U.S. patent application number 16/627143 was filed with the patent office on 2020-05-07 for logging device for measuring pressure into an underground formation and associated method.
This patent application is currently assigned to TOTAL SA. The applicant listed for this patent is TOTAL SA. Invention is credited to Pierre VENTRE.
Application Number | 20200141234 16/627143 |
Document ID | / |
Family ID | 59745312 |
Filed Date | 2020-05-07 |
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United States Patent
Application |
20200141234 |
Kind Code |
A1 |
VENTRE; Pierre |
May 7, 2020 |
LOGGING DEVICE FOR MEASURING PRESSURE INTO AN UNDERGROUND FORMATION
AND ASSOCIATED METHOD
Abstract
The invention relates to a logging device for measuring pressure
into an underground formation, comprising at least one formation
pressure sensor which comprises a tool body part and a probe
mounted on the tool body part, said probe comprising a fluid
withdrawal line. The tool body part comprises a flow line connected
to the fluid withdrawal line, at least one test chamber connected
to the flow line and an at least one respective closing system, and
at least one pressure sensor connected to the flow line. The probe
further comprises a rupture chamber and a pressure sensor connected
to the fluid withdrawal line and, a first isolating valve on the
fluid withdrawal line downstream of the rupture chamber and
upstream to the flow line adapted to isolate the rupture chamber
from the flow line when the rupture chamber is actuated.
Inventors: |
VENTRE; Pierre; (PAU Cedex,
FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOTAL SA |
COURBEVOIE |
|
FR |
|
|
Assignee: |
TOTAL SA
COURBEVOIE
FR
|
Family ID: |
59745312 |
Appl. No.: |
16/627143 |
Filed: |
June 27, 2017 |
PCT Filed: |
June 27, 2017 |
PCT NO: |
PCT/IB2017/000974 |
371 Date: |
December 27, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 47/06 20130101;
E21B 49/081 20130101; E21B 49/082 20130101; E21B 47/024 20130101;
E21B 49/10 20130101; E21B 49/00 20130101; E21B 49/083 20130101 |
International
Class: |
E21B 49/10 20060101
E21B049/10; E21B 47/06 20060101 E21B047/06; E21B 49/08 20060101
E21B049/08; E21B 49/00 20060101 E21B049/00; E21B 47/024 20060101
E21B047/024 |
Claims
1. A logging device for measuring pressure into an underground
formation containing a fluid, said logging device comprising: at
least one formation pressure sensor, said formation pressure sensor
comprising a tool body part and a probe mounted on the tool body
part, said probe comprising a fluid withdrawal line intended to be
placed in fluid communication with the underground formation after
rupture of a mud cake, the tool body part comprising a flow line
connected to the fluid withdrawal line, several parallel test
chambers connected to the flow line and several respective closing
systems adapted to fluidly isolate each test chamber from the flow
line, and at least one pressure sensor connected to the flow line,
wherein the probe further comprises a rupture chamber intended to
be actuated to rupture the mud cake by suction and a pressure
sensor connected to the fluid withdrawal line and, a first
isolating valve on the fluid withdrawal line downstream of the
rupture chamber and upstream to the flow line adapted to isolate
the rupture chamber from the flow line when the rupture chamber is
actuated.
2. The logging device according to claim 1, wherein the probe
further comprises a second isolating valve different from the first
isolating valve between the rupture chamber and the fluid
withdrawal line adapted to isolate the rupture chamber from the
fluid withdrawal line when at least one of test chambers is
actuated, or wherein the first isolating valve is a three-way valve
connected to the fluid withdrawal line adapted to isolate the
rupture chamber from the fluid withdrawal line when at least one of
the test chambers is actuated.
3. The logging device according to claim 2, further comprising a
control unit adapted to actuate the rupture chamber, the first
isolating valve and the second isolating valve, at least one of the
closing systems and at least one of the test chambers between a
first mud cake rupturing configuration wherein the first isolating
valve is closed, the second isolating valve is opened and the
rupture chamber is actuated and a second configuration wherein the
first isolating valve is opened, the second isolating valve is
closed, at least one of the closing systems are opened and at least
one of the test chambers is actuated, or wherein the logging device
further comprises a control unit adapted to actuate the rupture
chamber, the three-way valve, at least one of the closing system
and at least one of the test chambers between a first mud cake
rupturing configuration wherein the three-way valve allows only the
fluid circulation between the rupture chamber and the first end of
the fluid withdrawal line and the rupture chamber is actuated, and
a second configuration wherein the three-way valve allows only the
fluid circulation between the first end of the fluid withdrawal
line and the flow line, at least one of the closing systems is
opened and at least one of the test chambers is actuated.
4. The logging device according to claim 1, wherein the volume of
each of the test chambers is more than the volume of the rupture
chamber.
5. The logging device according to claim 1, wherein the rupture
chamber defines a cavity and comprises a piston movable into the
cavity between a retracted position and an extended position.
6. The logging device according to claim 1, further comprising a
plurality of different sensors and a processing unit, said sensors
being configured to provide measurements to the processing unit,
said processing unit being configured to process said measurements
to determine at least a value of a physical parameter of the
environment of the logging device and at least a redundant value of
the same physical parameter of the environment of the logging
device, the value and the redundant value being determined from at
least two different sensors measurements measuring different
physical parameters.
7. The logging device according to claim 6, wherein the plurality
of different sensors are chosen among a plurality of formation
pressure sensors at different heights, a plurality of hydrostatic
well pressure sensors at different heights, a gradio-manometer
sensor, a gamma-ray sensor, a cable tension sensor and/or an
inclinometer sensor.
8. The logging device according to claim 6, wherein at least one
first sensor of the plurality of sensors is configured to provide
at least one direct measurement of a value of a physical parameter
of the environment of the logging device to the processing unit and
the processing unit is configured to calculate at least one
redundant value of the same physical parameter through the
measurements of at least a second sensor among the plurality of
sensors, the second sensor measuring a physical parameter of the
environment of the logging device different from the physical
parameter of the environment of the logging device measured by the
first sensor.
9. The logging device according to claim 6, further comprising a
computation unit configured to calculate an uncertainty and/or a
coherence of the at least one physical parameter of the environment
of the logging device, based on the at least one value of the
physical parameter and on the at least one redundant value of the
same physical parameter obtained from the at least two different
sensors.
10. The logging device according to claim 6, further comprising a
communication unit configured to communicate the uncertainty and/or
the coherence of the at least one physical parameter to an
operator.
11. The logging device according to claim 6, further comprising an
automatic control unit configured to control at least one of the
test chambers and/or the rupture chamber, said automatic
controlling unit being connected to the computation unit and/or to
the processing unit in order to adjust the parameters of fluid
suction of at least one of the test chambers and/or the parameters
of the rupture chamber based on the measurements of at least one
sensor, on the at least one value and the at least one redundant
value of at least one physical parameter and/or based on an
uncertainty and/or a coherence of the physical parameter obtained
from the at least two different sensors.
12. A method for measuring pressure into an underground formation
containing a fluid using a logging device according to claim 1,
comprising the following steps: putting the probe in contact with a
mud cake of the underground formation, closing the first isolating
valve, actuating the rupture chamber so as to establish fluid
communication between the underground formation and the fluid
withdrawal line by rupturing the mud cake, opening the first
isolating valve, actuating at least one of the test chambers so as
to suction fluid inside the at least one of the test chambers,
ensuring fluid isolation of the at least one of the test chambers
from the flow line by closing the respective at least one of the
closing systems of the at least one of the test chambers, measuring
the pressure stabilization in the flow line.
13. The method according to claim 12, further comprising a step of
closing a second isolating valve different from the first isolating
valve between the rupture chamber and the fluid withdrawal line, to
isolate the rupture chamber from the fluid withdrawal line before
opening the first isolating valve, or wherein the first isolating
valve is a three-way valve connected to the fluid withdrawal line,
the method comprising a step of actuating the three-way valve to
isolate the rupture chamber from the fluid withdrawal line before
actuating the at least one of the test chambers.
14. The method according to claim 12, further comprising a step of
acquiring measurements with a plurality of sensors and processing
said measurements to determine at least a value of a physical
parameter of the environment of the logging device and at least a
redundant value of the same physical parameter of the environment
of the logging device, the value and the redundant value being
determined from at least two different sensors measurements
measuring different physical parameters.
15. The method according to claim 14, further comprising a step of
computing an uncertainty and/or a coherence of the at least one
physical parameter by the calculation unit based on the at least
one value of the physical parameter and on the at least one
redundant value of the physical parameter obtained from the at
least two different sensors.
16. The method according to claim 15, further comprising a step of
communicating the uncertainty and/or the coherence of the at least
one physical parameter to an operator by the communication
unit.
17. The method according to claim 14, further comprising a step of
automatic controlling of the at least one of the test chambers
and/or the rupture chamber so as to adjust the parameters of fluid
suction of the at least one of the test chambers and/or the
parameters of the rupture chamber based on the measurements of the
at least one sensor, based on the at least one value and the at
least one redundant value of at least one physical parameter and/or
based on an uncertainty and/or a coherence of the physical
parameter obtained from the at least two different sensors.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a U.S. National Phase Application under 35 U.S.C.
.sctn. 371 of International Patent Application No.
PCT/IB2017/000974, filed Jun. 27, 2017. The entire contents of
which are hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention concerns a logging device for
measuring pressure into an underground formation containing a
fluid, said logging device comprising at least one formation
pressure sensor, said formation pressure sensor comprising a tool
body part and a probe mounted on the tool body part, said probe
comprising a fluid withdrawal line intended to be placed in fluid
communication with the underground formation after rupture of a mud
cake, the tool body part comprising a flow line connected to the
fluid withdrawal line, at least one test chamber connected to the
flow line and at least one respective closing system adapted to
fluidly isolate the at least one test chamber from the flow line,
and at least one pressure sensor connected to the flow line.
BACKGROUND
[0003] This logging device is for example lowered in wells for oil
and gas exploration, for mining exploration or for aquifer
hydrological studies so as to determine punctually at various
measurement stations along the depth of the well, the formation
pressure. Formation pressure typically gives information concerning
the mobility of the fluids contained in the underground formation
and the permeability of said underground formation.
[0004] Classically, the pressure of the underground formation is
measured by locally imposing a vacuum on the wall of the well,
through fluid suction in the test chamber after the rupture of the
mud cake. The test chamber is then in fluid communication with the
underground formation and a predetermined volume of fluid is sucked
at a predetermined flow rate by the test chamber. This creates a
pressure drop in the flowline. This step is referred as the
drawdown. The drawdown continues with pressure dropping as the
volume of fluid is sucked by the test chamber. When the test
chamber stops sucking the fluid, the pressure starts to build-up.
Given a sufficient amount of time, the pressure in the flow line
reaches equilibrium with the formation pressure. The time evolution
of the pressure during the drawdown and during the build-up is
interpreted for example in terms of permeability of the underground
formation.
[0005] The main drawback of the current devices is that the
underground formation and the flow line of the logging device are
sometimes in poor fluid communication due to a partial rupture of
the mud cake, leading to inconsistent measurements of formation
pressure. Moreover, the tool capacity is not minimized in existing
devices. The pressure build up is then slower, which leads to an
uncertainty in the estimation of the formation pressure.
[0006] On the contrary, when the mud cake is partially porous, its
permeability may interfere with the permeability of the formation
leading to an over estimation of the pressure called
"supercharging".
SUMMARY
[0007] One aim of the invention is to increase the reliability and
the relevance of the measurements of formation pressure in the
underground formation.
[0008] To this end, the subject-matter of the invention is a
logging device of the aforementioned type, characterized in that
the probe further comprises a rupture chamber intended to be
actuated to rupture the mud cake by suction and a pressure sensor
connected to the fluid withdrawal line and, a first isolating valve
on the fluid withdrawal line downstream of the rupture chamber and
upstream to the flow line adapted to isolate the rupture chamber
from the flow line when the rupture chamber is actuated.
[0009] According to various embodiments, the logging device
according to the invention comprises one or more of the following
features, taken into consideration in isolation, or in accordance
with any technically possible combination: [0010] the probe further
comprises a second isolating valve different from the first
isolating valve between the rupture chamber and the fluid
withdrawal line adapted to isolate the rupture chamber from the
fluid withdrawal line when the at least one test chamber is
actuated, or wherein the first isolating valve is a three-way valve
connected to the fluid withdrawal line adapted to isolate the
rupture chamber from the fluid withdrawal line when the at least
one test chamber is actuated; [0011] the logging device further
comprises a control unit adapted to actuate the rupture chamber,
the first isolating valve and the second isolating valve, the at
least one closing system and the at least one test chamber between
a first mud cake rupturing configuration wherein the first
isolating valve is closed, the second isolating valve is opened and
the rupture chamber is actuated and a second configuration wherein
the first isolating valve is opened, the second isolating valve is
closed, the at least one closing system are opened and the at least
one test chamber is actuated, or wherein the logging device further
comprises a control unit adapted to actuate the rupture chamber,
the three-way valve, the at least one closing system and the at
least one test chamber between a first mud cake rupturing
configuration wherein the three-way valve allows only the fluid
circulation between the rupture chamber and the first end of the
fluid withdrawal line and the rupture chamber is actuated, and a
second configuration wherein the three-way valve allows only the
fluid circulation between the first end of the fluid withdrawal
line and the flow line, the at least one closing system are opened
and the at least one test chamber is actuated; [0012] the volume of
the at least one test chamber is more than the volume of the
rupture chamber; [0013] the rupture chamber defines a cavity and
comprises a piston movable into the cavity between a retracted
position and an extended position; [0014] the logging device
further comprises a plurality of different sensors and a processing
unit, said sensors being configured to provide measurements to the
processing unit, said processing unit being configured to process
said measurements to determine at least a value of a physical
parameter of the environment of the logging device and at least a
redundant value of the same physical parameter of the environment
of the logging device, the value and the redundant value being
determined from at least two different sensors measurements
measuring different physical parameters; [0015] the plurality of
different sensors are chosen among a plurality of formation
pressure sensors at different heights, a plurality of hydrostatic
well pressure sensors at different heights, a gradio-manometer
sensor, a gamma-ray sensor, a cable tension sensor and/or an
inclinometer sensor; [0016] at least one first sensor of the
plurality of sensors is configured to provide at least one direct
measurement of a value of a physical parameter of the environment
of the logging device to the processing unit and the processing
unit is configured to calculate at least one redundant value of the
same physical parameter through the measurements of at least a
second sensor among the plurality of sensors, the second sensor
measuring a physical parameter of the environment of the logging
device different from the physical parameter of the environment of
the logging device measured by the first sensor; [0017] the logging
device further comprises a computation unit configured to calculate
an uncertainty and/or a coherence of the at least one physical
parameter of the environment of the logging device, based on the at
least one value of the physical parameter and on the at least one
redundant value of the same physical parameter obtained from the at
least two different sensors; [0018] the logging device further
comprises a communication unit configured to communicate the
uncertainty and/or the coherence of the at least one physical
parameter to an operator; [0019] the logging device further
comprises an automatic control unit configured to control the at
least one test chamber and/or the rupture chamber, said automatic
controlling unit being connected to the computation unit and/or to
the processing unit in order to adjust the parameters of fluid
suction of the at least one test chamber and/or the parameters of
the rupture chamber based on the measurements of at least one
sensor, on the at least one value and the at least one redundant
value of at least one physical parameter and/or based on an
uncertainty and/or a coherence of the physical parameter obtained
from the at least two different sensors.
[0020] The subject-matter of the invention also relates to a method
for measuring pressure into an underground formation containing a
fluid using a logging device as described above, comprising the
following steps: [0021] putting the probe in contact with a mud
cake of the underground formation, [0022] closing the first
isolating valve, [0023] actuating the rupture chamber so as to
establish fluid communication between the underground formation and
the fluid withdrawal line by rupturing the mud cake, [0024] opening
the first isolating valve, [0025] actuating the at least one test
chamber so as to suction fluid inside the at least one test
chamber, [0026] ensuring fluid isolation of the at least one test
chamber from the flow line by closing the respective at least one
closing system of the at least one test chamber, [0027] measuring
the pressure stabilization in the flow line.
[0028] According to various embodiments, the method according to
the invention includes one or more of the following features:
[0029] the method further comprises a step of closing a second
isolating valve different from the first isolating valve between
the rupture chamber and the fluid withdrawal line, to isolate the
rupture chamber from the fluid withdrawal line before opening the
first isolating valve, or wherein the first isolating valve is a
three-way valve connected to the fluid withdrawal line, the method
comprising a step of actuating the three-way valve to isolate the
rupture chamber from the fluid withdrawal line before actuating the
at least one test chamber; [0030] the method further comprises a
step of acquiring measurements with a plurality of sensors and
processing said measurements to determine at least a value of a
physical parameter of the environment of the logging device and at
least a redundant value of the same physical parameter of the
environment of the logging device, the value and the redundant
value being determined from at least two different sensors
measurements measuring different physical parameters; [0031] the
method further comprises a step of computing an uncertainty and/or
a coherence of the at least one physical parameter by the
calculation unit based on the at least one value of the physical
parameter and on the at least one redundant value of the physical
parameter obtained from the at least two different sensors; [0032]
the method further comprises a step of communicating the
uncertainty and/or the coherence of the at least one physical
parameter to an operator by the communication unit; [0033] the
method further comprises a step of automatic controlling of the at
least one test chamber and/or the rupture chamber so as to adjust
the parameters of fluid suction of the at least one test chamber
and/or the parameters of the rupture chamber based on the
measurements of the at least one sensor, based on the at least one
value and the at least one redundant value of at least one physical
parameter and/or based on an uncertainty and/or a coherence of the
physical parameter obtained from the at least two different
sensors.
[0034] The invention also concerns a logging device for measuring
pressure into an underground formation containing a fluid, said
logging device comprising at least one formation pressure sensor,
said formation pressure sensor comprising a tool body part and a
probe mounted on the tool body part, said probe comprising a fluid
withdrawal line intended to be placed in fluid communication with
the underground formation after rupture of a mud cake, the tool
body part comprising a flow line connected to the fluid withdrawal
line, at least one test chamber connected to the flow line and an
at least one respective closing system adapted to fluidly isolate
the test chamber from the flow line, and at least one pressure
sensor connected to the flow line.
[0035] The logging device further comprises a plurality of
different sensors and a processing unit, said sensors being
configured to provide measurements to the processing unit, said
processing unit being configured to process said measurements to
determine at least a value of a physical parameter of an
environment of the logging device and at least a redundant value of
the same physical parameter of the environment of the device, the
value and the redundant value being determined from at least two
different sensors measurements measuring different physical
parameters.
[0036] The logging device according to the invention may or may not
comprise the feature by which the probe further comprises a rupture
chamber intended to be actuated to rupture the mud cake by suction
and a pressure sensor connected to the fluid withdrawal line and, a
first isolating valve on the fluid withdrawal line downstream of
the rupture chamber and upstream to the flow line adapted to
isolate the rupture chamber from the flow line when the rupture
chamber is actuated.
[0037] The logging device according to the invention comprises one
or more of the above features, taken into consideration in
isolation, or in accordance with any technically possible
combination.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] The invention will be better understood upon reading of the
following description, taken solely as an example, and made in
reference to the following drawings, in which:
[0039] FIG. 1 is a schematic view of the logging device according
to the invention inside a sub-vertical well,
[0040] FIG. 2 is a schematic view of the logging device of FIG. 1
inside an at least locally inclined portion of a well,
[0041] FIG. 3 is a partial schematic representation of the logging
device of FIG. 1 illustrating a probe of the logging device,
[0042] FIGS. 4 and 5 are schematic representations of a variant of
the logging device of FIG. 1 comprising deflectors and a
bow-spring,
[0043] FIG. 6 is a schematic representation of a three-way valve
used in variant of the first and the second isolating valves.
DETAILED DESCRIPTION
[0044] A logging device 1 for measuring pressure into an
underground formation 3 according to the invention is shown in FIG.
1 and FIG. 2. The logging device 1 is adapted to be lowered in a
well 5 drilled in the underground formation 3 containing a fluid.
The term "fluid" refers to gas, liquid or a mix of gas and liquid.
For example, in oil exploration, the fluid in the underground
formation 3 generally comprises a mix of water, oil and gas.
[0045] The well 5 is for example an exploration, a production or an
injection well for oil and gas or mining exploration or a well
performed for aquifer characterization studies.
[0046] The well 5 is here represented vertical. The well 5 may also
comprise inclined or even horizontal portions.
[0047] Typically, the logging device 1 comprises a downhole
formation pressure sensor 4 and a line 7 adapted to lower the
logging device 1 into the well 5. The line 7 is connected on the
surface to a hoisting system 9 adapted to lower or to raise the
logging device 1. For example, the hoisting system 9 is an
electrical winch. Moreover, the line 7 is an electric wireline
generally adapted to transmit the data measured by the logging
device to a data recording unit (not represented) located on the
surface, or a slickline.
[0048] The logging device 1 is lowered in the well 5 and stopped at
predetermined depths called measurement stations 11 where the
measurements are performed.
[0049] During the drilling of the well 5, the well 5 is filled with
a drilling fluid such as water-based or oil-based fluid. The
density of the drilling fluid is for example increased by adding
solids, such as salts and other additives, to form a drilling mud.
The drilling mud makes it possible to obtain a hydrostatic pressure
in the well 5 adapted to avoid the cave-in of the well 5 and
prevent the fluid of the underground formation 3 from escaping into
the well 5.
[0050] The drilling mud forms a layer on the inner wall of the
well, called mud cake 13. The mud cake 13 isolates the underground
formation 3 from the inside of the well 5.
[0051] As schematically visible on FIG. 3, the first formation
pressure sensor 4 comprises a tool body part 15 and a probe 17
mounted on the tool body part 15 to connect to the formation.
[0052] The probe 17 comprises a fluid withdrawal line 19. The tool
body part 15 extends along a longitudinal axis. It comprises a flow
line 21 connected to the fluid withdrawal line 19 and at least one
test chamber 23a, 23b, 23c, 23d.
[0053] The probe 17 is for example transversely extendable from the
tool body part 15 for sealing engagement with the wall of well 5.
Typically, the probe 17 transversely protrudes from the tool body
part 15 toward the wall of the well 5 and is anchored to the wall
of the well 5 at each measurement station 11.
[0054] For example, the extension of the probe 17 from the tool
body part 15 is carried out using hydraulic, mechanical and/or
electrical means or a combination thereof.
[0055] In reference to FIG. 3, the fluid withdrawal line 19
comprises a first end 25 intended to be placed in fluid
communication with the underground formation 3 after the rupture of
the mud cake 13. The fluid withdrawal line 19 comprises a second
end 27 intended to be connected to the flow line 21 of the tool
body part 15.
[0056] Typically, the probe 17 further comprises a packer 29
disposed around the first end 25 of the fluid withdrawal line
19.
[0057] The packer 29 is for example made with an elastomeric
material.
[0058] In a variant, the packer 29 consists in an inflatable
element.
[0059] According to another embodiment, the packer 29 consists in a
set of upper and lower inflatable elements respectively disposed
onto an upper portion and onto a lower portion of well,
respectively above and below the first end 25 of the fluid
withdrawal line 19.
[0060] At each measurement station 11, prior to the rupture of the
mud cake 13, the upper and lower inflatable elements are inflated
so as to exert a pressure onto the upper portion and the lower
portion of the well 5.
[0061] The packer 29 seals against the wall of the well 5 to
fluidly isolate a portion of the wall 5. The packer 29 allows
improving the effectiveness of formation pressure measurements.
[0062] The probe 17 further comprises at least one filter 31
adapted to filter the particles contained in the fluid of the
underground formation 3. For example, the filter 31 consists in a
strainer in stainless steel disposed on a portion of the first end
25 of the fluid withdrawal line 19.
[0063] The probe 17 further comprises a filter piston 33 movable
into the first end 25 of the fluid withdrawal line 19 between an
extended position towards the underground formation 3 and a
retracted position away from the underground formation 3.
[0064] Typically, the filter piston 33 is adapted to clean the
filter 31 from the particles disposed on the filter 31.
[0065] For example, the filter piston 33 is actuated before each
formation pressure measurement.
[0066] According to the invention, the probe 17 comprises a rupture
chamber 35 intended to be actuated to rupture the mud cake 13 by
suction. The rupture chamber 35 is for example a low pressure
chamber.
[0067] Typically, the rupture chamber 35 defines a cavity 36 and
comprises a piston 38 movable into the cavity 36 between a
retracted position and an extended position.
[0068] Typically, the suction pressure provided in the rupture
chamber 35 is linked to the mud cake rupture pressure which may
vary from one measurement station to another one. It does not
exceed a limited drawdown pressure chosen to preserve the packer 29
integrity (linked to the mechanical resistance of the packer
29).
[0069] In a preferred embodiment, the volume of each test chamber
23a, 23b, 23c, 23d is more than the volume of the rupture chamber
35. The volume of the rupture chamber 35 is typically comprised
between 1 cc and 5 cc, for example 3 cc. Typically, the volume of
the rupture chamber 35 is linked to the above-mentioned exerted
suction pressure and the internal fluid compressibility.
[0070] Typically, the probe 17 further comprises a pressure sensor
37 tapped on the fluid withdrawal line 19 intended to measure the
pressure in the fluid withdrawal line 19 when said fluid withdrawal
line 19 is in fluid communication with the underground formation
3.
[0071] The probe 17 also comprises a first isolating valve 39 on
the fluid withdrawal line 19 downstream of the rupture chamber 35
and upstream to the flow line 21 adapted to isolate the rupture
chamber 35 from the flow line 21 when the rupture chamber 35 is
actuated.
[0072] The terms "downstream" and "upstream" are defined relatively
to a movement of the fluid from the underground formation to the
test chamber 23a, 23b, 23c, 23d.
[0073] Advantageously, the probe 17 further comprises a second
isolating valve 41 between the rupture chamber 35 and the fluid
withdrawal line 19, adapted to isolate the rupture chamber 35 from
the fluid withdrawal line 19.
[0074] Preferably, the tool body part 15 comprises several parallel
test chambers 23a, 23b, 23c 23d which are each tapped on the flow
line 21. For example, the tool body part 15 comprises between 2 to
8 test chambers 23a, 23b, 23c, 23d, preferentially between 2 to 6,
typically 4 test chambers 23a, 23b, 23c, 23d as shown on FIG.
3.
[0075] Each test chamber 23a, 23b, 23c, 23d defines a test chamber
cavity 43a, 43b, 43c, 43d. Each test chamber cavity 43a, 43b, 43c,
43d comprises a piston 45a, 45b, 45c, 45d adapted to move in the
test chamber cavity 43a, 43b, 43c, 43d so as to cause a flow of
fluid from the underground formation 3 into the test chamber cavity
43a, 43b, 43c, 43d. Typically, the flow rate inside the test
chamber 23a, 23b, 23c, 23d is comprised between 0.1 cc/minute and
1000 cc/minute, preferentially between 0.1 cc/minute and 5
cc/minute.
[0076] Preferably, the pistons 45a, 45b, 45c, 45d are actuated by
respective electric motors connected to worm screws 47a, 47b, 47c,
47d. The electric motors allow controlling the rate of the fluid
flow inside the test chamber 23a, 23b, 23c, 23d.
[0077] Advantageously, the worm screws 47a, 47b, 47c, 47d have
different screw pitches depending on the test chambers 23a, 23b,
23c, 23d. Consequently, the flow rate of each test chamber 23a,
23b, 23c, 23d is different from one test chamber 23a, 23b, 23c, 23d
to another one.
[0078] The test chambers 23a, 23b, 23c, 23d have typically
different volumes according to the corresponding flow rates.
Typically, the volume of the test chamber 23a, 23b, 23c, 23d is
comprised between 1 cc and 1000 cc, for example 300 cc.
[0079] Typically, each test chamber 23a, 23b, 23c, 23d comprises a
respective closing system 49a, 49b, 49c, 49d adapted to fluidly
isolate the test chamber 23a, 23b, 23c, 23d from the flow line 21.
The closing system 49a, 49b, 49c, 49d is for example a valve
similar to the first isolating valve 39 and the second isolating
valve 41.
[0080] The tool body part 15 further comprises at least one
pressure sensor 51 connected to the flow line 19 intended to
measure the pressure in the flow line 19 and a fluid insulation
valve 51a interposed between the pressure sensor 51 and each test
chamber 23a, 23b, 23c, 23d. Then, the logging device 1 may be used
with a standard non-instrumented probe of the prior art when the
instrumented probe 17 described above can be removed from the tool
body part 15.
[0081] Advantageously, as shown in FIG. 1 and FIG. 2, the logging
device 1 comprises a control unit 53 adapted to actuate the rupture
chamber 35, the first isolating valve 39 and the second isolating
valve 41, the test chambers 23a, 23b, 23c, 23d, the valves 51a and
49a to 49d between a first configuration and a second
configuration.
[0082] Typically, the valves 49a to 49d and the pistons 45a, 45b,
45c, 45d are controlled independently by the control unit 53.
[0083] In the first mud cake rupturing configuration, the first
isolating valve 39 is closed, the second isolating valve 41 is
opened and the rupture chamber 35 is actuated.
[0084] The first configuration corresponds to a first step of a
measurement of formation pressure which consists in rupturing the
mud cake 13 and establishing a fluid communication between the
withdrawal line 19 and the underground formation 3.
[0085] In the second configuration, the first isolating valve 39 is
opened, the second isolating valve 41 is closed, at least one of
the test chambers 23a, 23b, 23c, 23d is actuated and the
corresponding valves 49a to 49d are opened.
[0086] Typically, the second isolating valve 41 and the valves 49a
to 49d are used to minimize the tool capacity during the build-up
stabilization measurement.
[0087] In a variant, instead of measuring the formation pressure
with the pressure sensor 51 or 52, the first isolating valve 39 is
closed and the formation pressure is measured with the pressure
sensor 37.
[0088] The second configuration corresponds to a second step of the
test which consists in the suction of the fluid of the underground
formation 3 into at least one of the test chambers 23a, 23b, 23c,
23d, once the mud cake rupture has been confirmed.
[0089] Typically, if more than one test chambers 23a, 23b, 23c, 23d
are used, they are actuated successively from the test chamber
having the minimal volume to the test chamber having the maximal
volume.
[0090] The control unit 53 is for example intended to select which
test chamber 23a, 23b, 23c, 23d to actuate and/or the sequence of
actuation of the test chambers 23a, 23b, 23c, 23d and/or the flow
rate of each test chamber 23a, 23b, 23c, 23d.
[0091] As seen in FIG. 1 or FIG. 2, the logging device 1 further
comprises a plurality of different sensors (4, 57, 59, 61, 63, 65,
67, 69). For example, in addition to the first formation pressure
sensor, the logging device further comprises a second formation
pressure sensor 57 located at a different height compared to the
first formation pressure sensor 4, a first hydrostatic well
pressure sensor 59 and a second hydrostatic well pressure sensor 61
disposed at different heights, a gradio-manometer sensor 63, a
gamma-ray sensor 65, a cable tension sensor 67 and an inclinometer
sensor 69.
[0092] The first formation pressure sensor 4 and the second
formation pressure sensor 57 are similar to the one described
above. For example, the first formation pressure sensor 4 and the
second formation pressure sensor 57 are separated by a distance D.
Typically, D is comprised between 1 meter and 5 meters, for example
equal to 1 meter. The first formation pressure sensor 4 and the
second formation pressure sensor 57 are totally independent from
one to each other. Each of the first formation pressure sensor 4
and the second formation pressure sensor 57 comprises all the
elements described above. Consequently, the first formation
pressure sensor 4 and the second formation pressure sensor 57
provide two independent measurements of the formation pressure of
two parts of the underground formation 3 separated by the distance
D. The first formation pressure sensor 4 and the second formation
pressure sensor 57 are for example also adapted to measure the
hydrostatic pressure caused by the column of fluid in the formation
3.
[0093] The first hydrostatic well pressure sensor 59 and the second
hydrostatic well pressure sensor 61 measure directly the pressure
caused by the column of fluid in the well 5. The first hydrostatic
well pressure sensor 59 and the second hydrostatic well pressure
sensor 61 are separated by a distance H. For example, H is
comprised between 0.5 m and 1.5 m, for example 1 m. The total
length of the tool may be 10 meters or more than 10 meters.
[0094] The gradiomanometer sensor 63 measures an average
measurement of the fluid density inside the well 5. The gamma-ray
sensor 65 measures the natural gamma-ray radiation of the
underground formation 3. Generally, the gamma-ray sensor 65 is a
scintillometer which comprises a crystal and at least one
photomultiplier tube which converts the energy of the gamma-ray
radiation in a proportional electric current. In particular, the
gamma-ray radiation depends on the geological nature of the
underground formation 3. Typically, the gamma-ray radiation depends
on the content of natural radioelements .sup.238U, .sup.40K and
.sup.232Th.
[0095] The natural gamma-ray recording is used as a readjusting
tool of the depth. The tool depth is matched to a reference depth
according to reference gamma-ray log acquired in the well 5 before
the formation pressure measurements.
[0096] The cable tension sensor 69 measures the tension of line 7
of the logging device 1. This measurement is generally used to
correct the surface displacement of the line 7 by the elongation of
the line 7 taken in combination with a measurement of the line
deployment obtained from the hoisting system 9.
[0097] The inclinometer 67 measures the inclination angle .alpha.
(FIG. 3) between the logging device and a vertical axis.
[0098] The logging device 1 further comprises a processing unit 71
connected to the plurality of sensors. The plurality of sensors is
configured to provide measurements to the processing unit 71.
[0099] The processing unit 71 is configured to process the
measurements of the plurality of sensors (4, 57, 59, 61, 63, 65,
67, 69) and to determine at least a value of a physical parameter
of the environment of the logging device 1 and at least a redundant
value of the same physical parameter of the environment of the
logging device 1, the value and the redundant value being
determined from at least two different sensors measurements
measuring different physical parameters.
[0100] According to one embodiment of the invention, at least one
first sensor (4, 57, 59, 61, 63, 65, 67, 69) of the plurality of
sensors (4, 57, 59, 61, 63, 65, 67, 69) is configured to provide at
least one direct measurement of a value of a physical parameter of
the environment of the logging device 1 to the processing unit 71.
The processing unit 71 is configured to calculate a redundant value
of the physical parameter through the measurements of at least a
second sensor (4, 57, 59, 61, 63, 65, 67, 69) among the plurality
of sensors (4, 57, 59, 61, 63, 65, 67, 69). The second sensor (4,
57, 59, 61, 63, 65, 67, 69) measures another physical parameter of
the environment of the logging device 1 different from the physical
parameter of the environment of the logging device 1 measured by
the first sensor.
[0101] The other physical parameter is for example of the same
physical nature as the physical parameter (for example pressures
measured at different heights). Advantageously, the other physical
parameter and the physical parameter are of a different physical
nature (for example density and pressure).
[0102] For example, the physical parameter is the fluid density
inside the well 5.
[0103] The gradiomanometer sensor 63 provides a first direct
measurement p.sub.1 of the fluid density inside the well 5 to the
processing unit 71.
[0104] A redundant value of the fluid density p.sub.2 inside the
well 5 is calculated by the processing unit 71 using at least three
other physical parameters, here the hydrostatic pressures P.sub.up
and P.sub.down, respectively provided by the first hydrostatic
pressure sensor 59 and by the second hydrostatic pressure sensor
61, and the inclination angle .alpha. provided by the inclination
sensor 67 (see FIG. 2), according to the following equation:
p.sub.2=(P.sub.down-P.sub.up)/gHcos(.alpha.) (1)
[0105] with g being the acceleration due to gravity and H being the
distance between the first hydrostatic pressure sensor 59 and the
second hydrostatic pressure sensor 61.
[0106] In a variant, the physical parameter is the hydrostatic
pressure determined at various heights along the logging device 1,
by for example the first hydrostatic pressure sensor 59, the second
hydrostatic pressure sensor 61, the first formation pressure sensor
4 and/or the second formation pressure sensor 57.
[0107] In another variant, the physical parameter is the depth of
the logging device. For example a first value of the depth z.sub.1
of the logging device is determined by the processing unit by using
a direct measurement of a length of the lowered line in the well
corrected from an elongation of the line using the cable tension
measurement provided by the cable tension sensor or the gamma-ray
reference matched depth z.sub.2.
[0108] In a variant, a third value z.sub.3, a fourth value z.sub.4
and a fifth value z.sub.5 is determined by using respectively the
hydrostatic pressure measured by the second hydrostatic well
pressure sensor, the first formation pressure sensor and the second
formation pressure sensor.
[0109] The logging device 1 further comprises a computation unit 73
configured to calculate an uncertainty and/or a coherence of the
physical parameter, based on the data collected from the at least
two different sensors (4, 57, 59, 61, 63, 65, 67, 69). More
specifically, the calculation of the uncertainty and/or the
coherence of the physical parameter is based on the values of the
physical parameter and on the redundant values of the physical
parameter obtained from the at least two different sensors (4, 57,
59, 61, 63, 65, 67, 69).
[0110] For example, the computation unit 73 calculates a coherence
of the hydrostatic well pressures provided by the first hydrostatic
pressure sensor 59, the second hydrostatic pressure sensor 61, the
first formation pressure sensor 4 and/or the second formation
pressure sensor 57. Typically, the variation of the measured
pressure should be linear with depth.
[0111] In a variant, the computation unit 73 calculates an
uncertainty and/or a coherence of the fluid density values p.sub.1
and p.sub.2, obtained as described above
[0112] Typically, the processing unit 73 is intended to determine
the success or the failure of the rupture of the mud cake 13 and of
the fluid communication with the underground formation 3.
[0113] For example, before the anchoring of the probe 17, the
processing unit 71 is configured to compare the pressure measured
by the pressure sensor connected to the fluid withdrawal line 19
with the hydrostatic pressure of the well 5 measured using the
first hydrostatic well pressure sensor 59, preferably corrected
from the hydrostatic pressure difference induced by the relative
position of sensor 59 and probe 17 on the logging device 1. If both
pressures are similar, the fluid withdrawal line 19 is not in good
fluid communication with the underground formation 3 due for
example to a seal failure.
[0114] Typically, the processing unit 71 is configured to monitor
the time evolution of the pressure measured by the first formation
pressure sensor 4 connected to the fluid withdrawal line 19. An
almost time constant pressure involves a failure of the rupture of
the mud cake 13.
[0115] In another variant, the computation unit calculates an
uncertainty of the depth of logging device using z.sub.1, z.sub.2,
z.sub.3, z.sub.4 and z.sub.5.
[0116] Advantageously, the logging device 1 comprises an automatic
control unit 75 configured to control the test chambers 23a, 23b,
23c, 23d and the rupture chamber 35. The automatic control unit 75
is connected to the computation unit 73 and to the processing unit
71. For example, the automatic control unit 75 adjusts the
parameters of fluid suction of the test chambers 23a, 23b, 23c,
23d, for example flow rate and/or sucked volume, and the parameter
of the rupture chamber 35 based on the measurements of the sensors
and on the coherence and/or the uncertainty of the redundant
parameters calculated by the processing unit 71.
[0117] For example, the rupture pressure imposed by the rupture
chamber 35, on the wall of the well 5 to rupture the mud cake 13
depends on the measurements of the sensors and on the
uncertainty/coherence of the physical parameters.
[0118] In a variant, the rupture pressure depends on the coherence
and/or uncertainty of the measurements at a previous measurement
station 11.
[0119] The logging device 1 according to the invention allows
automatic and real-time validation of the measurements performed in
the well 5 with a minimal input of the operator.
[0120] In a variant, the logging device 1 comprises a communication
unit 77 configured to communicate the uncertainty and/or the
coherence of the physical parameters to an operator at the
surface.
[0121] For example, the communication unit 77 informs the operator
in case of a failure of a formation pressure measurement.
[0122] The operator is then able to monitor, to control and to
manually adjust the parameters of the formation pressure sensor 4,
57 based on the information provided by the processing unit 71.
[0123] A method for measuring pressure into an underground
formation 3 containing a fluid using a logging device 1 according
to the invention will be described.
[0124] Initially, the plurality of sensors (4, 57, 59, 61, 63, 65,
67, 69) of the logging device 1 is calibrated in the surface,
outside of the well 5, at normal atmospheric pressure. For example,
the first formation pressure sensor 4 and the second formation
pressure sensor 57 should provide an infinite permeability. The
first hydrostatic well pressure sensor 59 and the second
hydrostatic well pressure sensor 61 should provide the value of the
atmospheric pressure.
[0125] In a next step, the plurality of sensors (4, 57, 59, 61, 63,
65, 67, 69) of the logging device 1 is calibrated in a casing. For
example, the measurements of the hydrostatic well pressure are
checked and calibrated. Typically, the leakage rate of the probe 17
is evaluated.
[0126] The logging device 1 is then lowered in the well 5 using the
line 7. At a measurement station 11, the probe 17 of each first
formation pressure sensor 4 and second formation pressure sensor 57
is put in contact with the mud cake 13 of the underground formation
3. The packer 29 is then deployed or inflated to seal the contact
between the probe 17 and the mud cake 13.
[0127] For example, the first test is made using the first
formation pressure sensor 4.
[0128] The first isolating valve 39 is closed so as to fluidly
isolate the probe 17 from the tool body part 15 of the logging
device 1.
[0129] Then, the second isolating valve 41 is opened so as to
establish a fluid communication between the rupture chamber 35 and
the fluid withdrawal line 19.
[0130] In a next step, the rupture chamber 35 is actuated so as to
rupture the mud cake 13 and establish a fluid communication between
the underground formation 3 and the fluid withdrawal line 19.
[0131] Then, the pressure in the fluid withdrawal line 19 is
checked using the pressure sensor 37.
[0132] The second isolating valve 41 is then closed so as to
fluidly isolate the rupture chamber 35 from the fluid withdrawal
line 19.
[0133] The first isolating valve 39 is opened so as to establish a
fluid communication between the flow line 21 and the fluid
withdrawal line 19. The first test chamber 23a is actuated. The
pressure equilibrium is typically measured with the pressure sensor
37 or the pressure sensor 51.
[0134] Measuring with the pressure sensor 37 allows decreasing the
capacity effects.
[0135] For example, the first test starts by actuating the first
test chamber 23a so as to suck the underground formation fluid
inside the withdrawal line 19.
[0136] Typically, the first test chamber 23a is filled by the fluid
up to a predetermined volume less than the total volume of the test
chamber 23a and the piston 45a is stopped. The closing system 49a
of the test chamber 23a fluidly isolates the test chamber 23a from
the flow line 21 at essentially the same time (preferably either at
exactly the same time, or slightly before).
[0137] The pressure in the flow line 21 is then measured by the
pressure sensor 51 for a certain time, for example between 5 s and
3600 s. This time may advantageously be automatically computed by a
software based on a predetermined time length objective set by the
operator.
[0138] Then, the next test is performed in the same way as
mentioned above with the same test chamber 23a or a second test
chamber 23b, 23c, 23d, or with the second formation pressure sensor
57.
[0139] In addition, the pressure inside each test chambers 23a,
23b, 23c and 23d and inside the rupture chamber 35 may be measured
using additional pressure sensors (not represented) located
downstream of the corresponding closing system 49a, 49b, 49c and
49d or the second isolating valve 35.
[0140] Typically, the pressure at the upstream and at the
downstream of the closing system 49a, 49b, 49c and 49d, or the
second isolating valve 35 and more generally, of either valve of
the logging device 1 is measured before the opening.
[0141] Once all the desired tests have been carried out, the packer
29 is withdrawn, the logging system 1 is unanchored and is
lowered/pulled up in the well 5 to the next measurement station 11
and a new series of tests starts.
[0142] Advantageously, the method comprises a step of acquiring
measurements with the plurality of sensors and processing the
measurements by the processing unit 71 of the measurements acquired
by the sensors (4, 57, 59, 61, 63, 65, 67, 69) to determine
redundant values of the same physical parameter of the environment
of the logging device 1 from at least two different
measurements.
[0143] For example, the measurements are acquired before each
rupture of the mud cake 13 and/or before actuating the test chamber
23a, 23b, 23c, 23d and/or after the entire desired tests have been
carried out.
[0144] For each acquired measurement, the method comprises a step
of calculating the uncertainty and/or the coherence of the physical
parameter of the environment of the logging device 1 from the
acquired redundant measurements (i.e. gradient consistency).
[0145] In one embodiment, the measurements and/or the uncertainty
and/or the coherence of the physical parameter are communicated to
the operator on the surface by the communication unit. The operator
has then information to adjust/control the parameters of the
logging device 1. More particularly, the operator is for example
able to decide to continue the test, to move the logging device 1,
to adjust the rupture pressure, to select the test chamber 23a,
23b, 23c, 23d, to repeat a measurement, etc.
[0146] In a variant, the method comprises a step of automatic
controlling of the test chamber 23a, 23b, 23c, 23d and/or the
rupture chamber 35 by the automatic control unit 75. For example,
during this step, a part or the operations mentioned above are
controlled by the automatic control unit 75. For example, the
automatic control unit 75 controls and adjusts the parameters of
the rupture pressure and the test chamber 23a, 23b, 23c, 23d based
on the measurements of the sensors and/or the uncertainty and/or
the coherence of the physical parameters.
[0147] In a variant, the method comprises a step of semi-automatic
controlling of the test chamber 23a, 23b, 23c, 23d and/or the
rupture chamber 35. Some parameters are automatic controlled by the
automatic control system and other parameters are manually
controlled by the operator for example after having received the
measurements of the sensors and/or the coherence and/or the
uncertainty of the physical parameters sent by the communication
unit 77.
[0148] In a variant, the first isolating valve 39 and the second
isolating valve 41 are replaced by a three-way valve 79 located on
the withdrawal line 19, as depicted in FIG. 6.
[0149] The three-way valve 79 is connected to the first end 25 of
the fluid withdrawal line 19. The three-way valve 79 typically
comprises a first configuration allowing only the fluid circulation
between the rupture chamber 35 and the first end 25 of the fluid
withdrawal line 19, a second configuration allowing only the fluid
circulation between the first end 25 of the fluid withdrawal line
19 and the flow line 21 and a third closing configuration wherein
no fluid circulation is allowed.
[0150] In a variant presented in FIG. 4 and FIG. 5, the probe 17 is
integral with the tool body part 15. Typically, the tool body part
15 comprises retractable deflectors 18 located around the probe 17.
During the moving of the logging device 1, the retractable
deflectors 18 project around the probe 17 so as to protect it (FIG.
5).
[0151] At each measurement station 11, the deflectors 18
withdraw.
[0152] Typically, the tool body part 15 comprises an active biasing
element 22 such as a bow-spring to press the probe 17 against the
wall of the well 5 (FIG. 6).
[0153] Typically, the active biasing element 22 is movable between
a retractable position along or inside the tool body part 15 and a
deployable position projecting to the wall of the well 5.
[0154] Typically, the active biasing element 22 and the deflectors
18 are mechanically separated.
[0155] Typically, the active biasing element 22 and the deflectors
18 operate simultaneously or in sequence.
[0156] After the measurement, the biasing element 22 is withdrawn
and the deflectors 18 are deployed to remove the probe 17 from the
wall of the well 5.
[0157] Optionally, the tool body part 15 may comprise injectors 26
to help the removing of the deflectors 18 by injecting fluid from
the well 5
[0158] The logging device 1 according to the invention allows
exerting an adapted suction pressure so as to ensure an effective
rupture of the mud cake 13 and to ensure a good fluid communication
between the underground formation 3 and the fluid withdrawal line
19. More particularly, the integration of the rupture chamber 35,
of the pressure sensor 37 and of the first isolating valve 39
inside the probe 17 contributes to limit the capacity effects and
to apply the adapted suction pressure to the mud cake 13 leading to
reliable and relevant formation pressure measurements.
* * * * *