Well shut-in sampling valve, oil testing string and operation method thereof

Abstract

The present invention is a shut-in sampling valve, a test oil pipe and an operation method thereof, wherein the shut-in sampling valve comprises a first outer protective pipe and a first sliding sleeve, wherein the upper pipe wall and the lower pipe wall of the first outer protective pipe are respectively provided with a first pressure hole and a first outer flow guide hole. A production channel is formed inside the first sliding sleeve, the first sliding sleeve can be slidably arranged in the first outer protective pipe, and a first inner flow guide hole that can communicate with the first outer flow guide hole is provided on the lower pipe wall of the first sliding sleeve. A sampling annulus that can communicate with the production channel is formed between the upper outer wall of the first sliding sleeve and the inner wall of the first outer protective pipe. When the first shear pin is sheared off, the first sliding sleeve can slide upward along the axial direction of the first outer protective pipe until the upper outer wall of the first sliding sleeve is in sealing contact with the upper inner wall of the first outer protective pipe, and the sampling annulus forms a sealed sampling space with both ends closed. The present invention can realize downhole shut-in sampling instantly after the fluid is discharged to obtain a qualified formation fluid sample.

Description

Technical Field

[0001] The invention relates to the technical field of oil testing in petroleum exploration and development, and in particular to a well shut-in sampling valve, an oil testing pipe column and an operating method thereof. Background Art

[0002] For oil testing of non-flowing wells in low permeability reservoirs, conventional oil testing technology is often used, whether before or after pressure testing. After suction (or N2 gas lift, sucker rod) to drain and produce, it is difficult to shut down the well to measure the pressure recovery curve and take samples downhole because the test valve is not lowered. After some conventional oil testing wells have successfully induced blowout and qualified production, it is necessary to pull out the sucker rod (or pump) in the well, then lower the pressure gauge to the bottom of the well, and shut down the wellhead to measure pressure recovery; however, it normally takes tens of minutes or even hours from stopping pumping to the pressure gauge being lowered to the predetermined position in the well. It is difficult to shut down the well in time to measure pressure recovery, resulting in early data loss of the pressure recovery curve, and it is difficult to overcome the influence of the wellbore storage effect, resulting in radial flow time delay and data acquisition quality degradation, resulting in pressure recovery curve morphology variation, model diagnosis difficulty, large errors in interpretation results or inability to interpret, resulting in inaccurate qualitative or quantitative understanding of the layer.

[0003] In addition, when conventional oil testing is used for exploration wells and development wells in low-yield and low-permeability reservoirs, due to poor formation fluid supply and limited drainage time, when wellhead sampling is used, the high proportion of wellbore fluid in the discharged fluid and the low proportion of formation production fluid can easily lead to problems such as inaccurate formation fluid characterization and unclear reservoir understanding.

[0004] Therefore, the inventor, relying on many years of experience and practice in related industries, proposes a shut-in sampling valve, a test oil string and an operating method thereof to overcome the defects of the prior art. Summary of the invention

[0005] The object of the present invention is to provide a shut-in sampling valve, a test oil pipe string and an operation method thereof, which can realize downhole shut-in sampling instantly after fluid discharge for production, so as to obtain qualified formation fluid samples.

[0006] The purpose of the present invention can be achieved by adopting the following technical solutions:

[0007] The present invention provides a shut-in sampling valve, comprising a first outer protective tube and a first sliding sleeve, wherein the upper tube wall and the lower tube wall of the first outer protective tube are respectively provided with a first pressurizing hole and a first outer flow guide hole; a production channel is formed inside the first sliding sleeve, the first sliding sleeve can be slidably arranged in the first outer protective tube, the first sliding sleeve can be connected to the first outer protective tube through a first shear nail, a first inner flow guide hole which can be communicated with the first outer flow guide hole is provided on the lower tube wall of the first sliding sleeve; a first step with an enlarged diameter is formed upward on the middle outer wall of the first sliding sleeve, and a first step with an enlarged diameter is formed on the middle outer wall of the first sliding sleeve. A sealed first inner pressure-transmitting annulus is formed between the outer wall of a sliding sleeve located above the first step and the inner wall of the first outer protective tube, and the first inner pressure-transmitting annulus is connected to the first pressurized hole and the first step; a sampling annulus that can be connected to the production channel is formed between the upper outer wall of the first sliding sleeve and the inner wall of the first outer protective tube; when the first shear pin is sheared off, the first sliding sleeve can slide upward along the axial direction of the first outer protective tube until the upper outer wall of the first sliding sleeve is in sealing contact with the upper inner wall of the first outer protective tube, and the sampling annulus forms a sealed sampling space with both ends closed.

[0008] In a preferred embodiment of the present invention, a first lower limit shoulder with an enlarged diameter is formed downwardly on the outer wall of the first sleeve and between the sampling annulus and the first inner pressure transmission annulus, and a first shock-absorbing pad is provided above the first lower limit shoulder; a first upper limit shoulder with a reduced diameter is formed upwardly on the inner wall of the first outer protective tube and between the sampling annulus and the first lower limit shoulder, and a preset moving distance is left between the first lower limit shoulder and the first upper limit shoulder; when the first shear nail is cut off, the first lower limit shoulder can be pressed against the first upper limit shoulder through the first shock-absorbing pad.

[0009] In a preferred embodiment of the present invention, a locking sleeve is connected to the lower end of the first sliding sleeve, a plurality of elastic claws are formed on the lower end tube wall of the locking sleeve, a convex ridge is protruded outward on the lower end outer wall of each elastic claw, and an annular locking groove is provided on the lower inner wall of the first outer protective tube and below the first outer guide hole; when the first shear nail is cut off, each convex ridge can be stuck in the locking groove.

[0010] In a preferred embodiment of the present invention, a lofting valve assembly is provided on the upper tube wall of the first outer protective tube; when the first shear nail is cut off, the lofting valve assembly can be connected to the sealed sampling space.

[0011] In a preferred embodiment of the present invention, the sample release valve assembly includes a sample release valve and a sample release plug, a first through hole and a second through hole which are interconnected and both penetrate the outer side wall of the first outer protective tube are provided in the side wall, and a lateral hole which penetrates the inner side wall of the first outer protective tube is provided in the side wall, the lateral hole is arranged opposite to the first through hole and can be connected to the first through hole; the sample release valve can be adjustably fixed in the first through hole and can block the lateral hole, and the sample release plug can be removably fixed in the second through hole.

[0012] In a preferred embodiment of the present invention, the first outer protective tube includes a first upper protective tube and a first lower protective tube which are sealed and fixed up and down, and a first stepped hole, a second stepped hole and a third stepped hole with successively decreasing apertures are formed on the inner wall of the first upper protective tube from bottom to top, and the top hole shoulder of the first stepped hole constitutes a first upper limit shoulder, the first pressurizing hole is opened on the tube wall of the first upper protective tube and corresponds to the position of the first stepped hole, and the first outer guide hole is opened on the tube wall of the first lower protective tube; the first convex ring and the second convex ring which are spaced apart up and down are formed on the upper outer wall of the first sleeve protruding outward, and the second convex ring is embedded in the first stepped hole, the top surface of the second convex ring constitutes the first lower limit shoulder, the bottom surface of the second convex ring constitutes the first step, and the first internal pressure transmission annulus is formed between the outer wall of the second convex ring and the hole wall of the first stepped hole; the first convex ring is seal-embedded in the second stepped hole, and a sampling annulus can be formed between the part of the first sleeve above the first convex ring and the hole wall of the second stepped hole.

[0013] The present invention also provides an oil test pipe string, comprising an oil pipe, a bypass joint, a packer, a pressure-conducting pipe, the above-mentioned shut-in sampling valve and a bottom plug connected in sequence from top to bottom; the lower part of the pressure-conducting pipe is sleeved on the upper outer side of the first outer protective pipe and forms a sealed first outer pressure-transmitting annulus with the upper outer wall of the first outer protective pipe, and the first outer pressure-transmitting annulus is connected with the first pressurized hole; an inner pressure-transmitting pipe passing through the interior of the packer is connected between the bypass joint and the pressure-conducting pipe, the upper end of the inner pressure-transmitting pipe is connected to the outside of the bypass joint through a first pressure-transmitting channel arranged in the bypass joint, and the lower end of the inner pressure-transmitting pipe is connected to the first outer pressure-transmitting annulus through a second pressure-transmitting channel arranged in the side wall of the pressure-conducting pipe; the production channel is connected to the oil pipe through a first side axial hole arranged in the side wall of the pressure-conducting pipe, the annulus between the packer and the inner pressure-transmitting pipe, and the second side axial hole arranged in the bypass joint.

[0014] In a preferred embodiment of the present invention, a first pressure gauge holder is connected between the shut-in sampling valve and the bottom plug, and a first pressure gauge capable of recording the pressure in the production channel is provided on the first pressure gauge holder.

[0015] In a preferred embodiment of the present invention, a well-opening valve is connected between the packer and the pressure-conducting pipe, and the well-opening valve includes a second outer protective pipe and a second sliding sleeve; a second outer flow guide hole and a second pressurizing hole are respectively provided on the upper pipe wall and the lower pipe wall of the second outer protective pipe; the second sliding sleeve can be slidably inserted into the second outer protective pipe, the second sliding sleeve can be connected to the second outer protective pipe through a second shear nail, and a second inner flow guide hole that can communicate with the second outer flow guide hole is provided on the upper pipe wall of the second sliding sleeve; a second step with an enlarged diameter is formed downwardly on the middle outer wall of the second sliding sleeve, and a second step with an enlarged diameter is formed on the outer wall of the second sliding sleeve. A sealed second inner pressure-transmitting annulus is formed between the lower part of the second step and the inner wall of the second outer protective tube, and the second inner pressure-transmitting annulus is connected with the second pressurizing hole and the second step; the inner pressure-transmitting tube is inserted into the second sleeve, and the gap between the inner pressure-transmitting tube and the second sleeve is connected with the production channel; the upper part of the pressure-conducting tube is sleeved on the outer side of the lower part of the second outer protective tube and forms a sealed second outer pressure-transmitting annulus with the lower outer wall of the second outer protective tube, and the second outer pressure-transmitting annulus is connected with the second pressurizing hole, and the second outer pressure-transmitting annulus is connected with the inner pressure-transmitting tube through a third pressure-transmitting channel arranged in the side wall of the pressure-conducting tube.

[0016] In a preferred embodiment of the present invention, a second upper limit shoulder with an enlarged diameter is formed upward on the outer wall of the second sleeve and located below the second inner pressure transmission annulus, and a second shock-absorbing pad is provided below the second upper limit shoulder; a second lower limit shoulder with a reduced diameter is formed downward on the inner wall of the second outer protective tube and located below the second upper limit shoulder, and a preset moving distance is left between the second upper limit shoulder and the second lower limit shoulder; when the second shear nail is cut off, the second upper limit shoulder can be abutted against the second lower limit shoulder through the second shock-absorbing pad.

[0017] In a preferred embodiment of the present invention, a first rupture disk is provided at the first pressurizing hole, and a second rupture disk is provided at the second pressurizing hole, and the rupture pressure value of the second rupture disk is greater than the rupture pressure value of the first rupture disk.

[0018] In a preferred embodiment of the present invention, a circulation valve, a second pressure gauge holder and a safety joint are sequentially connected between the oil pipe and the well opening valve from top to bottom, and the second pressure gauge holder is provided with a second pressure gauge capable of recording the pressure in the casing annulus.

[0019] In a preferred embodiment of the present invention, a negative pressure valve and a connecting nipple connected up and down are provided between the oil pipe and the circulation valve.

[0020] The present invention also provides an operating method of the above-mentioned oil testing pipe string, comprising the following steps:

[0021] S10, lowering the tubing string and setting the packer: lower the test tubing string into the well to the designed depth, form an oil-casing annulus between the test tubing string and the casing, adjust the test tubing string, and set the packer;

[0022] The shut-in sampling valve is opened to enter the well, the first inner flow guide hole is connected to the first outer flow guide hole, and the sampling annulus is connected to the production channel; the open-well valve is closed to enter the well, and the second inner flow guide hole and the second outer flow guide hole are staggered.

[0023] S20, inducing blowout and draining fluid, and calculating production: Inducing blowout and draining fluid from the test oil string, the fluid in the formation enters the oil pipe through the first outer diversion hole, the first inner diversion hole and the production channel in sequence, and the bottom hole flow pressure data is recorded through the first pressure gauge;

[0024] S30, shut-in sampling: pressurize the casing annulus above the packer to a first pressure value, and the hydraulic pressure sequentially passes through the first pressure transmission channel, the interior of the inner pressure transmission tube, the second pressure transmission channel, the first outer pressure transmission annulus, the first pressure hole and the first inner pressure transmission annulus and acts on the first step, the first shear pin is cut off, and the liquid pushes the first sliding sleeve upward, so that the first inner guide hole and the first outer guide hole are staggered, and a sealed sampling space is formed between the first sliding sleeve and the first outer protective tube to confine the fluid in the sealed sampling space; the pressure data recorded by the first pressure gauge can obtain the pressure recovery curve when the well is shut in;

[0025] S40, well killing, unsealing, and pulling out the tubing: perform well washing and well killing operations on the test tubing in sequence, then dismantle the wellhead, pull up the test tubing, unseal the packer, and pull out the test tubing.

[0026] In a preferred embodiment of the present invention, the following steps are further included between step S30 and step S40:

[0027] S35. Reopen the well for production: pressurize the casing annulus above the packer to a second pressure value, which is greater than the first pressure value. The hydraulic pressure passes through the first pressure transmission channel, the interior of the inner pressure transmission tube, the third pressure transmission channel, the second outer pressure transmission annulus, the second pressurized hole, and the second inner pressure transmission annulus in sequence and acts on the second step. The second shear pin is cut off, and the liquid pushes the second sliding sleeve downward, so that the second inner guide hole is connected to the second outer guide hole, and the fluid in the formation enters the oil pipe through the second outer guide hole and the second inner guide hole in sequence.

[0028] As described above, the shut-in sampling valve in the present invention is in an open state in the initial state through the cooperation of the first outer protective tube and the first sliding sleeve, and can carry out the drainage and production operation; when shutting in the well, the shut-in sampling valve can be closed by pressurizing the oil casing annulus, and the high-temperature and high-pressure fluid in the well can be confined in the sealed sampling space at the moment of shutting in the well, so as to realize the downhole shut-in sampling at the moment after the drainage and production, and realize the sampling under the conditions of the downhole opening of non-flowing wells and the near-reservoir depth under the stable flow state, which is conducive to obtaining qualified formation fluid and high-pressure physical property samples in the near-reservoir area of ​​low-yield wells, and overcomes the deficiency that it is difficult to obtain qualified formation fluid samples when the previous test valve is far away from the reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The following drawings are intended only to illustrate and explain the present invention, and do not limit the scope of the present invention.

[0030] Figure 1 : A structural schematic diagram of the oil testing pipe string provided by the present invention when a negative pressure valve and a connecting short joint are provided.

[0031] Figure 2 : It is a structural schematic diagram of the oil testing pipe string provided by the present invention when a negative pressure valve and a connecting short joint are not provided.

[0032] Figure 3 : It is a structural schematic diagram of the portion between the bypass joint and the bottom plug in the oil testing pipe string provided by the present invention when the well-opening valve is in a closed state and the well-closing sampling valve is in an open state.

[0033] Figure 4 :for Figure 3 An enlarged view of the structure of the well-opening valve.

[0034] Figure 5 :for Figure 3 An enlarged view of the structure of the well-closing sampling valve.

[0035] Figure 6 : A schematic structural diagram of the first outer protective tube provided by the present invention.

[0036] Figure 7 : A schematic structural diagram of the portion between the bypass joint and the bottom plug in the oil testing string provided by the invention when the well-opening valve is in an open state and the well-shut-in sampling valve is in a closed state.

[0037] Figure 8 :for Figure 7 The cross-sectional view along the AA direction. Figure 8 The center tube is not shown.

[0038] Description of Figure Numbers:

[0039] 101, oil pipe; 102, negative pressure valve; 103, connecting nipple; 104, circulation valve; 105, second pressure gauge support; 106, safety joint;

[0040] 1. Bypass joint; 11. Second side axial hole; 12. First pressure transmission channel;

[0041] 2. Internal pressure transmission pipe;

[0042] 3. Packer;

[0043] 4. The well valve can be opened;

[0044] 41. Second outer protective tube;

[0045] 411, second upper protective tube; 4111, second outer flow guide hole; 4112, limiting convex ring;

[0046] 412, second lower protective tube; 4121, second pressurizing hole; 41211, second rupture disk; 4122, second lower limit shoulder;

[0047] 42, second sliding sleeve; 421, second inner guide hole; 422, second step; 423, second limit shoulder; 424, third convex ring;

[0048] 43. Second shear nails;

[0049] 44. Second inner pressure transmission annulus;

[0050] 45. Second shock-absorbing pad;

[0051] 5. pressure-conducting pipe; 51. first side axial hole; 52. first external pressure-transmitting annulus; 53. second pressure-transmitting channel; 54. second external pressure-transmitting annulus; 55. third pressure-transmitting channel;

[0052] 6. Center tube;

[0053] 7. Shut-in sampling valve;

[0054] 71. First outer protective tube;

[0055] 711, first upper protective tube; 7111, first pressurizing hole; 71111, first rupture disk; 7112, first upper limit shoulder; 7113, first through hole; 7114, second through hole; 7115, lateral hole; 7116, process hole; 7117, first stepped hole; 7118, second stepped hole; 7119, third stepped hole;

[0056] 712, first lower protective tube; 7121, first outer flow guide hole; 7122, locking groove;

[0057] 72, first sliding sleeve; 721, production channel; 722, first inner guide hole; 723, first step; 724, first lower limit shoulder; 725, first convex ring; 726, second convex ring;

[0058] 73. First shear nail;

[0059] 74. The first inner pressure transmission annulus;

[0060] 75. Sampling annulus; 751. Sealed sampling space;

[0061] 76, locking sleeve; 761, elastic claw; 7611, convex ridge;

[0062] 77, lofting valve assembly; 771, lofting valve; 772, lofting plug; 773, safety valve;

[0063] 78. First shock pad;

[0064] 8. The first pressure gauge holder;

[0065] 9. Bottom blocking. DETAILED DESCRIPTION

[0066] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0067] like Figures 3 to 8 As shown, this embodiment provides a shut-in sampling valve 7, including a first outer protective tube 71 and a first sliding sleeve 72, and a first pressurizing hole 7111 and a first outer flow guide hole 7121 are respectively opened on the upper pipe wall and the lower pipe wall of the first outer protective tube 71.

[0068] A production channel 721 is formed inside the first sleeve 72. The first sleeve 72 can be slidably inserted into the first outer protective tube 71. The first sleeve 72 can be connected to the first outer protective tube 71 through the first shear nail 73. A first inner flow guide hole 722 that can communicate with the first outer flow guide hole 7121 is formed on the lower pipe wall of the first sleeve 72. A first step 723 with an enlarged diameter is formed upward on the middle outer wall of the first sleeve 72. A sealed first inner pressure transmission annulus 74 is formed between the outer wall of the first sleeve 72 and above the first step 723 and the inner wall of the first outer protective tube 71. The first inner pressure transmission annulus 74 is connected to the first pressurized hole 7111 and the first step 723. A sampling annulus 75 that can communicate with the production channel 721 is formed between the upper outer wall of the first sleeve 72 and the inner wall of the first outer protective tube 71. When the first shear pin 73 is cut off, the first sleeve 72 can slide upward along the axial direction of the first outer protective tube 71 until the upper outer wall of the first sleeve 72 is in sealing contact with the upper inner wall of the first outer protective tube 71, and the sampling annulus 75 forms a sealed sampling space 751 with both ends closed.

[0069] Specifically, the first sleeve 72 has at least a first working position and a second working position. When the first sleeve 72 is in the first working position, the first sleeve 72 is connected to the first outer protective tube 71 through the first shear nail 73, the first inner guide hole 722 is connected to the first outer guide hole 7121, the sampling annulus 75 is connected to the production channel 721, and the shut-in sampling valve 7 is in an open state; when the first sleeve 72 is in the second working position, the first shear nail 73 is cut off, the upper end outer wall of the first sleeve 72 is in sealing contact with the upper end inner wall of the first outer protective tube 71, and a sealed sampling space 751 is formed between the first sleeve 72 and the first outer protective tube 71, the first inner guide hole 722 and the first outer guide hole 7121 are staggered, and the shut-in sampling valve 7 is in a closed state. The volume of the formed sealed sampling space 751 is determined according to needs, for example, its volume can be 200 to 5000 ml.

[0070] When in use, the shut-in sampling valve 7 is lowered into the designated position underground along with the tubing in an open state. At this time, the shut-in sampling valve 7 is in the first working position, the first inner guide hole 722 is connected to the first outer guide hole 7121, and the fluid enters the production channel 721 through the first outer guide hole 7121 and the first inner guide hole 722, and then enters the oil pipe 101 through the upper tubing and is even discharged to the wellhead. At the same time, the fluid will also fill the sampling annulus 75. When it is necessary to shut in the well, pressure is applied to the casing annulus, and the pressure is transmitted to the first pressure hole 7111 and then to the first inner pressure transmission annulus 74. The high-pressure liquid acts on the first step 723 and applies pressure to the first sleeve 72. When the pressure reaches a certain value, the first shear pin 73 is sheared off, and the liquid pushes the first sleeve 72 to move upward until the upper outer wall of the first sleeve 72 is in sealing contact with the upper inner wall of the first outer protective tube 71. At this time, the upper end of the sampling annulus 75 is closed to form a sealed sampling space 751, and the fluid is confined in the sealed sampling space 751 to achieve shut-in sampling. At this time, the first sleeve 72 is in the second working position, and the shut-in sampling valve 7 is in a closed state.

[0071] Therefore, the shut-in sampling valve 7 in this embodiment is in an open state in the initial state through the cooperation of the first outer protective tube 71 and the first sliding sleeve 72, and can carry out the drainage and production operation; when shutting in the well, the shut-in sampling valve 7 can be closed by pressurizing the oil casing annulus, and the high-temperature and high-pressure fluid in the well can be confined in the sealed sampling space 751 at the moment of shutting in the well, so as to realize the downhole shut-in sampling at the moment after the drainage and production, and realize the sampling under the conditions of downhole opening of non-flowing wells and near-reservoir depth under stable flow state, which is conducive to obtaining qualified formation fluid and high-pressure physical property samples in the near-reservoir area of ​​low-yield wells, and overcomes the deficiency that it is difficult to obtain qualified formation fluid samples when the previous test valve is far away from the reservoir.

[0072] In the specific implementation, Figure 3 and Figure 5 As shown, a first lower limit shoulder 724 with an enlarged diameter is formed downwardly on the outer wall of the first sleeve 72 and between the sampling annulus 75 and the first inner pressure transmission annulus 74, and a first shock-absorbing pad 78 is provided above the first lower limit shoulder 724. A first upper limit shoulder 7112 with a reduced diameter is formed upwardly on the inner wall of the first outer protective tube 71 and between the sampling annulus 75 and the first lower limit shoulder 724, and a preset moving distance is left between the first lower limit shoulder 724 and the first upper limit shoulder 7112. When the first shear nail 73 is cut off, as shown in FIG. Figure 7 As shown, the first lower limit shoulder 724 can be pressed against the first upper limit shoulder 7112 through the first shock-absorbing pad 78.

[0073] Among them, the first shock-absorbing pad 78 is generally an annular rubber pad, which can be sleeved in the annular space between the first lower limit shoulder 724 and the first upper limit shoulder 7112, so as to play a role in vibration reduction when the first sleeve 72 moves upward to prevent tool damage. When designing, the preset moving distance between the first lower limit shoulder 724 and the first upper limit shoulder 7112 should be able to ensure that when the first lower limit shoulder 724 is pressed against the first upper limit shoulder 7112 through the first shock-absorbing pad 78, the first inner guide hole 722 and the first outer guide hole 7121 are staggered with each other, and a sealed sampling space 751 is formed between the first sleeve 72 and the first outer protective tube 71. In this way, when the first sleeve 72 moves upward, the first sleeve 72 and the upper inner wall of the first outer protective tube 71 are in sliding sealing contact, and the first upper limit shoulder 7112 constitutes a limit on the upward travel of the first sleeve 72, so as to avoid the first sleeve 72 moving upward too far and affecting the sampling of the sealed sampling space 751.

[0074] Furthermore, in order to avoid the downward movement of the first sliding sleeve 72 due to the high pressure on the upper part when the pipe string is pulled out after the construction, thereby affecting the sealing state of the sealing sampling annulus 75, as shown in FIG. Figure 5 As shown, a locking sleeve 76 is connected to the lower end of the first sliding sleeve 72, and a plurality of elastic claws 761 are formed on the lower end wall of the locking sleeve 76. A ridge 7611 is protruded outwardly on the lower outer wall of each elastic claw 761. An annular locking groove 7122 is formed on the lower inner wall of the first outer protective tube 71 and below the first outer guide hole 7121. When the first shear pin 73 is cut off, as shown in FIG. Figure 7 As shown, each ridge 7611 can be locked in the locking groove 7122.

[0075] Generally, the upper outer wall of the locking sleeve 76 is threadedly connected to the lower inner wall of the first sliding sleeve 72, and a slit is formed between two adjacent elastic claws 761, which runs through the bottom of the locking sleeve 76, so that each elastic claw 761 has a certain elasticity; each convex rib 7611 preferably adopts an arc-shaped rib. When the first sliding sleeve 72 is in the first working position, each convex rib 7611 radially presses on the inner wall of the first outer protective tube 71 below the locking groove 7122; when the first sliding sleeve 72 moves up to the second working position, the first sliding sleeve 72 moves up to the end of the stroke, and each convex rib 7611 is clamped in the locking groove 7122 to lock the position of the first sliding sleeve 72. Of course, the locking sleeve 76 may also adopt other structural forms, as long as the position of the first sleeve 72 can be locked after the first sleeve 72 is successfully moved up for sampling, so as to obtain a qualified PVT (Pressure-Volume-Temperature) sample (i.e., a sample of a mixture of oil, gas and water obtained under bottom hole pressure, temperature and closed volume conditions).

[0076] In practical applications, in order to facilitate the removal of the fluid trapped in the sealed sampling space 751 after the pipe string is pulled out, a sample-laying valve assembly 77 is provided on the upper pipe wall of the first outer protective pipe 71; when the first shear nail 73 is cut off, the sample-laying valve assembly 77 can be connected to the sealed sampling space 751.

[0077] More specifically, if Figure 8 As shown, the lofting valve assembly 77 includes a lofting valve 771 and a lofting plug 772. A first through hole 7113 and a second through hole 7114 are provided in the side wall of the first outer protective tube 71. The first through hole 7113 and the second through hole 7114 are connected to each other and penetrate the outer side wall thereof. A lateral hole 7115 is provided in the side wall of the first outer protective tube 71 and penetrates the inner side wall thereof. The lateral hole 7115 is arranged opposite to the first through hole 7113 and can be connected to the first through hole 7113. The lofting valve 771 can be adjustedly fixed in the first through hole 7113 and can block the lateral hole 7115. The lofting plug 772 can be detachably fixed in the second through hole 7114.

[0078] Generally, the first through hole 7113 and the second through hole 7114 are coaxially arranged and perpendicular to the axial direction of the lateral hole 7115. In order to facilitate the processing of the lateral hole 7115, a process hole 7116 penetrating the outer wall thereof is further arranged in the side wall of the first outer protective tube 71. The process hole 7116 is coaxially arranged with the lateral hole 7115 and the diameter of the process hole 7116 is larger than the diameter of the lateral hole 7115. A safety valve 773 is arranged in the process hole 7116 to block the process hole 7116. Before taking out the fluid sample, the sample valve 771 always blocks the lateral hole 7115, and the sample plug 772 blocks the second through hole 7114. When the tubing column is pulled out and the fluid sample needs to be taken out, the sampling plug 772 is first removed, and a sampling barrel or a sample transfer device is connected to the second through hole 7114; then the sampling valve 771 is partially rotated outward to expose the lateral hole 7115. At this time, the lateral hole 7115 is connected to the second through hole 7114, and the liquid in the sealed sampling space 751 can enter the sampling barrel or the sample transfer device through the lateral hole 7115 and the second through hole 7114, thereby completing the sampling or sample transfer of the fluid sample.

[0079] Furthermore, in order to facilitate processing and installation, as Figure 5 and Figure 6As shown, the first outer protective tube 71 includes a first upper protective tube 711 and a first lower protective tube 712 which are sealed and fixed up and down. A first step hole 7117, a second step hole 7118 and a third step hole 7119 with decreasing apertures are formed on the inner wall of the first upper protective tube 711 from bottom to top. The top hole shoulder of the first step hole 7117 constitutes a first upper limit shoulder 7112. The first pressurizing hole 7111 is opened on the tube wall of the first upper protective tube 711 and corresponds to the position of the first step hole 7117. The first outer guide hole 7121 is opened on the tube wall of the first lower protective tube 712. The upper outer wall of the first sleeve 72 protrudes outward to form a first convex ring 725 and a second convex ring 726 spaced apart from each other. The second convex ring 726 is embedded in the first stepped hole 7117. The top surface of the second convex ring 726 forms a first lower limit shoulder 724, and the bottom surface of the second convex ring 726 forms a first step 723. A first inner pressure transmission annulus 74 is formed between the outer wall of the second convex ring 726 and the hole wall of the first stepped hole 7117. The first convex ring 725 is sealingly embedded in the second stepped hole 7118, and a sampling annulus 75 can be formed between the portion of the first sleeve 72 above the first convex ring 725 and the hole wall of the second stepped hole 7118.

[0080] In general, the lower inner wall of the first upper protective tube 711 is threadedly connected to the upper outer wall of the first lower protective tube 712, and the first lower protective tube 712 can be connected to the first sleeve 72 through the above-mentioned first shear nail 73. When the first sleeve 72 is in the first working position, the first step 723 abuts against the upper end surface of the first lower protective tube 712. At this time, the lower end of the sampling annulus 75 is closed but the upper end is not closed, so it can be connected with the production channel 721. When the first sleeve 72 is in the second working position, the outer wall of the first sleeve 72 part above the first convex ring 725 is in sealing contact with the hole wall of the first stepped hole 7117, and a sealed sampling space 751 is formed between the sampling annulus 75 and the bottom hole shoulder of the first stepped hole 7117. It can be understood that the outer diameter of the second convex ring 726 is greater than the outer diameter of the first convex ring 725 , the locking groove 7122 is provided on the first lower protective tube 712 , and the lofting valve assembly 77 is provided on the tube wall of the first upper protective tube 711 corresponding to the second stepped hole 7118 .

[0081] In addition, multiple sealing rings are sleeved on the outer wall of the first sleeve 72 and located above and below the first inner flow guide hole 722 to ensure the sealing performance during the drainage and production; multiple sealing rings are sleeved on the outer wall of the second convex ring 726 and located above the first inner pressure transmission annulus 74 to ensure the sealing performance of the first inner pressure transmission annulus 74; multiple sealing rings are sleeved on the outer wall of the first convex ring 725, and multiple sealing rings are sleeved on the outer wall of the upper end of the first sleeve 72 and located above the first convex ring 725 to ensure the sealing performance of the sealed sampling space 751 formed after the second sleeve 42 moves up. It can be understood that an annular groove is opened on the corresponding outer wall of the second sleeve 42, and the sealing ring is embedded in the annular groove.

[0082] Furthermore, if Figures 1 to 8 As shown, this embodiment also provides a test oil string, including an oil pipe 101, a bypass joint 1, a packer 3, a pressure-conducting pipe 5, the shut-in sampling valve 7 and a bottom plug 9 connected in sequence from top to bottom.

[0083] The lower part of the pressure-conducting pipe 5 is sleeved on the upper outer side of the first outer protective pipe 71 and forms a sealed first outer pressure-transmitting annulus 52 with the upper outer wall of the first outer protective pipe 71. The first outer pressure-transmitting annulus 52 is communicated with the first pressurized hole 7111. An inner pressure-transmitting pipe 2 passing through the interior of the packer 3 is connected between the bypass joint 1 and the pressure-conducting pipe 5. The upper end of the inner pressure-transmitting pipe 2 is communicated with the outside of the bypass joint 1 through the first pressure-transmitting channel 12 provided in the bypass joint 1, and the lower end of the inner pressure-transmitting pipe 2 is communicated with the first outer pressure-transmitting annulus 52 through the second pressure-transmitting channel 53 provided in the side wall of the pressure-conducting pipe 5. The production channel 721 is communicated with the oil pipe 101 through the first side axial hole 51 provided in the side wall of the pressure-conducting pipe 5, the annulus between the packer 3 and the inner pressure-transmitting pipe 2, and the second side axial hole 11 provided in the bypass joint 1.

[0084] A central tube 6 may also be inserted into the first sleeve 72, the upper end of the central tube 6 is sealed and fixed to the pressure-conducting pipe 5 and communicates with the inner pressure-transmitting pipe 2, and the lower end thereof passes through the interior of the first pressure gauge holder 8 and is sealed and fixedly connected to the bottom plug 9. At this time, the gap between the central tube 6 and the first sleeve 72 constitutes the above-mentioned production channel 721. Of course, the position of the pressure-conducting pipe 5 corresponding to the bottom end of the inner pressure-transmitting pipe 2 may also be directly designed as a closed structure to simplify the structure.

[0085] When in use, after the pipe string is lowered into the designated position and sealed, the formation fluid enters the oil pipe 101 through the production channel 721, the first side axial hole 51, the annulus between the packer 3 and the inner pressure transmission pipe 2, and the second side axial hole 11. When shutting in the well, the oil casing annulus above the packer 3 is pressurized, and the pressure is transmitted to the first pressurized hole 7111 through the first pressure transmission channel 12, the inner pressure transmission pipe 2, the second pressure transmission channel 53 and the first outer pressure transmission annulus 52, and then transmitted to the first inner pressure transmission annulus 74 and acts on the first step 723. When the first shear nail 73 is cut off, the first sliding sleeve 72 moves up to realize the well shut-in sampling, which is easy to operate.

[0086] Furthermore, a first pressure gauge holder 8 is connected between the shut-in sampling valve 7 and the bottom plug 9, and a first pressure gauge capable of recording the pressure in the production channel 721 is provided on the first pressure gauge holder 8. Thus, the pressure data can be measured in time at the moment of shutting in the well by setting the first pressure gauge, thereby realizing the measurement of the pressure recovery curve under the shut-in condition in the downhole of the low permeability reservoir.

[0087] In practical applications, in order to reopen the well for production after shutting in the well for sampling, Figure 3 and Figure 4 As shown, a well-opening valve 4 is connected between the packer 3 and the pressure-conducting pipe 5. The well-opening valve 4 includes a second outer protective pipe 41 and a second sliding sleeve 42. A second outer flow guide hole 4111 and a second pressurizing hole 4121 are respectively opened on the upper pipe wall and the lower pipe wall of the second outer protective pipe 41.

[0088] The second sleeve 42 can be slidably inserted into the second outer protective tube 41. The second sleeve 42 can be connected to the second outer protective tube 41 through the second shear nail 43. The second inner flow guide hole 421 that can communicate with the second outer flow guide hole 4111 is opened on the upper pipe wall of the second sleeve 42. A second step 422 with an enlarged diameter is formed downward on the middle outer wall of the second sleeve 42. A sealed second inner pressure transmission annulus 44 is formed between the outer wall of the second sleeve 42 and below the second step 422 and the inner wall of the second outer protective tube 41. The second inner pressure transmission annulus 44 is connected with the second pressurized hole 4121 and the second step 422. The inner pressure transmission pipe 2 is inserted into the second sleeve 42, and the gap between the inner pressure transmission pipe 2 and the second sleeve 42 is connected with the production channel 721. The upper part of the pressure-conducting pipe 5 is sleeved on the outer side of the lower part of the second outer protective tube 41 and forms a sealed second outer pressure-transmitting annulus 54 with the lower outer wall of the second outer protective tube 41. The second outer pressure-transmitting annulus 54 is connected to the second pressurized hole 4121, and the second outer pressure-transmitting annulus 54 is connected to the inner pressure-transmitting pipe 2 through a third pressure-transmitting channel 55 provided in the side wall of the pressure-conducting pipe 5.

[0089] Specifically, the second sleeve 42 has at least a first position and a second position. When the second sleeve 42 is in the first position, the second sleeve 42 is connected to the second outer protective tube 41 through the second shear nail 43, the second inner flow guide hole 421 and the second outer flow guide hole 4111 are staggered, and the well valve 4 is in a closed state; when the second sleeve 42 is in the second position, the second shear nail 43 is cut off, and the second inner flow guide hole 421 is connected to the second outer flow guide hole 4111. The well valve 4 is in an open state. It can be understood that the above-mentioned production channel 721 is not connected to the interior of the inner pressure transmission tube 2.

[0090] When in use, the well-opening valve 4 is in a closed state, and the well-closing sampling valve 7 is in an open state. The pipe string is lowered into the designated position in the well and sealed. Figure 3As shown, at this time, the well opening valve 4 is in the first position, and the well closing sampling valve 7 is in the first working position, so that liquid can be discharged for production; when it is necessary to close the well, the well closing sampling valve 7 can be closed by pressurizing the oil casing annulus to complete the well closing sampling; after completing one well closing, if it is necessary to open the well for production again, the oil casing annulus above the packer 3 is pressurized again, and the pressure is transmitted to the second outer pressure transmission annulus 54 through the first pressure transmission channel 12, the inner pressure transmission pipe 2 and the third pressure transmission channel 55, and then transmitted to the second inner pressure transmission annulus 44 through the second pressurized hole 4121, and the high-pressure liquid acts on the second step 422 and pressurizes the second sliding sleeve 42. When the pressure reaches a certain value, the second shear nail 43 is sheared off, and the liquid pushes the second sliding sleeve 42 to move downward until the second inner guide hole 421 is connected with the second outer guide hole 4111, as shown in FIG. Figure 7 As shown, at this time, the second sliding sleeve 42 is in the second position, the well valve 4 is in the open state, and the drainage production can be carried out again.

[0091] Furthermore, in order to facilitate the downward movement of the second sliding sleeve 42 to limit the position, and to ensure that the second inner guide hole 421 can be connected with the second outer guide hole 4111 after the second sliding sleeve 42 moves downward, as shown in FIG. Figure 4 As shown, a second upper limit shoulder 423 with an enlarged diameter is formed upward on the outer wall of the second sleeve 42 and located below the second inner pressure transmission annulus 44, and a second shock-absorbing pad 45 is provided below the second upper limit shoulder 423. A second lower limit shoulder 4122 with a reduced diameter is formed downward on the inner wall of the second outer protective tube 41 and located below the second upper limit shoulder 423, and a preset moving distance is left between the second upper limit shoulder 423 and the second lower limit shoulder 4122. When the second shear nail 43 is cut off, as shown in FIG. Figure 7 As shown, the second upper limit shoulder 423 can be pressed against the second lower limit shoulder 4122 through the second shock absorbing pad 45 to form a limit. Generally, the second shock absorbing pad 45 is an annular rubber pad, which can be sleeved in the annular space between the second upper limit shoulder 423 and the second lower limit shoulder 4122 to play a vibration reduction role when the second sliding sleeve 42 moves downward to prevent tool damage.

[0092] In addition, in order to facilitate the positioning of the second sliding sleeve 42 during installation, a limiting convex ring 4112 is formed on the inner wall of the upper end of the second outer protective tube 41 and is located above the second sliding sleeve 42 and protrudes inward. When the second sliding sleeve 42 is in the first position, Figure 4 As shown, the upper end of the second sliding sleeve 42 rests against the bottom surface of the limiting protruding ring 4112 .

[0093] Furthermore, in order to facilitate processing and installation, the second outer protective tube 41 includes a second upper protective tube 411 and a second lower protective tube 412 which are sealed and connected up and down, a second outer flow guide hole 4111 is opened on the tube wall of the second upper protective tube 411, and a limiting convex ring 4112 is formed on the inner wall of the upper end of the second upper protective tube 411. A second pressurizing hole 4121 is opened on the tube wall of the second lower protective tube 412, and a second lower limiting shoulder 4122 is formed on the inner wall of the second lower protective tube 412. A third convex ring 424 is formed protruding outward from the middle outer part of the second sliding sleeve 42, the top surface of the third convex ring 424 constitutes a second step 422, the bottom surface of the third convex ring 424 constitutes a second upper limiting shoulder 423, and a second inner pressure transmission annulus 44 is formed between the outer wall of the third convex ring 424 and the inner wall of the second lower protective tube 412. Generally, the lower outer wall of the second upper protective tube 411 is threadedly connected to the upper inner wall of the second lower protective tube 412, and the second upper protective tube 411 is connected to the second sliding sleeve 42 through the second shear nail 43. When the second sliding sleeve 42 is in the first position, the second step 422 abuts against the lower end surface of the second upper protective tube 411.

[0094] It can be understood that multiple sealing rings are sleeved on the outer wall of the second sleeve 42 and located above and below the second inner guide hole 421, multiple sealing rings are sleeved on the outer wall of the third convex ring 424 and located below the second inner pressure transmission annulus 44, and multiple sealing rings are sleeved on the outer wall of the lower end of the second sleeve 42 and located below the third convex ring 424, so as to ensure the sealing at all locations.

[0095] In the specific implementation process, in order to better control the pressure when the shut-in sampling valve 7 is closed and the openable well valve 4 is opened, as shown in FIG. Figure 3 As shown, a first rupture disk 71111 is provided at the first pressurizing hole 7111 , and a second rupture disk 41211 is provided at the second pressurizing hole 4121 , and a rupture pressure value of the second rupture disk 41211 is greater than a rupture pressure value of the first rupture disk 71111 .

[0096] The structure of the rupture disk here is the prior art. After the tubing string is lowered into the designated position and sealed, the shut-in sampling valve 7 is in an open state, and the fluid can be discharged and production can be obtained, and the bottom hole flow pressure data is recorded through the above-mentioned first pressure gauge; when it is necessary to shut in the well, the oil casing annulus is pressurized to the rupture pressure value of the first rupture disk 71111, the pressure is transmitted to the inside of the shut-in sampling valve 7 and the first shear nail 73 is cut off, so that the shut-in sampling is closed and the sampling annulus 75 is simultaneously enclosed to form a sealed sampling space 751, and the downhole PVT sampling is completed, and the downhole instant shut-in + sampling is realized, and the first pressure gauge starts to record the shut-in pressure data; when it is necessary to open the well again, the oil casing annulus is pressurized to the rupture pressure value of the second rupture disk 41211, the pressure is transmitted to the inside of the well-opening valve 4 and the second shear nail 43 is cut off, so that the well-opening valve 4 is opened, and the well is opened again.

[0097] Furthermore, if Figure 2 As shown, a circulation valve 104, a second pressure gauge holder 105 and a safety joint 106 are sequentially connected between the oil pipe 101 and the well-opening valve 4 from top to bottom, and a second pressure gauge capable of recording the pressure in the casing annulus is provided on the second pressure gauge holder 105. Before the construction is completed and the pipe string is started, the circulation valve 104 is opened and clean water is pumped into the casing annulus for reverse circulation well washing to wash out the fluid and impurities in the pipe string.

[0098] The second pressure gauge is mainly used to check whether the packer 3 is set reliably and plays a role in leak detection. The safety joint 106 can be disengaged when the lower pipe string is stuck, so that the upper pipe string can be normally pulled out, and then the lower pipe string can be salvaged, making the construction safer and more reliable. The structures of the circulation valve 104, the second pressure gauge, the safety joint 106 and the above-mentioned first pressure gauge are all existing technologies and will not be repeated here.

[0099] Furthermore, in order to play an inducing role in the production of drainage, such as Figure 1 As shown, a negative pressure valve 102 and a connecting nipple 103 connected up and down are provided between the oil pipe 101 and the circulation valve 104.

[0100] Among them, the structure of the negative pressure valve 102 is the existing technology, and the negative pressure valve 102 and the connecting short section 103 constitute the induced spraying and drainage assembly. The negative pressure valve 102 has a ceramic piece that can block the inside of the negative pressure valve 102 to separate the inside of the pipe string above and below the negative pressure valve 102. When the pipe string is lowered into the well, a part of water can be added to the inside of the pipe string above the negative pressure valve 102 and the oil pipe 101 is not filled up; after the pipe string is lowered to the designated position underground and sealed, a rod is thrown into the pipe string to break the ceramic piece inside the negative pressure valve 102. The connecting short section 103 is a tubular structure with an inner diameter smaller than the inner diameter of the negative pressure valve 102. The broken ceramic piece can fall on the connecting short section 103, and the pipe string parts above and below the negative pressure valve 102 are connected.

[0101] When the pipe string is lowered, the shut-in sampling valve 7 is in an open state, and the interior of the pipe string below the negative pressure valve 102 is connected to the casing annulus; through the separation effect of the ceramic plate in the negative pressure valve 102, only a small amount of water is added to the upper pipe string, so that after the pipe string is connected from top to bottom, the liquid level in the pipe string is lower than the liquid level in the casing annulus, and a negative pressure is formed in the pipe string to achieve the effect of inducing spraying. Of course, other structures can also be used to achieve the effect of inducing spraying and draining as needed. For example, after the pipe string is sealed, a pump (the structure of the pump is the prior art) can be lowered into the pipe string through a steel wire to achieve suction and inducing spraying.

[0102] In summary, the oil testing string in this embodiment has the following advantages:

[0103] (1) It realizes the conventional oil test suction (or N2 gas lift, sucker rod pumping) of non-flowing wells, the downhole well shut-in measurement of pressure recovery and sampling immediately after production, and achieves the purpose of timely recording qualified pressure recovery curves and downhole sampling.

[0104] (2) The tubing string is provided with a shut-in sampling valve 7 near the reservoir, which enables sampling under the conditions of downhole opening of non-flowing wells and near-reservoir depth under stable flow conditions, which is conducive to obtaining qualified formation fluid and high-pressure physical property samples in the near-reservoir area of ​​low-yield wells, and overcomes the previous disadvantage that it is difficult to obtain qualified PVT samples when the test valve is far away from the reservoir.

[0105] (3) The pressure recovery curve of low permeability reservoirs under downhole shut-in conditions was achieved, which solved the problem of conventional well testing in non-flowing wells that was difficult to shut down, and also overcame the influence of wellbore storage effect when shutting in and measuring pressure recovery at the wellhead of flowing wells in low permeability reservoirs.

[0106] (4) Compared with existing formation testing technology, it is simpler to operate, requires fewer tools, and is less expensive.

[0107] Furthermore, this embodiment also provides an operation method of the above-mentioned oil testing string, comprising the following steps:

[0108] S10, lowering the tubing string and setting the packer: lower the test tubing string into the well to the designed depth, form an oil-casing annulus between the test tubing string and the casing, adjust the test tubing string, and set the packer 3.

[0109] Among them, the shut-in sampling valve 7 enters the well in an open state, the first inner guide hole 722 is connected to the first outer guide hole 7121, and the sampling annulus 75 is connected to the production channel 721; the open-well valve 4 enters the well in a closed state, and the second inner guide hole 421 and the second outer guide hole 4111 are staggered with each other.

[0110] In step S10, if the column Figure 1 As shown in FIG. 1 , the negative pressure valve 102 is provided. Then, in step S10, the pipe string should be lowered according to the designed test pressure difference, and clean water should be poured into the oil pipe 101 according to the oil test design requirements until the pipe string is lowered into the designated position. Figure 2 As shown, the negative pressure valve 102 is not provided. At this time, the inside of the tubing string is connected with the annulus of the casing, and the tubing string can be directly lowered.

[0111] S20, induce fluid flow and discharge, and determine production: induce fluid flow and discharge on the test oil string, and the fluid in the formation enters the oil pipe 101 through the first outer guide hole 7121, the first inner guide hole 722 and the production channel 721 in sequence (it may or may not be discharged from the ground after entering the oil pipe 101, depending on the production level), and the bottom hole flow pressure data is recorded through the first pressure gauge.

[0112] In step S20, if the column Figure 1 As shown in the figure, a negative pressure valve 102 is provided. Then, a rod needs to be thrown to open the negative pressure valve 102 so that negative pressure is formed in the pipe string to induce spraying and discharge fluid, and then enter the well flow test. If there is a negative pressure valve 102 in the pipe string, the negative pressure valve 102 is opened. Figure 2 As shown, no negative pressure valve 102 is provided, and after the pipe string is sealed, a pump can be lowered into the pipe string through a steel wire to achieve suction and injection.

[0113] S30, shut-in sampling: pressurize the casing annulus above the packer 3 to a first pressure value, and the hydraulic pressure sequentially passes through the first pressure transmission channel 12, the interior of the inner pressure transmission tube 2, the second pressure transmission channel 53, the first outer pressure transmission annulus 52, the first pressurized hole 7111 and the first inner pressure transmission annulus 74 and acts on the first step 723, the first shear pin 73 is cut off, and the liquid pushes the first sleeve 72 to move upward, so that the first inner guide hole 722 and the first outer guide hole 7121 are staggered with each other, and a sealed sampling space 751 is formed between the first sleeve 72 and the first outer protective tube 71 to confine the fluid in the sealed sampling space 751; the pressure data recorded by the first pressure gauge can obtain the pressure recovery curve when the well is shut in.

[0114] The first pressure gauge in this embodiment may have two probes, which can measure both pressure data and temperature data. The structure of the first pressure gauge is prior art.

[0115] S40, well killing, unsealing, and pulling out the tubing string: the well is washed and killed in sequence on the test tubing string, and then the wellhead is dismantled, the test tubing string is pulled up, the packer 3 is unsealed, and the test tubing string is pulled out.

[0116] In step S40, the circulation valve 104 is used for well washing, and the well washing operation can be performed after the circulation valve 104 is opened. After the test oil string is pulled out, if the fluid sample in the sealed sampling space 751 needs to be taken out, the connection between the pressure-conducting pipe 5 and the first outer protective pipe 71 needs to be disconnected first, and then the sample valve assembly 77 is used to perform sample laying or sample transfer operation.

[0117] Furthermore, the following steps are included between step S30 and step S40:

[0118] S35, reopening the well for production: pressurizing the casing annulus above the packer 3 to a second pressure value, which is greater than the first pressure value. The hydraulic pressure sequentially passes through the first pressure transmission channel 12, the interior of the inner pressure transmission tube 2, the third pressure transmission channel 55, the second outer pressure transmission annulus 54, the second pressurized hole 4121, and the second inner pressure transmission annulus 44 and acts on the second step 422. The second shear pin 43 is cut off, and the liquid pushes the second sliding sleeve 42 downward, so that the second inner guide hole 421 is connected to the second outer guide hole 4111, and the fluid in the formation enters the oil pipe 101 sequentially through the second outer guide hole 4111 and the second inner guide hole 421 (depending on the production level, the fluid may or may not be discharged from the ground after entering the oil pipe 101).

[0119] In this way, when it is necessary to open the well for production again, after completing step S35, the process proceeds to step S40; if it is not necessary to open the well for production again, the process proceeds directly to step S40 after completing step S30.

[0120] It should be noted that the upper and lower positions mentioned in this embodiment refer to the positions when used in a vertical well. However, in actual use, the shut-in sampling valve 7 and the oil testing string in this embodiment can be used not only in vertical wells, but also in horizontal wells.

[0121] The above are only exemplary embodiments of the present invention and are not intended to limit the scope of the present invention. Any equivalent changes and modifications made by any person skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A shut-in sampling valve, characterized in that: It comprises a first outer protective tube and a first sliding sleeve, wherein the upper tube wall and the lower tube wall of the first outer protective tube are respectively provided with a first pressurizing hole and a first outer flow guide hole; A production channel is formed inside the first sleeve, the first sleeve can be slidably inserted into the first outer protective tube, the first sleeve can be connected to the first outer protective tube by a first shear nail, and a first inner flow guide hole that can communicate with the first outer flow guide hole is opened on the lower tube wall of the first sleeve; a first step with a diameter enlarged upward is formed on the middle outer wall of the first sleeve, and a sealed first inner pressure transmission annulus is formed between the outer wall of the first sleeve and above the first step and the inner wall of the first outer protective tube, and the first inner pressure transmission annulus is communicated with the first pressurized hole and the first step; a sampling annulus that can communicate with the production channel is formed between the upper outer wall of the first sleeve and the inner wall of the first outer protective tube; When the first shear pin is cut off, the first sliding sleeve can slide upward along the axial direction of the first outer protective tube until the upper outer wall of the first sliding sleeve is in sealing contact with the upper inner wall of the first outer protective tube, so that the sampling annulus forms a sealed sampling space with both ends closed; A first lower limit shoulder with an enlarged diameter is formed downwardly on the outer wall of the first sliding sleeve and located between the sampling annulus and the first inner pressure transmission annulus, and a first shock-absorbing pad is provided above the first lower limit shoulder; a first upper limit shoulder with a reduced diameter is formed upwardly on the inner wall of the first outer protective tube and located between the sampling annulus and the first lower limit shoulder, and a preset moving distance is left between the first lower limit shoulder and the first upper limit shoulder; when the first shear nail is cut off, the first lower limit shoulder can be pressed against the first upper limit shoulder through the first shock-absorbing pad; The first outer protective tube comprises a first upper protective tube and a first lower protective tube which are sealed and fixed up and down, a first stepped hole, a second stepped hole and a third stepped hole whose apertures decrease sequentially from bottom to top are formed on the inner wall of the first upper protective tube, the top hole shoulder of the first stepped hole constitutes the first upper limit shoulder, the first pressurizing hole is opened on the tube wall of the first upper protective tube and corresponds to the position of the first stepped hole, and the first outer guide hole is opened on the tube wall of the first lower protective tube; The upper outer wall of the first sleeve protrudes outward to form a first convex ring and a second convex ring spaced apart from each other in an upper and lower direction. The second convex ring is embedded in the first stepped hole. The top surface of the second convex ring constitutes the first lower limit shoulder, and the bottom surface of the second convex ring constitutes the first step. The first internal pressure transmission annulus is formed between the outer wall of the second convex ring and the hole wall of the first stepped hole. The first convex ring is seal-embedded in the second stepped hole, and the sampling annulus can be formed between the portion of the first sleeve above the first convex ring and the hole wall of the second stepped hole.

2. The shut-in sampling valve according to claim 1, characterized in that: A locking sleeve is connected to the lower end of the first sliding sleeve, and a plurality of elastic claws are formed on the lower end tube wall of the locking sleeve. A convex ridge is protruded outward on the lower end outer wall of each elastic claw. An annular locking groove is provided on the lower inner wall of the first outer protective tube and below the first outer guide hole; when the first shear nail is cut off, each convex ridge can be stuck in the locking groove.

3. The shut-in sampling valve according to claim 1, characterized in that: A lofting valve assembly is provided on the upper tube wall of the first outer protective tube; when the first shear nail is cut off, the lofting valve assembly can be connected with the sealed sampling space.

4. The shut-in sampling valve according to claim 3, characterized in that: The sample release valve assembly includes a sample release valve and a sample release plug. A first through hole and a second through hole that are interconnected and both penetrate the outer side wall are provided in the side wall of the first outer protective tube, and a lateral hole that penetrates the inner side wall is provided in the side wall of the first outer protective tube. The lateral hole is arranged opposite to the first through hole and can be connected to the first through hole. The sample release valve can be adjustably fixed in the first through hole and can block the lateral hole, and the sample release plug can be detachably fixed in the second through hole.

5. A test oil string, characterized in that: It comprises an oil pipe, a bypass joint, a packer, a pressure-conducting pipe, a shut-in sampling valve according to any one of claims 1 to 4, and a bottom plug connected in sequence from top to bottom; The lower part of the pressure-conducting pipe is sleeved on the upper outer side of the first outer protective pipe and forms a sealed first outer pressure-transmitting annulus with the upper outer wall of the first outer protective pipe, and the first outer pressure-transmitting annulus is communicated with the first pressurized hole; an inner pressure-transmitting pipe passing through the interior of the packer is connected between the bypass joint and the pressure-conducting pipe, the upper end of the inner pressure-transmitting pipe is communicated with the outside of the bypass joint through a first pressure-transmitting channel provided in the bypass joint, and the lower end of the inner pressure-transmitting pipe is communicated with the first outer pressure-transmitting annulus through a second pressure-transmitting channel provided in the side wall of the pressure-conducting pipe; The production channel is connected with the oil pipe through a first side axial hole arranged in the side wall of the pressure-conducting pipe, an annulus between the packer and the inner pressure-transmitting pipe, and a second side axial hole arranged in the bypass joint.

6. The oil testing string according to claim 5, characterized in that: A first pressure gauge holder is connected between the shut-in sampling valve and the bottom plug, and a first pressure gauge capable of recording the pressure in the production channel is provided on the first pressure gauge holder.

7. The oil testing string according to claim 6, characterized in that: A well-opening valve is connected between the packer and the pressure-conducting pipe, and the well-opening valve includes a second outer protective pipe and a second sliding sleeve; A second outer flow guide hole and a second pressurizing hole are respectively provided on the upper tube wall and the lower tube wall of the second outer protective tube; the second sliding sleeve can be slidably arranged in the second outer protective tube, the second sliding sleeve can be connected to the second outer protective tube through a second shear nail, and a second inner flow guide hole that can communicate with the second outer flow guide hole is provided on the upper tube wall of the second sliding sleeve; a second step with an enlarged diameter is formed downward on the middle outer wall of the second sliding sleeve, and a sealed second inner pressure transmission annulus is formed between the outer wall of the second sliding sleeve and below the second step and the inner wall of the second outer protective tube, and the second inner pressure transmission annulus is communicated with the second pressurizing hole and the second step; The inner pressure transmission pipe is inserted into the second sliding sleeve, and the gap between the inner pressure transmission pipe and the second sliding sleeve is connected to the production channel; the upper part of the pressure-conducting pipe is sleeved on the outer side of the lower part of the second outer protective pipe and forms a sealed second outer pressure transmission annulus with the lower outer wall of the second outer protective pipe, the second outer pressure transmission annulus is connected to the second pressurizing hole, and the second outer pressure transmission annulus is connected to the inner pressure transmission pipe through a third pressure transmission channel arranged in the side wall of the pressure-conducting pipe.

8. The oil testing string according to claim 7, characterized in that: A second upper limit shoulder with an enlarged diameter is formed upward on the outer wall of the second sliding sleeve and located below the second inner pressure transmission annulus, and a second shock-absorbing pad is provided below the second upper limit shoulder; a second lower limit shoulder with a reduced diameter is formed downward on the inner wall of the second outer protective tube and located below the second upper limit shoulder, and a preset moving distance is left between the second upper limit shoulder and the second lower limit shoulder; when the second shear nail is cut off, the second upper limit shoulder can be pressed against the second lower limit shoulder through the second shock-absorbing pad.

9. The oil testing string according to claim 7, characterized in that: A first rupture disk is disposed at the first pressurizing hole, and a second rupture disk is disposed at the second pressurizing hole, and a rupture pressure value of the second rupture disk is greater than a rupture pressure value of the first rupture disk.

10. The oil testing string according to claim 7, characterized in that: A circulation valve, a second pressure gauge holder and a safety joint are sequentially connected between the oil pipe and the well-opening valve from top to bottom. The second pressure gauge holder is provided with a second pressure gauge capable of recording the pressure in the casing annulus.

11. The oil testing string according to claim 10, characterized in that: A negative pressure valve and a connecting nipple connected up and down are provided between the oil pipe and the circulation valve.

12. A method for operating a test oil string according to any one of claims 7 to 11, characterized in that: The steps include: S10, lowering the test string and setting the packer: lowering the test string into the well to a designed depth, forming an annulus between the test string and the casing, adjusting the test string, and setting the packer; Wherein, the shut-in sampling valve is put into the well in an open state, the first inner flow guide hole is communicated with the first outer flow guide hole, and the sampling annulus is communicated with the production channel; the openable well valve is put into the well in a closed state, and the second inner flow guide hole and the second outer flow guide hole are staggered with each other; S20, inducing blowout and draining fluid, and calculating production: inducing blowout and draining fluid from the test oil string, and the fluid in the formation enters the oil pipe through the first outer diversion hole, the first inner diversion hole and the production channel in sequence, and the bottom hole flow pressure data is recorded through the first pressure gauge; S30, shut-in sampling: pressurize the casing annulus above the packer to a first pressure value, and the hydraulic pressure sequentially passes through the first pressure transmission channel, the interior of the inner pressure transmission tube, the second pressure transmission channel, the first outer pressure transmission annulus, the first pressurized hole, and the first inner pressure transmission annulus and acts on the first step, the first shear pin is cut off, and the liquid pushes the first sliding sleeve upward, so that the first inner guide hole and the first outer guide hole are staggered, and the sealed sampling space is formed between the first sliding sleeve and the first outer protective tube to confine the fluid in the sealed sampling space; the pressure data recorded by the first pressure gauge can obtain the pressure recovery curve when the well is shut in; S40, well killing, unsealing, and pulling out the tubing string: the well is washed and killed in sequence on the test oil tubing string, and then the wellhead is dismantled, the test oil tubing string is pulled up, the packer is unsealed, and the test oil tubing string is pulled out.

13. The method for operating the oil testing string according to claim 12, characterized in that: The following steps are also included between step S30 and step S40: S35, reopening the well for production: pressurizing the casing annulus above the packer to a second pressure value, wherein the second pressure value is greater than the first pressure value, and hydraulic pressure sequentially passes through the first pressure transmission channel, the interior of the inner pressure transmission pipe, the third pressure transmission channel, the second outer pressure transmission annulus, the second pressurized hole and the second inner pressure transmission annulus and acts on the second step, the second shear pins are cut off, and the liquid pushes the second sliding sleeve downward, so that the second inner guide hole is connected to the second outer guide hole, and the fluid in the formation sequentially enters the oil pipe through the second outer guide hole and the second inner guide hole.

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