Packer-screen assembly, test tubing string and operating procedures

Abstract

This invention belongs to the field of petroleum exploration and development technology, and discloses a packer-screen pipe combination device, a test tubing string, and an operating method. The combination device includes a pressure transmission pipe and a screen pipe. The screen pipe further includes a mandrel, a reset mechanism, and an outer cylinder. The mandrel is sandwiched between the pressure transmission pipe and the outer cylinder, forming a first annulus with the pressure transmission pipe. A second flow guide channel and a first flow guide channel are respectively provided on the mandrel and the outer cylinder. The second flow guide channel connects to the first annulus. The mandrel can move axially under external force. The reset mechanism enables the mandrel to move upwards and provides two different stroke endpoints for two consecutive upward movements of the mandrel, namely the first endpoint and the second endpoint. The first endpoint and the second endpoint correspond to the opening and closing of the screen pipe. In use, only an external force needs to be applied to the mandrel and then released; the opening and closing state of the screen pipe can be switched under the action of the reset mechanism, and the number of well opening and closing operations is unlimited.

Description

Technical Field

[0001] This invention relates to the field of petroleum exploration and development technology, and in particular to a packer-screen tube assembly, a test tubing string, and an operating method. Background Technology

[0002] Traditional perforation-testing combined operation uses Johnston's multi-flow test valve or Halliburton's LPR-N valve, selective test valve and other downhole test valves for operation to achieve negative pressure perforation and multiple well opening and closing. However, it has the following shortcomings in low-permeability reservoir testing: (1) Traditional test valves can only be set above the packer, which is far from the reservoir, resulting in a long test pocket; if a low-permeability reservoir is encountered, the fluid production is low and the pressure recovery speed is slow. The above traditional process is sometimes unable to overcome the wellbore storage effect of low-permeability and ultra-low-permeability reservoirs, resulting in some wells (1) No radial flow was observed when the well was shut in, making it impossible to interpret formation parameters and obtain qualified formation fluid samples, which affected the oil test conclusions and the accurate characterization of formation fluids; (2) Traditional downhole test valves such as multi-flow test valves, LPR-N valves, and selective test valves have disadvantages such as complex structure, high operation difficulty, and high labor intensity, which require a large number of construction personnel and high proficiency, resulting in high cost and high failure rate of traditional perforation-testing combined operations; (3) When using the oil test string and process of traditional test valves, after the oil test is completed, it is necessary to kill the well, pull out the test string, and then run another completion string for production.

[0003] Chinese invention patent CN201510237285.5 discloses a packer-switchable screen tube combination device. Using this packer-switchable screen tube combination device to form a test string, the opening and closing of the production channel for fluid inflow and outflow in the test string can be controlled without a test valve. It has a simple structure and low cost. However, the device has shortcomings: it uses several screen tube sub-units, lacks a reset mechanism, and has a limited total number of opening and closing operations, with no more than two well openings and two well closings each, making it difficult to meet the needs of multiple well openings and closings during well testing and completion operations. Summary of the Invention

[0004] One of the objectives of this invention is to provide a packer-screen assembly that allows for unlimited well opening and closing times, thus meeting the needs of multiple well opening and closing operations during well testing and completion.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A packer-screen tube assembly includes a pressure-transmitting connector, a packer, a screen tube, and a pressure-guiding connector connected in sequence, and also includes a pressure-transmitting tube. Both the pressure-transmitting connector and the pressure-guiding connector have axially penetrating cavities. The front end of the pressure-transmitting tube is inserted into the pressure-transmitting connector but not communicating with its cavity, and the rear end of the pressure-transmitting tube is inserted into the cavity of the pressure-guiding connector. The pressure-transmitting connector has a pressure-transmitting channel connecting the pressure-transmitting tube and the outside of the connector. The screen tube includes:

[0007] The outer cylinder is provided with a first flow channel connecting its inner wall and its outer wall;

[0008] A mandrel is located between the outer cylinder and the pressure transmitting tube. The mandrel is axially movable. A first annulus is formed between the mandrel and the pressure transmitting tube. The rear end of the first annulus is closed, and the front end of the first annulus is connected to the inner cavity of the pressure transmitting joint. A second flow channel is provided on the mandrel to connect the first annulus and its own outer wall.

[0009] The reset mechanism enables the mandrel to move upward and provides two different travel endpoints for two consecutive upward movements of the mandrel. The two travel endpoints are a first endpoint and a second endpoint, respectively. When the mandrel reaches the first endpoint, the second guide channel is connected to the first guide channel. When the mandrel reaches the second endpoint, the second guide channel is disconnected from the first guide channel.

[0010] Preferably, the reset mechanism includes a shift sleeve, a pin, and a reset spring. The shift sleeve is sleeved on the spindle and is axially limited to the spindle. The shift sleeve is provided with a shift groove. One end of the pin is fixed to the outer cylinder, and the other end is inserted into the shift groove. One end of the reset spring abuts against the spindle, and the other end abuts against the outer cylinder.

[0011] The transposition groove is formed by connecting a first Y-shaped groove and a second Y-shaped groove arranged in a circumferentially staggered manner. Both the first and second Y-shaped grooves include a first branch, a second branch, and a third branch. The first branch extends along the axial direction of the transposition sleeve. The second and third branches are both L-shaped and connected to the first branch. One end of the second branch connected to the first branch extends along the axial direction of the transposition sleeve, and the other end of the second branch is inclined away from the third branch. One end of the third branch connected to the first branch is also inclined away from the first branch, and the other end of the third branch extends along the axial direction of the transposition sleeve. The second and third branches of adjacent first and second Y-shaped grooves are connected. The length of the first branch of the first Y-shaped groove is less than the length of the first branch of the second Y-shaped groove. When the pin is located at the end of the first branch of the first Y-shaped groove away from the second and third branches, the spindle is located at the first endpoint. When the pin is located at the end of the first branch of the second Y-shaped groove away from the second and third branches, the spindle is located at the second endpoint.

[0012] Preferably, a pressurizing chamber and an air chamber are provided axially between the mandrel and the outer cylinder, the pressurizing chamber being able to communicate with the pressure transmission pipe, and the air chamber containing enclosed air.

[0013] Preferably, the pressurizing chamber is connected to the pressurizing chamber via a pressurizing channel, and a rupture disc is provided in the pressurizing channel.

[0014] Preferably, the outer cylinder includes an upper connector, a lower connector, and a cylinder body. The front end of the upper connector is connected to the packer, the rear end of the upper connector is inserted into the cylinder body and connected to the cylinder body, the front end of the lower connector is inserted into the cylinder body and connected to the cylinder body, and the rear end of the lower connector is inserted into the inner cavity of the pressure guiding connector and connected to the pressure guiding connector.

[0015] Preferably, the upper connector includes a fixed connector, a protective connector, a shear connector, and a rupture disc connector. The front end of the fixed connector is connected to the packer. The shear connector and the protective connector are respectively sealed to the inner and outer sides of the fixed connector. The shear connector and the protective connector enclose a second annulus. The front end of the rupture disc connector is sandwiched between the shear connector and the protective connector and is sealed to both of them. The rear end of the rupture disc connector is sandwiched between the mandrel and the outer cylinder and is sealed to both. The rupture disc connector, the shear connector, and the mandrel together enclose the pressurizing chamber. The air chamber is formed by the rupture disc connector and the mandrel. The rupture disc is disposed in the mounting hole opened in the rupture disc connector. The two sides of the mounting hole correspond to the pressurizing chamber and the second annulus, respectively. A connecting channel is opened in the fixed connector. One end of the connecting channel communicates with the pressure transmission pipe, and the other end communicates with the second annulus. The second annulus, the connecting channel, and the mounting hole together constitute the pressurizing channel.

[0016] Preferably, the pressure transmitting tube is segmented, comprising a first branch and a second branch arranged axially at intervals. The front end of the first branch is inserted into the pressure transmitting joint and sealed to the pressure transmitting joint. The rear end of the first branch is inserted into the fixed joint and communicates with the pressure transmitting channel. The front end of the second branch is inserted into the fixed joint and sealed to the fixed joint. The rear end of the second branch passes through the shearing joint, the mandrel, and the lower joint in sequence and communicates with the inner cavity of the pressure guiding joint. The interface of the connecting channel communicating with the pressure transmitting tube is located between the first branch and the second branch.

[0017] Preferably, a shear pin is also provided between the mandrel and the outer cylinder.

[0018] The second objective of this invention is to provide a test tubing string, comprising a depth calibration sub, a circulation valve, a first pressure gauge carrier, a safety joint, any of the aforementioned packer-screen assembly, a second pressure gauge carrier, an ignition head, and a perforation gun assembly connected in sequence. The depth calibration sub is connected to the wellhead via tubing. The second pressure gauge carrier carries a transmitter and a pressure gauge, and can transmit pressure data to the packer via the transmitter.

[0019] The third objective of this invention is to provide an operating method for an oil tubing string, used for operating the aforementioned oil testing tubing string, characterized by comprising the following steps:

[0020] With the screen tube set to the open position, the oil testing string is assembled and lowered into the wellbore, forming an annulus between the oil testing string and the wellbore.

[0021] After reaching the predetermined depth, the depth is checked, the test tubing string is adjusted, and the packer is set. The tubing is then set and installed at the wellhead.

[0022] After pressurizing the annulus of the oil sleeve by p1, the pressure is released, and perforation is delayed.

[0023] According to the design procedure, the oil casing annulus is pressurized multiple times p2 (p2>p1) and then depressurized to complete the required well opening and closing procedures and number of times, and to obtain complete and accurate formation data.

[0024] After testing, production can begin directly as needed.

[0025] Alternatively: Open the circulation valve to perform well control, unseal the packer, and retrieve the test tubing.

[0026] The beneficial effects of this invention are as follows: The packer-screen assembly of this invention is equipped with a reset mechanism. This reset mechanism allows the mandrel, which has been moving downwards under external force, to move upwards after being depressurized. The reset mechanism has two different stroke endpoints, limiting the upward stroke of the mandrel. When the mandrel reaches these two different stroke endpoints, it is in a state where the second guide channel is connected to the first guide channel, and in a state where the second guide channel is offset from the first guide channel, corresponding to the open and closed states of the screen. This allows for unlimited well opening and closing near the reservoir, improving the quality of oil testing data. Furthermore, the pressure for each opening and closing operation does not need to be increased compared to the previous operation, reducing the pressure requirements on the casing. Simultaneously, the packer-screen assembly of this invention can also be used for integrated operations of perforation, testing, acidizing, post-acidizing testing, and production commissioning. It eliminates the need for complex downhole testing tools such as multi-flow testers, LPR-N valves, and selective test valves, enabling fluid padding, negative pressure creation, blowout induction, perforation, and multiple well opening and closing tests. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the packer-screen tube combination device in an embodiment of the present invention;

[0028] Figure 2 yes Figure 1 Enlarged structural diagram at point A;

[0029] Figure 3 yes Figure 1 Enlarged structural diagram at point B;

[0030] Figure 4 yes Figure 1 Enlarged structural diagram at point C;

[0031] Figure 5 This is a schematic diagram of the pressure transmission connector in an embodiment of the present invention;

[0032] Figure 6This is a schematic diagram of the upper connector in an embodiment of the present invention;

[0033] Figure 7 This is a schematic diagram of the transposition sleeve in an embodiment of the present invention;

[0034] Figure 8 This is a schematic diagram of the structure of the pilot oil tubing string in the implementation of this invention.

[0035] In the diagram: 1. Pressure transmission connector; 11. Plug; 2. Packer; 3. Screen tube; 31. Outer cylinder; 311. Upper connector; 3111. Fixed connector; 3112. Shear connector; 3113. Protective connector; 3114. Rupture disc connector; 3115. Rupture disc; 312. Cylinder body; 3121. Transposition cylinder section; 3122. Spring cylinder section; 313. Lower connector; 32. Spindle; 321. Power shaft section; 322. Reset shaft section; 3221. First retaining ring; 3222. Second retaining ring; 33. Reset spring; 34. Transposition sleeve; 341. Transposition groove; 3411. First branch; 3412. Second branch; 3413. Third branch; 35. Pin; 36. Shear pin; 4. Pressure guide connector; 5. Pressure transmission pipe; 51. First branch pipe; 52. Second branch pipe;

[0036] a. Pressure transmission channel; b. First flow guide channel; c. Second flow guide channel; d. First annulus; e. Second annulus; f. Pressurization chamber; g. Air chamber; h. Connection channel; i. Production channel; j. Mounting hole; k. Oil sleeve annulus;

[0037] 100. Packer-screen assembly; 200. Depth adjustment section; 300. Circulation valve; 400. First pressure gauge carrier; 500. Second pressure gauge carrier; 600. Perforation gun assembly; 700. Wellbore. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0039] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0041] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0042] Figures 1-8The illustration shows a packer-screen pipe combination device 100 proposed in an embodiment of the present invention. The combination device includes a pressure transmitting joint 1, a packer 2, a pressure transmitting pipe 5, a screen pipe 3, and a pressure guiding joint 4. The pressure transmitting joint 1, the packer 2, the screen pipe 3, and the pressure guiding joint 4 are connected in series from the front end to the rear end (the front end refers to the end closer to the wellhead, and the rear end refers to the end farther away from the wellhead). The packer 2 can seal the annulus k formed between the packer-screen pipe combination device 100 and the wellbore 700. The pressure transmitting joint 1 and the pressure guiding joint 4 are both provided with an axially penetrating inner cavity. The front end of the pressure transmitting pipe 5 is inserted into the pressure transmitting joint 1 but does not communicate with the inner cavity of the pressure transmitting joint 1. The rear end passes through the packer 2 and the screen pipe 3 and is inserted into the inner cavity of the pressure guiding joint 4. The pressure transmitting pipe 5 can transmit the pressure of the annulus k to the inner cavity of the pressure guiding joint 4 through the pressure transmitting channel a provided in the pressure transmitting joint 1. The screen tube 3 includes a reset mechanism, a spindle 32, and an outer cylinder 31. The outer cylinder 31 is provided with a first guide channel b that connects its inner wall and its outer wall. The spindle 32 is located between the pressure transmission tube 5 and the outer cylinder 31 and can move axially under the action of external force. A first annulus d is formed between the spindle 32 and the pressure transmission tube 5. The rear end of the first annulus d is closed, and the front end is connected to the inner cavity of the pressure transmission connector 1. The spindle 32 is provided with a second guide channel c that connects the first annulus d and its outer wall. The spindle 32 can move axially downward under the action of external force. The reset mechanism can make the spindle 32 move upward and provide two different stroke endpoints for two adjacent upward movements of the spindle 32, namely the first endpoint and the second endpoint. When the spindle 32 moves to the first endpoint, the second guide channel c on the spindle 32 is connected to the first guide channel b on the outer cylinder 32. When the spindle 32 moves to the second endpoint, the second guide channel c on the spindle 32 is offset from the first guide channel b on the outer cylinder 31.

[0043] The mandrel 32 of the packer-screen assembly 100 can descend under a certain external force. When the external force is removed, the reset mechanism can drive the mandrel 32 upward and provide two different endpoints for two adjacent upward movements of the mandrel 32. When the mandrel 32 reaches the first endpoint, the second guide channel c on the mandrel 32 connects with the first guide channel b on the outer cylinder 32, and the screen 3 opens. When the mandrel 32 reaches the second endpoint, the second guide channel c on the mandrel 32 is offset from the first guide channel b on the outer cylinder 31, and the screen 3 closes. In other words, by applying a downward external force to the mandrel 32 and then releasing the pressure, the screen 3 can be switched from open to closed or from closed to open under the action of the reset mechanism. The screen 3 can be opened or closed an unlimited number of times, allowing the fluid in the formation to flow out to the surface through the first annulus d, thereby meeting the needs of multiple well opening and closing operations during oil testing. Moreover, the high pressure of the annulus k required for multiple openings and closings does not need to be increased step by step, and the pressure-bearing capacity requirement of the entire assembly is low. The packer-screen assembly 100 described above can also be used with perforation-testing or well completion / production string systems to achieve reservoir stimulation and production operations. For example, when connected to the perforating gun assembly 600, the annular pressure can be transmitted from the annulus k through the pressure transmission connector 1, pressure transmission pipe 5, and pressure guide connector 4 to the perforating gun assembly 600, thus achieving perforation. It is understood that the pressure applied to the annulus k during perforation must be less than the external force required for the mandrel 32 to descend, to prevent the screen 3 from switching on and off unexpectedly.

[0044] refer to Figure 3 As shown, the reset mechanism includes a shift sleeve 34, a pin 35, and a reset spring 33. The shift sleeve 34 is sleeved on the spindle 32 and axially limited by the spindle 32. The shift sleeve 34 is provided with a shift groove 341. One end of the pin 35 is fixedly connected to the outer cylinder 31, and the other end is inserted into the shift groove 341. One end of the reset spring 33 is connected to the spindle 32, and the other end is connected to the outer cylinder 31. Under the action of the reset spring 33 and the pin 35, the shift sleeve 34 can move upward and rotate.

[0045] refer to Figure 7As shown, the transposition groove 341 is formed by connecting a first Y-shaped groove and a second Y-shaped groove arranged in a circumferentially staggered manner. Both the first Y-shaped groove and the second Y-shaped groove include a first branch 3411, a second branch 3412, and a third branch 3413. The first branch 3411 extends along the axial direction of the transposition sleeve 34. The second branch 3412 and the third branch 3413 are both L-shaped and connected to the first branch 3411. The end of the second branch 3412 connected to the first branch 3411 extends along the axial direction of the transposition sleeve 34, while the other end is inclined away from the third branch 3413. The end of the third branch 3413 connected to the first branch 3411 is inclined away from the first branch 3411, while the other end extends along the axial direction of the transposition sleeve 34. The second branches 3412 and the third branches 3413 of adjacent first Y-shaped grooves and second Y-shaped grooves are connected. The difference is that the length of the first branch 3411 of the first Y-shaped groove is less than the length of the first branch 3411 of the second Y-shaped groove.

[0046] When the shift sleeve 34 moves downward with the mandrel 32 under the action of external force, overcoming the elastic force of the return spring 33, the pin 35 moves upward relative to it. It enters the third branch 3413 of the adjacent first Y-shaped groove from the first branch 3411 of the second Y-shaped groove via the guidance of the second branch 3412. After depressurization, under the elastic force of the return spring 33 and the guidance of the third branch 3413, the pin 35 enters the first branch 3411 of the first Y-shaped groove and moves to the end of the first branch 3411 away from the second branch 3412 and the third branch 3413. At this time, the mandrel 32 reaches the first endpoint, the first guide channel b and the second guide channel c are connected, and the screen tube 3 is opened. To close the screen tube 3, simply... When an external force is applied to the mandrel 32, the shifting sleeve 34, under the action of the external force, overcomes the elastic force of the return spring 33 and moves downward with the mandrel 32. Meanwhile, the pin 35 moves upward relative to the mandrel 32, entering the third branch 3413 of the adjacent second Y-shaped groove from the first branch 3411 of the first Y-shaped groove through the guidance of the second branch 3412. After pressure relief, under the elastic force of the return spring 33 and the guidance of the third branch 3413, the pin 35 enters the first branch 3411 of the second Y-shaped groove and moves to the end of the first branch 3411 away from the second branch 3412 and the third branch 3413. At this time, the mandrel 32 reaches the second endpoint, the first guide channel b and the second guide channel c close, and the screen tube 3 closes. In practical applications, simply repeating the above operation allows the screen tube 3 to be opened and closed an unlimited number of times.

[0047] In other embodiments, the reset mechanism can also be designed with reference to the structural principle of a ballpoint pen. Ballpoint pens are existing technology and will not be described further here.

[0048] refer to Figure 2 , Figure 5 and Figure 6As shown, in order to facilitate the application of external force to the mandrel 32, a pressurizing chamber f and an air chamber g are provided axially between the mandrel 32 and the outer cylinder 31. The pressurizing chamber f can be connected to the pressure transmission pipe 5. The air chamber g is filled with air. By pressurizing the annulus k of the oil sleeve, the pressure in the pressurizing chamber f is made greater than the pressure in the air chamber g, which pushes the mandrel 32 downward. After depressurization, the reset mechanism drives the mandrel 32 upward, and the second guide channel c is displaced, realizing the opening and closing of the screen tube 3.

[0049] For example, the pressurization chamber f is connected to the pressure transmission pipe 5 through the pressurization channel. In order to avoid axial displacement between the mandrel 32 and the outer cylinder 31 caused by excessive pressure in the pressurization chamber f during the lowering of the screen pipe 3, a rupture disc 3115 is provided in the pressurization channel. Only when the pressure in the annulus k of the oil and casing is greater than the pressure required for the rupture disc 3115 to rupture can the pressure in the annulus k of the oil and casing be transmitted to the pressurization chamber f.

[0050] refer to Figure 1 and Figure 6 As shown, the outer cylinder 31 includes an upper connector 311, a lower connector 313, and a cylinder body 312. The front end of the upper connector 311 is connected to the packer 2, and the rear end is inserted into the cylinder body 312 and connected to it. The front end of the lower connector 313 is inserted into the cylinder body 312 and connected to it, and the rear end is inserted into the inner cavity of the pressure guide connector 4 and connected to it. One end of the return spring 33 abuts against the front end face of the lower connector 313, and the other end abuts against the spindle 32. The first flow channel b is also opened on the lower connector 313.

[0051] Furthermore, the upper connector 311 includes a fixed connector 3111, a protective connector 3113, a shear connector 3112, and a rupture disc connector 3114. The front end of the fixed connector 3111 is sealed and screwed to the packer 2. The shear connector 3112 and the protective connector 3113 are respectively sealed and screwed to the inner and outer sides of the fixed connector 3111. The front end of the mandrel 32 is inserted into the shear connector 3112. The shear connector 3112 and the protective connector 3113 together form a second annular space e. The rupture disc connector 3114... The front end of 14 is sandwiched between the shear joint 3112 and the protective joint 3113 and is sealed to the shear joint 3112 and the protective joint 3113 to block the rear end of the second annular cavity e. The rear end of the rupture disc joint 3114 is sandwiched between the mandrel 32 and the outer cylinder 31 and is sealed to the mandrel 32 and the outer cylinder 31. The rupture disc joint 3114, the shear joint 3112 and the mandrel 32 together form the pressurized cavity f, while the air cavity g is formed by the rupture disc joint 3114 and the mandrel 32. The rupture disc 3115 is disposed within the mounting hole j opened in the rupture disc connector 3114. The two sides of the mounting hole j correspond to the pressurization chamber f and the second annulus e, respectively. A connecting channel h is provided within the fixed connector 3111. One end of the connecting channel h communicates with the pressure transmission pipe 5, and the other end communicates with the second annulus e. The second annulus e, the connecting channel h, and the mounting hole j together constitute the pressurization channel. Since the pressurization channel communicates with the pressure transmission pipe 5, and the pressure transmission pipe 5 communicates with the pressure transmission channel a, the pressurization channel can communicate with the oil sleeve annulus k after the rupture disc 3115 ruptures. Based on the above configuration, when installing the rupture disc 3115, it is only necessary to open a radially penetrating mounting hole j on the rupture disc connector 3114, and then install the rupture disc 3115 within the mounting hole j.

[0052] refer to Figure 3 As shown, to achieve axial positioning of the mandrel 32 and the transposition sleeve 34, the mandrel 32 is provided with a first retaining ring 3221 and a second retaining ring 3222 spaced apart along the axial direction. The second retaining ring 3222 is located at the end of the first retaining ring 3221 away from the upper connector 311. The transposition sleeve 34 is sleeved on the mandrel 32 and located between the first retaining ring 3221 and the second retaining ring 3222. For ease of installation, one of the first retaining ring 3221 and the second retaining ring 3222 is detachably connected to the mandrel 32, while the other can be integrally formed with the mandrel 32. For example, the mandrel 32 is segmented, including a power shaft segment 321 and a reset shaft segment 322 connected axially. The pressurization chamber f and the air chamber g are both enclosed by the power shaft segment 321 and the outer cylinder 31. The second flow channel c, the first retaining ring 3221 and the second retaining ring 3222 are all located in the reset shaft segment 322. The split mandrel 32 can reduce the difficulty of inserting the mandrel 32 into the outer cylinder 31.

[0053] Understandably, the screen tube 3 can only be fully opened when the first guide channel b and the second guide channel c are aligned, and the screen tube 3 can be closed simply by offsetting the first guide channel b and the second guide channel c. Therefore, when machining the transposition sleeve 34, the length accuracy of the first branch 3411 of the first Y-shaped groove is required to be high. Based on this, when the first guide channel b and the second guide channel c are aligned, the first retaining ring 3221 abuts against the end face of the rupture disc joint 3114 away from the packer 2, and together with the transposition groove 341, limits the upward movement of the spindle 32, improves the reliability of reset, and avoids the positional deviation of the first endpoint caused by damage to the transposition groove 341 after multiple uses.

[0054] refer to Figure 6 As shown, to reduce the machining difficulty of the connecting channel h, the connecting channel h includes a radial channel and an axial channel. One end of the radial channel penetrates the side wall of the fixed joint 3111 and is sealed with a threaded plug 11, while the other end is connected to the pressure transmission pipe 5. One end of the axial channel is connected to the radial channel, and the other end is connected to the second annulus e. During machining, the radial channel and the axial channel can be machined along the radial and axial directions of the fixed joint 3111 respectively, and then the threaded plug 11 is inserted into the end of the radial channel that penetrates the side wall of the fixed joint 3111.

[0055] A shear pin 36 is radially provided between the mandrel 32 and the outer cylinder 31. When the pressure difference between the mandrel 32 and the outer cylinder 31 is greater than the shear force that the shear pin 36 can withstand, the shear pin 36 is sheared, and the mandrel 32 and the outer cylinder 31 can move axially. This can prevent the axial displacement between the mandrel 32 and the outer cylinder 31 caused by excessive pressure in the second annulus e during the well running process.

[0056] In this embodiment, to reduce the difficulty of connecting the connection channel h to the pressure transmission pipe 5, the pressure transmission pipe 5 is segmented, including a first branch pipe 51 and a second branch pipe 52 spaced axially. The front end of the first branch pipe 51 is inserted into the pressure transmission connector 1 and sealed and screwed to the pressure transmission connector 1, and the rear end is inserted into the fixed connector 3111. The first branch pipe 51 is connected to the pressure transmission channel a. The front end of the second branch pipe 52 is inserted into the fixed connector 3111 and sealed and screwed to the fixed connector 3111. The rear end of the second branch pipe 52 passes through the shear connector 3112, the mandrel 32, and the lower connector 313 in sequence and is connected to the inner cavity of the pressure guiding connector 4. The interface between the connection channel h and the pressure transmission pipe 5 is located between the first branch pipe 51 and the second branch pipe 52. Therefore, the connection channel h only needs to penetrate the inner wall of the fixed connector 3111 to achieve connection with the pressure transmission pipe 5.

[0057] In order to allow the first annular cavity d to connect smoothly with the inner cavity of the pressure transmission connector 1, a production channel i is also provided in the fixed connector 3111. The rear end of the production channel i is connected to the first annular cavity d, and the front end is connected to the inner cavity of the pressure transmission connector 1.

[0058] refer to Figure 3 As shown, in this embodiment, the cylinder 312 is further divided into two parts, including a transposition cylinder section 3121 and a spring cylinder section 3122 connected along the axial direction. The pin 35 is fixed to the transposition cylinder section 3121, and the rear end of the transposition cylinder section 3121 is inserted into the spring cylinder section 3122 and screwed to the spring cylinder section 3122.

[0059] For non-flowing well testing in low-permeability reservoirs, both pre- and post-pressure testing often employ conventional testing techniques. After pumping (or N2 gas lift, sucker rod) to drain fluid and test production, the lack of a test valve makes it difficult to achieve downhole shut-in pressure recovery curve measurement. In some conventional well testing projects, after successful induction of flow and qualified production testing, the sucker rod (or pump) needs to be retrieved before lowering the pressure gauge to the bottom of the well for wellhead shut-in pressure recovery. However, the time from stopping pumping to the pressure gauge reaching the predetermined position in the well can take tens of minutes or even hours. This makes timely shut-in pressure recovery difficult, resulting in early data loss of the pressure recovery curve. Furthermore, it is difficult to overcome the effects of wellbore reservoir accumulation, causing radial flow time delays and reduced data acquisition quality. This leads to variations in the pressure recovery curve shape, making model diagnosis difficult, resulting in significant errors or inability to interpret the results, and causing inaccurate qualitative or quantitative understanding of the formation.

[0060] To address the aforementioned problems, based on the packer-screen assembly 100 of the present invention, another embodiment of the present invention also proposes a test tubing string, as referenced. Figure 8 As shown, the assembly includes a depth calibration sub 200, a circulation valve 300, a first pressure gauge carrier 400, a safety joint, the packer-screen assembly 100, a second pressure gauge carrier 500, and a perforating gun assembly 600, connected sequentially from front to back via tubing. The depth calibration sub 200 is connected to the wellhead via tubing and is used to correct the depth of the wellbore where the test tubing string is located. The circulation valve 300 can be an RD valve or a circulation sleeve, etc. The second pressure gauge carrier 500 carries a transmitter and a storage pressure gauge, and can transmit pressure data to the packer 2 via the transmitter. As needed, a cable is lowered into the receiver for docking and reception. The first pressure gauge carrier 400 serves as a backup structure for the second pressure gauge carrier 500, and the measured data can be cross-referenced with the data measured by the second pressure gauge carrier 500. The packer-screen assembly 100 can transmit the annular pressure k to the perforating gun assembly 600, through which perforation is performed.

[0061] In another embodiment of the present invention, a method for operating the above-mentioned oil testing string is provided, comprising the following steps:

[0062] S10: Set screen pipe 3 to the open position, and after assembling the oil testing tubing string, lower it into the wellbore 700;

[0063] S20: After reaching the predetermined depth, perform depth calibration, adjust the depth of the test tubing string, and set packer 2. Set tubing hangers and install wellhead.

[0064] S30: If negative pressure needs to be created, the liquid level can be lowered by suction; otherwise, proceed with S40.

[0065] S40: After pressurizing the annulus k and then depressurizing p1, the perforation is delayed.

[0066] During the pressurization process, the annular fluid enters the pressure guide joint 4 through the pressure transmission channel a and the pressure transmission pipe 5, and then enters the perforation gun assembly 600 to achieve ignition and perforation.

[0067] S50: Pressurize the annulus k of the oil casing to p2 (p2>p1), depressurize, close the screen pipe 3, measure the downhole static pressure or pressure recovery status, and overcome the influence of wellbore storage effect.

[0068] During the pressurization process, the high-pressure liquid enters the pressurization chamber f through the pressure transmission channel a, pressure transmission pipe 5, pressurization channel, and rupture disc 3115, pushing the mandrel 32 downward. After depressurization, the mandrel 32 moves upward, and the first guide channel b and the second guide channel c are staggered.

[0069] S60: Pressurize the annulus k, depressurize p2, and open the screen tube 3.

[0070] During well drilling, determine whether PVT sampling should be performed as needed;

[0071] And decide whether to induce a flow based on the oil and gas flow; conduct production assessment and sampling according to industry standards and geological design requirements;

[0072] S70: Complete the required well opening and closing procedures and number of times according to the design procedure, and obtain complete and accurate formation data;

[0073] S80: Based on the well opening and closing test results, determine whether acidizing or unblocking operations are required; if acidizing or unblocking is required, perform the acidizing or unblocking operations while the well is open.

[0074] After acidizing or unblocking, drain the fluid, test, and determine production; determine production and take samples according to industry standards and geological design requirements; complete the required well opening and closing procedures and number of times according to the design procedure, and obtain complete and accurate formation data;

[0075] Determine whether production is required based on the results of preliminary tests. If production is required, proceed with the production transition process according to the production requirements. If production is not required, execute S90.

[0076] If acidification or unblocking is not performed, proceed with S90;

[0077] S90: Pressurize the annulus k to p3, open the circulation valve 300, circulate, kill the well, unseal the packer 2, and pull out the test tubing.

[0078] Using the above-mentioned oil testing string and operation method eliminates the need for complex testing tools such as multi-flow testers, LPR-N valves, and selective test valves. It enables integrated operations such as fluid padding, negative pressure generation, induction of flow, perforation, testing, acidizing, and post-acid testing. Moreover, the screen is located below the packer, reducing the risk of string leakage. After oil testing, production can be started directly without well control, avoiding secondary reservoir contamination. Since the screen can be opened and closed multiple times after production, production enhancement operations or well dynamic monitoring can be carried out as needed during the production process.

[0079] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A packer-screen tube assembly, comprising a pressure-transmitting connector (1), a packer (2), a screen tube (3), and a pressure-guiding connector (4) connected in sequence, and further comprising a pressure-transmitting tube (5), wherein both the pressure-transmitting connector (1) and the pressure-guiding connector (4) are provided with an axially penetrating inner cavity, the front end of the pressure-transmitting tube (5) is inserted into the pressure-transmitting connector (1) but not communicating with the inner cavity of the pressure-transmitting connector (1), the rear end of the pressure-transmitting tube (5) is inserted into the inner cavity of the pressure-guiding connector (4), and the pressure-transmitting connector (1) is provided with a pressure-transmitting channel (a) connecting the pressure-transmitting tube (5) and the outside of the pressure-transmitting connector (1), characterized in that, The sieve tube (3) includes: The outer cylinder (31) is provided with a first flow channel (b) that connects its inner wall and its outer wall. A mandrel (32) is located between the outer cylinder (31) and the pressure transmission tube (5). The mandrel (32) is axially movable. A first annulus (d) is formed between the mandrel (32) and the pressure transmission tube (5). The rear end of the first annulus (d) is closed. The front end of the first annulus (d) is connected to the inner cavity of the pressure transmission connector (1). A second flow channel (c) is provided on the mandrel (32) to connect the first annulus (d) and its own outer wall. The reset mechanism enables the spindle (32) to move upward and provides two different travel endpoints for two consecutive upward movements of the spindle (32), namely the first endpoint and the second endpoint. When the spindle (32) moves to the first endpoint, the second guide channel (c) is connected to the first guide channel (b). When the spindle (32) moves to the second endpoint, the second guide channel (c) is disconnected from the first guide channel (b). The reset mechanism includes a shift sleeve (34), a pin (35), and a reset spring (33). The shift sleeve (34) is sleeved on the spindle (32) and is axially limited to the spindle (32). The shift sleeve (34) is provided with a shift groove (341). One end of the pin (35) is fixed to the outer cylinder (31), and the other end is inserted into the shift groove (341). One end of the reset spring (33) abuts against the spindle (32), and the other end abuts against the outer cylinder (31). The transposition groove (341) is formed by connecting a first Y-shaped groove and a second Y-shaped groove arranged in a circumferentially staggered manner. Both the first Y-shaped groove and the second Y-shaped groove include a first branch (3411), a second branch (3412), and a third branch (3413). The first branch (3411) extends axially along the transposition sleeve (34). The second branch (3412) and the third branch (3413) are both L-shaped and connected to the first branch (3411). One end of the second branch (3412) connected to the first branch (3411) extends axially along the transposition sleeve (34). The other end of the second branch (3412) is inclined away from the third branch (3413). One end of the third branch (3413) connected to the first branch (3411) is inclined away from the first branch (3411). The other end of the third branch (3413)... The end extends axially along the transposition sleeve (34), and the second branch (3412) and the third branch (3413) of the adjacent first Y-shaped groove and second Y-shaped groove are connected. The length of the first branch (3411) of the first Y-shaped groove is less than the length of the first branch (3411) of the second Y-shaped groove. When the pin (35) is located at the end of the first branch (3411) of the first Y-shaped groove away from the second branch (3412) and the third branch (3413), the mandrel (32) is located at the first end point. When the pin (35) is located at the end of the first branch (3411) of the second Y-shaped groove away from the second branch (3412) and the third branch (3413), the mandrel (32) is located at the second end point. Periodic pressure is applied to the mandrel (32) to achieve the switching between the first end point and the second end point. A pressurizing chamber (f) and an air chamber (g) are provided axially between the mandrel (32) and the outer cylinder (31). The pressurizing chamber (f) can communicate with the pressure transmission pipe (5), and the air chamber (g) is enclosed with air. The pressurizing chamber (f) is connected to the pressure transmission pipe (5) through a pressurizing channel, and a rupture disc (3115) is provided in the pressurizing channel.

2. The packer-screen tube assembly according to claim 1, characterized in that, The outer cylinder (31) includes an upper connector (311), a lower connector (313), and a cylinder body (312). The front end of the upper connector (311) is connected to the packer (2), and the rear end of the upper connector (311) is inserted into the cylinder body (312) and connected to the cylinder body (312). The front end of the lower connector (313) is inserted into the cylinder body (312) and connected to the cylinder body (312), and the rear end of the lower connector (313) is inserted into the inner cavity of the pressure guide connector (4) and connected to the pressure guide connector (4).

3. The packer-screen tube assembly according to claim 2, characterized in that, The upper connector (311) includes a fixed connector (3111), a protective connector (3113), a shear connector (3112), and a rupture disc connector (3114). The front end of the fixed connector (3111) is connected to the packer (2). The shear connector (3112) and the protective connector (3113) are respectively sealed to the inner and outer sides of the fixed connector (3111). The shear connector (3112) and the protective connector (3113) form a second annulus (e). The front end of the rupture disc connector (3114) is sandwiched between the shear connector (3112) and the protective connector (3113) and is sealed to the shear connector (3112) and the protective connector (3113). The rear end of the rupture disc connector (3114) is sandwiched between the mandrel (32) and the outer cylinder (31). The mandrel (32) and the outer cylinder (31) are sealed together. The rupture disc joint (3114), the shear joint (3112) and the mandrel (32) together form the pressurizing chamber (f). The air chamber (g) is formed by the rupture disc joint (3114) and the mandrel (32). The rupture disc (3115) is set in the mounting hole (j) opened in the rupture disc joint (3114). The two sides of the mounting hole (j) correspond to the pressurizing chamber (f) and the second annulus (e) respectively. A connecting channel (h) is opened in the fixed joint (3111). One end of the connecting channel (h) is connected to the pressure transmission pipe (5) and the other end is connected to the second annulus (e). The second annulus (e), the connecting channel (h) and the mounting hole (j) together constitute the pressurizing channel.

4. The packer-screen tube assembly according to claim 3, characterized in that, The pressure transmission tube (5) is segmented, and the pressure transmission tube (5) includes a first branch tube (51) and a second branch tube (52) arranged axially at intervals. The front end of the first branch tube (51) is inserted into the pressure transmission connector (1) and sealed to the pressure transmission connector (1). The rear end of the first branch tube (51) is inserted into the fixed connector (3111). The first branch tube (51) is connected to the pressure transmission channel (a). The front end of the second branch tube (52) is inserted into the fixed connector (3111) and sealed to the fixed connector (3111). The rear end of the second branch tube (52) passes through the shear connector (3112), the mandrel (32), and the lower connector (313) in sequence and is connected to the inner cavity of the pressure guiding connector (4). The interface of the connecting channel (h) connected to the pressure transmission tube (5) is located between the first branch tube (51) and the second branch tube (52).

5. The packer-screen tube assembly according to claim 1, characterized in that, A shear pin (36) is also provided between the mandrel (32) and the outer cylinder (31).

6. A test tubing string, characterized in that, The device includes a depth adjustment sub (200), a circulation valve (300), a first pressure gauge carrier (400), a safety connector, a packer-screen assembly as described in any one of claims 1-5, a second pressure gauge carrier (500), an ignition head and a perforating gun assembly (600), connected in sequence. The depth adjustment sub (200) is connected to the wellhead by tubing. The second pressure gauge carrier (500) carries a transmitter and stores a pressure gauge, and transmits pressure data to the packer (2) via the transmitter.

7. A method for operating a test tubing string, used to operate the test tubing string as described in claim 6, characterized in that, Includes the following steps: The screen tube (3) is set to the open state. After the oil test string is assembled, it enters the wellbore. An oil-jacket annulus (k) is formed between the oil test string and the wellbore. After reaching the predetermined depth, the depth of the test tubing string is checked and adjusted, and the packer (2) is set and the tubing is installed at the wellhead; The annulus (k) is pressurized by p1 and then depressurized, followed by a delayed perforation. According to the design procedure, the annulus (k) is pressurized multiple times (p2>p1) and then depressurized to complete the required well opening and closing procedures and number of times, and to obtain complete and accurate formation data. After testing, production can begin directly as needed. Alternatively: Open the circulation valve (300), perform well control, unseal the packer, and retrieve the test tubing.

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