High-pressure reservoir perforation, multi-section fracturing and drainage and mining integrated fracturing pipe column and method

Abstract

The invention relates to the technical field of petroleum and natural gas well completion and yield increase, in particular to a high-pressure reservoir perforation, multi-section fracturing and drainage and mining integrated fracturing string and method.The high-pressure reservoir perforation, multi-section fracturing and drainage and mining integrated fracturing string comprises a guide head, a screen pipe, a check valve, a first spray gun, a well completion sliding sleeve, a safety connector and an oil pipe which are sequentially installed together from bottom to top. The tubular column is reasonable and compact in structure and convenient to use, perforation, segmented transformation and liquid drainage production procedures of multiple sets of high-pressure reservoirs can be completed through one tubular column, the operation period can be greatly shortened, the operation cost and the operation risk can be reduced, the purposes of reducing reservoir damage and improving the single-well yield and the recovery efficiency to the maximum extent are achieved through snubbing operation, and the production efficiency of the high-pressure reservoirs is improved. During hydraulic sand blasting perforation fracturing construction, the first spray gun and the second spray gun correspond to different layers in an oil and gas well respectively, the packer is located between the two oil and gas layers, the first spray gun is in an open state, and the second spray gun and the packer are in a closed state.

Description

Technical Field

[0001] The invention relates to the technical field of oil and natural gas completion and production enhancement, and is a high-pressure reservoir perforation, multi-stage fracturing, drainage and production integrated fracturing string and method. Background Art

[0002] The conventional tubing transmission perforation and fracturing measures completion and transformation operation process generally includes firstly running the perforation string for perforation, using high-density well killing hydraulic well, pulling out the perforation string, then running the fracturing string for fracturing transformation, spraying and draining, and finally pulling out the fracturing string and running the completion and production string for production. This conventional fracturing completion measure has problems such as long operation cycle, low efficiency, high risk, and great damage to the formation.

[0003] Conventional hydraulic jet staged fracturing completion transformation string and fracturing method is a relatively mature staged completion transformation string and method, which can realize the integrated operation of low-pressure wells and normal-pressure wells without well suppression, perforation, and fracturing transformation. The operation process generally includes hydraulic sandblasting perforation of the first section, fracturing transformation of the first perforation section, depressurization, hydraulic sandblasting perforation of the second section, fracturing transformation of the second perforation section, depressurization, and completing the fracturing transformation of the remaining sections in sequence. This fracturing completion measure has a long depressurization cycle for high-pressure reservoirs and does not have the conditions for hydraulic sandblasting perforation in the second section. Therefore, conventional hydraulic jet staged fracturing string and fracturing method cannot realize multi-section continuous operation of high-pressure reservoirs, and the string cannot achieve continuous production after the oil and gas well stops blowing.

[0004] Conventional transmission perforation operations have high well control risks. The formation pressure coefficient of high-pressure reservoirs exceeds 1.7. Controlled by reservoir structure and heterogeneity, there are significant differences in formation pressure between different wells and different oil layers. Perforation operations are required before conventional fracturing. Since conventional tubing transmission, cable transmission perforation, and fracturing string operation after perforation require well killing operations, there is a high well control risk when using a density well killing fluid system to operate different layers.

[0005] Conventional fracturing completion and transformation well killing operations cause great damage to the reservoir. In order to reduce the risk of well control operations, before conventional perforating and tubing tripping operations, a suitable density of well killing fluid is generally selected according to the maximum predicted reservoir pressure. After the reservoir is perforated, the high-density well killing fluid enters the reservoir section with relatively low formation pressure, causing serious damage to the low-permeability reservoir. Therefore, from the perspective of reservoir protection work, the fracturing method of using conventional perforating guns to perforate each oil layer in advance and then inserting multi-stage fracturing tools has poor applicability in this type of reservoir.

[0006] It is difficult to run the completion string after conventional fracturing and completion transformation. After the high-pressure reservoir is fracturing and transformation, the wellhead pressure is high. Pulling out the fracturing string and running the production string requires the use of a higher density well killing fluid to kill the well again. The operation cycle is long, the cost is high, the risk is high, and the drainage capacity of the artificial fracture is greatly damaged. Conventional fracturing and completion transformation technology has poor adaptability.

[0007] Conventional hydraulic sandblasting perforation multi-stage fracturing strings and fracturing methods are difficult to achieve multi-stage fracturing of high-pressure reservoirs. Conventional hydraulic sandblasting perforation staged fracturing transformation technology is the product of the combination of hydraulic jetting and fracturing technology. It is a technology that integrates perforation, fracturing production increase measures and one string to achieve multi-stage construction. It solves the technical problems of conventional perforation technology causing great damage to the reservoir and high well control risks. It is suitable for single-stage sand fracturing transformation of high-pressure reservoirs and multi-stage sand fracturing transformation of low-pressure and normal-pressure formations. It is a relatively mature fracturing technology, but it cannot meet the needs of multi-stage continuous fracturing transformation of high-pressure reservoirs. This is mainly because, unlike low-pressure and normal-pressure reservoirs, conventional When the hydraulic sandblasting perforation multi-stage fracturing process is used for layer transfer, due to the high formation pressure coefficient of the high-pressure and low-permeability formation, the high pump stop pressure of the first layer of fracturing, the long crack closure time, and the long pressure release cycle controlled by the oil nozzle, it is impossible to carry out the second layer of hydraulic sandblasting perforation operation under high wellhead pressure conditions (the perforation operation requires opening the casing and controlling the pressure). The conventional fixed-pipe multi-gun multi-stage hydraulic jet fracturing process and the single-gun dragging multi-stage hydraulic jet fracturing process suitable for low-pressure and normal-pressure reservoirs cannot achieve multi-layer continuous fracturing transformation of high-pressure reservoirs. Summary of the invention

[0008] The present invention provides a high-pressure reservoir perforation, multi-stage fracturing, and integrated drainage and production fracturing string and method, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of conventional fracturing completion measures such as long operation cycle, low efficiency, high risk, and great damage to the formation.

[0009] One of the technical solutions of the present invention is achieved through the following measures: a high-pressure reservoir perforating, multi-stage fracturing, and integrated drainage and production fracturing string and method, including a guide head, a screen, a check valve, a first spray gun, a completion sleeve, a safety joint and an oil pipe installed together in sequence from bottom to top, at least one partition assembly is arranged in sequence from bottom to top between the first spray gun and the completion sleeve, the partition assembly includes an oil pipe short circuit, a packer and a second spray gun fixedly installed together in sequence from bottom to top, the lowest oil pipe short circuit and the upper end of the first spray gun are fixedly installed together, the upper end of the uppermost second spray gun and the lower end of the completion sleeve are fixedly installed together, and at least one gas lift valve is arranged on the oil pipe from bottom to top.

[0010] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions: The above-mentioned first spray gun may include a first spray gun tube and a first nozzle. The upper end of the first spray gun tube and the lower end of the lowest oil pipe short-circuit are fixedly installed together. A plurality of first spray holes connected inside and outside are staggeredly arranged at upper and lower intervals on the outside of the first spray gun tube, and a first nozzle is fixedly installed in each first spray hole.

[0011] The above-mentioned second spray gun may include a second spray gun tube, a sealing sleeve and a second nozzle. A fixing ring is fixedly installed on the inner side of the upper part of the second spray gun tube, and a sealing sleeve is slidably installed in the fixing ring. At least one radially penetrating mounting screw hole is distributed along the circumference on the inner side of the lower part of the fixing ring. A limiting ring groove is provided on the outer side of the upper part of the sealing sleeve corresponding to the position of the mounting screw hole, and a shear nail with an end located in the limiting ring groove is threaded in the mounting screw hole. A plurality of second spray holes connected inside and outside are staggered and arranged at upper and lower intervals on the outer side of the second spray gun tube corresponding to the position below the fixing ring, and a second nozzle is fixedly installed in each second spray hole. At least one upper sealing member is provided at an upper and lower interval between the outer side of the sealing sleeve corresponding to the position between the uppermost second spray hole and the lower end of the fixing ring and the inner side of the second spray gun tube, and at least one lower sealing member is provided at an upper and lower interval between the outer side of the sealing sleeve corresponding to the position below the lowermost second spray hole and the inner side of the second spray gun tube.

[0012] The above-mentioned packer may be a step-by-step expansion packer.

[0013] The second technical solution of the present invention is achieved by the following measures: a fracturing method, comprising the following steps: S1, prepare the target well; S2, lower the high-pressure reservoir perforation, multi-stage fracturing, and drainage and production integrated fracturing string into the well to the designed depth, and align the first nozzle and the second nozzle to the designed position; S3, performing hydraulic sandblasting perforation on the first section of the well wall corresponding to the first nozzle according to the positive circulation process; S4, after the first section of the well wall is hydraulically sandblasted and perforated, the first section is subjected to fracturing transformation. After the first section of the fracturing transformation is completed, the pump is stopped, the first plugging ball is dropped from the wellhead, and the pump is started to set the lowest packer; S5, stop the pump again, open the casing gate, ensure that the wellhead tubing pressure is greater than the wellhead casing pressure, put the second plugging ball in from the wellhead, start the pump again, and the sealing sleeve in the second spray gun pipe at the bottom moves downward to open the second nozzle; S6, performing hydraulic sandblasting perforation on the second section of the well wall corresponding to the second nozzle at the bottom according to the positive circulation process; S7, after the hydraulic sandblasting perforation of the second section of the well wall is completed, the second section is subjected to fracturing transformation, and the pump is stopped after the fracturing transformation of the second section is completed; S8, if it is necessary to perform hydraulic sandblasting perforation on the well wall between the second section of the well wall and the wellhead, plugging balls are successively inserted from bottom to top, and after each plugging ball is inserted, the sealing sleeve in the spray gun tube moves downward and then the second nozzle at the corresponding position is opened, and then hydraulic sandblasting perforation and fracturing transformation are performed on the well wall corresponding to the second nozzle according to the positive cycle process, and hydraulic sandblasting perforation and fracturing transformation are repeated from bottom to top on the well wall between the second section of the well wall and the wellhead until all the well walls are hydraulically sandblasted perforated and fracturing transformation is completed; if hydraulic sandblasting perforation is performed only on the first section of the well wall and the second section of the well wall, the hydraulic sandblasting perforation and fracturing transformation are terminated; S9, install nozzles of appropriate specifications according to the wellhead pressure to carry out blowout and drainage production; S10, after stopping spraying, use ground gas lift equipment to inject nitrogen or natural gas from the casing for gas lift drainage or production, open the gas lift valve, and reduce the ground gas lift pressure.

[0014] The following is a further optimization and / or improvement of the second technical solution of the above invention: In the above steps S4, S7 and S8, after the hydraulic sandblasting perforation is completed, a test squeeze is performed to verify whether the perforation is successful. If it is unsuccessful, a second perforation is required.

[0015] In the above step S2: after the high-pressure reservoir perforation, multi-stage fracturing, and integrated drainage and production fracturing string is lowered into the well to the designed depth, the depth is calibrated by electrical measurement, and the positions of the first spray gun and the second spray gun are adjusted by short-circuiting the wellhead oil pipe to ensure that the first nozzle and the second nozzle are facing the designed position.

[0016] In the above step S10: nitrogen or natural gas is injected from the casing for gas lift drainage or production, and then according to the wellbore liquid level height and the gas lift pressure, the gas lift valves are opened from top to bottom in sequence as the wellbore liquid level decreases, thereby reducing the surface gas lift pressure.

[0017] The above step S1 comprises: S11, clearing the target well; S12, scraping and cleaning the target well.

[0018] The invention has a reasonable and compact structure and is easy to use. It can complete the perforation, segmented transformation and drainage production processes of multiple sets of high-pressure reservoirs in one trip of the tubing string, which can greatly shorten the operation cycle, reduce the operation cost and operation risk, and achieve the purpose of reducing reservoir damage and maximizing the single well production and recovery rate through non-well pressure operation. During the hydraulic sandblasting perforation fracturing construction, the first spray gun and the second spray gun correspond to different layers in the oil and gas well respectively, the packer is between the two oil and gas layers, the first spray gun is in an open state, and the second spray gun and the packer are in a closed state. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] AttachedFigure 1 This is a schematic diagram of the main structure of the first embodiment with only one partition component.

[0020] Attached Figure 2 This is a schematic diagram of the front cross-sectional structure of the first spray gun in Example 1.

[0021] Attached Figure 3 It is a schematic diagram of the front cross-sectional structure of the second spray gun in Example 1.

[0022] Attached Figure 4 This is a schematic diagram of the main structure of the first embodiment with only two partition components.

[0023] The codes in the accompanying drawings are: 1 is a guide head, 2 is a screen tube, 3 is a check valve, 4 is a tubing short circuit, 5 is a gas lift valve, 6 is a completion sleeve, 7 is a safety joint, 8 is a tubing, 9 is a packer, 10 is a first spray gun pipe, 11 is a first nozzle, 12 is a second spray gun pipe, 13 is a sealing sleeve, 14 is a second nozzle, 15 is a shear pin, 16 is an upper seal, 17 is a lower seal, and 18 is a fixing ring. DETAILED DESCRIPTION

[0024] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0025] In the present invention, for the convenience of description, the relative position relationship of each component is described according to the attached Figure 1 The positional relationships such as front, back, top, bottom, left, and right are described according to the layout directions of the drawings in the specification.

[0026] The present invention will be further described below in conjunction with embodiments and drawings: Embodiment 1: As shown in the attached Figure 1 , 2 As shown in Figures 3 and 4, the high-pressure reservoir perforating, multi-stage fracturing, and integrated production and drainage fracturing string includes a guide head 1, a screen 2, a check valve 3, a first spray gun, a completion sleeve 6, a safety joint 7, and an oil pipe 8, which are installed together in sequence from bottom to top. At least one partition assembly is arranged between the first spray gun and the completion sleeve 6 from bottom to top. The partition assembly includes an oil pipe short circuit 4, a packer 9, and a second spray gun, which are fixedly installed together in sequence from bottom to top. The lowermost oil pipe short circuit 4 is fixedly installed with the upper end of the first spray gun, and the upper end of the uppermost second spray gun is fixedly installed with the lower end of the completion sleeve 6. At least one gas lift valve 5 is arranged on the oil pipe 8 from bottom to top.

[0027] According to the requirements, the guide head 1, the screen 2, the check valve 3, the tubing short-circuit 4, the completion sleeve 6, the safety joint 7 and the tubing 8 are all existing known technologies. Between each two adjacent partition components, the upper end of the second spray gun below and the lower end of the tubing short-circuit 4 above are fixedly installed together. The fracturing string in the present invention integrates perforation, multi-stage fracturing, drainage and production integrated string design, which can realize the perforation, segmented transformation and drainage production processes of multiple sets of high-pressure reservoirs in one trip, which can greatly shorten the operation cycle, reduce the operation cost and operation risk, and achieve the purpose of reducing reservoir damage and maximizing the single well production and recovery rate through non-suppression operation. During the hydraulic sandblasting perforation fracturing construction, the first spray gun and the second spray gun correspond to different layers in the oil and gas well respectively, and the packer 9 is between the two oil and gas layers. The first spray gun is in an open state, and the second spray gun and the packer 9 are in a closed state. The present invention has a reasonable and compact structure, is easy to use, and has the characteristics of safety, labor saving, simplicity and high efficiency.

[0028] The above-mentioned high-pressure reservoir perforation, multi-stage fracturing, and integrated drainage and production fracturing strings can be further optimized and / or improved according to actual needs: Embodiment 2: As an optimization of the above embodiment, as shown in the attached Figure 1 , 2 As shown in Figure 4, the first spray gun includes a first spray gun tube 10 and a first nozzle 11. The upper end of the first spray gun tube 10 and the lower end of the lowest oil pipe short circuit 4 are fixedly installed together. A plurality of first spray holes connected inside and outside are staggered and arranged at intervals from top to bottom on the outer side of the first spray gun tube 10. A first nozzle 11 is fixedly installed in each first spray hole. According to the needs, a mounting screw sleeve is fixedly installed between the first nozzle 11 and the inner wall of the first spray hole, and the lower end of the first spray gun tube 10 and the upper end of the check valve 3 are fixedly installed together. During use, after the high-pressure reservoir perforating, multi-stage fracturing, and integrated drainage and production fracturing string are lowered into the target position in the well, the target position can be directly hydraulically sandblasted and perforated without throwing a ball to seal the well wall with the packer 9, which simplifies the process and improves the fracturing efficiency.

[0029] Embodiment 3: As an optimization of the above embodiment, as shown in the attached Figure 1 , 3As shown in Figures 4 and 5, the second spray gun includes a second spray gun tube 12, a sealing sleeve 13 and a second nozzle 14. A fixing ring 18 is fixedly installed on the inner side of the upper part of the second spray gun tube 12, and the sealing sleeve 13 is slidably installed in the fixing ring 18. At least one radially penetrating mounting screw hole is distributed along the circumference on the inner side of the lower part of the fixing ring 18. A limiting ring groove is provided on the outer side of the upper part of the sealing sleeve 13 corresponding to the position of the mounting screw hole. A shear nail 15 with an end located in the limiting ring groove is screwed in the mounting screw hole. A plurality of second spray holes connected inside and outside are staggered and arranged at upper and lower intervals on the outer side of the second spray gun tube 12 corresponding to the position below the fixing ring 18. A second nozzle 14 is fixedly installed in each second spray hole. At least one upper sealing member 16 is arranged at an upper and lower interval between the outer side of the sealing sleeve 13 corresponding to the position between the uppermost second spray hole and the lower end of the fixing ring 18 and the inner side of the second spray gun tube 12. At least one lower sealing member 17 is arranged at an upper and lower interval between the outer side of the sealing sleeve 13 corresponding to the position below the lowermost second spray hole and the inner side of the second spray gun tube 12. According to the requirements, the upper seal 16 and the lower seal 17 are both existing well-known O-rings, the lower end of the second spray gun tube 12 and the upper end of the oil pipe short-circuit 4 at the adjacent position below are fixedly installed together, the upper end of the second spray gun tube 12 and the lower end of the oil pipe short-circuit 4 at the adjacent position above are fixedly installed together, the inner side of the upper end of the sealing sleeve 13 is a cone with a large upper portion and a small lower portion, the inner diameter of the small diameter section at the upper end of the sealing sleeve 13 is smaller than the inner diameter of the fixing ring 18, and a disassembly screw sleeve is fixedly installed between the second nozzle 14 and the inner wall of the second spray hole. During use, through such a setting, after the blocking ball is put into the second spray gun tube 12 and the pressure is held, the shear nail 15 can be cut off, and then the sealing sleeve 13 slides downward into the packer 9, so that the packer 9 is seated on the well wall, and at the same time, the second nozzle 14 is opened, and hydraulic sandblasting and perforating operations can be carried out, which is convenient and simple to operate.

[0030] Embodiment 4: As an optimization of the above embodiment, as shown in the attached Figure 1 , 4 As shown, the packer 9 is a step-by-step expansion packer 9. According to the requirements, the step-by-step expansion packer 9 is a prior art known in the art, such as the step-by-step expansion packer with the announcement number CN212508202U. During use, step-by-step setting can be achieved, and during the fracturing process, different layers of the wellbore wall can be set in sequence from bottom to top, thereby improving the fracturing efficiency.

[0031] Embodiment 5: As an optimization of the above embodiment, as shown in the attached Figure 1 , 2 As shown in , 3 and 4, the fracturing method using high-pressure reservoir perforation, multi-stage fracturing and integrated drainage and production fracturing string includes the following steps: S1, prepare the target well; S2, lower the high-pressure reservoir perforation, multi-stage fracturing, and drainage integrated fracturing string into the well to the designed depth, and align the first nozzle 11 and the second nozzle 14 to the designed position; S3, performing hydraulic sandblasting perforation on the first section of the well wall corresponding to the first nozzle 11 according to the positive circulation process; S4, after the first section of the well wall is hydraulically sandblasted and perforated, the first section is subjected to hydraulic fracturing. After the first section of hydraulic fracturing is completed, the pump is stopped, the first plugging ball is dropped from the wellhead, and the pump is started to seat the lowermost packer 9; S5, stop the pump again, open the casing gate, ensure that the pressure of the wellhead oil pipe 8 is greater than the casing pressure at the wellhead, put the second plugging ball into the wellhead, start the pump again, and the sealing sleeve 13 in the second spray gun pipe 12 at the bottom moves downward to open the second nozzle 14; S6, hydraulic sandblasting and perforating the second section of the well wall corresponding to the second nozzle 14 at the bottom according to the positive circulation process; S7, after the hydraulic sandblasting perforation of the second section of the well wall is completed, the second section is subjected to fracturing transformation, and the pump is stopped after the fracturing transformation of the second section is completed; S8, if it is necessary to perform hydraulic sandblasting perforation on the well wall between the second section of the well wall and the wellhead, plugging balls are successively inserted from bottom to top, and each time the plugging balls are inserted, the sealing sleeve 13 in the spray gun tube moves downward and then the second nozzle 14 at the corresponding position is opened, and then hydraulic sandblasting perforation and fracturing transformation are performed on the well wall corresponding to the second nozzle according to the positive cycle process, and hydraulic sandblasting perforation and fracturing transformation are repeated from bottom to top on the well wall between the second section of the well wall and the wellhead until all the well walls are hydraulically sandblasted and perforated and fracturing transformation is completed; if hydraulic sandblasting perforation is performed only on the first section of the well wall and the second section of the well wall, the hydraulic sandblasting perforation and fracturing transformation are terminated; S9, install nozzles of appropriate specifications according to the wellhead pressure to carry out blowout and drainage production; S10, after stopping the spraying, nitrogen or natural gas is injected from the casing by using the surface gas lift equipment to perform gas lift drainage or production, and the gas lift valve 5 is opened to reduce the surface gas lift pressure.

[0032] In steps S4, S7 and S8, after the hydraulic sandblasting perforation is completed, a test squeeze is performed to verify whether the perforation is successful. If it is unsuccessful, a second perforation is required.

[0033] In step S2: after the high-pressure reservoir perforation, multi-stage fracturing, and integrated drainage and production fracturing string is lowered into the well to the designed depth, the depth is electrically measured and calibrated, and the positions of the first spray gun and the second spray gun are adjusted by short-circuiting the wellhead oil pipe 8 to ensure that the first nozzle 11 and the second nozzle 14 are facing the designed position.

[0034] In step S10: nitrogen or natural gas is injected from the casing to perform gas lift drainage or production, and then the gas lift valves 5 are opened in sequence from top to bottom as the wellbore liquid level decreases, according to the wellbore liquid level height and the gas lift pressure, so as to reduce the surface gas lift pressure.

[0035] Step S1 includes: S11, clearing the target well; S12, scraping and cleaning the target well.

[0036] The fracturing process using high-pressure reservoir perforation, multi-stage fracturing, and integrated fracturing string: The first step is to clear the well, using a clearing gauge that meets the inner diameter requirements of the casing + fracturing tubing combination to clear the well to the bottom of the artificial well; The second step is scraping and washing the well to ensure that no sedimentation occurs in the wellbore after scraping and washing the well to block the spray gun nozzle and the bottom screen pipe 2; The third step is to assemble the high-pressure reservoir perforation, multi-stage fracturing, and integrated drainage and production fracturing string; The fourth step is to lower the high-pressure reservoir perforation, multi-stage fracturing, and integrated drainage and production fracturing string to the designed well depth, and then calibrate the depth by electrical measurement. The spray gun position is adjusted by short-circuiting the wellhead tubing to ensure that the spray gun nozzle is facing the designed position during construction. Step 5: Connect the ground process of fracturing construction and pass the pressure test; Step 6: Use the positive circulation process to perform hydraulic sandblasting perforation on the first section of the wellbore according to the designed pumping process. After the perforation is completed, a test squeeze is performed to verify whether the perforation is successful. If it is unsuccessful, a second perforation is performed. Step 7: Complete the first section of wellbore fracturing construction according to the designed pumping process; Step 8: After the pump is stopped for the first section of well wall construction, the first plugging ball is put into the wellhead. After the first plugging ball is in place, the pressure shear nails of the oil pipe 8 are cut off, and the second spray gun sealing sleeve 13 at the bottom is opened. After the sealing sleeve 13 moves down, the liquid inlet hole of the seal packer 9 is sealed, and the displacement is quickly increased so that the bottom seal packer 9 is seated on the well wall; Step 9: After the bottom packer 9 is seated on the well wall, the pump is stopped, the casing gate is opened, the pressure of the wellhead tubing 8 is ensured to be greater than the casing pressure at the wellhead, and the second sealing ball is dropped from the wellhead. After the second sealing ball is in place, the pressurized shear pins of the tubing 8 are cut off, and the bottom second spray gun sealing sleeve 13 is opened. After the sealing sleeve 13 moves downward, it seals the liquid inlet hole of the packer 9, and the packer 9 is seated on the well wall, and at the same time, the bottom second spray gun nozzle is in working state; Step 10: Use the positive circulation process to perform hydraulic sandblasting perforation on the second section of the wellbore according to the designed pumping process. After the perforation is completed, a test squeeze is performed to verify whether the perforation is successful. If it is unsuccessful, a second perforation is performed; Step 11: Complete the second section of well wall fracturing construction according to the designed pumping process. The well wall corresponding to the first spray gun is the first section, and the well wall corresponding to the second spray gun is the second section. At this time, the number of construction sections is 2; The well wall corresponding to the first spray gun is the first section, and the well wall corresponding to the second spray gun is the second section. If the number of construction sections is ≥ 3, at least one partition assembly is added to the second spray gun, such as: when the number of construction sections is 3, one partition assembly is added to the second spray gun, that is, two tubing short circuits 4, two packers 9, and two second spray guns are connected above the first spray gun; when the number of construction sections is 4, two partition assemblies are added to the second spray gun, that is, three tubing short circuits 4, three packers 9, and three second spray guns are connected above the first spray gun; In the twelfth step, if the number of construction sections is 3, a partition component is added to the second spray gun, that is, two oil pipe short circuits 4, two packers 9 and two second spray guns are connected above the first spray gun, and the well wall corresponding to the upper second spray gun is the third section. After the eleventh step is completed, the pump is stopped, and the third sealing ball is put into the wellhead. After the third sealing ball is in place, the oil pipe 8 is pressurized to open the sealing sleeve 13 of the packer 9 above the second spray gun at the bottom, and the displacement is quickly increased to make the packer 9 seal the well wall; after the packer 9 seals the well wall, the pump is stopped, the casing gate is opened to ensure that the pressure of the wellhead oil pipe 8 is greater than the pressure of the wellhead casing, and the fourth sealing ball is put into the wellhead. After the fourth sealing ball is in place, the oil pipe 8 is pressurized to open the sealing sleeve 13 of the upper second spray gun, so that the nozzle of the upper second section spray gun is in working state; a positive circulation process is adopted, and hydraulic sandblasting perforation is performed on the third section well wall according to the designed pumping process. After the perforation is completed, a test squeeze is performed to verify whether the perforation is successful. If it is unsuccessful, a secondary perforation is performed; If the number of construction sections is 4, two partition components are added to the second spray gun, that is, three oil pipe short circuits 4, three packers 9 and three second spray guns are connected above the first spray gun. The well walls corresponding to the three second spray guns are the fourth section, the third section and the second section from top to bottom, and the well wall corresponding to the first spray gun is the first section. When the number of construction sections is 3, after the fracturing is completed, the pump is stopped and the fifth plugging ball is put into the wellhead. After the fifth plugging ball is in place, the oil pipe 8 is pressurized to open the sealing sleeve 13 of the packer 9 above the middle second spray gun to quickly increase the drainage After the packer 9 is seated on the well wall, the pump is stopped, the casing gate is opened, and the pressure of the wellhead tubing 8 is ensured to be greater than the casing pressure at the wellhead. The sixth plugging ball is put into the wellhead. After the sixth plugging ball is in place, the tubing 8 is pressurized to open the upper second spray gun sealing sleeve 13, so that the upper second section spray gun nozzle is in working state. The fourth section well wall is hydraulically sandblasted and perforated according to the designed pumping process by adopting a positive circulation process. After the perforation is completed, a test squeeze is performed to verify whether the perforation is successful. If it is unsuccessful, a secondary perforation is performed. If the number of construction sections is greater than 4, complete the fracturing operations of the remaining construction sections in sequence according to the above steps; Step 13: Install appropriate size nozzles according to the wellhead pressure to carry out blowout and drainage production; Step 14. After stopping the spraying, use the surface gas lift equipment to inject nitrogen or natural gas from the casing to perform gas lift drainage or production. According to the wellbore liquid level height and the gas lift pressure, as the wellbore liquid level decreases, the gas lift valves 5 are opened from top to bottom in sequence, thereby reducing the surface gas lift pressure.

[0037] The beneficial effects achieved by the present invention are as follows: the present invention does not require well pressure operation for pulling up and down the tubing, and can realize one-trip tubing perforation, multi-stage fracturing and integrated production and drainage, which can reduce 3-4 trips of tubing pulling up and down operations; after one stage of fracturing construction is completed, there is no need to release the pressure, wash the well, or introduce a pressurized dragging device before the second stage of hydraulic sandblasting perforation, and the innovative tubing tool design and fracturing method can quickly realize the layer-transfer hydraulic sandblasting perforation and fracturing, with a short operation cycle and low cost; a plurality of gas lift valves 5 are arranged on the tubing of the present invention, which are opened at different production pressures. After the fracturing transformation well stops spraying, there is no need to pull out the fracturing transformation tubing, and continuous gas lift production can be achieved by using the tubing of the present invention.

[0038] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A high-pressure reservoir perforation, multi-stage fracturing, drainage and production integrated fracturing string, characterized in that It includes a guide head, a screen pipe, a check valve, a first spray gun, a completion sleeve, a safety joint and an oil pipe which are installed together in sequence from bottom to top. At least one partition assembly is arranged in sequence from bottom to top between the first spray gun and the completion sleeve. The partition assembly includes an oil pipe short connection, a packer and a second spray gun which are fixedly installed together in sequence from bottom to top. The lowest oil pipe short connection is fixedly installed with the upper end of the first spray gun, the upper end of the uppermost second spray gun is fixedly installed with the lower end of the completion sleeve, and at least one gas lift valve is arranged on the oil pipe from bottom to top.

2. The high-pressure reservoir perforation, multi-stage fracturing, and drainage integrated fracturing string according to claim 1 is characterized in that The first spray gun includes a first spray gun tube and a first nozzle. The upper end of the first spray gun tube and the lower end of the lowest oil pipe short-circuit are fixedly installed together. A plurality of first spray holes connected inside and outside are staggered and arranged at intervals up and down on the outer side of the first spray gun tube. A first nozzle is fixedly installed in each first spray hole.

3. The high-pressure reservoir perforation, multi-stage fracturing, and drainage-production integrated fracturing string according to claim 1 or 2, characterized in that The second spray gun includes a second spray gun tube, a sealing sleeve and a second nozzle. A fixing ring is fixedly installed on the inner side of the upper part of the second spray gun tube, and a sealing sleeve is slidably installed in the fixing ring. At least one radially penetrating mounting screw hole is distributed along the circumference on the inner side of the lower part of the fixing ring. A limiting ring groove is provided on the outer side of the upper part of the sealing sleeve corresponding to the position of the mounting screw hole, and a shear nail with an end located in the limiting ring groove is screwed in the mounting screw hole. A plurality of second spray holes connected inside and outside are staggeredly arranged at upper and lower intervals on the outer side of the second spray gun tube corresponding to the position below the fixing ring, and a second nozzle is fixedly installed in each second spray hole. At least one upper sealing member is provided at upper and lower intervals between the outer side of the sealing sleeve corresponding to the position between the uppermost second spray hole and the lower end of the fixing ring and the inner side of the second spray gun tube, and at least one lower sealing member is provided at upper and lower intervals between the outer side of the sealing sleeve corresponding to the position below the lowermost second spray hole and the inner side of the second spray gun tube.

4. The high-pressure reservoir perforation, multi-stage fracturing, and drainage-production integrated fracturing string according to claim 1 or 2, characterized in that The packer is a step-by-step expansion packer.

5. The high-pressure reservoir perforation, multi-stage fracturing, drainage and production integrated fracturing string according to claim 3, characterized in that The packer is a step-by-step expansion packer.

6. A fracturing method using the high-pressure reservoir perforation, multi-stage fracturing, and drainage-production integrated fracturing string as claimed in any one of claims 1 to 5, characterized in that The steps include: S1, prepare the target well; S2, lower the high-pressure reservoir perforation, multi-stage fracturing, and drainage and production integrated fracturing string into the well to the designed depth, and align the first nozzle and the second nozzle to the designed position; S3, performing hydraulic sandblasting perforation on the first section of the well wall corresponding to the first nozzle according to the positive circulation process; S4, after the first section of the well wall is hydraulically sandblasted and perforated, the first section is subjected to fracturing transformation. After the first section of the fracturing transformation is completed, the pump is stopped, the first plugging ball is dropped from the wellhead, and the pump is started to set the lowest packer; S5, stop the pump again, open the casing gate, ensure that the wellhead tubing pressure is greater than the wellhead casing pressure, put the second plugging ball in from the wellhead, start the pump again, and the sealing sleeve in the second spray gun pipe at the bottom moves downward to open the second nozzle; S6, performing hydraulic sandblasting perforation on the second section of the well wall corresponding to the second nozzle at the bottom according to the positive circulation process; S7, after the hydraulic sandblasting perforation of the second section of the well wall is completed, the second section is subjected to fracturing transformation, and the pump is stopped after the fracturing transformation of the second section is completed; S8, if it is necessary to perform hydraulic sandblasting perforation on the well wall between the second section of the well wall and the wellhead, plugging balls are successively inserted from bottom to top, and after each plugging ball is inserted, the sealing sleeve in the spray gun tube moves downward and then the second nozzle at the corresponding position is opened, and then hydraulic sandblasting perforation and fracturing transformation are performed on the well wall corresponding to the second nozzle according to the positive cycle process, and hydraulic sandblasting perforation and fracturing transformation are repeated from bottom to top on the well wall between the second section of the well wall and the wellhead until all the well walls are hydraulically sandblasted perforated and fracturing transformation is completed; if hydraulic sandblasting perforation is performed only on the first section of the well wall and the second section of the well wall, the hydraulic sandblasting perforation and fracturing transformation are terminated; S9, install nozzles of appropriate specifications according to the wellhead pressure to carry out blowout and drainage production; S10, after stopping spraying, use ground gas lift equipment to inject nitrogen or natural gas from the casing for gas lift drainage or production, open the gas lift valve, and reduce the ground gas lift pressure.

7. The fracturing method according to claim 6, characterized in that In steps S4, S7 and S8, after the hydraulic sandblasting perforation is completed, a test squeeze is performed to verify whether the perforation is successful. If it is unsuccessful, a second perforation is required.

8. The fracturing method according to claim 6 or 7, characterized in that In step S2: after the high-pressure reservoir perforation, multi-stage fracturing, and integrated drainage and production fracturing string is lowered into the well to the designed depth, the depth is calibrated by electrical measurement, and the positions of the first spray gun and the second spray gun are adjusted by short-circuiting the wellhead oil pipe to ensure that the first nozzle and the second nozzle are facing the designed position.

9. The fracturing method according to claim 6 or 7, characterized in that In step S10: nitrogen or natural gas is injected from the casing to perform gas lift drainage or production, and then the gas lift valves are opened in sequence from top to bottom as the wellbore liquid level decreases according to the wellbore liquid level height and the gas lift pressure, thereby reducing the surface gas lift pressure; or / and, step S1 includes: S11, clearing the target well; S12, scraping and cleaning the target well.

10. The fracturing method according to claim 8, characterized in that In step S10: nitrogen or natural gas is injected from the casing to perform gas lift drainage or production, and then the gas lift valves are opened in sequence from top to bottom as the wellbore liquid level decreases according to the wellbore liquid level height and the gas lift pressure, thereby reducing the surface gas lift pressure; or / and, step S1 includes: S11, clearing the target well; S12, scraping and cleaning the target well.

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