Note: Descriptions are shown in the official language in which they were submitted.
~ 185'~5B
.
The present invention relates to arrangements for
drilling holes, and more particularly, to arrangements for
full hole drilling without coring.
There is presently a wide use of full hole drill-
ing of oil, gas, and water production wells, as well as for
drilling prospective structural holes and exploratory holes
in gas-bearing and oil-bearing regions, in supra-ore strata
in detailed exploration of deposits with well-studied and
comparatively simple structure, overburdening loose deposits
in drilling mapping, prospecting and exploration holes, in
rocks of the platform mantle in explorations of deposits
extending in the Pre-Cambrian platform base, hydrogeological,
seismic and blasting holes.
Two-, three- and four-roller rock bits and four-
roller drill heads are most widely used in full hole drilling.
When operating under optimal conditions, these bits make it
possible to develop very high mechanical drilling speeds.
In full hole drilling, as well as in drllling by
any other method, complications frequently occur which are
caused by an instability of rocks forming the hole walls,
water inflows and especially absorption of drilling fluid in
seamy and vesicular rocks and in rocks exhibiting high
permeability. These complications disrupt optimal drilling
conditions, substantially lower the drilling speed and
frequently cause complete suspension of drilling until the
complication is eliminated. This results in lower produc-
tivity and considerable increase in the hole cost so that
effective methods of fighting complications represent one of
the most important problems in drilling.
In the majority of cases, the process of hole
drilling is suspended for a time during which the complication
is eliminated, however, there are techniques for eliminating
1 ~6575~
complications whlch may be implemented without interruptions
of the hole drilling. Using such techniques, a plugging
material is added to drilling fluids in the form of jelly-
like polymeric clots filled with a finely divided material,
adding also a mineral granular material if necessary~
However, when such technique is used, a plugging material
is diluted with the drilling fluid and circulated together
therewith to stick to the surfaces of a pump, supply pipe-
line, casing pipes and hole walls not always in the places
where it is required, without, at any rate, enabling to
obtain a permanent non-metal consolidation of walls.
The design of drilling implements in using such
techniques is conventional and includes a bit having a
passage for drilling fluid attached to a drill pipe string
and a hole wall former and centralizer arranged above the
bit outside the drill pipe string, which closes the space
between the hole walls and the drill pipe string.
This arrangement does not enable the conduct of
operations for elimination of complications or case-less
con~olidation of hole walls without interrupting tha drill-
ing process, that is concurrently with the hole drilling.
This is due to the fact that a plugging material
is fed to the point of its application to the hole walls in a
liquefied, low-concentration form because it should be
diluted for being pumped through the whole drill pipe string.
This also causes the need to use plugging mater_als with
long hardening time which, in turn, does not permit the
plugging material to gain sufficient strength in the most
vital bottom zone.
Still one important disadvantage resides in that
during the feeding of an inert filler to the hole, the
drilled rocX, which exhibits maximum physical and chemical
t ~ ~5756
affinity with the rocks forming the hole walls since it is
the product of their comminution, is removed out of the hole.
The main object of the invention is to elimina~e
appearing complications concurrently with continuing drill-
ing of a hole without interrupting the drilling process.
Another object of the invention is to provide for
the possibility of non-metal consolidation of the hole walls
concurrently with drilling and to obtain non-metallically
cased hole or a portion thereof.
Still another object of the invention is to reduce
the consumption of expensive plugging materials.
The invention resides in that in an arrangement for
full hole drilling, comprising a bit having a passage for
admitting drilling fluid to the hole bottom, attached to a
drill pipe string, and a hole wall former provided above the
bit which closes the space between the hole walls and the
drill pipe string, according to the invention, a container
containing a plugging material is provided in the interior
of the drill pipe string immediately above the bit, which is
adapted to let drilling fluid between the walls of the
container containing a plugging material and the drill pipe
string and to feed a plugging material under the action of a
displacing agent, the bit having an axial bore of a diameter
which is greater than the inside diameter of the container,
the bore being adapted to receive the lower end of the
container.
The container is preferably removable for its
replacement without lifting the drill pipe string to the
surface.
In order to provide for using as filler the rock
drilled by the bit, the container may be filled with a
plugging material comprising a granular binder for a plugging
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mix.
The container may comprise a cylindrical pipe which
has a removable plug in its lower part and a stemming in the
upper part which is adapted to force a plugging material out
of the container. The plug is made of a material that can be
easily destroyed by the bit during the operation of the
arr ang~ment .
The upper end of the container may be provided with
a nipple for engaging a hose for handling the container and
for feeding a displacing agent thereto.
The above-described arrangement for full hole
drilling ensures a continuous drilling of a hole, reliable
elimination of complications or non-metal consolidation of
the hole walls.
The invention will now be described with reference
to a specific embodiment illustrated in the accompanying
drawings, in which:
Figure 1 is a longitudinal section of an arrangement
for full hole drilling (in a transportation
position) according to the invention,
Figure 2 is a sectional view taken along the line
II-II in Figure 1, and
Figure 3 is an embodiment of an independent supply
of a displacing agent.
The arrangement for full hole drilling herein
described represents a modification of a conventional drilling
equipment and does not make it necessary to introduce any
substantial changes, in particular, the bit may comprise any
rock breaking tool used in the rotary percussion drilling.
Said arrangement comprises a roller bit 1 which is
attached to a drill pipe string 2 (Figure 1) with the inter-
position of a former 3.
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The former 3 may comprise any structural member
which ensures the closure of the space between the hole walls
and the drill pipe string, such as an auger 4 having its
flights hand opposite to the rotary direction of the drill
pipe string 2.
A cylindrical container 5 containing a plugging
material 6 is provided in the interior of the drill pipe
string 2.
The container 5 may comprise a cylindrical pipe
which is plugged at bottom and top, a cylindrical sealed
bulb made of a plastic material or a rod made of a pressed
plugging material having the surface encapsulated (water-
proofed) with a waterproofing layer. The container may be
integral with the bit or, which is preferred, it may be
removable for its replacement without withdrawing the bit
from the hole.
The plugging material 6 may comprise a dry quick-
setting mix, such as a gypsum and cement mix, a paste-like
mixture of various polymeric materials with hardeners, cement,
polymerizable, clayey and like pulverulent materials which
are conventionally used as binders.
The lower end of the container 5 is sealed with a
plug 7 (change plug) made from a readily destroyable material
and cooperates with a central bore 8 of the roller bit 1
destroying the plug 7 after it is pushed out of the container
5, and the upper end of the container 5 is sealed with a
stemming 9 which may have different embodiments, for instance,
like the one shown in Figure 1, and having an inlet opening
10 which simultaneously acts as a valve seat, and an outlet
opening ll, and the container 5 has an opening 12 aligned with
the opening ll for the passage of drilling fluid into the
space between the container 5 and the inner walls of the drill
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pipe string 2 which has locating members 13 for guiding and
centering the container 5. The top locating member may
comprise a continuous ring 14 having its central opening
diameter equal to the outside diameter of the container 5,
and the remaining locating members comprise individual
projections. The body of the roller bit 1 has a passage 15
for admitting drilling fluid to the hole bottom when the bore
8 of the bit 1 is closed by the container 5. The upper por-
tion of the container 5 has a socket 16 for engagement with
an end piec~ of a fishing device 17. For forcing the material
6 from the container 5, a ball 18 is thrown into the interior
of the drill pipe string to close the opening 10 of the
stemming 9.
In another embodiment illustrated in Figure 3, the
stemming 9' comprises a cylindrical piston plug and a device
for engaging and sealing an end piece 20 of a cable-hose 21
which is designed for handling the container 5 and for feed-
ing the displacing fluid.
The above-described structural arrangements do not
exhaust all possible modifications of the arrangement accord-
ing to the invention. In practice, the arrangement may
comprise a terminal portion of a conventional drilling string,
with the replacement of the container 5 containing the plug-
ging material being possible only after the withdrawing of
the whole drilling string to the surface.
These modifications do not, however, affect the
structural features of the arrangement according to the
invention and are mainly concerned with methods of operation
of the arrangement and some minor structural modifications of
secondary components.
The arrangement for full hole drilling functions in
the following manner.
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Under normal drilling conditions, drilling fluid
is admitted through openings 10, 11 of the stemming 9 and the
opening 12 of the container 5, intertube space between the
container 5 and the inner walls of the drillpipe string 1 and
along the passage 15 to the bit 2 and to the hole bottom.
Upon the occurrence of a complication, such as
water absorption and loss of drilling fluid, a steel ball 18
is thrown into the interior of the drill pipe string and the
ball falls to the end of the stemming 9 to close the opening
10 thereby sealing-off the passage for drilling fluid to the
intertube space. Pressure of drilling fluid inside the drill
pipe string abruptly increases over the stemming 9 so as to
~hear pins 23 retaining the stemming 9 which is forced down
through the container 5 to force out, through the plugging
material 6, the plug 7 and to open the outlet for admission
of the plugging material 6 to the bit 1 whereby the plug 7
is destroyed by the bit 1. After having forced out the plug
7 and a portion of the plugging material 6, the stemming 9
which continues to move down through the container 5 opens
the opening 12 in the wall of the container 5 so as to pro-
vide for normal supply of drilling fluid to the drilling bit
1. The plugging material 6 crushed and ground by the rollers
of the bit 1 is mixed with the drilled rock and drilling
fluid and is concentrated by the flights of the auger 4 of
the former 3 in the lower portion of the hole adjacent to the
hole bottom to be thrown against the hole walls. Centrifugal
forces and the pressure of the drilling implement squeeze out
an excess of water from the mass. A thick and viscous mass
of the plugging material 6 filled with broken rock is forced
into voids and seams of the rocks forming the hole walls,
compacted and starts hardening.
A rubbing member 22 floats the plugging material 6
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1 16$75fi
and sizes the hole shaft so as to effect an additional com-
paction of the mass to dehydrate it and to cut off an excess
of the mass.
After all plugging material 6 is consumed, a fishing
device 17 is lowered on a rope to engage with its end pieces
the socket 16, to withdraw the container 5 and to replace it
with a fresh container.
The plugging process is repeated if necessary until
the complication is completely eliminated.
In another preferred embodiment of the arrangement
having the device 19 shown in Figure 3 for engaging and
sealing the end piece 20 of the cable-hose 21, the plugging
material 6 is forced out with a displacing agent (fluid or
gas), the cable-hose being also used for lowering and lifting
the container 5.
It will be apparent that the replacement of the
container 5 immediately adjacent to the hole bottom as
described above is only possible if permitted by the design
and dimensions of members of the drilling string 1. Such
replacement is, therefore, preferred in drilling large-diameter
holes such as of a diameter larger than 112 mm. In drilling
holes of smaller diameter, it is more preferable to replace
the containers 5 at the surface level and, if possible, simul-
taneously with the replacement of the bit tip so that the
container 5 is to be chosen to contain such quantity of a
plugging material 6 which is enough for drilling an interval
of the hole drilled with one bit. This reduced time loss for
lifting and lowering operations.
In case the arrangement according to the invention is
used for non-metal consolidation of hole walls by providing a
proofing layer over the entire surface of the hole, the plug-
ging material 6 is continuously forced out during the hole
f ~5~
drilling. When the plugging material is consumed, the drill-
ing is interrupted, the container 5 is replaced, and the
drilling begins anew to a desired depth.
An intense mixing of the drilled rock with the
plugging material occurs, the rock functioning as an inert
aggregate and, owing to the affinity thereof with the rocks
forming the hole walls, improving the quality of the proofing
system and reducing the consumption of the plugging material
fed to the hole bottom.
It should be emphasized that since a part of the
broken rock which is mixed wit'n the plugging material
functioning as a binder is a component ~ filler - of the
plugging material, the plugging material 6 is saved and the
quality of sealing of the absorption channels or consolidation
of the hole wall is improved since the similarity of compo-
sition of the filler and the rock forming the hole walls
enable their better cohesion.
The invention may be used in eliminating complica-
tions in the full hole drilling, for non-metal consolidation
of the hole walls which is effected concurrently with drilling,
in making wells and chambers, in enlarging and repairing
earlier drilled holes, in drilling through unstable intervals
of holes in uncemented sands, swelling and soaking clays,
etc.
