Staged fracturing pump stopping test oil well packer and control system thereof

Abstract

The invention relates to the technical field of oil production engineering, in particular to a staged fracturing pump stopping test oil well packer and a control system thereof.The staged fracturing pump stopping test oil well packer comprises a central pipe, the upper end and the lower end of the central pipe are connected with an upper connector and a lower connector respectively, a rubber barrel is arranged on the periphery of the central pipe, and a thin groove is formed in the position, corresponding to the rubber barrel, of the central pipe; a traditional through hole is replaced by the thin groove, high-pressure fluid in the rubber sleeve can only be slowly decompressed through the thin groove after a pump is stopped, it is ensured that the rubber sleeve is kept in an expansion sealing state in a testing period, intersection fluid channeling is avoided, and pressure drop data of a well mouth and a well bottom truly reflects the characteristics of cracks and stratums; meanwhile, after the test is finished and the pressure of the high-pressure fluid in the central pipe is reduced to a certain value, the internal and external pressure difference of the first through hole pushes the piston to move upwards so as to open the second through hole, the fluid in the rubber sleeve can be rapidly discharged through the second through hole, the rubber sleeve rapidly shrinks and resets, the deblocking time is greatly shortened, and the single well fracturing operation efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field production engineering technology, and in particular to a well packer for staged fracturing and pump shutdown testing and its control system. Background Technology

[0002] With the widespread application of fracturing measures in oilfields, post-fracturing assessment technology is receiving increasing attention, and corresponding post-fracturing testing technologies are constantly being improved. Before large-scale fracturing, a small-scale fracturing test (also known as "mini-fracturing") must be conducted: a small amount of high-pressure fracturing fluid is injected to open the formation, then the pump is stopped, and the rate of pressure drop at the wellhead or bottom hole is observed. This rate reflects the condition of the fracture itself and the surrounding formation; therefore, the accuracy of the pump-stop test is crucial. Currently used K344 fracturing packers are prone to unsealing during pump-stop testing, causing communication between the two sections. This leads to pressure cross-flow, and the pressure data monitored on the surface becomes distorted by this cross-flow interference, making it impossible to accurately calculate fracture and formation parameters, resulting in inaccurate subsequent large-scale fracturing design.

[0003] For example, Chinese patent CN110500059B discloses a rapidly retracting expandable packer cartridge. In this design, the rapid retraction function is achieved by the assistance and acceleration of the cartridge retraction, which improves the unsealing capability. However, the cartridge must not be unsealed during pump stop testing. When the pump stops, the spring's retraction force may cause the packer to unseal prematurely, directly damaging the test. Another Chinese patent CN215292428U discloses a controllable expandable packer. This design can straighten and stabilize the cartridge, preventing the cartridge from twisting during tubing rotation and causing sealing failure. It can effectively protect the cartridge, ensure the sealing effect, and filter the liquid passing through the through-hole. However, it cannot control the speed of cartridge setting and unsealing. Summary of the Invention

[0004] Therefore, it is necessary to provide a segmented fracturing pump shutdown test packer and its control system to address the problem that current packers cannot control the unsealing speed according to demand.

[0005] The above objectives are achieved through the following technical solutions: A packer for staged fracturing and pump shutdown testing of an oil well includes: A central tube, with an upper connector and a lower connector connected to its upper and lower ends respectively; A rubber tube is installed on the outer periphery of the central tube and located at the midpoint of the length of the central tube. The central tube has multiple fine grooves extending along the axial direction of the central tube on its side wall corresponding to the rubber tube. The multiple fine grooves are evenly distributed along the circumference of the central tube. An upper steel bowl is fixedly sleeved on the outer periphery of the upper end of the central tube, forming an adjustment cavity between the upper steel bowl and the outer periphery of the central tube. A first gap exists between the two ends of the rubber sleeve and the outer wall of the central tube, and the first gap connects the adjustment cavity and the inner periphery of the rubber sleeve. A piston is slidably disposed in the adjustment cavity along the axial direction, and a second gap exists between the inner periphery of the piston and the outer periphery of the central tube. A first through hole and a second through hole are opened on the side wall of the upper steel bowl. The piston is configured to block or open the first through hole or the second through hole when it moves axially.

[0006] Furthermore, connecting cylinders are respectively provided at both ends of the rubber tube. One end of the connecting cylinder is fixedly connected to one end of the upper steel cup, and the other end of the connecting cylinder is fixedly connected to the rubber tube. The connecting cylinder and the outer periphery of the central tube have the first gap.

[0007] Furthermore, the outer periphery of the rubber tube is provided with multiple scrapers, which are evenly distributed along the circumference of the rubber tube. A conical scraper is provided at the middle position of the outer side of the multiple scrapers. The multiple scrapers are configured to move synchronously along the radial and axial directions of the rubber tube when the rubber tube expands, and to rotate along the circumference of the rubber tube.

[0008] Furthermore, both sides of the scraper are inclined surfaces and are respectively provided with a limiting groove and a limiting block. The limiting blocks on adjacent scrapers are located in the limiting grooves. A guide rod is provided on one end of the scraper. An axially elastic sliding cylinder is provided on the outer periphery of the central tube. Multiple circumferentially evenly distributed arc-shaped grooves are provided on the end face of the sliding cylinder near the guide rod. The guide rod is slidably disposed in the arc-shaped grooves.

[0009] Furthermore, a fixed cylinder is provided on the outer periphery of the upper steel bowl, and an annular groove is provided on one end of the fixed cylinder near the sliding cylinder. An elastic element is provided in the annular groove, and the elastic element is connected to the sliding cylinder, so that the sliding cylinder has a tendency to return to its original position.

[0010] Furthermore, the elastic element is a compression spring.

[0011] Furthermore, an elastic scraper is provided on one end of the plurality of scrapers away from the guide rod, and the elastic scraper slides in contact with the outer periphery of the rubber tube.

[0012] Furthermore, a lower steel cup is provided on the outer periphery of the central tube. The lower steel cup is threadedly connected to the lower connector. A retaining ring is provided on the outer periphery of the lower connector. The retaining ring is conical, with its small end facing the lower end of the lower steel cup.

[0013] Furthermore, a steel cup locking ring is threaded onto the lower connector, and the steel cup locking ring abuts against the lower steel cup.

[0014] The present invention also provides a control system for a well packer used in staged fracturing and pump shutdown testing, comprising the following steps: Step S100: When the control system moves the segmented fracturing pump stop test well packer to a designated position inside the drilling casing, the rubber sleeve expands. Step S200: When a pump stop test is required, the control system stops inputting high-pressure fluid into the drilling casing, and the packer sleeve of the segmented fracturing pump stop test well maintains a sealed state for a preset time. Step S300: After the pump shutdown test is completed, the high-pressure fluid pressure inside the drilling casing decreases to a preset value, and the rubber sleeve of the well packer for the segmented fracturing pump shutdown test is unsealed.

[0015] The beneficial effects of this invention are: This invention utilizes a fine groove on the central tube to replace the traditional through-hole. The small size of the groove significantly limits flow, ensuring that the high-pressure fluid inside the cartridge can only be slowly depressurized through the groove after the pump stops. This maintains the cartridge in an expanded and sealed state throughout the testing period, preventing inter-stage flow and allowing the wellhead and bottomhole pressure drop data to accurately reflect the fracture and formation characteristics. This provides precise parameters (such as fracture conductivity and formation permeability) for large-scale fracturing design. Furthermore, after the test is completed, when the pressure of the high-pressure fluid inside the central tube decreases to a certain value, the pressure difference between the inside and outside of the first through-hole pushes the piston upward to open the second through-hole. The fluid inside the cartridge can then be quickly discharged through the second through-hole, and the cartridge quickly contracts and resets, significantly shortening the unsealing time and improving the efficiency of single-well fracturing operations.

[0016] This invention features multiple scrapers that expand radially, move axially, and rotate circumferentially simultaneously as the casing expands. The conical scraper blades on the outer side of the scrapers can remove impurities such as mud cake and sand particles from the inner wall of the casing, and the circumferential rotation can cut stubborn deposits, ensuring that the casing wall where the casing is attached is smooth and clean, avoiding sealing gaps caused by impurities, and reducing the probability of fracturing fluid leakage.

[0017] This invention features an elastic scraper on the scraper. When the rubber tube expands and contracts, the elastic scraper can slide and scrape away residual impurities on the outer periphery of the rubber tube, preventing impurities from affecting the seal during the next use, extending the service life of the rubber tube, and reducing tool replacement costs. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the packer in a segmented fracturing pump shutdown test when it is not expanded, according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the internal structure of a well packer for segmented fracturing and pump shutdown testing according to an embodiment of the present invention; Figure 3 for Figure 2 A partially enlarged view of part A of the packer in a segmented fracturing pump shutdown test well provided in one embodiment; Figure 4 for Figure 2 A partially enlarged view of part B of the packer in a segmented fracturing pump shutdown test well provided in one embodiment; Figure 5 for Figure 2 A partially enlarged view of part C of the packer in a segmented fracturing pump shutdown test well provided in one embodiment; Figure 6 This is a schematic diagram of the structure of the packer during the expansion test of a segmented fracturing pump shutdown test according to an embodiment of the present invention; Figure 7 for Figure 6 A schematic diagram of the internal structure of the packer during expansion in a segmented fracturing pump shutdown test, provided in one embodiment; Figure 8 for Figure 7 A partially enlarged view of part D of the packer in a segmented fracturing pump shutdown test well provided in one embodiment; Figure 9 An exploded view of multiple scrapers of a well packer for segmented fracturing and pump shutdown testing according to an embodiment of the present invention; Figure 10 A schematic diagram of the packer of an oil well undergoing a staged fracturing pump shutdown test, provided in an embodiment of the present invention, showing the state in which multiple scrapers are retracted together; Figure 11 A schematic diagram showing the radial expansion of multiple scrapers in a well packer used for segmented fracturing and pump shutdown testing, provided in an embodiment of the present invention. Figure 12 This is a schematic diagram of the structure of the sliding cylinder of the packer for a segmented fracturing pump shutdown test well provided in an embodiment of the present invention.

[0019] in: 100. Central tube; 101. Fine groove; 110. Upper connector; 120. Lower connector; 121. Retaining ring; 130. Rubber sleeve; 131. Connecting cylinder; 140. Upper steel cup; 141. First through hole; 142. Second through hole; 150. Lower steel cup; 151. Steel cup locking ring; 160. Adjusting cavity; 170. Piston; 171. First sealing ring; 172. Second sealing ring; 173. Third sealing ring; 180. First gap; 190. Second gap.

[0020] 200, scraper; 210, conical scraper blade; 220, limiting groove; 230, limiting block; 240, guide rod; 250, elastic scraper blade; 260, sliding cylinder; 261, arc groove; 270, fixed cylinder; 271, annular groove; 280, elastic element. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0022] The component designations used in this document, such as "first" and "second," are merely for distinguishing the described objects and do not have any sequential or technical meaning. The terms "connection" and "linkage" used in this invention, unless otherwise specified, include both direct and indirect connections (linkages). It should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description. They 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, and therefore should not be construed as limiting the invention.

[0023] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0024] The following reference Figures 1-12 This invention describes a packer for a segmented fracturing pump shutdown test well.

[0025] A packer for a segmented fracturing and pump shutdown test well includes a central tube 100. An upper connector 110 and a lower connector 120 are connected to the upper and lower ends of the central tube 100, respectively. Both the upper connector 110 and the lower connector 120 are hollow. The upper connector 110 connects to the upper end of the central tube 100, and the lower connector 120 connects to the lower end of the central tube 100. A rubber sleeve 130 is fitted around the outer periphery of the central tube 100, located at the midpoint of the length of the central tube 100. Both ends of the rubber sleeve 130 are fixed to the outer periphery of the central tube 100, and the axis of the rubber sleeve 130 coincides with the axis of the central tube 100. The rubber sleeve 130 is specifically positioned at the midpoint of the length of the central tube 100. It is flexible. In the prior art, the connection between the packer 130 and the central tube 100 is continuous. Specifically, the central tube 100 has a through hole. In use, the packer needs to be inserted into the casing of the well (not shown in the figure). When the packer moves to the designated position, it stops moving and high-pressure fluid is introduced into the casing of the well. The high-pressure fluid will enter the central tube 100 and then enter the packer 130 through the through hole on the central tube 100. The high-pressure fluid pushes the packer 130 to expand radially outward, so that the outer circumference of the packer 130 can abut against the inner wall of the casing, thereby sealing the designated part of the inner wall of the casing. When it is necessary to unseal, the liquid pressure inside the casing can be reduced.

[0026] Before large-scale fracturing operations, small-scale fracturing tests are required. After the packer seals the designated location, the pump needs to be stopped, that is, the high-pressure fluid input into the casing is stopped. At this time, the pressure inside the casing no longer increases, but gradually decreases. The rate at which it decreases reflects the condition of the fracture itself and the surrounding formation. Therefore, the accuracy of the pump stop test is crucial. However, in the existing technology, the packer releases the seal too quickly during the pump stop test, which reduces the accuracy of the pump stop test.

[0027] Based on this, the present invention replaces the through hole of the central tube 100 with a fine groove 101. The fine groove 101 is located on the outer periphery of the central tube 100 corresponding to the position of the rubber sleeve 130, and multiple fine grooves 101 are provided. Multiple fine grooves 101 extend along the axial direction of the central tube 100 and are evenly distributed along the circumference of the central tube 100. Multiple fine grooves 101 are all connected to the rubber sleeve 130. When high-pressure fluid enters the central tube 100, the high-pressure fluid enters the rubber sleeve 130 through the fine groove 101, thereby causing the rubber sleeve 130 to begin to expand radially outward to seal the sleeve. When the pump stops, the input of high-pressure fluid will stop, and the pressure inside the central tube 100 will no longer increase. Since the fine groove 101 on the central tube 100 of the present invention is much smaller than the traditional through hole, the pressure relief speed of the rubber sleeve 130 is slow, which can ensure that the rubber sleeve 130 is in a sealed state for a certain period of time, reducing the impact on pump stop testing.

[0028] Simultaneously, after the pump stop test is completed, it is necessary to accelerate the retraction speed of the rubber sleeve 130. This invention provides an upper steel cup 140 on the outer periphery of the upper end of the central tube 100, such as... Figure 2 and Figure 3 As shown, an adjustment cavity 160 is formed between the upper steel cup 140 and the outer periphery of the central tube 100. A first gap 180 is formed between both ends of the rubber sleeve 130 and the outer wall of the central tube 100, connecting the adjustment cavity 160 and the inner periphery of the rubber sleeve 130. A piston 170 is slidably disposed circumferentially within the adjustment cavity 160. A second gap 190 is formed between the inner periphery of the piston 170 and the outer periphery of the central tube 100, connecting the second gap 190 and the first gap 180. A first through hole 141 and a second through hole 142 are provided on the side wall of the upper steel cup 140, with the first through hole 141 located above the second through hole 142. Three sealing rings are provided on the outer periphery of the piston 170. For ease of description, the upper sealing ring is named the first sealing ring 171, and the middle sealing ring is named the second sealing ring 171. The sealing ring is named the second sealing ring 172, and the sealing ring below it is named the third sealing ring 173. The diameter of the first sealing ring 171 is larger than the diameter of the second sealing ring 172. The diameter of the second sealing ring 172 is the same as the diameter of the third sealing ring 173. There is a first space between the first sealing ring 171 and the second sealing ring 172, and a second space between the second sealing ring 172 and the third sealing ring 173. When the piston 170 is at the bottom of the adjusting cavity 160, the first space corresponds to the first through hole 141, and the second space corresponds to the second through hole 142. When the piston 170 is at the top of the adjusting cavity 160, the first space and the first through hole 141 are interleaved, and the second space and the second through hole 142 are interleaved. The second through hole 142 is connected to the outside.

[0029] It should be noted that during the sealing of the sleeve, high-pressure fluid enters the central tube 100. The high-pressure fluid passes through the groove 101 on the central tube 100 and enters the inner circumference of the rubber sleeve 130. Furthermore, the high-pressure fluid passes through the first gap 180 and the second gap 190 into the adjusting cavity 160. The high-pressure fluid pushes the piston 170 upwards, causing the piston 170 to move to the lowest point of the adjusting cavity 160. At this time, the piston 170 blocks the first through hole 141 and the second through hole 142, thus not affecting the expansion of the rubber sleeve 130 by the high-pressure fluid, thereby allowing the rubber sleeve 130 to seal the designated position of the sleeve. When unsealing is required, the pressure of the high-pressure fluid inside the central tube 100 decreases, creating a pressure difference between the inside and outside of the first through hole 141, and the pressure on the outside of the first through hole 141 decreases. When the force is greater than the internal pressure, the high-pressure fluid pushes the bottom end of the first sealing ring 171 upward (because the bottom area of ​​the first sealing ring 171 is larger than the top area of ​​the second sealing ring 172, the pressure on the first sealing ring 171 is greater when the high-pressure fluid acts on both the first sealing ring 171 and the second sealing ring 172 at the same time), thereby pushing the piston 170 upward. When the piston 170 moves upward and its bottom end passes the second through hole 142, it opens the second through hole 142. The high-pressure fluid inside the regulating cavity 160 will be discharged through the second through hole 142, thereby reducing the amount of high-pressure fluid inside the regulating cavity 160. This allows the high-pressure fluid inside the rubber sleeve 130 to be discharged through the second through hole 142, and the rubber sleeve 130 can retract and reset, thus quickly unsealing.

[0030] It is understandable that when a pump stop test is required, stopping the pumping of high-pressure fluid into the casing causes the pressure of the high-pressure fluid inside the central tube 100 to gradually decrease instead of increase. The groove 101 in this invention prevents the rubber sleeve 130 from immediately contracting, thus facilitating other pressure tests when the pump is stopped. When the liquid pressure inside the central tube 100 decreases to a certain value, the piston 170 inside the upper iron arm will gradually open the second through hole 142, allowing the high-pressure fluid inside the rubber sleeve 130 to be discharged through the second through hole 142, thereby causing the rubber sleeve 130 to contract rapidly to achieve the function of unsealing.

[0031] Specifically, such as Figure 7 and Figure 8 As shown, to facilitate the connection of the rubber sleeve 130, connecting sleeves 131 are respectively provided at both ends of the rubber sleeve 130, and a lower steel cup 150 is provided on the outer periphery of the lower end of the central tube 100. One end of the two connecting sleeves 131 is respectively fixed to the inner periphery of the upper steel cup 140 and the lower steel cup 150 by threaded connection, and there is a first gap between the two connecting sleeves 131 and the central tube 100 to facilitate the passage of high pressure fluid.

[0032] More specifically, such as Figure 2 and Figure 3As shown, in this embodiment, the upper connector 110 and the lower connector 120 are threadedly connected to the upper and lower ends of the central tube 100, respectively, and the upper connector 110 and the lower connector 120 are restricted from rotating with the ends of the central tube 100 by limiting pins. Meanwhile, the upper steel cup 140 is threadedly connected to the upper connector 110, and sealing rings are provided on the inner circumferences of the upper steel cup 140 and the lower steel cup 150 to increase sealing performance. Furthermore, to further ensure the connection strength of the lower steel cup 150, a steel cup locking ring 151 is threadedly connected to the lower connector 120. Figure 5 As shown, one end of the steel cup locking ring 151 abuts against the lower steel cup 150 to restrict the lower steel cup 150, thereby increasing the connection strength between the lower steel cup 150 and the central tube 100.

[0033] In a further embodiment, a plurality of scrapers 200 are provided on the outer periphery of the glue cylinder 130 of the present invention. The plurality of scrapers 200 are evenly distributed along the circumference of the glue cylinder 130. A tapered scraper strip 210 is provided at the middle position of the outer side of the plurality of scrapers 200. The plurality of scrapers 200 are configured to move radially and axially along the glue cylinder 130 when the glue cylinder 130 expands, and the plurality of scrapers 200 can also rotate around the circumference of the glue cylinder 130. The plurality of scrapers 200 can clean the surface of the sleeve sidewall. It is understood that if impurities are attached to the surface of the sleeve sidewall... When the rubber sleeve 130 expands and comes into contact with the side wall of the sleeve, these impurities or particles can affect the sealing performance of the rubber sleeve 130 in sealing the sleeve, thus causing leakage. Therefore, in order to prevent leakage, the multiple scrapers 200 in this embodiment will clean the impurities or other particles on the side wall of the sleeve before the rubber sleeve 130 expands, so that the side wall of the sleeve that the rubber sleeve 130 comes into contact with when it expands is in a smooth and clean state. After the rubber sleeve 130 expands, it fits more tightly with the side wall of the sleeve, which can improve the sealing performance of the rubber sleeve 130.

[0034] Specifically, such as Figure 9 , Figure 10 and Figure 11As shown, to enable the multiple scrapers 200 to rotate radially, axially, and circumferentially along the rubber cylinder 130 when it expands, both sides of the multiple scrapers 200 in this embodiment are inclined surfaces. Limiting grooves 220 and limiting blocks 230 are respectively provided on the two sides. The limiting grooves 220 extend along the inclined surfaces of the scrapers 200, and the limiting blocks 230 on the sides of adjacent scrapers 200 are located within the limiting grooves 220. When the rubber cylinder 130 expands, the outer periphery of the rubber cylinder 130 pushes the multiple scrapers 200 outwards radially along the rubber cylinder 130. The limiting blocks 230 on adjacent scrapers 200 slide within the limiting grooves 220, thereby allowing the multiple scrapers 200 to gradually approach the inner wall of the sleeve. To enable the multiple scrapers 200 to move circumferentially and axially along the rubber cylinder 130, a limiter is provided at one end of each scraper 200. A guide rod 240 is fixedly installed on the upper part, and a sliding cylinder 260 with axial elastic sliding is provided on the outer periphery of the central tube 100. Multiple circumferentially evenly distributed arc-shaped grooves 261 are provided on the end face of the sliding cylinder 260 near the guide rod 240. The number of arc-shaped grooves 261 is the same as the number of guide rods 240. The guide rod 240 is located in the arc-shaped grooves 261. When multiple scrapers 200 spread outward radially along the rubber tube 130, the guide rods 240 of multiple scrapers 200 slide in the arc-shaped grooves 261, so that multiple scrapers 200 can rotate around the circumference of the rubber tube 130. At the same time, the sliding cylinder 260 can slide elastically along the axial direction of the rubber tube 130. When the rubber tube 130 expands, it will push multiple scrapers 200 away from the rubber tube 130, thereby avoiding the scrapers 200 from affecting the fit between the rubber tube 130 and the inner wall of the sleeve.

[0035] It should be noted that the scraper 200 of the present invention has two sets, and the two sets of scraper 200 have the same structure. The positions of the two sets of scraper 200 are symmetrical about the midpoint of the length of the glue cylinder 130, as shown below. Figure 1 and Figure 6 As shown, when the rubber sleeve 130 expands, it will push the two sets of scrapers 200 at the same time, causing the two sets of scrapers 200 to move away from each other. During the process of moving away from each other, multiple scrapers 200 in each set will spread outward along the radial direction of the rubber sleeve 130, so that the conical scraper strips 210 on the multiple scrapers 200 scrape off impurities or other particles on the side wall of the sleeve, thereby playing a cleaning role.

[0036] Specifically, in this embodiment, an elastic element 280 is provided on one side of the sliding cylinder 260. The elastic element 280 is a compression spring. The elastic element 280 gives the sliding cylinder 260 a tendency to return to its original position. When the rubber cylinder 130 is not expanded, the elastic element 280 pushes the two sliding cylinders 260, and the two sliding cylinders 260 drive multiple scrapers 200 to be located on the outer periphery of the rubber cylinder 130. When the rubber cylinder 130 expands, the multiple scrapers 200 are pushed, thereby compressing the elastic element 280. When the rubber cylinder 130 contracts, the two sliding cylinders 260 will return to their original position under the action of the elastic element 280. At the same time, a tension spring (not shown in the figure) is provided in the limiting groove 220. One end of the tension spring is fixedly connected to the limiting groove 220, and the other end of the tension spring is fixedly connected to the limiting block 230. When the rubber cylinder 130 contracts, the tension spring will pull the limiting block 230 to return to its original position in the limiting groove 220, thereby causing the multiple scrapers 200 to contract and return to their original position.

[0037] More specifically, in this embodiment, a fixing cylinder 270 is fixedly provided on the outer periphery of the upper steel bowl 140 and the lower steel bowl 150, such as... Figure 8 and Figure 10 As shown, a ring groove 271 is provided on one end of the fixed cylinder 270 near the sliding cylinder 260. One end of the elastic member 280 is fixed in the ring groove 271, and the other end of the elastic member 280 is fixedly connected to the sliding cylinder 260. The size of the ring groove 271 is the same as the size of the sliding cylinder 260. The sliding cylinder 260 can slide axially in the ring groove 271, thereby providing space for the axial movement of the sliding cylinder 260.

[0038] In a further embodiment, an elastic scraper strip 250 is provided on one end of the plurality of scrapers 200 away from the guide rod 240, such as... Figure 8 and Figure 9 As shown, the elastic scraper 250 is elastic and slides in contact with the outer wall of the glue cylinder 130. When the glue cylinder 130 expands, causing the multiple scrapers 200 to move along the axial direction of the glue cylinder 130, the elastic scraper 250 scrapes the outer wall of the glue cylinder 130, reducing impurities or other particles on the outer wall of the glue cylinder 130. When the glue cylinder 130 contracts, the multiple scrapers 200 will also reset, allowing the elastic scraper 250 to scrape the outer wall of the glue cylinder 130 again, further reducing impurities or other particles on the outer wall of the glue cylinder 130.

[0039] Specifically, in this embodiment, a retaining ring 121 is provided on the outer periphery of the lower connector 120. The retaining ring 121 is conical, and the small end of the retaining ring 121 faces the lower end of the lower steel cup 150. When the packer moves inside the sleeve, the retaining ring 121 can engage with a designated position inside the sleeve, thereby stopping the packer at the designated position. Furthermore, the conical shape of the retaining ring 121 provides a certain guiding function, ensuring that the packer is centered when it stops moving.

[0040] The specific usage process of the segmented fracturing pump shutdown test packer provided by the present invention will be described in conjunction with the above embodiments: Before large-scale fracturing operations, a small-scale fracturing test is conducted. Each wellbore is equipped with a casing (not shown in the figure). The plugging device of this invention is placed in the casing. After the plugging device moves to a designated position, it stops moving. High-pressure fluid is then pumped into the casing. The high-pressure fluid enters the central tube 100 within the casing. Through the grooves 101 on the central tube 100, the high-pressure fluid enters the cavity between the rubber sleeve 130 and the central tube 100. As the pumped high-pressure fluid increases, the liquid pressure inside the central tube 100 increases. The rubber sleeve 130 expands radially outward, causing its outer circumference to fit tightly against the inside of the casing, thus sealing the designated position on the casing. After sealing, a pump shutdown test is required. At this time, the pumping of high-pressure fluid into the casing is stopped, and the liquid pressure inside the casing no longer increases. Due to the small size of the grooves 101 on the central tube 100, the rubber sleeve 130 depressurizes very slowly under low pressure differential conditions, ensuring that the rubber sleeve 130 remains sealed for a certain period, thus reducing the impact on the pump shutdown test.

[0041] During the expansion of the rubber sleeve 130, the middle part of the rubber sleeve 130 expands first, thereby pushing multiple scrapers 200 to expand outward. As the rubber sleeve 130 gradually expands from the middle to both ends, the rubber sleeve 130 pushes the two sets of scrapers 200 to gradually move away from each other, so that the conical scraper strips 210 on the scrapers 200 can scrape off impurities or other particles on the inner wall of the sleeve. When the multiple scrapers 200 expand outward, the guide rods 240 on the scrapers 200 slide in the arc grooves 261 and rotate around the circumference of the rubber sleeve 130. When the multiple scrapers 200 rotate around the circumference, the conical scraper strips 210 can cut the impurities on the inner wall of the sleeve, thereby further improving the cleanliness of the inner wall of the sleeve and improving the sealing performance between the outer circumference of the rubber sleeve 130 and the inside of the sleeve.

[0042] When the rubber sleeve 130 needs to be unsealed, the pressure of the high-pressure fluid in the central tube 100 needs to be reduced. At this time, the pressure outside the first through hole 141 is greater than the pressure inside. The high-pressure fluid in the sleeve comes into contact with the lower end of the first sealing ring 171 and the upper end of the second sealing ring 172 on the piston 170 through the first through hole 141. Since the area of ​​the first sealing ring 171 is larger than the area of ​​the second sealing ring 172, the high-pressure fluid pushes the piston 170 to move upward, so that the bottom of the piston 170 passes through the second through hole 142 to open the second through hole 142. The high-pressure fluid inside the rubber sleeve 130 flows through the gap into the adjusting cavity 160 and then is discharged through the second through hole 142, so that the rubber sleeve 130 can retract and reset.

[0043] During the shrinking process of the rubber sleeve 130, as the rubber sleeve 130 expands and pushes the two sets of scrapers 200 away from each other, the two sets of scrapers 200 respectively drive the sliding cylinder 260 to compress the elastic element 280. When the rubber sleeve 130 shrinks, the elastic element 280 drives the sliding cylinder 260 to reset, and the sliding cylinder 260 drives the two sets of scrapers 200 to reset. The reset process is the opposite of the expansion process. During the reset process, the elastic scraper strip 250 on the scraper 200 can scrape the outer circumference of the rubber sleeve 130 to clean the outer circumference of the rubber sleeve 130, preventing impurities or other particles from adhering to the outer circumference of the rubber sleeve 130 during the next use, which would affect the sealing performance.

[0044] The present invention also provides a packer control system for staged fracturing and pump shutdown testing of oil wells, applied to the aforementioned packer for staged fracturing and pump shutdown testing of oil wells, comprising the following specific steps: Step S100: When the control system moves the segmented fracturing pump stop test well packer to a designated position inside the drilling casing, the rubber sleeve 130 expands. The control system includes a drive system, which includes drive elements (such as a traction mechanism and a drive motor). The drive elements are used to drive the packer of the segmented fracturing pump stop test well to move inside the drilling casing and stop after moving to a designated position. After reaching the designated position, the control system controls the pump to start, and the pump inputs high-pressure fluid into the drilling casing. The high-pressure fluid enters the rubber sleeve 130 through the groove 101 on the central tube 100, thereby pushing the rubber sleeve 130 to expand radially outward to seal the designated position of the drilling casing.

[0045] Step S200: When a pump stop test is required, the control system stops inputting high-pressure fluid into the drilling casing, and the rubber sleeve 130 of the well packer for the segmented fracturing pump stop test maintains a sealed state for a preset time. When a pump stop test is required, the control system stops inputting high-pressure fluid into the drilling casing. At this time, the pressure inside the drilling casing no longer increases. The small size of the groove 101 on the central tube 100 allows the high-pressure fluid in the rubber sleeve 130 to slowly depressurize through the groove 101, ensuring that the rubber sleeve 130 maintains an expanded and sealed state within a preset time (the time required for the test), avoiding inter-segment flow, and allowing the pressure drop data at the wellhead and bottom hole to truly reflect the fracture and formation characteristics.

[0046] Step S300: After the pump shutdown test is completed, the high-pressure fluid pressure inside the drilling casing decreases to a preset value, and the rubber sleeve 130 of the well packer for the segmented fracturing pump shutdown test is unsealed.

[0047] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0048] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A segmented fracturing pump-off test well packer, characterized in that, The utility model relates to a kind of segmented fracturing pump test oil well packer, including: Center tube, upper joint and lower joint are connected with the upper and lower ends of the center tube respectively; Rubber tube, the rubber tube is installed in the outer periphery of the center tube and is located at the midpoint position of the length of center tube, the side wall of the center tube is provided with a plurality of thin grooves extending along the axial direction of the center tube, and the plurality of thin grooves are uniformly distributed along the circumference of the center tube; Upper steel bowl, the outer periphery of the upper end of the center tube is fixedly sleeved, the upper steel bowl and the outer periphery of the center tube form adjustment cavity, the first gap between the two ends of the rubber tube and the outer side wall of the center tube, the first gap is communicated with the adjustment cavity and the inner periphery of the rubber tube, the piston is arranged in the adjustment cavity and slides along the axial direction, the second gap between the inner periphery of the piston and the outer periphery of the center tube, the first through hole and the second through hole are formed in the side wall of the upper steel bowl, and the piston is configured to block or open the first through hole or the second through hole when moving axially.

2. The frac-holdup test well packer of claim 1, wherein, The two ends of the rubber tube are respectively provided with connecting barrels, one end of the connecting barrel is fixedly connected to one end of the upper steel bowl, and the other end of the connecting barrel is fixedly connected to the rubber tube, and the connecting barrel and the outer periphery of the center tube have the first gap.

3. The staged fracturing pump-down test well packer of claim 2, wherein, The outer periphery of the rubber tube is provided with a plurality of scrapers, the plurality of scrapers are uniformly distributed along the circumference of the rubber tube, the outer side of the plurality of scrapers is provided with a tapered scraper strip at the intermediate position, and the plurality of scrapers are configured to move synchronously along the radial direction and the axial direction of the rubber tube when the rubber tube expands, and rotate along the circumference of the rubber tube.

4. The staged fracturing pump-down test well packer of claim 3, wherein, The two side edges of the scraper are both inclined surfaces and are respectively provided with a limiting groove and a limiting block, the limiting block on the adjacent scraper is located in the limiting groove, a guide rod is arranged on one end of the scraper, the outer periphery of the center tube is provided with a sliding barrel that slides axially elastically, a plurality of arc-shaped grooves are arranged on the end face of the sliding barrel close to the guide rod, and the guide rod is arranged in the arc-shaped groove.

5. The staged fracturing pump-down test well packer of claim 4, wherein, The outer periphery of the upper steel bowl is provided with a fixed barrel, the end of the fixed barrel close to the sliding barrel is provided with a ring groove, the ring groove is provided with an elastic element, the elastic element is connected with the sliding barrel, and the elastic element makes the sliding barrel have a restoring tendency.

6. The staged fracturing pump-down test well packer of claim 5, wherein, The elastic element is a compression spring.

7. The staged fracturing pump-down test well packer of claim 4, wherein, The end of the plurality of scrapers away from the guide rod is provided with an elastic scraper strip, and the elastic scraper strip is in sliding contact with the outer periphery of the rubber tube.

8. The frac-kick-off test well packer of claim 1, wherein, The outer periphery of the center tube is also provided with a lower steel bowl, the lower steel bowl is threadedly connected with the lower joint, the outer periphery of the lower joint is provided with a check ring, the check ring is tapered, and the small end of the check ring faces the lower end of the lower steel bowl.

9. The staged fracturing pump-down test well packer of claim 8, wherein, The lower joint is threadedly connected with a steel bowl locking ring, and the steel bowl locking ring abuts against the lower steel bowl.

10. A staged fracturing pump-off-test well packer control system adapted for use with the staged fracturing pump-off-test well packer of any of claims 1-9, wherein, The utility model relates to a kind of segmented fracturing pump test oil well packer, including the following steps: Step S100, when the control system moves the segmented fracturing pump test oil well packer to the specified position inside the drilling casing, the rubber tube is expanded; Step S200, when the need for pump test is stopped, the control system stops inputting high-pressure fluid inside the drilling casing, and the rubber tube of the segmented fracturing pump test oil well packer maintains a sealed state within a preset time; Step S300, after the pump test is completed, the pressure of the high-pressure fluid inside the drilling casing is reduced to a preset value, and the rubber tube of the segmented fracturing pump test oil well packer is unsealed.

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