Oil testing methods and oil testing strings

Abstract

The present invention provides an oil testing method and an oil testing string. The oil testing method includes the following steps: placing a perforating gun into a sleeve and perforating multiple predetermined oil testing layers; removing the perforating gun and placing the oil testing string into the sleeve, aligning multiple electrically controlled test tubes of the oil testing string with the multiple oil testing layers; separating and sealing the multiple oil testing layers with the oil testing string; testing the multiple oil testing layers with the oil testing string; performing reverse circulation well killing on the oil testing string; and removing the oil testing string. The present invention solves the problems of multiple steps and high risks associated with existing oil testing processes.

Description

Technical Field

[0001] The present invention relates to the technical field of oil testing of evaluation wells, in particular to an oil testing method and an oil testing string. Background Art

[0002] During oil and gas field exploration and evaluation, because the oil and gas properties and productivity of each reservoir are unknown, current oil testing techniques all rely on layer-by-layer up- or down-testing. This means conducting independent oil and production tests on each layer to confirm the fluid properties and productivity of each reservoir and provide data support for subsequent development and evaluation (only the up-testing is described in detail). After the S1 layer oil testing is completed, the bridge plug under the perforated interval is sealed and cement is injected 5 to 10 meters deep. Then, oil testing is conducted on the next layer (up-testing) (repeating the S1 layer testing steps).

[0003] For exploration and appraisal wells, since the fluid properties and production capacity of each layer are unknown, each layer needs to be independently tested and tested to confirm the reservoir fluid properties and production capacity. For example, after drilling, coring and logging interpretation, two layers are found to have good performance and may contain industrial oil flow. In this case, both layers need to be tested to confirm the fluid properties and production capacity. The two layers are defined as S1 and S2 from bottom to top. The S1 layer is tested first. The conventional single-layer test process includes:

[0004] 1) Use tubing structure to deepen the well bottom;

[0005] 2) Perforating with tubing structure to open the S1 layer and break the blockage;

[0006] 3) Lower the fracturing string and withdraw the fluid to increase production;

[0007] 4) Use the wireline car to measure the flow temperature and pressure of the production layer and the pressure and temperature gradient along the wellbore;

[0008] 5) Use a wireline car sampler to perform downhole PVT sampling;

[0009] 6) A bridge plug is used under the tubing structure to seal the S1 layer.

[0010] After sealing, the S2 layer is tested (repeating the S1 process). Finally, the bridge plug is drilled out and the well is ready for production. This operation requires bottomhole exploration, perforating with tubing, running the fracturing string, measuring pressure gradients, pressure recovery, and downhole PVT sampling for each layer. Furthermore, a bridge plug must be run before returning to the surface to seal the formation. After the test, the bridge plug is drilled out using a coiled tubing structure. This involves multiple steps (involving tubing lifting and lowering, wireline operations, etc.), is time-consuming, labor-intensive, and costly. Furthermore, the repetitive nature of these operations increases the risk of well control.

[0011] In other words, the existing oil test process has the problems of many steps and high risks. Summary of the Invention

[0012] The main purpose of the present invention is to provide a well testing method and a well testing string to solve the problems of multiple steps and high risks in the well testing process in the prior art.

[0013] To achieve the above-mentioned object, according to one aspect of the present invention, a method for oil testing is provided, comprising the following steps: placing a perforating gun into a casing and perforating a plurality of preset oil testing layers; removing the perforating gun and placing an oil testing string into the casing, aligning a plurality of electrically controlled test tubes of the oil testing string with the plurality of oil testing layers; separating and sealing the plurality of oil testing layers with the oil testing string; testing the plurality of oil testing layers with the oil testing string respectively; performing reverse circulation well killing on the oil testing string; and removing the oil testing string.

[0014] Furthermore, the test oil string separates and seals multiple test oil layers, including the following steps: the ground control box closes multiple electrically controlled test tubes of the test oil string to isolate the sleeve from the oil pipe structure; the oil pipe structure is pressurized, and multiple packers on the oil pipe structure expand and abut against the sleeve to seal, so that the area between adjacent sleeves and the oil pipe structure is separated by the packers into multiple independent test sections.

[0015] Furthermore, the oil testing string conducts oil testing on multiple oil testing layers respectively, including the following steps: step S1; the ground control box opens one of the multiple electric-controlled test cylinders; step S2: if the oil testing layer corresponding to the opened electric-controlled test cylinder produces oil, step S3 is executed; if the corresponding oil testing layer does not produce oil, step S3 is skipped and step S4 is executed directly; step S3: an unstable well test is performed on the oil testing layer corresponding to the opened electric-controlled test cylinder; step S4: after the oil testing layer corresponding to the opened electric-controlled test cylinder is fracturing, an unstable well test is performed on the oil testing layer corresponding to the opened electric-controlled test cylinder; steps S1 to S4 are repeated to conduct oil testing on different oil testing layers until the oil testing of all oil testing layers is completed.

[0016] Furthermore, during an unstable well test on the test oil layer corresponding to the opened electric-controlled test cylinder, the size of the surface oil nozzle is changed, and the electric-controlled test cylinder records the flow temperature and flow pressure of the oil.

[0017] Furthermore, during the unstable well test on the test oil layer corresponding to the opened electric-controlled test cylinder, the opened electric-controlled test cylinder is closed, and a pressure recovery test is performed on the test oil layer.

[0018] Furthermore, during the unstable well test of the test oil layer corresponding to the opened electric-controlled test cylinder, after the electric-controlled test cylinder is closed, the oil remaining in the electric-controlled test cylinder is sampled.

[0019] Furthermore, performing reverse circulation well killing on the test oil string includes the following steps: the ground control box closes all the electronically controlled test tubes, opens the back-pressure well valve of the test oil string, and introduces fluid into the oil pipe structure through the back-pressure well valve.

[0020] Furthermore, during the process of removing the test oil string, if the density inside the tubing structure is equal to the density inside the sleeve, the test oil string is removed.

[0021] According to another aspect of the present invention, there is provided an oil test string, in which the above-mentioned oil test method is applied to the oil test string, which comprises: an oil pipe structure; an electrically controlled test cylinder, wherein the number of the electrically controlled test cylinders is multiple, and the multiple electrically controlled test cylinders are sleeved on the oil pipe structure at intervals, and the electrically controlled test cylinders are connected to the interior of the oil pipe structure; a packer, wherein the number of the packers is multiple, and the packers are sleeved on the oil pipe structure, and a packer is arranged between two adjacent electrically controlled test cylinders; and a ground control box, wherein the cables of the ground control box pass through the packers and are electrically connected to each electrically controlled test cylinder.

[0022] Furthermore, the oil test string also includes a back-pressure well valve, which is arranged above all the seals. The oil pipe structure has multiple oil pipes, and the multiple oil pipes are connected in sequence to form the oil pipe structure. At least the oil pipe located below the back-pressure well valve has a central oil hole and an offset hole. The electrically controlled test tube is connected to the central oil hole, and the cable is inserted into the offset hole and electrically connected to the electrically controlled test tube.

[0023] By applying the technical solution of the present invention, the oil testing method includes the following steps: placing a perforating gun into a sleeve and perforating a plurality of preset oil testing layers; removing the perforating gun and placing an oil testing string into the sleeve, aligning a plurality of electrically controlled test tubes of the oil testing string with the plurality of oil testing layers; separating and sealing the plurality of oil testing layers with the oil testing string; testing the plurality of oil testing layers with the oil testing string respectively; performing reverse circulation well killing on the oil testing string; and removing the oil testing string.

[0024] The perforating gun is placed in the sleeve to simultaneously perforate multiple test oil layers, which increases perforation efficiency and avoids the need for the perforating gun to be repeatedly inserted into the sleeve, thus reducing the operator's working time and workload. The test oil string is placed in the sleeve, while ensuring that the multiple electronically controlled test cylinders are aligned with the multiple test oil layers one by one, so that the multiple electronically controlled test cylinders can correspond to their corresponding test oil layers, thereby controlling the oil produced by the test oil layers to enter the oil pipe structure through the corresponding electronically controlled test cylinders. The test oil string separates and seals the multiple test oil layers, making the multiple test oil layers independent of each other, so that each test oil layer can be tested separately. The test oil string tests the multiple test oil layers separately, and there is no need to repeatedly pull out the test oil string when testing each test layer separately. This greatly reduces the operating procedures, reduces the operation of perforating the oil field, and increases the safety of working in the oil field. Reverse circulation well killing is performed on the test oil string, so that the pressure in the tubing structure is the same as the pressure in the casing, which can effectively avoid oil spraying when the test oil string is withdrawn, greatly increasing the safety of the oil test. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 The figure shows the positional relationship between the perforating gun and the oil testing layer according to an optional embodiment of the present invention; and

[0027] Figure 2 The figure shows the positional relationship between the oil testing string and the oil testing layer according to an optional embodiment of the present invention;

[0028] Figure 3 Shown Figure 2 Schematic diagram of the structure of the electronically controlled test tube;

[0029] Figure 4 Shown Figure 2 A schematic diagram of the structure when the central valve of the electronically controlled test cylinder is in a closed state;

[0030] Figure 5 Shown Figure 2 A schematic structural diagram of the wiring head of the electronically controlled test barrel;

[0031] Figure 6 Shown Figure 2 Schematic diagram of the structure of the lateral valve of the electronically controlled test cylinder.

[0032] The above drawings include the following reference numerals:

[0033] 10. Perforating gun; 20. Sleeve; 30. Test layer; 40. Test string; 41. Electrically controlled test tube; 411. Cylinder; 4111. Main body; 4112. First joint; 4113. Second joint; 412. Center valve; 413. Lateral valve; 4131. Sleeve inner tube; 4132. Lateral seal; 4133. Protective sleeve; 4134. Return spring; 414. Sampling structure; 415. Drive structure; 4151. First drive unit; 4152. Second drive unit; 4153. Third drive unit; 42. Oil pipe structure; 43. Packer; 44. Back-pressure well valve; 50. Ground control box; 60. Terminal block; 61. Electric wire; 62. Protective tube; 63. Filling material; 64. Sealing structure; 641. Sealing packing; 642. First locking device; 643. Packing cap; 644. Second locking device; 70. Measurement and control circuit board; 80. Direct-reading pressure gauge; 90. Storage-type electronic pressure gauge. DETAILED DESCRIPTION

[0034] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0035] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0036] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity direction; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above directional words are not used to limit the present invention.

[0037] In order to solve the problems of multiple steps and high risks in the oil testing process in the prior art, the present invention provides an oil testing method and an oil testing string.

[0038] like Figures 1 to 6 As shown, the oil testing method includes the following steps: placing a perforating gun 10 into a sleeve 20 and perforating a plurality of preset oil testing layers 30; removing the perforating gun 10 and placing an oil testing string 40 into the sleeve 20, aligning a plurality of electrically controlled test tubes 41 of the oil testing string 40 with the plurality of oil testing layers 30; separating and sealing the plurality of oil testing layers 30 with the oil testing string 40; testing the plurality of oil testing layers 30 with the oil testing string 40 respectively; performing reverse circulation well killing on the oil testing string 40; and removing the oil testing string 40.

[0039] The perforating gun 10 is placed in the sleeve 20 to simultaneously perforate multiple test layers 30, increasing perforation efficiency and avoiding the need for the perforating gun 10 to be repeatedly inserted into the sleeve 20. This reduces the operator's work time and workload. The test string 40 is placed in the sleeve 20, ensuring that the multiple electronically controlled test cylinders 41 are aligned with the multiple test layers 30. This allows the multiple electronically controlled test cylinders 41 to correspond to their corresponding test layers 30, controlling the oil produced from the test layers 30 to enter the tubing structure through the corresponding electronically controlled test cylinders 41. The test string 40 separates and seals the multiple test layers 30, making them independent from one another and facilitating separate oil testing of each test layer 30. The test string 40 tests each of the multiple test layers 30 separately, eliminating the need to repeatedly withdraw the test string 40 during each test. This significantly reduces the number of operational steps, minimizes perforation operations in the oil field, and increases safety in the oil field. Reverse circulation is performed on the test oil string 40 to kill the well, so that the pressure in the oil pipe structure 42 is the same as the pressure in the sleeve 20 and is greater than the formation pressure. This can effectively avoid oil spraying when the test oil string 40 is extracted, greatly increasing the safety of the oil test.

[0040] Specifically, the test oil string 40 separates and seals multiple test oil layers 30, including the following steps: the ground control box 50 closes the multiple electrically controlled test cylinders 41 of the test oil string 40 to isolate the sleeve 20 from the tubing structure 42; the tubing structure 42 is pressurized, and the multiple packers 43 on the tubing structure 42 expand and abut against the sleeve 20 to seal, so that the area between adjacent sleeves 20 and the tubing structure 42 is separated into multiple independent test sections by the packers 43. The setting of the ground control box 50 allows the electrically controlled test cylinders 41 to be operated at any time, which increases the convenience of controlling the electrically controlled test cylinders 41. The electrically controlled test cylinders 41 are electrically controlled and can be operated at any time. The sealing and opening operations of the test oil layer 30 can be controlled at any time, making the oil testing process more convenient. All electronically controlled test tubes 41 on the oil testing string 40 are closed, making the tubing structure 42 and the casing 20 independent of each other. Pressure is then applied to the tubing structure 42, gradually increasing the pressure therein. The packers 43 expand under the pressure of the tubing structure 42. Once the packers 43 abut and seal against the casing 20, pressure is halted. The multiple packers 43 now divide the casing 20 into multiple independent testing sections, each containing an electronically controlled test tube 41 and a testing layer 30. This allows independent oil testing to be performed on each testing layer 30.

[0041] Specifically, the oil testing string 40 performs oil testing on multiple oil testing layers 30 respectively, including the following steps: Step S1: The ground control box 50 opens one of the multiple electric control test tubes 41; Step S2: If the oil testing layer 30 corresponding to the opened electric control test tube 41 produces oil, then step S3 is executed; if the corresponding oil testing layer 30 does not produce oil, then step S3 is skipped and step S4 is executed directly; Step S3: An unstable well test is performed on the oil testing layer 30 corresponding to the opened electric control test tube 41; Step S4: After the oil testing layer 30 corresponding to the opened electric control test tube 41 is fractured, an unstable well test is performed on the oil testing layer 30 corresponding to the opened electric control test tube 41; Steps S1 to S4 are repeated to perform oil testing on different oil testing layers 30 until the oil testing of all oil testing layers 30 is completed. This arrangement allows oil testing on any oil testing layer 30, regardless of the location of the oil testing layer 30, thereby increasing the convenience of oil testing. After the test oil layer 30 produces oil, an unstable well test is performed on the test oil layer 30 to test the oil production performance of each test oil layer 30.

[0042] Specifically, during an unstable well test of the test oil layer 30 corresponding to the opened electronically controlled test cylinder 41, the size of the surface oil nozzle is changed, and the electronically controlled test cylinder 41 records the oil flow temperature and pressure. The electronically controlled test cylinder 41 is equipped with a pressure sensor and a temperature sensor, both of which are electrically connected to the surface control box 50. When the surface oil nozzle is changed to perform an unstable well test on the test oil layer 30, the pressure sensor measures the flow pressure of the oil within the tubing structure, and the temperature sensor measures the flow temperature of the oil within the tubing structure. The flow temperature and pressure are reflected in real time on the surface control box 50, thereby monitoring the flow temperature and pressure in real time, ensuring the stability of the test oil environment and avoiding potential safety hazards.

[0043] Specifically, during the unstable well test of the test oil layer 30 corresponding to the opened electric control test cylinder 41, the opened electric control test cylinder 41 is closed and a pressure recovery test is performed on the test oil layer 30. In this way, logging data of the test oil layer 30 is collected for subsequent operations on the test oil layer 30.

[0044] Specifically, during an unstable well test of the oil test layer 30 corresponding to the open electronically controlled test cylinder 41, after closing the electronically controlled test cylinder 41, the oil remaining in the electronically controlled test cylinder 41 is sampled. The electronically controlled test cylinder 41 has a sampling structure within it. When the electronically controlled test cylinder 41 is open, oil flows through the electronically controlled test cylinder 41 into the oil pipe structure 42. At this point, some oil flows into the sampling structure. After closing the electronically controlled test cylinder 41, the oil remains in the sampling structure. Oil samples from different oil test layers 30 can be obtained from different electronically controlled test cylinders 41, reducing the number of separate sampling operations, simplifying the operational steps, and saving costs.

[0045] Specifically, reverse circulation well killing of the test oil string 40 includes the following steps: the ground control box 50 closes all electrically controlled test tubes 41, opens the backpressure well valves 44 of the test oil string 40, and introduces fluid into the tubing structure 42 through the backpressure well valves 44. After testing each test oil layer 30, the ground control box 50 closes all electrically controlled test tubes 41, opens the backpressure well valves 44 on the test oil string 40, and introduces high-density fluid into the tubing structure 42 through the backpressure well valves 44, thereby increasing the pressure in the tubing structure 42 so that the pressure and density in the sleeve 20 and the tubing structure 42 are the same. At the same time, the pressure at the backpressure well valves 44 is greater than the formation pressure to prevent oil from blowing out of the surface.

[0046] It should be noted that the back-pressure well valve 44 has basically the same function as the electronically controlled test tube 41 , but the back-pressure well valve 44 only has a switch function and does not have downhole sampling, pressure measurement and other functions. It is only used for circulating well pressure when removing the test oil string 40.

[0047] Specifically, during the process of removing the test string 40, if the density within the tubing structure 42 equals the density within the casing 20, the test string 40 is removed. A high-density fluid is introduced into the tubing structure 42 to increase the pressure and density within the tubing structure 42. When the density within the tubing structure 42 equals the density within the casing 20, the test string 40 is removed. Simultaneously, the pressure at the backpressure well valve 44 is maintained above the formation pressure to prevent the oil in the casing 20 from being blown out.

[0048] like Figure 2 As shown, the above-described oil testing method is applied to an oil testing string 40, which includes a tubing structure 42, an electronically controlled test tube 41, a packer 43, and a ground control box 50. Multiple electronically controlled test tubes 41 are spaced apart and connected to the interior of the tubing structure 42. Multiple packers 43 are also present, each of which is sleeved onto the tubing structure 42, with one packer 43 positioned between two adjacent electronically controlled test tubes 41. The cables of the ground control box 50 pass through the packers 43 and are electrically connected to each electronically controlled test tube 41. This arrangement ensures that only one electronically controlled test tube 41 is positioned between two adjacent packers 43. During operation of the oil testing string 40, each oil testing zone 30 can undergo independent oil testing. The cables of the ground control box 50 pass through the packers 43 and are electrically connected to each electronically controlled test tube 41, facilitating control of each electronically controlled test tube 41.

[0049] Optionally, the test well string 40 also includes a back-pressure well valve 44, which is positioned above all packers 43. The tubing structure 42 comprises multiple tubings, which are sequentially connected to form the tubing structure 42. At least the tubing below the back-pressure well valve 44 has a central oil hole and an offset hole. The electrically controlled test tube 41 communicates with the central oil hole, and a cable is inserted into the offset hole to electrically connect to the electrically controlled test tube 41. The central oil hole facilitates oil flow, while the offset hole accommodates and protects the cable, ensuring stable operation of the test well string 40 and enhancing operational safety.

[0050] like Figure 3 and Figure 4As shown, the electronically controlled test cylinder 41 includes a cylinder body 411 , a central valve 412 , a side valve 413 , a sampling structure 414 and a driving structure 415 . The two ends of the cylinder 411 are respectively connected to different electronically controlled test cylinders 41, and the circumferential side wall of the cylinder 411 at one end close to the ground has a lateral through hole connected to the interior of the cylinder 411, and the electronically controlled test cylinder 41 also includes the following respectively arranged inside the cylinder 411: a central valve 412 is arranged at one end of the cylinder 411 away from the lateral through hole, when the central valve 412 is closed, the central valve 412 divides the interior of the cylinder 411 into two independent spaces located on both sides of the central valve 412; a lateral valve 413 is arranged at one end of the cylinder 411 close to the lateral through hole, when the lateral valve 413 is opened, the lateral through hole is connected to the interior of the cylinder 411, and when the lateral valve 413 is closed, the lateral valve 413 seals the lateral through hole; a sampling structure 414 is close to the lateral through hole relative to the central valve 412; a driving structure 415 is arranged on the inner side wall of the petroleum cylinder and is respectively driven and connected to the central valve 412, the lateral valve 413 and the sampling structure 414.

[0051] When using the intelligent oil testing mandrel of the above structure, when different oil layers need to be tested, it is only necessary to close the central valve 412 of the intelligent oil testing mandrel of the corresponding oil layer and open the lateral valve 413, and open the central valve 412 and close the lateral valve 413 of other intelligent oil testing mandrels. In this way, only the oil in the oil layer to be tested can enter the interior of the cylinder 411 through the lateral valve 413 of the corresponding intelligent oil testing mandrel, and be sampled through the sampling structure 414 to complete the oil test. In this process, the opening and closing of the central valve 412 and the opening and closing of the lateral valve 413 are driven by the driving structure 415, and the sampling structure is also driven by the driving structure 415. Therefore, the intelligent oil testing mandrel in the present application effectively simplifies the oil testing process, thereby effectively solving the problem of complex oil testing process in the prior art.

[0052] like Figure 3 As shown, the cylinder 411 includes a main body 4111, a first connector 4112, and a second connector 4113. The main body 4111 has a lateral through hole, and the center valve 412, the lateral valve 413, the sampling structure 414, and the drive structure 415 are all arranged inside the main body 4111; the first connector 4112 is connected to the end of the main body 4111 away from the lateral through hole, and one end of the first connector 4112 extends into the interior of the main body 4111 and is connected to the center valve 412. When the center valve 412 is opened, the interior of the first connector 4112 is connected to the interior of the main body 4111; the second connector 4113 is connected to the end of the main body 4111 away from the first connector 4112. By providing the first connector 4112 and the second connector 4113, it can be effectively ensured that the intelligent oil testing working cylinder can be more easily connected to the oil pipe structure.

[0053] like Figure 3 and Figure 4 As shown, the drive structure 415 includes a first drive unit 4151, a second drive unit 4152, and a third drive unit 4153. The first drive unit 4151 is driven and connected to the center valve 412, the second drive unit 4152 is driven and connected to the side valve 413, and the third drive unit 4153 is driven and connected to the sampling structure 414. The drive structure 415 also includes two terminal blocks 60, which are respectively provided at both ends of the cylinder body 411 and electrically connected to the first drive unit 4151, the second drive unit 4152, and the third drive unit 4153. This arrangement can effectively ensure that the drive structure 415 can respectively drive the center valve 412, the side valve 413, and the sampling structure 414, thereby effectively ensuring the performance of the intelligent oil testing mandrel.

[0054] like Figure 5 As shown, one end of the terminal block 60 extends into the interior of the barrel 411, and the other end of the terminal block 60 is located outside the barrel 411. The terminal block 60 includes a wire 61, a protective tube 62, a filler 63, and a sealing structure 64. The protective tube 62 is sleeved over the wire 61; the filler 63 is filled between the wire 61 and the protective tube 62; and the sealing structure 64 is sleeved over the protective tube 62.

[0055] like Figure 5 As shown, the sealing structure 64 includes at least one sealing packing 641, a first locking device 642, at least one packing pressure cap 643, and a second locking device 644. The first locking device 642 is sleeved on the outside of the protective tube 62, and there is a accommodating space between the first locking device 642 and the protective tube 62. The sealing packing 641 is arranged in the accommodating space; the packing pressure cap 643 corresponds to the sealing packing 641 one by one, and the packing pressure cap 643 is arranged in the accommodating space. One end of the packing pressure cap 643 abuts the first locking device 642, and the other end of the packing pressure cap 643 abuts the sealing packing 641; the second locking device 644 is sleeved on the end of the protective tube 62 away from the cylinder 411, and the end of the sealing device close to the cylinder 411 abuts the first locking device 642. Through this arrangement, a three-level sealing structure 64 of the terminal 60 can be achieved, thereby effectively preventing the terminal 60 from entering the liquid and thus preventing the terminal 60 from short-circuiting.

[0056] like Figure 6As shown, the lateral valve 413 includes a sliding sleeve inner tube 4131 , a lateral seal 4132 , a protective sliding sleeve 4133 and a return spring 4134 . The drive structure 415 is drivably connected to the sleeve inner tube 4131 to drive the sleeve inner tube 4131 to slide along the length of the cylinder 411. At least one lateral seal 4132 is provided on each side of the lateral through hole, and the lateral seal 4132 is disposed between the sleeve inner tube 4131 and the cylinder 411. When the lateral valve 413 is closed, one end of the protective sleeve 4133 abuts the inner sidewall of the cylinder 411, and the other end of the protective sleeve 4133 abuts the sleeve inner tube 4131. A return spring 4134 is disposed between the protective sleeve 4133 and the cylinder 411, with one end of the return spring 4134 abutting the protective sleeve 4133 and the other end of the return spring 4134 abutting the cylinder 411. The length of the return spring 4134 is aligned with the length of the cylinder 411. The provision of the protective sleeve 4133 and the return spring 4134 effectively protects the lateral seal 4132 from erosion by fracturing sand.

[0057] Specifically, the intelligent oil testing mandrel further includes a pressure measuring structure, which is disposed between the central valve 412 and the lateral valve 413 .

[0058] Specifically, the pressure measurement structure includes a measurement and control circuit board 70, a direct-reading pressure gauge 80 and a storage electronic pressure gauge 90, which are respectively arranged along the length direction of the cylinder 411. The measurement and control circuit board 70 is connected to the direct-reading pressure gauge 80, and the measurement and control circuit board 70 is close to the center valve 412 relative to the direct-reading pressure gauge 80.

[0059] In one specific embodiment of the present application, a direct-reading pressure gauge 80 transmits the monitored downhole pressure and temperature to a surface controller via a wire 61. This is used to monitor downhole flow temperature and pressure in real time, record the downhole flow temperature and pressure conditions for each well testing system, and enable system prediction and rapid decision-making during the well testing process. A storage-type electronic pressure gauge 90 serves as a backup for the direct-reading pressure gauge 80, with each function controlled by an independent motor.

[0060] Preferably, there are two lateral through holes, and the two lateral through holes are symmetrically arranged relative to the axis of the cylinder 411.

[0061] In one specific embodiment of the present application, an intelligent oil testing mandrel uses wires 61 for power and data transmission. It is lowered into the well along with the tubing structure, with one intelligent oil testing mandrel lowered into each test zone. A surface control box, via wires 61, controls the opening and closing of the intelligent oil testing mandrel, the opening and closing of the central channel of the tubing structure, and the downhole PVT sampling, fracturing, production testing, and shut-down and re-pressurization processes.

[0062] The above-mentioned oil testing method does not require multiple movements of the oil testing string 40, and can achieve real-time measurement of pressure and temperature of each layer downhole. It has the advantages of no isolation and no testing, and fast and efficient up and down switching, which reduces operating costs while achieving efficient oil testing.

[0063] Obviously, the embodiments described above are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0064] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, tasks, devices, components and / or combinations thereof.

[0065] It should be noted that the terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0066] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for oil testing, characterized in that: The steps include: Putting a perforating gun (10) into a sleeve (20) and perforating a plurality of preset oil test layers (30); The perforating gun (10) is removed and the oil test string (40) is placed into the sleeve (20), and the plurality of electrically controlled test tubes (41) of the oil test string (40) are aligned with the plurality of oil test layers (30); The oil testing string (40) separates and seals the plurality of oil testing layers (30); The oil testing string (40) performs oil testing on a plurality of the oil testing layers (30) respectively; Performing reverse circulation well killing on the oil testing string (40); Taking out the oil test string (40); The oil testing string (40) performs oil testing on a plurality of the oil testing layers (30) respectively, comprising the following steps: Step S1: The ground control box (50) opens one of the plurality of electric control test cylinders (41); Step S2: if the oil test layer (30) corresponding to the opened electric control test cylinder (41) produces oil, then step S3 is executed; if the corresponding oil test layer (30) does not produce oil, then step S3 is skipped and step S4 is directly executed; The step S3: performing an unstable well test on the oil test layer (30) corresponding to the opened electric control test cylinder (41); The step S4: after fracturing the test oil layer (30) corresponding to the opened electric control test cylinder (41), performing an unstable well test on the test oil layer (30) corresponding to the opened electric control test cylinder (41); Repeating steps S1 to S4 to perform oil testing on different oil testing layers (30) until the oil testing of all the oil testing layers (30) is completed; The electrically controlled test cylinder (41) comprises a cylinder body (411), a central valve (412), a lateral valve (413), a sampling structure (414), and a driving structure (415), wherein the driving structure (415) is respectively connected to the central valve (412), the lateral valve (413), and the sampling structure (414); When the oil testing string (40) is used to test the oil in a plurality of the oil testing layers (30), the central valve (412) of the electric-controlled test cylinder (41) corresponding to the oil testing layer (30) is closed and the lateral valve (413) is opened, while the central valve (412) of the other electric-controlled test cylinders (41) is opened and the lateral valve (413) is closed, so that the oil in the oil testing layer (30) to be tested can enter the interior of the cylinder (411) through the lateral valve (413) of the corresponding electric-controlled test cylinder (41), and be sampled through the sampling structure (414) to complete the oil testing.

2. The oil testing method according to claim 1, characterized in that: The oil testing string (40) separates and seals the plurality of oil testing layers (30) and includes the following steps: The ground control box (50) closes the multiple electric control test tubes (41) of the oil test string (40) to isolate the sleeve (20) from the oil pipe structure (42); The tubing structure (42) is pressurized, and the multiple packers (43) on the tubing structure (42) expand and abut against the sleeve (20) for sealing, so that the area between the adjacent sleeves (20) and the tubing structure (42) is separated into multiple independent test sections by the packers (43).

3. The oil testing method according to claim 1, characterized in that: During an unstable well test of the oil test layer (30) corresponding to the opened electric control test cylinder (41), the size of the surface oil nozzle is changed, and the electric control test cylinder (41) records the flow temperature and flow pressure of the oil.

4. The oil testing method according to claim 1, characterized in that: During an unstable well test on the oil test layer (30) corresponding to the opened electric control test cylinder (41), the opened electric control test cylinder (41) is closed, and a pressure recovery test is performed on the oil test layer (30).

5. The oil testing method according to claim 4, characterized in that: During an unstable well test of the oil test layer (30) corresponding to the opened electric control test cylinder (41), after closing the electric control test cylinder (41), the oil remaining in the electric control test cylinder (41) is sampled.

6. The oil testing method according to claim 1, characterized in that: The reverse circulation well killing of the test oil string (40) comprises the following steps: a ground control box (50) closes all the electric control test tubes (41), opens the back-pressure well valve (44) of the test oil string (40), and introduces fluid into the oil pipe structure (42) through the back-pressure well valve (44).

7. The oil testing method according to claim 1, characterized in that: During the process of removing the oil test string (40), if the density inside the oil pipe structure (42) is equal to the density inside the sleeve (20), the oil test string (40) is removed.

8. A test oil string, characterized in that: The oil testing method according to any one of claims 1 to 7 is applied to the oil testing string (40), and the oil testing string (40) comprises: Oil pipe structure (42); An electrically controlled test cylinder (41), wherein the electrically controlled test cylinder (41) is in plurality, and the plurality of electrically controlled test cylinders (41) are sleeved on the oil pipe structure (42) at intervals, and the electrically controlled test cylinder (41) is in communication with the interior of the oil pipe structure (42); A packer (43), wherein the packers (43) are multiple and are sleeved on the oil pipe structure (42), and one packer (43) is provided between two adjacent electric control test cylinders (41); A ground control box (50) is provided, wherein the cables of the ground control box (50) pass through the packer (43) and are electrically connected to each of the electric control test cylinders (41).

9. The oil testing string according to claim 8, characterized in that: The oil test string (40) further includes a back-pressure well valve (44), which is arranged above all the packers (43). The oil pipe structure (42) has a plurality of oil pipes, which are sequentially connected to form the oil pipe structure (42). At least the oil pipe located below the back-pressure well valve (44) has a central oil hole and an offset hole. The electrically controlled test tube (41) is connected to the central oil hole, and the cable is inserted into the offset hole and electrically connected to the electrically controlled test tube (41).

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