U.S. patent application number 13/628600 was filed with the patent office on 2013-03-28 for downhole sampling tool.
This patent application is currently assigned to WELLTEC A/S. The applicant listed for this patent is WELLTEC A/S. Invention is credited to Jorgen HALLUNDBAEK, Lars MANGAL, Ricardo Reves VASQUES.
Application Number | 20130075078 13/628600 |
Document ID | / |
Family ID | 44677750 |
Filed Date | 2013-03-28 |
United States Patent
Application |
20130075078 |
Kind Code |
A1 |
HALLUNDBAEK; Jorgen ; et
al. |
March 28, 2013 |
DOWNHOLE SAMPLING TOOL
Abstract
The present invention relates to a downhole sampling tool for
taking out fluid samples of a fluid present in a casing having an
internal cross-sectional casing area. The downhole sampling tool
comprises a first tool part and a second tool part, a sampling
inlet arranged in the first part, and an actuation unit arranged in
the second part adapted to move the sampling inlet into contact
with the fluid in a first part of the casing area for taking out a
fluid sample of the fluid present in that part of the casing
area.
Inventors: |
HALLUNDBAEK; Jorgen;
(Graested, DK) ; MANGAL; Lars; (Hellerup, DK)
; VASQUES; Ricardo Reves; (Holte, DK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
WELLTEC A/S; |
Allerod |
|
DK |
|
|
Assignee: |
WELLTEC A/S
Allerod
DK
|
Family ID: |
44677750 |
Appl. No.: |
13/628600 |
Filed: |
September 27, 2012 |
Current U.S.
Class: |
166/105 |
Current CPC
Class: |
E21B 49/082
20130101 |
Class at
Publication: |
166/105 |
International
Class: |
E21B 27/00 20060101
E21B027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 28, 2011 |
EP |
11183078.2 |
Claims
1. A downhole sampling tool (1) for taking out fluid samples of a
fluid (2) present in a casing (3) having an internal
cross-sectional casing area, the downhole sampling tool comprising
a first tool part (4) and a second tool part (5), a sampling inlet
(6) arranged in the first part, a pump unit for sucking the fluid
in through the sample inlet, and an actuation unit (7) arranged in
the second part, adapted to move the sampling inlet into contact
with the fluid in a first part of the casing area for taking out a
fluid sample of the fluid present in that part of the casing
area.
2. A downhole sampling tool according to claim 1, wherein the
actuation unit is adapted to move the sample inlet between a
retracted and a projected position.
3. A downhole sampling tool according to claim 1, wherein the
second tool part comprises a through-going recess (18) in which the
arm member is arranged and projects from.
4. A downhole sampling tool according to claim 1, wherein the
actuation unit comprises a hydraulic cylinder for moving the
sampling inlet between the retracted and the projected
position.
5. A downhole sampling tool according to claim 1, wherein the
actuation unit comprises an electrical motor for moving the
sampling inlet between the retracted and the projected
position.
6. A downhole sampling tool according to claim 1, wherein the
sampling inlet is arranged in an outer surface of the first tool
part.
7. A downhole tool according to claim 2, wherein the first tool
part comprises a plurality of sampling inlets.
8. A downhole sampling tool according to claim 1, wherein the first
tool part is an arm member (8) movably connected with the second
tool part.
9. A downhole sampling tool according to claim 4, wherein the arm
member comprises the sampling inlet.
10. A downhole sampling tool according to claim 5, wherein the arm
member comprises a fluid channel (10) extending between the
sampling inlet and an opening (30) arranged in an opposite end (31)
of the arm member in relation to the sampling inlet.
11. A downhole sampling tool according to claim 1, wherein the
actuation unit is adapted to rotate the first tool part.
12. A downhole sampling tool according to claim 4, wherein the
second tool part comprises a recess (18) in which the arm member is
arranged and projects from.
13. A downhole sampling tool according to claim 1, wherein the
actuation unit comprises an anchor unit (52) adapted to move the
second tool part in a radial direction of the sampling tool.
14. A downhole sampling tool according to claim 1, wherein the
first tool part comprises a first arm part (41) and a second arm
part (42) rotatably connected at one end, the first arm part being
securely rotatably connected to the second tool part at the
opposite end, and the second arm part being axially movably
arranged in the second tool part at the opposite end.
15. A downhole sampling tool according to claim 10, wherein the
sampling inlet is arranged at the one end where the first and
second arm parts are rotatably connected.
16. A downhole sampling tool according to claim 1, further
comprising a pump (9) being in fluid communication with the
sampling inlet.
17. A downhole sampling tool according to claim 1, further
comprising a sample chamber (19) being in fluid communication with
the sampling inlet.
18. A downhole sampling tool according to claim 1, further
comprising sample testing equipment (11) being in fluid
communication with the sampling inlet for performing a sample test
on the fluid sample.
19. A downhole sampling tool according to claim 1, wherein the
sampling tool comprises a capacitance measuring unit (50) for
identifying the phase of the fluid, such as gas (21) and water
(23).
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a downhole sampling tool
for taking out fluid samples of a fluid present in a casing having
an internal cross-sectional casing area.
BACKGROUND ART
[0002] When a well producing oil or gas is producing too much
water, the water may be water occurring naturally in the reservoir,
or it may come from a displacement fluid, such as sea water,
injected to displace the zone of oil or gas. Since natural
reservoir water has another content of minerals than the injected
water, an examination of the water can determine where the water
comes from. However, by measuring the water at the top of the well,
the naturally occurring water may be mixed with the displacement,
making the measurements misleading. It is therefore necessary to
obtain measurements downhole in order to determine which water
source the water comes from.
SUMMARY OF THE INVENTION
[0003] It is an object of the present invention to wholly or partly
overcome the above disadvantages and drawbacks of the prior art.
More specifically, it is an object to provide an improved sampling
tool for taking out samples of the fluid in a casing downhole.
[0004] The above objects, together with numerous other objects,
advantages, and features, which will become evident from the below
description, are accomplished by a solution in accordance with the
present invention by a downhole sampling tool for taking out fluid
samples of a fluid present in a casing having an internal
cross-sectional casing area, the downhole sampling tool comprising
[0005] a first tool part and a second tool part, [0006] a sampling
inlet arranged in the first part, and [0007] an actuation unit
arranged in the second part, adapted to move the sampling inlet
into contact with the fluid in a first part of the casing area for
taking out a fluid sample of the fluid present in that part of the
casing area.
[0008] In an embodiment, the downhole sampling tool may further
comprise a pump unit for sucking the fluid in through the sample
outlet.
[0009] Furthermore, the actuation unit may be adapted to move the
sample inlet between a retracted and a projected position.
[0010] Moreover, the second tool part may comprise a through-going
recess in which the arm member is arranged and projects from.
[0011] Additionally, the actuation unit may comprise a hydraulic
cylinder for moving the sampling inlet between the retracted and
the projected position.
[0012] Also, the actuation unit may comprise an electrical motor
for moving the sampling inlet between the retracted and the
projected position.
[0013] Further, the pump unit may be arranged in the first tool
part.
[0014] In addition, the pump may be in fluid connection with the
sampling inlet.
[0015] In an embodiment, the sampling inlet may be arranged in an
outer surface of the first tool part.
[0016] Said first tool part may comprise a plurality of sampling
inlets.
[0017] The sampling inlets may be angularly displaced around the
outer surface of the first tool part.
[0018] Moreover, the sampling inlets may be arranged with a mutual
angle which is equal to or less than 180.degree., preferably equal
to or less than 90.degree., more preferably equal to or less than
45.degree., and even more preferably equal to or less than
30.degree..
[0019] Also, the first tool part may comprise a first element and a
second element.
[0020] Further, the second element may extend or be adapted to
extend in a radial direction in relation to the first element.
[0021] Additionally, the sampling inlet may be arranged on the
second element.
[0022] Furthermore, the second element may be radially displaceable
in relation to the first element.
[0023] In addition, the actuation unit may rotate the first element
of the first tool part in relation to the second tool part.
[0024] Said first tool part may comprise a plurality of second
elements.
[0025] Also, the first tool part may be an arm member movably
connected with the second tool part.
[0026] Moreover, the arm member may comprise the sampling
inlet.
[0027] Further, the sampling inlet may be arranged in one end part
of the arm member, and the arm member may be connected with the
second tool part in another opposing end part.
[0028] Additionally, the arm member may comprise a fluid channel
extending between the sampling inlet and an opening arranged in an
opposite end of the arm member in relation to the sampling
inlet.
[0029] The opening may be in fluid communication with a fluid
channel in the second tool part.
[0030] In an embodiment, a tube may extend along the arm and the
sampling inlet may be arranged in one end of the tube.
[0031] In addition, the actuation unit may be adapted to rotate the
first tool part.
[0032] Also, the actuation unit may be adapted to rotate the arm
member.
[0033] In an embodiment, the second tool part may comprise a recess
in which the arm member is arranged and projects from.
[0034] Moreover, the arm member may be moveable between a retracted
position and a projected position.
[0035] Furthermore, the actuation unit may comprise an anchor unit
adapted to move the second tool part in a radial direction of the
sampling tool.
[0036] Additionally, the first tool part may be adapted to be
displaced radially in relation to the second tool part.
[0037] Also, the second tool part may have an end facing the first
tool part, the end comprising a groove having a predetermined
pattern enabling movement of a corresponding projection arranged on
the first tool part in the groove.
[0038] In an embodiment, the first tool part may comprise a first
arm part and a second arm part rotatably connected at one end, the
first arm part being securely rotatably connected to the second
tool part at the opposite end, and the second arm part being
axially movably arranged in the second tool part at the opposite
end.
[0039] Said first arm part and second arm part constitute the
second element of the first tool part, and the second element is
connected to the first element of the first tool part.
[0040] Moreover, the actuation unit may rotate the first element of
the first tool part and thereby the first and second arm parts.
[0041] Further, the sampling inlet may be arranged at the one end
where the first and second arm parts are rotatably connected.
[0042] In addition, the axial movement of the second arm part at
the opposite end may provide a radial displacement of the sampling
inlet.
[0043] The first tool part may comprise a plurality of first and
second arm part sets.
[0044] Also, the sampling tool may comprise a driving unit.
[0045] In an embodiment, the driving unit may comprise retractable
wheels.
[0046] Furthermore, the wheels may be adapted to move the second
tool part in a radial direction of the sampling tool by projecting
the wheels in a radial direction of the sampling tool.
[0047] In another embodiment, the driving unit may comprise
caterpillar tracks, etc.
[0048] The downhole sampling tool as described above may further
comprise a pump being in fluid communication with the sampling
inlet.
[0049] Moreover, the sampling tool may comprise a motor for driving
the pump.
[0050] Also, the downhole sampling tool as described above may
comprise a sample chamber being in fluid communication with the
sampling inlet.
[0051] Further, the downhole sampling tool as described above may
comprise sample testing equipment being in fluid communication with
the sampling inlet for performing a sample test on the fluid
sample.
[0052] Said sample testing equipment may first identify the phase
of the fluid sample and second the content of the fluid sample.
[0053] Additionally, the sample testing equipment may comprise
elect odes for identifying a salinity content of the fluid
sample.
[0054] A communication device may be arranged in connection with
sample testing equipment for communicating sample test data to an
operator or a processing device.
[0055] Furthermore, the sampling tool may comprise a storing device
for storing sample test data.
[0056] Also, the sample testing equipment may comprise a
fibre-optic sensor based on surface-plasmon resonance for
determining the refractive index and used for measuring the degree
of salinity of the fluid sample.
[0057] In addition, the sample testing equipment may comprise
microwave radiometry for determining the dielectric constant of the
fluid sample.
[0058] In an embodiment, a sensor may be arranged in connection
with the sampling inlet, the sensor detecting the phase of the
fluid present in the casing area.
[0059] Moreover, the sample testing equipment may comprise a gas
sensor, such as an infrared point sensor, an ultrasonic gas
detector, an electrochemical gas detector or a semiconductor
sensor.
[0060] Additionally, the sample testing equipment may comprise a
capacitance measuring unit for identifying the phase of the fluid
sample.
[0061] Further, the sampling tool may comprise a capacitance
measuring unit for identifying the phase of the fluid, such as gas
and water.
[0062] The sampling tool may further comprise a radioactive source
emitting gamma rays for identifying the phase of the fluid, such as
gas and water.
[0063] Said fluid may be gas or water.
[0064] In an embodiment, the sample testing equipment may comprise
an indication unit adapted to indicate the presence of a
predetermined tracer in the fluid sample.
[0065] The tracer may be radioactive source or a chemical.
[0066] Also, the tracer may be a gas or a fluid.
[0067] Moreover, the sampling tool may be tubular extending in an
axial direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0068] The invention and its many advantages will be described in
more detail below with reference to the accompanying schematic
drawings, which for the purpose of illustration show some
non-limiting embodiments and in which
[0069] FIG. 1 shows a downhole sampling tool according to the
present invention,
[0070] FIG. 2 shows a cross-sectional internal area of the fluid in
the casing,
[0071] FIG. 3 shows a partial cross-sectional view of the sampling
tool of FIG. 1,
[0072] FIG. 4 shows a partial view of the inside of the sampling
tool of FIG. 1,
[0073] FIG. 5 shows a partial cross-sectional view of another
embodiment of the sampling tool,
[0074] FIG. 6 shows another embodiment of the sampling tool,
[0075] FIGS. 7a and 7b show a front view of the sampling tool of
FIG. 6,
[0076] FIG. 8 shows yet another embodiment of the sampling
tool,
[0077] FIG. 9 shows yet another embodiment of the sampling tool,
and
[0078] FIG. 10 shows yet another embodiment of the sampling
tool.
[0079] All the figures are highly schematic and not necessarily to
scale, and they show only those parts which are necessary in order
to elucidate the invention, other parts being omitted or merely
suggested.
DETAILED DESCRIPTION OF THE INVENTION
[0080] FIG. 1 shows a downhole sampling tool 1 for taking out fluid
samples of a fluid 2 present in a casing 3 downhole or a casing 3
in a borehole. The sampling tool 1 comprises a first tool part 4, a
second tool part 5 and a sampling inlet 6 arranged in the first
part. In order to sample fluid from all areas of the casing, the
sampling tool 1 comprises an actuation unit 7 arranged in the
second part, adapted to move the sampling inlet into contact with
the fluid in a first part of the casing area for taking out a fluid
sample of the fluid present in that part of the casing area. The
first part 4 is in FIG. 1 an arm member 8, and the sampling inlet 6
is arranged in the end of the arm member 8. The arm member 8 is
rotated by the actuation unit 7 between a retracted position in the
sampling tool 1 and a projected position, as shown in FIG. 1. The
sampling tool 1 comprises a pump unit for sucking the fluid in
through the sample inlet in order to measure fluid samples in the
sampling tool and/or store samples of borehole fluid in the
sampling tool for further investigation. It is essential to the
tool that the tool comprises a pump for sucking fluid samples into
the sampling tool.
[0081] The sampling tool 1 comprises a through-going recess 18
through which the arm member can pass to project on opposite sides
of the recess of the sampling tool 1, as indicated by the arrow in
FIG. 1. By having a through-going recess 18, the versatility of the
tool is drastically increased since the actuation unit may project
in two directions for each stationary position of the tool. This
enables close to a doubling of the sampling speed, since the arm
member may be projected to both sides of the sampling tool without
rearranging the sampling tool. Furthermore the through-going recess
18 enables the user to avoid problems projecting the arm member in
situations where the arm member has been blocked or jammed in one
direction. The user may in these situations unblock or unjam the
arm member by projecting the arm member in the opposite direction.
Jamming is a serious and very cost-intensive problem during
downhole operations.
[0082] Due to the spatial limitations downhole, the actuation unit
7 may be capable of moving the sample inlet 6 between a retracted
and a projected position to save space during movement of the
downhole tool in a retracted position and to reach into the
borehole fluid in the projected position. One tool is furthermore
capable of fitting a broader range of well sizes in that the width
of the tool can be changed.
[0083] When a well producing oil 22 or gas 21 is producing too much
water, the water 23 may be water occurring naturally in the
reservoir, or it may be displacement fluid, such as sea water,
injected to displace the zone of oil or gas. The natural reservoir
water has another content of minerals than the injected water, and
by taking out samples and measuring the fluid flowing in the casing
3, it can be determined which water source the water comes from.
When producing oil, the displacement fluid may also be injected gas
or steam. In deviated or horizontal wells, the fluid divides into
fluid phases so that the water 23 is located in the bottom part of
the casing, as illustrated in the cross-sectional internal area of
the casing shown in FIG. 2. In order to take a sample of the water,
the first tool part 4 needs to be moved so that the sampling inlet
6 is arranged in the water phase of the fluid and thus in the
bottom to be able to take out a sample of water, as shown in FIG.
2. The sampling tool 1 has an actuation unit to be able to move the
first part of the sampling tool 1 into a certain area of interest
of the casing. In the event that the fluid phase to be investigated
is the gas phase 21, the actuation unit 7 needs to move the first
tool part 4 so that the sampling inlet is located in the area of
the cross-sectional internal area of the casing comprising gas,
which in FIG. 2 is the top part of the casing.
[0084] As shown in FIGS. 1 and 3, the sampling inlet is arranged in
one end part of the arm member 8, and the arm member is connected
with the second tool part 5 in another opposing end part. The arm
member 8 comprises a fluid channel 10 extending between the
sampling inlet and an opening 30 arranged in an opposite end 31 of
the arm member in relation to the sampling inlet. The opening 30 is
in fluid communication with a fluid channel 32 in the second tool
part 5. The sampling tool 1 further comprises a pump 9 intended to
pump fluid in through the sampling inlet through a fluid channel 10
in the arm member and further past the pump 9 to sample testing
equipment 11 in order to test the sample of fluid before ejecting
the fluid back into the casing through an outlet 12.
[0085] The arm member 8 is moved between a projected and a
retracted position by the actuation unit 7, which is shown in FIG.
4. The arm member is rotatably connected to the second tool part 5
by means of a shaft 14 connected with a gear wheel 15 driven by a
toothed shaft 16 which is axially displaced by a second gear wheel
17 driven by an electrical motor 38. In this way, the electrical
motor drives the arm member 8 between the retracted position and
the projected position.
[0086] As shown in FIG. 5, the sampling tool 1 comprises sample
chambers 19 fluidly connected with a control device 20 controlling
the fluid from the sample testing equipment 11. When the fluid has
been tested in the sample testing equipment, the control device
receives a signal from the sample testing equipment 11 to either
let the tested fluid out through outlet 12 or to lead the fluid
into the sample chambers 19 to collect a sample in one of the
chambers 19. The inlets of the sample chambers 19 comprise a
one-way valve so that when the first sample chamber is filled, the
fluid cannot escape the chamber again. The valve of the second
sample chamber may then be activated by the control device when a
new sample needs to be collected. The sample chambers comprise a
movable piston dividing the chamber into a first chamber part 24
and a second chamber part 25. The first chamber part 24 comprises
gas so that when the fluid is let into the chamber, the piston is
moved towards the bottom 26 of the chamber opposite the inlet valve
27 compressing the gas.
[0087] The fluid let into the sample chambers may also be
controlled by a hydraulic block so that the fluid is let from the
control device to one hydraulic block instead of having one valve
at the inlet of every sample chamber 19.
[0088] In FIG. 6, the sampling tool comprises a plurality of
sampling inlets arranged in an outer surface 28 of the first tool
part 4. The first tool part 4 is moved so that a sampling inlet 6
is brought into a section of the cross-sectional area of the casing
3, e.g. a top section, as shown in FIG. 7a, in order to take out a
sample of the fluid in that section. In FIG. 7b, the first tool
part is moved sideways to take out a sample near an opening 29 in
the casing wall, e.g. a perforation or a leak caused by erosion. As
illustrated, water 23 enters through the opening 29 and is mixed
with oil and/or gas on the opposite side of the tool, and it is
therefore important to take a sample just outside the opening to
determine the content of the fluid entering the opening. The fluid
entering the opening may also be oil as intended, and then it can
be established that the water does not enter through that
perforation.
[0089] Thus, the first tool part 4 of the sampling tool of FIGS.
6-7b is adapted to be displaced radially in relation to the second
tool part 5. In order to do so, the second tool part has an end
facing the first tool part 4, the end comprising a groove having a
predetermined pattern enabling movement of a corresponding
projection arranged on the first tool part in the groove. In this
way, the projection of the first tool part 4 slides back and forth
or up and down in the groove of the second tool part 5 to displace
the first tool part in relation to the second tool part to bring
the sampling inlet into contact with fluid in a certain area of the
casing.
[0090] In FIGS. 6-7b, the sampling inlets are angularly displaced
around the outer surface of the first tool part. Thus, the sampling
inlets are arranged with a mutual angle which is equal to or less
than 45.degree.. In another embodiment, the sampling inlets are
arranged with a mutual angle which is equal to or less than
180.degree., preferably equal to or less than 90.degree., and even
more preferably equal to or less than 30.degree.. As shown in FIGS.
7a and 7b, the sampling tool has only three inlets angularly
displaced at an angle of 45.degree..
[0091] In FIG. 8, the first tool part of the downhole sampling tool
comprises a first arm part 41 and a second arm part 42 rotatably
connected a first end 41a, 42a, the first arm part being securely
rotatably connected inside the tool housing at the opposite end of
the arm part, and the second arm part being axially movably
arranged in the first tool part at the opposite end. The axial
movement of the second arm part at the opposite end provides a
radial displacement of the sampling inlet in relation to the tool.
The second tool part comprises a motor for rotation of the first
tool part and thus also the first and second arm part, as
illustrated by the arrow 44, to bring the inlet 6 arranged in the
first end 41a into contact with fluid in a certain area in the
casing 3.
[0092] In FIG. 9, the first tool part of the downhole sampling tool
also comprises a set of arm parts 41, 42, i.e. a first arm part 41
and a second arm part 42, being rotatably connected at their first
ends 41a, 42a. In this embodiment, the first arm part is securely
rotatably connected with the second tool part at the opposite end
of the arm part, and the second arm part is axially movably
arranged in the second tool part at the opposite end. The sampling
tool 1 comprises several sets of arm parts so as to reach several
fluid areas inside the casing, e.g. a top part and a bottom part of
the casing, as shown in FIG. 9.
[0093] The second arm part 42 of FIGS. 8 and 9 is rotatably
connected with a piston 45 which is moved by means of fluid forcing
the piston towards the arm parts. In order to retract the second
arm part, the piston may compress a spring (not shown) arranged
inside the piston housing, or the second arm part is just retracted
when retracting the sampling tool from the well, e.g. when meeting
a restriction in the well, such as a landing nipple.
[0094] The arm member 8 may also be a probe radially projected from
the sampling tool housing, as shown in FIG. 10. The sampling tool
further comprises a motor located in the second tool part 5 for
rotation of the first tool part 4 in relation to the second tool
part 5. The arm member 8 comprises a fluid channel 10 fluidly
connected with the pump 9 for suction of well fluid into the tool
and into the sampling testing equipment 11 and further out through
an outlet 12.
[0095] As shown in FIG. 11, the actuation unit of the downhole
sampling tool may further comprise a hydraulic cylinder 71 for
moving the sampling inlet between the retracted and the projected
position by pushing a crank member 71 of the arm member 8.
Alternatively, the actuation unit may comprise an electrical motor
(not shown) for moving the sampling inlet between the retracted and
the projected position.
[0096] Referring to FIG. 1, the sampling tool 1 further comprises a
(driving unit 60 comprising retractable wheel arms 61 having one
end rotatably connected with the housing 62 of the driving unit 60
and a wheel 63 arranged in the other end 64 opposite the end
rotatably connected with the housing. Each wheel comprises a motor
adapted to move the second tool part in a radial direction of the
sampling tool by projecting the wheel arms in a radial direction of
the sampling tool. In another embodiment, the driving unit
comprises caterpillar tracks or similar movable arrangement. The
driving unit is connected to a pump for forcing the wheel arms to
project and the wheels to turn and thus drive the sampling tool
forward in the well. The pump 65 is driven by a motor 66 which is
powered through a wireline 68 via an electrical control unit
67.
[0097] The sampling tool may further comprise a logging tool 50
e.g. arranged in front of the tool to determine the fluid phase in
the casing fluid to be able to arrange the sampling inlet in the
fluid phase that needs to be investigated. In the event that the
logging tool has determined a presence of gas, oil and water, the
sampling inlet 6 in the first tool part can be moved to the gas
phase to test a sample of gas or into the water phase to test a
sample of water to determine whether the gas or water comes from
the displacement fluid or whether it is gas or water naturally
occurring in the formation. The logging tool is capable of
determining the gas, oil and water phase, as illustrated in FIG. 2,
and based on such an image, the first tool part is moved. The
logging tool may comprise electrodes arranged in the periphery of
the logging tool 50, such as a capacitance measuring unit,
measuring the capacitance between the electrodes.
[0098] The sampling tool 1 may also comprise an anchor unit 52, as
shown in FIG. 6, having anchors 53 radially projectable from the
tool housing 54. The anchors 53 of the downhole sampling tool may
also be comprised in the actuation unit 7 so that the anchor unit
is adapted to move the second tool part 5 in a radial direction of
the sampling tool.
[0099] The sampling tool further comprises a communication device
56 arranged in connection with sample testing equipment 11 for
communicating sample test data to an operator or a processing
device 55, as shown in FIG. 6. The data from the sample testing
equipment may be stored in a storing device 57, and before the data
is communicated to an operator, the data is processed so that only
data comprising new information is communicated.
[0100] In one embodiment, the fluid channel 10 from the sampling
inlet to the pump may be a tube extending along the arm member, and
the sampling inlet may be arranged in one end of the tube.
[0101] The sampling testing equipment may comprise a gas detector,
such as an infrared point sensor, ultrasonic gas detectors,
electrochemical gas detectors and semiconductor sensors.
[0102] Also, the sample testing equipment may first identify the
phase of the fluid sample, such as gas or liquid, and second the
content of the fluid sample.
[0103] The sample testing equipment may comprise electrodes for
identifying a salinity content of the fluid sample. The electrodes
are arranged on opposite sides of the chamber in the testing
equipment, and when a sample is present, power is supplied to the
electrodes in order to determine the salinity of the sample. This
is especially expedient when the fluid sample is water. The water
occurring naturally in the reservoir is expected to have a lower
salinity than the salt water typically injected into the formation
to displace the oil or gas to be produced.
[0104] The sample testing equipment may also comprise a fibre-optic
sensor based on surface-plasmon resonance for determining a
refractive index, which is used for measuring the degree of
salinity of the fluid sample. The sensor has a transducing element
consisting of a multilayer structure deposited on a side-polished
monomode optical fibre.
[0105] Furthermore, the sample testing equipment may additionally
comprise microwave radiometry for determining a dielectric constant
of the fluid sample. For instance, measurements of the dielectric
constant may be conducted at S-bond and L-band.
[0106] The sample testing equipment may also comprise a capacitance
measuring unit for identifying the phase of the fluid sample. By
measuring the capacitance between a plurality of electrodes, the
phases of the fluid can be determined.
[0107] Furthermore, the sampling tool may also comprise a
radioactive source emitting gamma rays for identifying the phase in
the casing fluid to be able to arrange the sampling inlet in the
fluid phase that needs to be investigated. In the event that the a
radioactive source has determined the presence of gas, oil and
water, the sampling inlet in the first tool part can be moved to
the gas phase to test a sample of gas or in the water phase to test
a sample of water to determine if the gas or water comes from the
displacement fluid or the natural gas or water occurring in the
formation.
[0108] In some circumstances, a tracer may be added to the
displacement fluid. The sample testing equipment may advantageously
comprise an indication unit adapted to indicate the presence of the
tracer in the fluid sample so that it may easily be detected that
the fluid sample is part of the displacement fluid.
[0109] The tracer may be a colour or another chemical tracer that
is easily detected from the other chemical components present in
the displacement fluid. The tracer may be radioactive source, a
colour or another chemical that is easily detected from the other
chemical components present in the displacement fluid, and the
tracer may be a gas or a liquid.
[0110] The invention also relates to a method for taking out fluid
samples of a fluid present in a casing having an internal
cross-sectional casing area, the method comprising [0111] arranging
the sampling tool in a casing, [0112] positioning the sampling
inlet of the sampling tool in a predetermined part of the
cross-sectional casing area, and [0113] taking out a fluid sample
of the fluid present in that part of the casing area.
[0114] The method may comprise a subsequent step of testing the
fluid sample for its phase.
[0115] The method may also comprise the step of testing the fluid
sample for content, e.g. salinity content.
[0116] Furthermore, the sampling inlet may be moved, enabling
taking out an additional fluid sample in that part of the casing
area.
[0117] Additionally, the sampling tool may comprise a plurality of
sampling inlets, and several fluid samples may be taken out in that
part of the casing area by the plurality of sampling inlets.
[0118] Moreover, the sample inlet or plurality of inlets may be
moved by radial movement, axial movement, rotation or a combination
thereof.
[0119] The sampling tool may comprise a capacitance measuring unit
for identifying the phase of the fluid, such as gas and/or water,
the positioning of the sampling tool being performed based on the
phase measurements of the capacitance measuring unit.
[0120] Although the invention has been described in the above in
connection with preferred embodiments of the invention, it will be
evident for a person skilled in the art that several modifications
are conceivable without departing from the invention as defined by
the following claims.
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