Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02544711 2006-05-03
Measuring device and drilling apparatus for deep wells
The present invention relates to a measuring device
according to the precharacterizing clause of Claim 1
and a drilling apparatus according to Claim 16.
EP 0 102 672 B1 has disclosed a measuring device for
connection to a drill column for deep wells, having an
electrically operated measuring unit for measuring
relevant data, the measuring device being designed for
supplying electrical energy via the drill column. The
measuring device converts soil properties into
electrical signals and is driven into the soil for soil
investigations. Owing to the arrangement of the
measuring device provided at the end of the drill
column, with the known measuring device only measured
data can be recorded which relate to the soil region
surrounding the measuring head at the end of the drill
column. It is not possible with the known measuring
device to record measured data above the bottom of the
borehole.
One object of the present invention is to develop a
measuring device according to the precharacterizing
clause of Claim 1.
The abovementioned object is achieved by the
characterizing features of Claim 1.
In principle, the measuring device can be provided at
a:ny desired point in the drill string. The measuring
d~=_vice can be arranged directly adjacent to the bit
unit, with the result that measured values can be taken
from the bottom of the borehole. The arrangement of a
plurality of measuring devices in one drill string is
a=_so easily possible. In order to measure relevant
data, the measuring device is supplied with electrical
energy via the drill column. In the same manner, the
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data transfer or signal transfer takes place from the
measuring device to the surface. In this case, an
evaluation device is provided at the surface, the
measuring device being electrically coupled to the
evaluation device. In this case, the electrical
coupling is used firstly for the data transfer or
signal transfer from the measuring device to the
surface and can secondly also be used for the transfer
of control commands.
The measuring device has a stable outer housing for
accommodating and thus protecting the individual
functional units. In order for it to be possible for it
~~o be integrated in the drill column ar the drill
:string or to be connected to parts of the drill string,
l.he housing has screw connections at both of its ends .
mhe screw connections should preferably have an
internal thread such that the housing corresponds to a
bush from a connection point of view.
The functional units of the measuring device may have
a.n associated transformer, in particular a voltage
transformer, which converts the measured signals
recorded by the measuring unit such that the converted
signals, which may have a different frequency from the
electrical energy supplied, are correctly identified by
the evaluation device. Moreover, the evaluation device
may also be designed such that the measured signals are
derived from the energy consumption of the measuring
wait.
Depending on the application, the measuring unit can
have a plurality of measuring instruments for the
purpose of recording various data. In this case, in
px-inciple all of the known measurement and/or analysis
methods can be used, in which case it goes without
saying that a correspondingly robust design is provided
in terms of the conditions in the borehole. Moreover,
th.e individual measuring instruments may be of modular
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design, with the result that, if necessary, one type of
measuring instrument can be replaced by another type of
measuring instrument if the measuring device is used
for a different application.
In principle it is possible for the sensors of the
measuring unit to be provided on the outside on the
housing, with the result that the measured values are
taken from the medium which flows past the housing on
the outside. In order to protect the measuring unit and
in particular the sensors or measured value pickups,
:however, a possible solution is to provide the sensors
:in a flow path within the housing. In order to guide
i~he medium under investigation past the sensors of the
measuring unit, at least one electrically operated pump
~_s provided which is connected in terms of flow to the
measuring unit. In this context, it is favourable then
t:o provide an electrically operated two-way valve
adjacent to the measuring unit in order to divert the
medium under investigation, if necessary, either into
the annular space or else into the drill column.
In connection with the above-described pump, a possible
solution is to provide at least one filter and/or
valves. A filter connected upstream makes it possible
t~~ largely prevent the pump and/or the sensors from
being adversely affected. Owing to upstream valves, the
flow path to the pump can be sealed, which is important
i=, for certain reasons, no measurement is intended to
be carried out and no medium is intended to reach the
measuring device.
While the invention makes it possible to take measured
values during drilling, in principle it is also
possible to interrupt the drilling operation for a
short period of time and to take samples of the medium
in the region of the bottom of the borehole. For this
purpose, the measuring device has an electrically, in
particular electrohydraulically, operated packer. The
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packer is provided for the purpose of dividing the
annular space into a section above the packer and a
section beneath the packer. In this case, the two
sections are virtually sealed off. In the inserted
state, the packer does not protrude beyond the housing
or only protrudes beyond the housing to an
insignificant extent. In the withdrawn state, the
packer bears against the wall of the borehole. In order
to achieve a virtually sealing function, the packer has
a plurality of packer segments, which at least
partially overlap one another at least in the inserted
state.
~n order to take a sample once the packer has been
withdrawn, it is necessary to interrupt the circulation
c>f the borehole mud. Owing to the fact that the mud is
at a standstill, floating particles, which are
constituents of the mud, may sink and become deposited
cn the upper side of the packer. This can lead to
difficulties when reinserting the packer. In order to
eliminate this problem, an in particular electrically
operated lubricant supply device is provided above the
packer, by means of which a layer of lubricant is
applied to the upper side of the packer segments in the
withdrawn state of the packer segments or when the
packer segments are being withdrawn. The layer of
lubricant in this case acts firstly as a protective
layer and secondly as a sliding layer, which favours
reinsertion of the packer into the housing.
If, in the withdrawn state of the packer, the borehole
mu.d sinks in the upper part, considerable loading of
the packer may result. For this reason, the invention
provides for the pump to be designed to lower the level
of the annular space beneath the packer in the
withdrawn state of the packer. In this context, the
inflow opening of the housing into the measuring device
is in this case provided beneath the packer, while the
outflow opening in the housing is located above the
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packer.
Owing to the various drive possibilities, a possible
solution is to provide an electrically operated control
unit for the purpose of driving the functional units,
as necessary. The control unit, if necessary, is driven
at the surface via the evaluation device, in which the
measured values are displayed, evaluated and processed.
A generator which is provided at the surface is
generally used for supplying energy to the measuring
device. In order to ensure operation of the measuring
device even in the event of operational faults of the
generator, the measuring device has an energy store for
an emergency power supply. Finally, this energy store
is a rechargeable battery provided in the housing.
Exemplary embodiments of the invention will be
described below with reference to the drawing, in
which:
Figure 1 shows a schematic view of a drill column
introduced into a borehole,
Figure 2 shows a schematic view of the pipe end of a
drilling pipe,
Figure 3 shows a schematic view of part of a bush,
Figure 4 shows a cross-sectional view of part of a
drilling pipe,
Figure 5 shows a detailed view of part of a drilling
pipe,
Figure 6 shows a detailed view of a bush,
Figure 7 shows a schematic partial view of a drilling
pipe which has been screwed into a bush, and
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Figure 8 shows a schematic view of a measuring device
according to the invention.
Figure 1 shows a schematic illustration of a drilling
apparatus 1. The drilling apparatus 1 has a drilling
head 2 which is arranged at the surface and a drill
~~olumn 3, which is located in a borehole 4 in the
drilling state. A bit unit 5 is located at the lower
end of the drill column 3. In the exemplary embodiment
illustrated, a measuring device 6, which is connected
t:o an evaluation device 8, which is located at the
surface, via a conductor 7, is located directly above
the bit unit 5. The measuring device 6 makes it
possible to record measured values during drilling
which can then be evaluated directly via the evaluation
device 8.
T~~e drill column 3 itself in this case comprises a
large number of alternately arranged drilling pipes 10
and bushes 11. Drilling pipes 10 of the type in
question may have a length of up to 10 m or longer,
while the drilling column 3 for deep wells may have a
length of several thousand metres.
Figure 2 and the detailed illustration shown in Figure
4 illustrate part of a drilling pipe 10. The drilling
pipe 10 has a drilling pipe body 12 made from an
electrically conductive material. Provision is now made
for at least one electrical pipe conductor 7a to be
passed through the drilling pipe body 12, said
electrical pipe conductor 7a being connected at the
end, to be precise at both ends, to a pipe contact
connection 13 provided on the drilling pipe body 12,
the pipe conductor 7a and the pipe contact connection
13 being electrically insulated from the drilling pipe
body 12. As in shown in particular in Figure 4, the
pipe conductor 7a is fixed to the pipe inner side 14.
For this purpose, a longitudinal groove 15 for the pipe
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conductor 7a is provided on the pipe inner side 14. In
this case, the groove 15 is dovetailed. In principle,
however, any other groove shape is also possible. The
groove 15 runs parallel to the centre axis of the
drilling pipe 10. The depth of the groove 15 is in this
case greater than the outer diameter of the pipe
~~onductor 7a. The pipe conductor 7a is held in the
groove 15 by means of an insulation 16. In addition to
its fixing function, the insulation 16 also has an
electrically insulating function. In addition to the
insulation 16, the pipe conductor 7a has a conductor
insulation 17, which extends over the entire length of
the pipe conductor 7a. As can further be seen in Figure
4, an electrical insulating layer 18 is vapour-
deposited over the entire surface of the pipe inner
side 14 and also covers the groove 15 and thus the pipe
conductor 7a. The insulating layer 18 is applied over
t:he entire surface of the pipe inner side 14.
The pipe contact connection 13 is provided on the end-
side front face 19 of the pipe end of the drilling pipe
10. In this case, it goes without saying that in each
case a corresponding pipe contact connection 13 is
provided at both ends of the drilling pipe body 12,
even if this is not described in any more detail below.
The pipe contact connection 13 is of circumferential
design and has the form of a contact ring. Moreover,
the pipe contact connection 13 is arranged on an
insulating ring 20 resting on the front face 19. The
insulating ring 20, which is made from an elastic
material, has an annular groove 21 for the purpose of
accommodating the pipe contact connection 13. In this
case, the annular groove 21 is deeper than the height
of the pipe contact connection 13.
Moreover, the pipe contact connection 13 is in this
case spring-loaded in the direction away from the front
face 19, namely in the direction towards the bush 11 to
be connected to the drilling pipe 10.
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A pin 22, on which an external thread 23 is provided,
is located at the two pipe ends of the drilling pipe
10. A step 24, which merges at its end with the pipe
outer side 25, is located between the pins 22 having
the external thread 23. A circumferential seal 26,
which in this case is an O ring, is located at the
l.ransition between the step 24 and the external thread
23. Instead of the seal 26, or in addition to said
seal, a ring seal can also be arranged on the step 24.
E'igure 4 and the detailed illustration shown in Figure
6 show part of a bush 11. The bush 11 has a bush body
27 made from an electrically conductive material. An
electrical bush conductor 7b is passed through the bush
body 27 and is connected at the end, to be precise at
both ends of the bush body 27, to bush contact
connections 28, even if this is nat specifically
illustrated. The bush conductor 7b and the bush contact
connections 28 are electrically insulated from the bush
body 27.
The bush conductor 7b is fixed to the bush inner side
2°~. For this purpose, a longitudinal groove 30 is
provided on the bush inner side 29 of the bush body 27.
The groove 30 has the same design as the groove 15.
Moreover, the groove 30 runs parallel to the centre
axis of the bush 11. The illustration does not show the
fa~~t that the bush conductor 7b is cast into the groove
30 via an insulation and is moreover sheathed by a
conductor insulation. Furthermore, an electrical
insulating layer 31 is vapour-deposited onto the bush
inner side 29, as is also the case for the pipe inner
side 14, said insulating layer 31 also covering the
bush conductor 7b.
As can be seen in particular in Figure 6, the bush
contact connection 28 is provided on a front-side
shoulder 32. The shoulder 32 is located between the
CA 02544711 2006-05-03
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internal thread 33 and the bush inner side 29. The bush
contact connection 28 is of circumferential design and
is arranged on an insulating ring 20 resting on the
shoulder 32. The insulating ring 20 corresponds in
terms of type and design to the insulating ring 20
provided on the drilling pipe 10, i.e. has an annular
groove 21 for the purpose of accommodating the bush
~~ontact connection 28, the annular groove 21 being
deeper than the height of the bush contact connection
28. Moreover, the bush contact connection 28 is spring-
loaded in the direction away from the shoulder 32. The
spring-loading may be designed as regards the contact
connections 13, 28 such that one or more springs, for
example small helical compression springs, act on the
respective underside of the contact connection.
furthermore, spring tongues may be provided on the
respective contact connection. The spring tongues can
in principle point inwards andlor outwards, in which
case outwardly pointing spring tongues can then
protrude beyond the actual contact connection and cause
the electrical contact to be made.
In this case, a circumferential seal 35 is located on
the outer front face 34 of the bush body 27. The outer
front face 34 is located between the internal thread 33
and the bush outer side 36.
The drilling pipes 10 and bushes 11, as described
above, in conjunction with the pipe conductors 7a and
bush conductors 7b result in a two-pole energy and data
transmission system via the drill column 3. In this
case, one pole is formed by the drill column body,
which comprises the drilling pipe bodies 12 and the
bush bodies 27, while the other pole is formed by the
conductor 7, which comprises the pipe conductors 7a and
the bush conductors 7b as well as the contact
connections 13 and 28. The system according to the
invention moreover provides the advantage that the
drill column 3 and thus the two poles can be extended
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as desired since, owing to a drilling pipe 10 being
screwed to a bush 11, the electrical connection is
formed via the contact connections 13, 28 on the one
hand and via the material of the drilling pipe body 12
and the bush body 27 on the other hand.
Energy is supplied to the conductor 7 and data tapped
off from it via a slipring collector (not illustrated),
which is provided on the first drilling pipe 10. The
slipring collector is connected to the pipe conductor
'a and insulated from the drilling pipe body 12. The
~~lipring collector is in turn connected to the
evaluation device 8, while the drill column body forms
the connection to earth.
Figure 8 shows a schematic illustration of the
measuring device 6. In this case, the measuring device
6 is connected to the last drilling pipe 10 of the
drill column 3. In this case, the measuring device 6
has an electrically operated measuring unit 40, with
which it is possible to measure relevant data on the
state of the rock, the drilling mud or the raw material
to be obtained. The measuring device 6 is in this case
supplied with electrical energy via the above-described
conductor 7. In this case, it goes without saying that
the measuring device 6 has a contact connection
corresponding to the contact connections 13, 28 and an
extension of the conductor 7, even if this is not
specifically illustrated.
The measuring device 6 has an outer housing 41, in
which the measuring unit 40 and further functional
units are accommodated, which functional units will be
explained in more detail below. The housing 41 has in
each case screw connections 42, 43 at its two ends for
connection to the drill string and the bit unit 5. The
screw connections 42, 43 correspond to those of the
bush 11. However, reference will be made to the fact
that, in principle, it is also possible for other screw
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connections to be provided, in particular even those
having an external thread. Finally, it is merely
critical that the measuring device 6 can be integrated
in the drill column 3.
'~'he measuring device 6 has a transformer 44 for the
purpose of converting measured signals recorded via the
measuring unit 40 for subsequent transfer to the
evaluation device 8. The illustration does not show the
fact that the measuring unit 40 may have a plurality of
different measuring instruments for recording a wide
variety of data relating to the relevant medium. The
individual measuring instruments should be of modular
design, with the result that, if necessary, it is
possible to replace measuring instruments. In the
exemplary embodiment illustrated, the sensors or the
measured value pickups are provided in the flow path 45
within the housing 41. In principle, however, it is
also possible for the measured value pickups to be
d_Lrected outwards into the annular space via outer
openings in the housing 41.
Furthermore, an electrically operated pump 46 is
provided which supplies the medium under investigation
to the measuring unit 40 via the flow path 45. An
electrically operated valve unit 47 having at least one
two-way valve is provided above the measuring unit 40
in order to divert the medium under investigation, if
necessary, into the annular space or else via the drill
column 3. For this purpose, corresponding outflow
openings 48 are provided in the housing 41. In this
case, at least one filter 49 and a valve unit 50 are
connected upstream of the pump 46. The valve unit 50 is
used for sealing inflow openings 51 provided in the
housing 41.
Furthermore, an electrohydraulic packer 52 is provided.
The packer 52 has a plurality of packer segments, which
are not illustrated in any more detail. In the inserted
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state of the packer 52, which is illustrated in Figure
8, the packer segments at least partially overlap one
another. The packer 52 is overall designed such that,
in the withdrawn state, it divides the annular space
into an upper and a lower part and in the process at
least substantially seals off these sections. Directly
above the packer 52 is a lubricant supply device 53,
which is used for applying a layer of lubricant to the
upper side of the packer segments in the withdrawn
state. The lubricant supply device 53 can be operated
electrically or else mechanically. The mechanically
operated lubricant supply is preferably mechanically
coupled to the packer 52 if the lubricant supply is
actuated when the packer segments are being withdrawn.
furthermore, the measuring device 6 in this case has a
control unit 54 for driving the individual functional
units and an energy store 55, as necessary.
Moreover, it goes without saying that the
abovementioned functional units do not necessarily need
to be arranged in the sequence illustrated. As long as
the operation of the measuring device 6 is not called
into question, other arrangements can also be selected.
However, it is necessary to take care that the packer
5~? is located between the lower inflow openings 51 and
the upper outflow openings 48 in order to make it
possible to lower the level of the annular space
beneath the withdrawn packer 52 via the pump 46.
Moreover, a string section, which forms the flow path
45 and has a through-opening which communicates with
the drill column 3 or the opening therein and the bit
unit 5, is located in the housing 41. Moreover, the
outflow openings 48 and the inflow openings 51
communicate with the string section forming the flow
path 45. In this case, a nonreturn valve 56, which
closes the through-opening, is located at the end of
the string section. Said nonreturn valve 56 has an
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electric drive (not illustrated).
No detailed illustration is provided to show that the
individual functional units of the measuring device 6
are electrically connected to the two above-described
poles, which makes electrical energy supply and, as far
as the measuring unit 40 or the control unit 54 are
concerned, data exchange with the evaluation device 8
possible.
=Lnstead of the above-described embodiment, in which the
<drill string is open in the housing 41 of the measuring
device 6, it is in principle also possible for the
measuring device 6 to have a passage pipe section,
4JhlCh is connected either at both ends or else at one
end to the drill column and at the other end to the bit
unit 5. The medium is then passed through corresponding
flow paths through the housing and in the process also
past the measuring unit 40 for analysis purposes. In
this case too, provision may be made for the already
measured medium to either be output to a drill string
or else into the annular space. A corresponding valve
unit which opens into the drill string is required in
this case.
The invention makes it possible to measure the state of
the medium in the borehole continuously prior to,
during and after drilling. The data can be evaluated
immediately in the evaluation device 8. Hydrological
changes, for example, during drilling are thus
identified without delay and sampling is also
immediately possible. For this purpose, in the
embodiment illustrated the nonreturn valve 56 closes
off the drilling pipe at the bottom while the packer 52
is being withdrawn. The pump 46 then conveys the
medium, once the outflow openings 48 have been closed
b:y means of the valve unit 47, through the drill string
to the surface.
