission line 103 and terminal 102. At this point in the
system operation, the computer is provided with suffi-
cient input data to provide a cross check on the sum-
mation of the flow rate produced at each of the drainage-
type oil well sites against the summa~ion of the pro-
duction flow rates of the respective constitutent fluids
- oil, gas and water. Oil from the separator is supplied
to the collection tank 128 which normally will be
located above the surface. The gas being produced by
the miné can flow either to gas pipe lines for supply
` 15 to a market, to a storage tank or can be used to re-
pressure the oil field being drained by the mine.
Water being produced by the system either can be dis-
charged to,waste or can be pumped back to maintain
pressure on the oil field being drained.
Figure 14 is a schçmatic illustration of an
alternative production control installation for use at
the respective drainage-type oil weli sites 19, 19' and
l9n. For the sake of simplicity, the illustration shown
- in Figure 14 does not include the conductivity analyzer
25 111, the pressure sensor 112, the temperature sensor 113
or the main flow sensor 122 in order not to unduly com-
- plicate the drawings. However, it is anticipated that
all of these sensing instruments would be included in
the alternative embodiment shown in Figure 14 but have
not been illustrated in order not to unduly complicate
the drawings. The significant elements such as the
holding tank 114 and the main flow control valves 116
have been illustrated however in order to show the
alternative system connection points.
~220797
-46-
The alternative installation shown in Figure 14
is intended for use with those mine fields where it is
anticipated that secondary treatment processes will have
to be applied in order to maximlze oil production from
the petroleum mine,, Seconaary treatment processes and
agents used in such processes are well kno~m in conven~
tional oil well production systems, and hence need not
be described in detail. In such secondary treatment
processes, a secondary treatment agent such as steamr
water, pressurized gas, ~r other similar agent is intro~
duced into the oil ~earing sand strata~ or the gas cap
above the oil ~earing sand strata or the water ta~le
below the oil bearing sand strata.. In order to intro-
duce such secondary treatment agents, a separate line
lS working secondary treatment supply piping system (,not
shown in overall systems context~ indicated in part at
133 in Figure 14 is connected to the discharge conduit
117 interconnecting the hold;ng tank 114 with the main
mine workin~s drainage oil collection pip~ng system 24
In this alternative installation~ the valve 116 will
have to be a separate motor~operated valve under the
control of the main control computer via terminal 102
and data transmission system 103 whereby the valve 11~
selectively can be closed in order-to introduce secondary
treatment agents into the well head at any one of tfie
drainage~type oil well sites 19~ Prior to the intro~
duction of any such secondary treatment agents t the
main drainage valves 116 are closed by their associated
motor 116M ~;a the main control computer,
The seconaary treatment agents are ;ntroduced via
the pipin~ system 133 by means of an on-off control ~al~e
134 whose on-off condition is indicated back at the main
control computer console via the limit switches 119 and
, 121 and which can be opened or closed from tXe main
control computer console by motor 134M via the main
control'computer terminal 102 and data transmissio~
~220797
-47-
system 103. A flow sensor 135 cGnnected in a secondary
treatment agent supply pipeline 133 measures the flow
of the secondary treatment agents passing through the
pipeline and supplies the flow rate back to the main
control computer via data transmission 103 and terminal
102.
With a well head installation constructed as
shown in Figure 14, the flow of secondary treatment agents-
such as steam, water, gas, surfactants or other secondary
recovery enhancing agents is measured by the flow rate
senso~ 135 appropriate for the secondary treatment
medium being used. The resulting electrical signal is
transmitted back to the main control computer console
for display and recording and use by supervisory per-
sonnel in working the mine field. Pressuri.zation ofthe mine field secondary treatment agents is accom-
plished from the main control console first by operating
the motor 116M to close the main drainage control valve
116 and thereafter operating the motor 134M to open or
close the secondary treatment agent flow control valve
134. The limit switches 119 and 121 provide positive
feedback signals to the main computer control console
for displaying the operating condition of the secondary
treatment agent flow control valve 134. The flow rate~
sensor 135 keeps supervisory personnel advised of the
rate of introduction of the secondary treatment agent
and the computer can integrate the f~ow rate over pre-
determined periods of time to display and record the
total amount of secondary treatment agent being intro-
duced for the period in question, It is anticipatedthat not all of the well sites in any sub-group or other
groupings of well sites would be pressurized with
seconaary treatment agents at the same time, but that
. such secondary treatment processes would be used to
, .
~ZZ0797
-48-
enhance oil recovery at other adjacent sites in a pre-
determined pattern of pressurization and secondary
-treatment. Consequently, at the producing oil well
sites, the pressure at the well head, the temperature
S of the well head and the classification of the fluids
being produced will be recorded by that particular well
site's sensing instrumentation and fed back to the main
control computer for recording, display and use ~y
supervisory personnel in enhancing oil recovery from
the petroleum mine. If desired, the same supply system
can be employed to depressurize~a partic~lar oil well
site by bleeding off gases, water and the like to a
collection point above ground to the desired extent to
return a particular site to gravity-drain type of opera-
tion as opposed to a pressurization-sgueeze type of
operation again under the control of the main computer
and supervisory personnel at the main computer control
console.
In addition to the above-described forms of
secondary treatment, there-are other known secondary
treatment procedures which have been successfully` used
to enhance oil well production and which utilize electro-
magnetic radiation in the form of either radio frequency
wave or microwave propogation of electromagnetic waves
through the oil bearing sands. This is achieved with
suitable electrode emplacement and excitation by a
radio wave frequency or microwave frequency signal
source for propogating such electromagnetic waves through
the oil bearing sands. The present invention contemplates
the use of such electromagnetic waves secondary treatment
procedures by suitable emplacement of the required
electrodes and radio frequency signal transmitters at
strategic points in the ~ccess tunnels as well as in the
access vertical shafts to enhance collection at the
:12207~q
-49-
,
- drainage-type oil well sites. It is anticipated that in
any such system, control over the electromagnetic wave
signal producing equipment would be achieved via the
main control computer by the mine workings supervisory
personnel.
Figure 12 is a schematic diagram of the air
supply and personnel protection detection and control
systems required for safe operation of the mine workings.
These protective sys'ems include an air flow monitoring
and control system shown ~enerally at 141, a gas detec-
tion and control system shown generally at 142, a fire
detection and protection control system shown generally
at 143, a mine flooding detection and protection control
system shown generally at 144, and a vital motor protec-
tion control system shown generally at 145. All of thesedetection and protection control systems have elements
located at strategic points throughout the mine workings,
the network of which is shown at 16 and are comprised
generally by the access tunnels 16 which extend through
the lower competent rock level below the oil field being
mined. As will become apparent, all of the personnel
protective systems listed above and to be described in
detail hereafter, provide sensory inputs to the main
control computer via data transmission links and the
input terminals so that supervisory mine personnel
operating from the computer control console can continu-
ously monitor safety conditions within the mine workings
and undertake protective measures whenever such measures
are indicated.
AIR FLOW ANI~ MONITORING CONTROL SYSTEM
Adequa~e fresh air supply for personnel in the mine
worXing is assured by a number of air blowers shown at
151 which are located at strategic points throughout
the mine workings for supplying forced air through
35 ducting indicated at 152 having suitable air discharge
1220797
-50-
outlets at preselected points throughout the mine
working access tunnel 16 network. At selected points
throughout this air supply ducting system air flow
sensors PT~153 are installed for measuring the flow
rate of air at these points in the air supply ducting
system. The air flow rate sensors 153 have their outputs
supplied back through the data transmission system 103
and input terminals 102 to the main control computer for
display and recording and use by supervisory personnel
in maintaining safe conditions in the mine. In the
event that air supply to any particular section of the
mine is interrupted, the main control computer auto-
matically or under the control of the supervisory pers-
onell can signal both a visual and audible alarm indicated
at 155 located throughout the mine workings in order to
alert personnel in the mine of the danger.
GAS DETECTION AND PROTECTION SYSTEM
The gas detection and control system 142 may
comprise a system such as the mine safety appliance
series 500 system shown generally at 142 in Figure 16.
This system includes a number of methane gas sensors
indicated at 161 for sensing the build-up of methane or
other dangerous gases within the mine workings access
tunnels or vertical shafts and providing an output
signal of the build-up of such dangerous gases back to
the main control computer via the data transmission
system 103 and terminals 102. The gas protection system
further includes a series of gas-tight doors shown at
162 in both Figures 12 and 16 of the drawings which can
be opened and closed by motors 163 under the control of
the main control computer via terminals 102 and data
transmission system 103. Limit switches 119 and 121
sense whether the door is opened or closed and provide
output signals back to the main control ~computer via the
data transmission system 103 and terminals 102 as a
backup indication to supervisory personnel of either
~2z079q
-51-
the opened or closed condition of the doors 162. Manually
operated electric switches shown àt 164 are installed on
each side of every door 162 so that personnel caught in
a section which is being closed off can open the door for
egress. When a door is thus opened, the main control
computer automatically recloses it after a predetermined
time interval should conditions not permit the personnel
seeking to escape from a section enough-time to reclose
the door after opening.it.
A further function of the gas detection and pro-
tection system 142 shown in Figures 12 and 16 is to immed-
iately sound a local alarm shown at 155 which is located
at regular intervals along each section of the mine working~.
The local alarm 155 provides both a visual and sound warning
15 - signal to personnel who may be located in an affected
section. It is anticipated that in a petroleum mine, all
personnel will be rigorously trained in safety procedures.
These safety procedures will include the required carrying
of oxygen masks which can be donned by all personnel
entering the mine immediately upon the occurrance of an
alarm signal by the alarms 155 in a section where they may
be working. The personnel thus assured of an adequate
oxygen supply then can work themselves out of an isolated
section of the mine in the event that the condition requires
immediate closing and sealing off by the airtight doors 162
and CO2 flooding of an endangered section of the mine
workings.
FIRE DETECTION AND PROTECTION SYSTEM
The fire detection and protection system 143 is
shown in greater detail in Figure 15 of the drawings. The
system is comprised by a plurality of smoke/temperature
sensors shown generally at 164 in Fiuure 15 which supply
alarm signals to a central control panel 143 commected
- through data transmission system 103 and terminal 102
back to the main control computer. The fire protection
and detèction system 143 can be installed so as to auto-
matically activate the`cardox-type carbon dioxi~e fire
`~ ~
1220797
52
extin~uishing system shown generally at 165 for immediate
C2 flooding of any fire tFlat might occur in a given section
of the mine workings. Simultaneously~ the occurrance of an
alarm condition and presence o~ the fire is signalled back
5 throu~h the main control computer for use by supervisory
personnel in ascertaining what other further protective
measures might E)e taken. Concurrently with the activation
of the carbon dioxide (CO2) extinguishing system, fire pro-
tection system 143 is connected to activate the drive
10 motors 163 for automatically closing the air and gas-tight
doors 162 for isolating particular sections of the mine
workings as described a~jove with respect to the gas detecl-
tion and protection control system. The limit switches 119
and 121 monitor the condition of the doors 162 and signal
15 back to the main control computer whether the door is open
or closed. Here again~ the presence of manually actuated
switches 164 on either side of the sealing doors 162 can
be manually actuated by any personnel present in the affected
section to allow egress of such personnel. The fire pro-
20 tection system 143 also instantaneously sounds the localalarm 155 to advise mine personnel of the onset of a danger
should they ~e in a section of the mine workings affected
by the detected fire A further protective step which can
be taken by the supervi:sory personnel at the control console
25 of the main control computer, is to discontinue the supply
of ~rentilati:ng air to an affected section after detection
of the onset of a fire alarm condition~ This can be safely
done since any affected personnel will be carrying oxygen
masks which they will have donn~d.
MINE FLOODING PROTECTION AND DETECTION SYSTEM
In the event of flooding of any part of the mine`
workings ~y water or other liquid~ level sensing switches
shown at 171 in ;Figure 1~ and comprising part of the
flood detection and control system 144r will sense the
build-up of water a~nd siynal the occurance of a floodin~
~2Z0797
-53-
condition to the main control computer via data trans-
mission system 103 and computer`input/output terminal
102. The level sensing switches 171 will be distributed
throughtout the floor of the mine working for sensing
the occurrance of flooding in any section o~ the mine.
Level sensing switch 171 also is connected to acutate
the nearest sump pump shown at 172 whose motor 173 is
monitored by a temperature sensor 174 supplying its
output signal through data transmission link 103 and
terminal 102 back to the main control computer which
can monitor then safe operation of the sump pumps. As
an additional piece of data, a pressure sensor indicated
at 175 monitors the discharge pre.ssure of the sump pump
172 and supplies its output signal back through data
link 103 and terminal 102 to the main control computer.
Thus, the level sensing switches 171 can sense the
build-up of water or oil on the mine floor and siqnal this
condition ~ac~ to Ihe main control computer. Simultan-
; eously, the a~fected sump pumps 172 will be actuated
to pump out the liquid through an appropriate discharge
conduit (not shown) which transports the flood waters
to a remote point for discharge safely away from the
mine workings. During operation, the sump pumps are
monitored by the temperature sensor 174 and pressure
output sensor 175 and the outputs of these sensors are
supplied back to the main control computer for use by
supervisory personnel in monitoring safe operation of
the mine flooding protection system thus comprised~
VITAL MOTOR PROTECTION SYSTEM
In adaition to the detecting and protecting system
described above, all of the vital motors employed in the
personnel protective safety systems of the mine such as
air blower motors, sump pumps, safety door closure
motors, valve motors and the like are monitored by
temperature sensors such as 174 for the sump pump motor
~22079~7
-54-
-
.
and temperature sensors such as 176 shown used in con-
junction with the drive motors 177 for driving air
blowers 151. Similar temperature sensors for the isola
tion sealing doors 162 drive motors, the valve drive
motors and the like have not been shown for the sake
of simplicity. The temperature sensors thus comprised
all are connected back to -the data transmission system
link 103 and computer input/output terminal 102 to the
main control computer to facilitate monitoring of the
safe operation of these vital motors throughout the mine
workings personnel protective systems.
From the foregoing description, it will be
appreciated that the status of all operating parameters
of the petroleum mine together with the status of the
personnel protective systems can be sensed by instrumen-
tation and the outputs are presented to mine supervisory per
sonnel on a cathode ray tube or other display which is
a part of the control console of the main control
computer~ l~ith this data and the in-place sensors,
control valves, drive motors and the like the mine
supervisory personnel can remotely start or sto~ all
motors, open and close all doors and valves, and
activate any alarm systems such as horns, lights, CO2
fire extinguishing systems and the li~e.
Having described several methods, systems and
forms of apoaratus to be employed in carrying out the
novel method of underground mining of petroleum according
to the invention, it is believed that other modifications,
changes and variations to the described methods, svstems,
and apparatus will occur to those skilled in the art in
the li~ht of the above teachings. It is therefore to be ~
understood that all such obvious changes to those of
ord-nary skill in the art are believed to coma within
the scope of the invention as defined by the appended
claims.
