Downhole positioning pup joint, downhole tool string and downhole separate layer flow testing method

Abstract

This invention discloses a downhole positioning sub, a downhole tool string, and a downhole stratified flow rate testing method. The downhole positioning sub includes a cylindrical body, at least two support claws, a locking and releasing assembly, and a first elastic element. The cylindrical body is used for detachable connection of a flow meter. The support claws are movably connected to the cylindrical body and have a retracted state and an extended state. The locking and releasing assembly is used to lock the support claws in the retracted state and to release the lock on the support claws. The first elastic element is used to switch the support claws from the retracted state to the extended state when the lock is released, and to keep the support claws fully extended. The support claws are fully extended when they are inside the tubing, and when the fully extended support claws are lowered from the tubing into the water distributor, they abut against the water distributor. In this embodiment of the invention, the accuracy of test data during downhole stratified flow rate testing can be improved.

Description

Technical Field

[0001] This invention relates to the field of downhole stratified flow rate testing technology, and in particular to a downhole positioning sub, a downhole tool string, and a downhole stratified flow rate testing method. Background Technology

[0002] With the continuous advancement of fine water injection technology in oilfields, the layer division of water injection wells has become increasingly refined, and the number of small-patch injection wells has increased significantly. In these wells, the distance between the packer and the water distributor is usually less than 20 meters, or even less than 10 meters.

[0003] Layered flow rate testing is a core method for understanding the water absorption of each layer in an injection well and ensuring the accuracy of the test data. Currently, a ground-based wire rope winch is typically used to lower the flow meter into the injection well. Specifically, the flow meter needs to be lowered into a straight section of oil pipe at a certain distance above the distributor to ensure the accuracy of the test data.

[0004] However, due to multiple factors such as zero-point error of the steel wire, oil compensation distance, steel wire elongation, wear of the metering wheel, and personnel operation, the lowering position of the flow meter may have errors, which can reach several meters. This can easily cause the flow meter to stop in the water distributor or packer instead of in the required straight oil pipe section, thus affecting the accuracy of the test data, for example, causing the test data to be distorted. Summary of the Invention

[0005] This invention provides a downhole positioning sub, a downhole tool string, and a downhole stratified flow rate testing method, aiming to improve the accuracy of test data during downhole stratified flow rate testing.

[0006] This invention provides a downhole positioning sub, which is used to be lowered into a water injection well. The water injection well includes tubing and multiple water distributors, and the minimum inner diameter of the water distributors is smaller than the inner diameter of the tubing. The downhole positioning section includes a cylindrical body, at least two support claws, a locking and releasing assembly, and a first elastic element. The cylindrical body is used for detachable connection of a flow meter, and the outer diameter D1 of the cylindrical body is smaller than the minimum inner diameter of the water distributor. The support claw is movably connected to the cylindrical body. The support claw has a retracted state and an extended state. In the retracted state, the support claw does not protrude from the outer surface of the cylindrical body. In the extended state, the support claw protrudes from the outer surface of the cylindrical body. The locking release component is used to lock the support claw in a retracted state and to release the lock on the support claw; the first elastic member is used to switch the support claw from a retracted state to an extended state when the lock on the support claw is released, and to keep the support claw fully extended. When the support claw is inside the oil pipe, it is fully extended. When the fully extended support claw is lowered from the oil pipe into the water distributor, it abuts against the water distributor.

[0007] In this embodiment of the invention, during downhole stratified flow rate testing, the point where the extended support claw abuts against the water distributor is used as a reference. The downhole tool string is then lifted, allowing the support claw in the downhole tool string to be precisely positioned above the abutment at a set value. Since the relative position of the flow meter and the support claw is fixed, the flow meter can also be precisely positioned in a straight oil pipe at a certain distance above the water distributor, ensuring the accuracy of the test data. This avoids errors in the lowering depth of the flow meter caused by multiple factors such as zero-point error of the wire rope, oil replenishment distance, wire rope elongation, wear of the metering wheel, and personnel operation.

[0008] Optionally, when the support claw is fully extended, the maximum distance between the axis of the cylindrical body and the outer surface of the support claw in the horizontal direction is L1, where L1 is greater than half the minimum inner diameter of the water distributor and less than half the inner diameter of the oil pipe.

[0009] Optionally, the cylindrical body is provided with at least two first pins, and at least two of the support claws are rotatably connected to the cylindrical body through at least two first pins; The support claw has a locking part located on the upper side of the first pin and a claw body located on the lower side of the first pin. The locking release assembly is used to lock the locking part, thereby locking the support claw in a retracted state, and to release the locking part, thereby releasing the locking of the support claw.

[0010] Optionally, the number of the support claws is two, and the locking release component is located on the upper side of the support claws; The locking release assembly includes a locking wheel and a trigger. The cylindrical body has an installation port. The locking wheel is rotatably connected to the cylindrical body and is located inside the installation port, and does not protrude from the outer surface of the cylindrical body. The locking wheel has an clearance groove. The locking wheel has a locked state and a released state. In the locked state, part of the locking wheel is located between the two locking parts to lock the locking parts, thereby locking the support claw in the retracted state. In the released state, the position of the clearance groove corresponds to the position of the locking part. The trigger is used to rotate the locking wheel from the locked state to the released state. When the locking wheel rotates from the locked state to the released state, the locking part is released. The first elastic member causes the claw body to rotate outward and unfold, and the locking part rotates toward the clearance groove, thereby switching the support claw from the retracted state to the unfolded state.

[0011] Optionally, the locking wheel is provided with a mounting groove, the trigger is rotatably connected to the mounting groove, and the trigger protrudes from the outer surface of the cylindrical body; In the locked state, the clearance groove is located on the right side of the locking part, and the locking wheel is provided with a stop structure. The stop structure cooperates with the locking part to prevent the locking wheel in the locked state from rotating counterclockwise, thereby keeping the locking wheel in the locked state. The locking release assembly further includes a second elastic element, which is used to maintain the trigger element in a first position when the locking wheel is in a locked state. In the first position, the maximum distance between the axis of the cylindrical body and the outer surface of the trigger element in the horizontal direction is L2. L2 is greater than half of the minimum inner diameter of the water distributor and less than half of the inner diameter of the oil pipe. When the trigger rotates clockwise from the first position to the second position, the trigger drives the locking wheel to rotate clockwise, thereby causing the locking wheel to rotate from the locked state to the released state. In the second position, along the horizontal direction, the maximum distance between the axis of the cylindrical body and the outer surface of the trigger is L3, and L3 is equal to half of the minimum inner diameter of the water distributor.

[0012] Optionally, the cylindrical body has a receiving cavity. In the retracted state, the support claw retracts into the receiving cavity, and the support claw does not protrude from the outer surface of the cylindrical body.

[0013] Optionally, the cylindrical body has an upper connecting portion for detachably connecting the flow meter or the first protective cap; And / or, the cylindrical body also has a lower connecting portion for detachably connecting a weighting rod or a second protective cap.

[0014] This invention provides a downhole tool string, including a flow meter and a downhole positioning sub section as described above that is detachably connected to the flow meter.

[0015] This invention provides a downhole stratified flow rate testing method, comprising: S101, a downhole tool string is provided, wherein the downhole tool string includes a downhole positioning section as described above, a flow meter detachably connected to the downhole positioning section, and a locking release assembly locks the support claw in a retracted state; S102, the downhole tool string is lowered into the water injection well using a wire winch until it is lowered to the point where the downhole positioning section is located below the lowest-level water distributor; S103, the downhole tool string is raised until the support claw is above the lowest-level water distributor and below the adjacent packer; wherein, after being lowered to below the lowest-level water distributor and before being raised to above the lowest-level water distributor and below the adjacent packer, the locking release assembly releases the lock on the support claw, so that the support claw switches from the retracted state to the extended state under the action of the first elastic member; S104, lower the downhole tool string until the tension of the wire in the wire winch decreases, and the decrease is greater than or equal to the set change amount, and record the lowering depth reading at this time as the first reading; S105, Raise the downhole tool string until the lowering depth reading is the first reading plus the set value; S106, Record the output value of the flow meter; S107, Raise the downhole tool string until the support claw is above the water distributor of the previous stage and below the adjacent packer; S108, lower the downhole tool string until the tension of the wire in the wire winch decreases, and the decrease is greater than or equal to the set change amount, and record the lowering depth reading at this time as the second reading; S109, Raise the downhole tool string until the lowering depth reading is the second reading plus the set value; S110, Record the output value of the flow meter; The process repeats from S107 to S110 until the next water distributor becomes the highest-level water distributor.

[0016] Optionally, when the downhole positioning sub is raised past the lowest level water distributor, the locking release component releases the locking of the support claw, and the support claw switches from the retracted state to the extended state under the action of the first elastic element.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other objects, features and advantages of the present invention more obvious and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a water injection well provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a downhole tool string provided in an embodiment of the present invention; Figure 3 A schematic diagram of a downhole positioning sub provided in an embodiment of the present invention. Figure 1 ; Figure 4 A schematic diagram of a downhole positioning sub provided in an embodiment of the present invention. Figure 2 ; Figure 5 A schematic diagram of a downhole positioning sub provided in an embodiment of the present invention. Figure 3 ; Figure 6 A partial schematic diagram of a downhole positioning sub provided in an embodiment of the present invention; Figure 7 A schematic diagram of a locking and releasing assembly in a downhole positioning sub provided in an embodiment of the present invention; Figure 8 A flowchart illustrating the steps of a downhole stratified flow rate testing method provided in an embodiment of the present invention.

[0019] Figure label: 10-Downhole positioning sub, 11-Cylindrical body, 111-Receiving cavity, 112-Installation port, 113-Upper connecting part, 114-Lower connecting part, 12-Support claw, 121-Locking part, 122-Claw body, 13-First elastic element, 14-First pin, 15-Locking wheel, 151-Allowing groove, 152-Installation groove, 153-Thinning groove, 155-First sidewall, 156-First bottom wall, 16-Trigger element, 17-Second pin, 18-Second elastic element, 19-Sealing ring; 20-Flow meter, 30-Weight rod, 40-First protective cap, 50-Second protective cap, 60-Oil pipe, 70-Water distributor, 80-Package. Detailed Implementation

[0020] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0021] Reference Figure 1 and Figure 2 This invention provides a downhole tool string for lowering into a water injection well, specifically a stratified water injection well. The water injection well includes tubing 60, multiple water distributors 70, and multiple packers 80. The minimum inner diameter of each water distributor 70 is smaller than the inner diameter of the tubing 60, and the minimum inner diameter of each packer 80 is greater than or equal to the minimum inner diameter of the water distributor 70. If the downhole tool string can pass smoothly through a water distributor 70, it can also pass smoothly through a packer 80. Multiple water distributors 70 are arranged sequentially from top to bottom; for example, four water distributors 70 are arranged sequentially.

[0022] The downhole tool string includes a flow meter 20 and a downhole positioning section 10 detachably connected to the flow meter 20. The flow meter 20 can be a storage-type ultrasonic flow meter. The outer diameter of the flow meter 20 is smaller than the minimum inner diameter of the distributor 70.

[0023] As an example, from bottom to top, the downhole tool string includes a rope cap, a flow meter 20, a downhole positioning section 10, and a weighting rod 30. As yet another example, from bottom to top, the downhole tool string includes a rope cap, a flow meter 20, a downhole positioning section 10, and a second protective cap 50. The rope cap is used to connect to the wire of the wire rope winch to enable the raising and lowering of the downhole tool string. The weighting rod 30 is used to increase the weight of the downhole tool string.

[0024] Reference Figures 3 to 5 This invention also provides a downhole positioning section 10, which, as part of the downhole tool string, is lowered into the injection well. Specifically, the downhole positioning section 10 is used in injection wells where the distance between the distributor 70 and the adjacent packer 80 is less than 10 meters. The downhole positioning section 10 is made entirely of metal, such as steel or wear-resistant alloy.

[0025] The downhole positioning sub 10 includes a cylindrical body 11, at least two support claws 12, a locking and releasing assembly, and a first elastic element 13. The cylindrical body 11 is used for detachable connection of the flow meter 20, and the outer diameter D1 of the cylindrical body 11 is smaller than the minimum inner diameter of the water distributor 70. The support claws 12 are movably connected to the cylindrical body 11 and have a retracted state and an extended state, as shown in the reference. Figure 3 and Figure 4 In the retracted state, the support claw 12 does not protrude from the outer surface of the cylindrical body 11, as shown in the reference. Figure 5 In the extended state, the support claw 12 protrudes from the outer surface of the cylindrical body 11; the locking release assembly is used to lock the support claw 12 in the retracted state and to release the lock on the support claw 12; the first elastic member 13 is used to switch the support claw 12 from the retracted state to the extended state when the lock on the support claw 12 is released, and to keep the support claw 12 fully extended; the support claw 12 is fully extended when it is located in the oil pipe 60, and when the fully extended support claw 12 is lowered from the oil pipe 60 into the water distributor 70, it abuts against the water distributor 70.

[0026] The number of support claws 12 is preferably two, and the first elastic element 13 is preferably a spring. The flow meter 20 can be connected to the upper part of the cylindrical body 11. The outer diameter D1 of the cylindrical body 11 is smaller than the minimum inner diameter of the water distributor 70, referring to... Figure 3 In the retracted state, the support claw 12 does not protrude from the outer surface of the cylindrical body 11, so that when the downhole positioning section 10 is lowered into the water injection well, it can pass smoothly and unobstructed through the various water distributors 70 and packers 80, thus ensuring smooth lowering.

[0027] Reference Figure 8 This invention also provides a downhole stratified flow rate testing method, comprising: S101 provides a downhole tool string.

[0028] The downhole tool string includes a downhole positioning sub 10, a flow meter 20 detachably connected to the downhole positioning sub 10, and a locking release assembly that locks the support claw 12 in the retracted state. As an example, from bottom to top, the downhole tool string includes a rope cap, a flow meter 20, a downhole positioning sub 10, and a weighted rod 30. As yet another example, from bottom to top, the downhole tool string includes a rope cap, a flow meter 20, a downhole positioning sub 10, and a second protective cap 50.

[0029] S102, the downhole tool string is lowered into the water injection well using a wire winch until it is lowered to the point where the downhole positioning section is located below the lowest-level water distributor.

[0030] In the water injection well, multiple water distributors 70 are arranged sequentially from top to bottom. The water distributor 70 located at the top is the highest-level water distributor 70, and the water distributor 70 located at the bottom is the lowest-level water distributor 70. For example, when four water distributors 70 are arranged sequentially from top to bottom, the first water distributor 70 is the highest-level water distributor 70, and the fourth water distributor 70 is the lowest-level water distributor 70.

[0031] The depth of the lowest-level water distributor 70 is known and denoted as S1. Since there will be an error between the lowering depth reading and the actual depth of the downhole tool string when using a wire winch to lower the downhole tool string, the downhole positioning section 10 in the downhole tool string must be lowered to a depth reading of S1 + ΔS1 before lowering it below the lowest-level water distributor 70, even with the error in the lowering depth.

[0032] ΔS1 is a compensation amount reserved based on the error of the lowering depth. ΔS1 can be set according to actual needs. For example, when the error of the lowering depth is ±3 meters, ΔS1 is set to 4 meters to 6 meters to ensure that even if there is an error in the lowering depth, the downhole positioning sub 10 in the downhole tool string can still be lowered below the lowest water distributor 70.

[0033] S103, raise the downhole tool string until the support claw is above the lowest water distributor and below the adjacent packer.

[0034] During the process of raising the downhole tool string until the support claw 12 is above the lowest-level water distributor 70 and below the adjacent packer 80, the downhole positioning sub 10 will pass through the lowest-level water distributor 70.

[0035] Because there will be an error between the lowering depth reading and the actual depth of the downhole tool string when using a wire rope winch, when the downhole tool string is raised to a position where the support claw 12 is above the lowest-level water distributor 70 and below the adjacent packer 80, the downhole positioning sub 10 needs to be raised to a lowering depth reading of S1-ΔS2. This ensures that even with an error in the lowering depth, the support claw 12 remains above the lowest-level water distributor 70 and below the adjacent packer 80. Here, ΔS2 is a compensation amount reserved based on the lowering depth error. ΔS2 can be set according to actual needs. For example, if the lowering depth error is ±3 meters and the distance between the water distributor 70 and the adjacent packer 80 is 10 meters, ΔS2 can be set to 4-6 meters.

[0036] After being lowered below the lowest-level water distributor 70, the support claw 12 is raised until it is above the lowest-level water distributor 70 and below the adjacent packer 80. This releases the locking mechanism, allowing the support claw 12 to switch from a retracted state to an extended state under the action of the first elastic member 13. When the support claw 12 is above the lowest-level water distributor 70 and below the adjacent packer 80, it is positioned within the straight oil pipe 60 and is fully extended.

[0037] In some embodiments, the locking release assembly is a mechanical locking release assembly; when the downhole positioning sub 10 is raised past the lowest-level water distributor 70, the locking release assembly releases the lock on the support claw 12, and the support claw 12 switches from a retracted state to an extended state under the action of the first elastic member 13. For example, the mechanical locking release structure includes a locking wheel 15 and a trigger member 16.

[0038] In some embodiments, the locking release assembly is an electromechanical locking release assembly; after being lowered below the lowest level water distributor 70 and before the downhole tool string is raised, the electromechanical locking release structure is controlled to release the lock on the support claw 12.

[0039] S104, lower the downhole tool string until the tension of the wire in the wire winch decreases, and the decrease is greater than or equal to the set change amount, and record the lowering depth reading at this time as the first reading.

[0040] When the fully extended support claw 12 is lowered from the oil pipe 60 into the lowest-level water distributor 70, it will abut against the water distributor 70. At this point, the water distributor 70 exerts an upward supporting force on the support claw 12, significantly reducing the tension on the wire rope in the wire rope winch. Therefore, when the tension on the wire rope in the wire rope winch decreases, and the decrease is greater than or equal to a set change amount, it indicates that the extended support claw 12 has abutted against the lowest-level water distributor 70. The set change amount can be pre-calibrated according to actual working conditions.

[0041] Changes in tension are a significant, stable, and easily interpretable signal. They avoid the ambiguity of relying on experience to judge whether the resistance is reliable in traditional methods, and can reduce the skill requirements of operators and the probability of misjudgment.

[0042] S105, raise the downhole tool string until the lowering depth reading is the first reading plus the set value.

[0043] The set value can be set according to actual needs, for example, it can be 3 meters to 6 meters. Preferably, the set value is 5 meters. When the lowering depth reading is the first reading plus the set value, the support claw 12 in the downhole tool string is located at the set value above the aforementioned abutment point. In this step, the downhole tool string is lifted with the abutment point of the extended support claw 12 and the lowest-level water distributor 70 as a reference, so that the support claw 12 can be accurately positioned at the set value above the aforementioned abutment point. Since the relative position of the flow meter 20 and the support claw 12 is fixed, the flow meter 20 can also be accurately positioned in the straight tubing 60 at a certain distance above the lowest-level water distributor 70 to ensure the accuracy of the test data.

[0044] S016, record the output value of the flow meter.

[0045] S107, Raise the downhole tool string until the support claw is above the water distributor of the previous stage and below the adjacent packer.

[0046] The "upper-level water distributor 70" refers to the water distributor 70 located above and adjacent to the water distributor 70 that the downhole positioning sub 10 passes through in the aforementioned operation steps. For example, if four water distributors 70 are arranged sequentially from top to bottom, when S107 to S110 are executed for the first time, the "upper-level water distributor 70" refers to the third water distributor 70. The specific implementation of this step is the same as S103, except that it targets water distributors 70 at different locations, and will not be described again here.

[0047] S108, lower the downhole tool string until the tension of the wire in the wire winch decreases, and the decrease is greater than or equal to the set change amount, and record the lowering depth reading at this time as the second reading.

[0048] The specific implementation method of this step is the same as that of S104, except that it is for water distributors 70 in different locations, which will not be described again here.

[0049] S109, Raise the downhole tool string until the lowering depth reading is the second reading plus the set value.

[0050] The specific implementation method of this step is the same as that of S105, except that it is for water distributors 70 at different locations, which will not be described again here. In this step, the point where the extended support claw 12 abuts against the water distributor 70 of the previous stage is used as a reference. The downhole tool string is lifted up so that the support claw 12 in the downhole tool string can be accurately positioned at the set value above the abutment point. Since the relative position of the flow meter 20 and the support claw 12 is fixed, the flow meter 20 can also be accurately positioned in the straight tubing 60 at a certain distance above the water distributor 70 of the previous stage to ensure the accuracy of the test data.

[0051] S110 records the output value of the flow meter.

[0052] The process repeats from S107 to S110 until the next water distributor becomes the highest-level water distributor.

[0053] By cyclically executing steps S107 to S110, in the aforementioned downhole stratified flow rate testing method, the downhole positioning sub 10 passes through multiple water distributors 70 sequentially from bottom to top. The flow meter 20 is then positioned sequentially within a straight tubing 60 at a certain distance above each water distributor 70, allowing for flow rate testing of each stratum from bottom to top. After the cyclic execution of steps S107 to S110 is completed, the flow rate data for each stratum can be calculated using a decrementing method.

[0054] For example, if the four water distributors 70 are set sequentially from top to bottom, when executing S107 to S110 for the first time, the water distributor 70 of the previous level refers to the third water distributor 70; when executing S107 to S110 for the second time, the water distributor 70 of the previous level refers to the second water distributor 70; and when executing S107 to S110 for the last time, the water distributor 70 of the previous level refers to the first water distributor 70. In the above downhole stratified flow test method, the downhole positioning sub 10 will pass through the four water distributors 70 sequentially from bottom to top.

[0055] In summary, in this embodiment of the invention, during downhole stratified flow rate testing, the point where the extended support claw 12 abuts against the water distributor 70 is used as a reference. The downhole tool string is then lifted, allowing the support claw 12 in the downhole tool string to be precisely positioned above the aforementioned abutment point at a set value. Since the relative position of the flow meter 20 and the support claw 12 is fixed, the flow meter 20 can also be precisely positioned within the straight oil pipe 60 at a certain distance above the water distributor 70. This ensures the accuracy of the test data and avoids errors in the lowering depth of the flow meter 20 caused by multiple factors such as zero-point error of the wire rope, oil replenishment distance, wire rope elongation, wear of the metering wheel, and personnel operation.

[0056] In some embodiments, refer to Figure 5 When the support claw 12 is fully extended, the maximum distance between the axis of the cylindrical body 11 and the outer surface of the support claw 12 in the horizontal direction is L1. L1 is greater than half of the minimum inner diameter of the water distributor 70 and less than half of the inner diameter of the oil pipe 60.

[0057] In this embodiment, L1 is less than half the inner diameter of the oil pipe 60, allowing the support claw 12 to be smoothly lowered into the oil pipe 60 when fully extended. L1 is greater than half the minimum inner diameter of the water distributor 70, ensuring that when the fully extended support claw 12 is lowered from the oil pipe 60 into the water distributor 70, it abuts against the first narrowing transition point between the minimum inner diameter of the water distributor 70 and another larger inner diameter adjacent above it. It is understood that the fully extended support claw 12 can also abut against other narrowing transition points above the minimum inner diameter of the water distributor 70.

[0058] In some embodiments, the difference between L1 and half the inner diameter of tubing 60 is small, for example, less than or equal to 3 mm. In this case, the two fully extended support claws 12 can also help to straighten the downhole tool string, effectively improve the centering of flow meter 20 in tubing 60, provide a stable and centered measurement environment for flow meter 20, and effectively reduce the test error caused by the eccentricity of flow meter 20, thereby ensuring the accuracy of test data in both positioning and testing stages.

[0059] In some embodiments, refer to Figures 3 to 5 The cylindrical body 11 is provided with at least two first pins 14, and at least two support claws 12 are rotatably connected to the cylindrical body 11 through the at least two first pins 14. The support claw 12 has a locking part 121 located on the upper side of the first pin 14 and a claw body 122 located on the lower side of the first pin 14. The locking and releasing assembly is used to lock the locking part 121, thereby locking the support claw 12 in a retracted state, and to release the locking part 121, thereby releasing the locking of the support claw 12. In this embodiment, the support claw 12 adopts a rotatable connection, which results in a compact structure.

[0060] In some embodiments, refer to Figures 3 to 7 There are two support claws 12. The locking release assembly is located on the upper side of the support claw 12. The locking release assembly includes a locking wheel 15 and a trigger 16. The cylindrical body 11 has an installation port 112. The locking wheel 15 is rotatably connected to the cylindrical body 11 and is located inside the installation port 112. It does not protrude from the outer surface of the cylindrical body 11. The locking wheel 15 has an avoidance groove 151. The locking wheel 15 is used to lock the locking part 121, thereby locking the support claw 12 in the retracted state, and is used to release the locking part 121, thereby releasing the locking of the support claw 12.

[0061] Locking wheel 15 has a locked state and an unlocked state, see reference. Figure 3 and Figure 4 In the locked state, part of the locking wheel 15 is located between the two locking parts 121 to lock the locking parts 121, thereby locking the support claw 12 in the retracted state. (Refer to...) Figure 5 and Figure 6 In the released state, the position of the clearance groove 151 corresponds to the position of the locking part 121; the trigger member 16 is used to rotate the locking wheel 15 from the locked state to the released state, and the locking wheel 15 is rotated by... Figure 3 and Figure 4 The locked state shown is rotated to Figure 5 and Figure 6 When the release state is displayed, the locking part 121 is released, the first elastic member 13 causes the claw body 122 to rotate outward and unfold, and the locking part 121 rotates toward the clearance groove 151, thereby switching the support claw 12 from the retracted state to the unfolded state.

[0062] The locking wheel 15 has two end faces that are arranged opposite each other along its thickness direction. Thinning grooves 153 are respectively opened at the bottom of the two end faces. In the locked state, the inner surface of the locking part 121 contacts the first bottom wall 156 of the thinning groove 153 to lock the locking part 121, thereby locking the support claw 12 in the retracted state.

[0063] The number of clearance grooves 151 can be a single connected groove or two disconnected grooves. Preferably, there are two clearance grooves 151, and in the released state, the positions of the two clearance grooves 151 correspond to the positions of the two locking parts 121, respectively. The locking wheel 15 has two end faces that are arranged opposite to each other along its thickness direction, and the two clearance grooves 151 are respectively formed on the two end faces.

[0064] In some embodiments, refer to Figures 3 to 5 The locking wheel 15 has a mounting groove 152, the trigger 16 is rotatably connected to the mounting groove 152, and the trigger 16 protrudes from the outer surface of the cylindrical body 11.

[0065] In the locked state, the clearance groove 151 is located on the right side of the locking part 121, and the locking wheel 15 is provided with a stop structure. The stop structure cooperates with the locking part 121 to prevent the locking wheel 15 from rotating counterclockwise in the locked state, thereby keeping the locking wheel 15 in the locked state. The stop structure can be the first sidewall 155 of the thinned groove 153.

[0066] The locking release assembly also includes a second elastic element 18, which is used to release the locking wheel 15 when it is in a certain position. Figure 4 When the shown locked state is reached, the trigger 16 is maintained in the position. Figure 4 In the first position shown, in the horizontal direction, the maximum distance between the axis of the cylindrical body 11 and the outer surface of the trigger 16 is L2. L2 is greater than half the minimum inner diameter of the water distributor 70 and less than half the inner diameter of the oil pipe 60. L2 can be less than L1. Specifically, the trigger 16 is rotatably connected to the mounting groove 152 via the second pin 17. The second elastic element 18 can be a torsion spring. (Refer to...) Figure 4 In the first position, there may be a small gap between the side of the trigger 16 near the clearance groove 151 and the locking wheel 15.

[0067] As the trigger 16 rotates clockwise from the first position to the second position, it drives the locking wheel 15 to rotate clockwise, thereby causing the locking wheel 15 to rotate from the locked state to the released state; see reference. Figure 6 In the second position, along the horizontal direction, the maximum distance between the axis of the cylindrical body 11 and the outer surface of the trigger 16 is L3, where L3 is equal to half the minimum inner diameter of the water distributor 70. (Refer to...) Figure 6 In the second position, the side of the trigger 16 near the clearance groove 151 contacts the locking wheel 15 in the released state. Under the action of the second elastic member 18, the trigger 16 has a slight tendency to rotate back to its original position counterclockwise, for example, less than 1° counterclockwise.

[0068] It should be noted that the difference between the first position and the second position is that the position of the trigger 16 relative to the cylindrical body 11 is different.

[0069] In this embodiment, the locking release component is a mechanical locking release component; when the downhole positioning sub 10 is lifted past the lowest level water distributor 70, the locking release component releases the lock on the support claw 12, and the support claw 12 switches from the retracted state to the extended state under the action of the first elastic member 13.

[0070] In the downhole tool string provided by S101, trigger 16 is in the position Figure 4 In the first position shown, the locking wheel 15 is in the locked state and the support claw 12 is in the retracted state.

[0071] In S102, during the process of lowering the downhole tool string into the injection well using a wire winch, the trigger 16 is initially located inside the tubing 60. Since L2 is less than half the inner diameter of the tubing 60, the trigger 16 in its first position can be smoothly lowered into the tubing 60. However, since L2 is greater than half the minimum inner diameter of the water distributor 70, when the trigger 16 is blocked by the narrowing transition of the packer 80 or the first narrowing transition of the water distributor 70, the narrowing transition will cause the trigger 16 to rotate counterclockwise until it can pass through the narrowing transition and the minimum inner diameter. During this process, the stop structure cooperates with the locking part 121 to prevent the locking wheel 15 in its locked state from rotating counterclockwise, thus maintaining the locking wheel 15 in its locked state. After passing the packer 80 or the water distributor 70, when the trigger 16 is located inside the tubing 60, it returns to its first position under the action of the second elastic element 18.

[0072] In S103, as the downhole tool string is lifted and the downhole positioning sub 10 is lifted past the lowest-level water distributor 70, the trigger 16 is blocked by the second narrowing transition point between the smallest inner diameter of the lowest-level water distributor 70 and the larger inner diameter adjacent below it. The second narrowing transition point causes the trigger 16 to rotate clockwise. After rotating clockwise, the trigger 16 first contacts the locking wheel 15, and then drives the locking wheel 15 to rotate clockwise. When the trigger 16 rotates to the second position, the locking wheel 15 rotates to the release state, releasing the lock on the support claw 12. Under the action of the first elastic element 13, the support claw 12 rotates from the retracted state to the extended state. At this time, the support claw 12 can be either partially extended or fully extended.

[0073] After the support claw 12 is extended, as it passes through the minimum inner diameter of the lowest-level water distributor 70 from bottom to top, the support claw 12 will retract inward under the pressure of the inner wall of the minimum inner diameter of the water distributor 70, but will not retract completely, so as to pass through the minimum inner diameter of the water distributor 70 smoothly. After the support claw 12 passes through the lowest-level water distributor 70 from bottom to top, when it is located inside the oil pipe 60, the support claw 12 is fully extended.

[0074] After the trigger 16 passes the lowest-level water distributor 70 from bottom to top and is located inside the oil pipe 60, under the action of the second elastic member 18, the trigger 16 rotates slightly counterclockwise to return to its original position, for example, by less than 1° counterclockwise, so that there is a small gap between the side of the trigger 16 near the relief groove 151 and the locking wheel 15. At this time, the relative position of the trigger 16 to the locking wheel 15 in the released state is the same as the relative position of the trigger 16 to the locking wheel 15 in the locked state in the first position. In S107, when the trigger 16 passes the previous-level water distributor 70 from bottom to top, the trigger 16 rotates slightly clockwise to rotate to the second position where it contacts the locking wheel 15 in the released state. Then, similarly, after the trigger 16 passes the previous-level water distributor 70 from bottom to top and is located inside the oil pipe 60, under the action of the second elastic member 18, the trigger 16 rotates slightly counterclockwise to return to its original position.

[0075] It should be noted that after the test is completed, the support claw 12 can be manually pressed down to put the support claw 12 in the retracted state. Then, the locking wheel 15 can be manually rotated counterclockwise to rotate the locking wheel 15 to the locked state, thereby resetting the downhole positioning sub 10.

[0076] In this embodiment, the mechanical locking and releasing assembly does not rely on electromagnetic signals or precision electronic sensors, exhibits strong anti-interference capabilities, and is suitable for complex downhole environments with high temperature, high pressure, and multiphase flow, ensuring high reliability. The downhole positioning sub 10 adopts a fully mechanical structure, exhibiting strong environmental adaptability and stable and reliable operation. This downhole positioning sub 10 can be reliably applied to complex well conditions with small clamping distances and high positioning requirements, effectively avoiding repeated testing due to inaccurate stopping point positioning and saving operating costs.

[0077] In some embodiments, refer to Figures 3 to 5 The cylindrical body 11 has a receiving cavity 111. In the retracted state, the support claws 12 retract into the receiving cavity 111, and the support claws 12 do not protrude from the outer surface of the cylindrical body 11. The number of receiving cavities 111 is equal to the number of support claws 12. In the retracted state, the two support claws 12 retract into the two receiving cavities 111 respectively. The receiving cavities 111 ensure that the support claws 12 do not protrude from the outer surface of the cylindrical body 11 in the retracted state.

[0078] In some embodiments, refer to Figures 3 to 6 The cylindrical body 11 has an upper connecting part 113, which is used for detachably connecting the flow meter 20 or the first protective cap 40.

[0079] The upper connecting part 113 can be connected to the flow meter 20 or the first protective cap 40 by a threaded connection. The outer wall of the upper connecting part 113 may have external threads, and the flow meter 20 or the first protective cap 40 may have mating internal threads. A sealing ring 19 is provided between the bottom of the external thread and the flow meter 20 or the first protective cap 40. The sealing ring 19 can be an O-ring made of fluororubber or polytetrafluoroethylene. When the downhole positioning sub 10 is in use, the upper connecting part 113 is connected to the flow meter 20. When the downhole positioning sub 10 is not in use, the upper connecting part 113 is connected to the first protective cap 40 to protect the upper connecting part 113.

[0080] In some embodiments, refer to Figure 3 and Figure 4 The cylindrical body 11 also has a lower connecting part 114, which is used to detachably connect the weight bar 30 or the second protective cap 50.

[0081] The lower connecting part 114 can be connected to the weight rod 30 or the second protective cap 50 via a threaded connection. The inner wall of the lower connecting part 114 has an internal thread, and the weight rod 30 or the second protective cap 50 has a mating external thread. A sealing ring 19 is provided between the bottom of the internal thread and the weight rod 30 or the second protective cap 50. When the downhole positioning sub 10 is in use, the lower connecting part 114 is connected to the weight rod 30 or the second protective cap 50. When the downhole positioning sub 10 is not in use, the lower connecting part 114 is connected to the second protective cap 50 to protect the lower connecting part 114.

[0082] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0083] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other modifications under the guidance of the present invention without departing from the spirit and scope of the present invention, and all of these modifications are within the protection scope of the present invention.

Claims

1. A downhole positioning sub, characterized in that, The downhole positioning sub is used to be lowered into the water injection well, which includes tubing and multiple water distributors, the minimum inner diameter of which is smaller than the inner diameter of the tubing. The downhole positioning section includes a cylindrical body, at least two support claws, a locking and releasing assembly, and a first elastic element. The cylindrical body is used for detachable connection of a flow meter, and the outer diameter D1 of the cylindrical body is smaller than the minimum inner diameter of the water distributor. The support claw is movably connected to the cylindrical body. The support claw has a retracted state and an extended state. In the retracted state, the support claw does not protrude from the outer surface of the cylindrical body. In the extended state, the support claw protrudes from the outer surface of the cylindrical body. The locking release component is used to lock the support claw in a retracted state and to release the lock on the support claw; the first elastic member is used to switch the support claw from a retracted state to an extended state when the lock on the support claw is released, and to keep the support claw fully extended. When the support claw is inside the oil pipe, it is fully extended. When the fully extended support claw is lowered from the oil pipe into the water distributor, it abuts against the water distributor.

2. The downhole positioning sub according to claim 1, characterized in that, When the support claw is fully extended, the maximum distance between the axis of the cylindrical body and the outer surface of the support claw in the horizontal direction is L1. L1 is greater than half the minimum inner diameter of the water distributor and less than half the inner diameter of the oil pipe.

3. The downhole positioning sub according to claim 1, characterized in that, The cylindrical body is provided with at least two first pins, and at least two support claws are rotatably connected to the cylindrical body through at least two first pins respectively; The support claw has a locking part located on the upper side of the first pin and a claw body located on the lower side of the first pin. The locking release assembly is used to lock the locking part, thereby locking the support claw in a retracted state, and to release the locking part, thereby releasing the locking of the support claw.

4. The downhole positioning sub according to claim 3, characterized in that, The number of support claws is two, and the locking release component is located on the upper side of the support claws; The locking release assembly includes a locking wheel and a trigger. The cylindrical body has an installation port. The locking wheel is rotatably connected to the cylindrical body and is located inside the installation port, and does not protrude from the outer surface of the cylindrical body. The locking wheel has an clearance groove. The locking wheel has a locked state and a released state. In the locked state, part of the locking wheel is located between the two locking parts to lock the locking parts, thereby locking the support claw in the retracted state. In the released state, the position of the clearance groove corresponds to the position of the locking part. The trigger is used to rotate the locking wheel from the locked state to the released state. When the locking wheel rotates from the locked state to the released state, the locking part is released. The first elastic member causes the claw body to rotate outward and unfold, and the locking part rotates toward the clearance groove, thereby switching the support claw from the retracted state to the unfolded state.

5. The downhole positioning sub according to claim 4, characterized in that, The locking wheel has a mounting groove, the trigger is rotatably connected to the mounting groove, and the trigger protrudes from the outer surface of the cylindrical body; In the locked state, the clearance groove is located on the right side of the locking part, and the locking wheel is provided with a stop structure. The stop structure cooperates with the locking part to prevent the locking wheel in the locked state from rotating counterclockwise, thereby keeping the locking wheel in the locked state. The locking release assembly further includes a second elastic element, which is used to maintain the trigger element in a first position when the locking wheel is in a locked state. In the first position, the maximum distance between the axis of the cylindrical body and the outer surface of the trigger element in the horizontal direction is L2. L2 is greater than half of the minimum inner diameter of the water distributor and less than half of the inner diameter of the oil pipe. When the trigger rotates clockwise from the first position to the second position, the trigger drives the locking wheel to rotate clockwise, thereby causing the locking wheel to rotate from the locked state to the released state. In the second position, along the horizontal direction, the maximum distance between the axis of the cylindrical body and the outer surface of the trigger is L3, and L3 is equal to half of the minimum inner diameter of the water distributor.

6. The downhole positioning sub according to any one of claims 1 to 5, characterized in that, The cylindrical body has a receiving cavity. In the retracted state, the support claw retracts into the receiving cavity, and the support claw does not protrude from the outer surface of the cylindrical body.

7. The downhole positioning sub according to any one of claims 1 to 5, characterized in that, The cylindrical body has an upper connecting part, which is used to detachably connect the flow meter or the first protective cap; And / or, the cylindrical body also has a lower connecting portion for detachably connecting a weighting rod or a second protective cap.

8. A downhole tool string, characterized in that, Includes a flow meter and a downhole positioning sub as described in any one of claims 1 to 7, which is detachably connected to the flow meter.

9. A method for testing stratified flow rate in downhole wells, characterized in that, include: S101, providing a downhole tool string, wherein the downhole tool string includes a downhole positioning sub as described in any one of claims 1 to 7, a flow meter detachably connected to the downhole positioning sub, and a locking release assembly locking the support claw in a retracted state; S102, the downhole tool string is lowered into the water injection well using a wire winch until it is lowered to the point where the downhole positioning section is located below the lowest-level water distributor; S103, the downhole tool string is raised until the support claw is above the lowest-level water distributor and below the adjacent packer; wherein, after being lowered to below the lowest-level water distributor and before being raised to above the lowest-level water distributor and below the adjacent packer, the locking release assembly releases the lock on the support claw, so that the support claw switches from the retracted state to the extended state under the action of the first elastic member; S104, lower the downhole tool string until the tension of the wire in the wire winch decreases, and the decrease is greater than or equal to the set change amount, and record the lowering depth reading at this time as the first reading; S105, Raise the downhole tool string until the lowering depth reading is the first reading plus the set value; S106, Record the output value of the flow meter; S107, Raise the downhole tool string until the support claw is above the water distributor of the previous stage and below the adjacent packer; S108, lower the downhole tool string until the tension of the wire in the wire winch decreases, and the decrease is greater than or equal to the set change amount, and record the lowering depth reading at this time as the second reading; S109, Raise the downhole tool string until the lowering depth reading is the second reading plus the set value; S110, Record the output value of the flow meter; The process repeats from S107 to S110 until the next water distributor becomes the highest-level water distributor.

10. The downhole stratified flow rate testing method according to claim 9, characterized in that, When the downhole positioning sub is raised past the lowest level water distributor, the locking release component releases the locking of the support claw, and the support claw switches from the retracted state to the extended state under the action of the first elastic element.

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