Hydraulic pulse-type soluble segmented acid fracturing slide sleeve and pulse acid fracturing construction method

Abstract

A hydraulic pulse-type soluble segmented acid fracturing slide sleeve and a pulse acid fracturing construction method. The slide sleeve comprises a slide sleeve outer cylinder (1) and a rotary valve assembly, and flow-passing holes (101) are formed on the slide sleeve outer cylinder (1); the rotary valve assembly comprises a valve core (2) and a valve ball (13), and the valve ball (13) can block a passage (203); a flow guide channel (206) and flow splitting channels (207) are formed between the outer wall of the valve core (2) and the inner wall of the slide sleeve outer cylinder (1); the slide sleeve outer cylinder (1) has a first position and a second position in the axial direction; when the valve core (2) is located at the first position, the outer wall of the valve core (2) blocks the flow-passing holes (101); an acid fracturing working fluid flowing through the flow guide channel (206) can push the valve core (2) to move from the first position to the second position along the slide sleeve outer cylinder (1), and push the valve core (2) to continuously rotate at the second position, so that the flow splitting channels (207) are alternately communicated with the flow-passing holes (101), the acid fracturing working fluid is discharged from the flow-passing holes as hydraulic pulses, hydraulic pulses with a proper frequency can be excited at the bottom of a well, energy attenuation is reduced, and the formation of a complex fracture network is promoted in a stratum.

Description

Hydraulic pulse soluble segmented acid fracturing sliding sleeve and pulse acid fracturing construction method

[0001] Related applications

[0002] This application claims priority to Chinese patent application No. 202311719439.5 filed on December 14, 2023, and cites the contents disclosed in the above patent application as part of this application. Technical Field

[0003] The present application relates to the technical field of oil and natural gas extraction, and further to a downhole tool for oil and natural gas drilling and acid fracturing, and in particular to a hydraulic pulse soluble segmented acid fracturing sleeve and a pulse acid fracturing construction method. Background Art

[0004] Acid fracturing is a key measure for increasing production and injection in carbonate reservoirs. Horizontal well acid fracturing often utilizes vertical well stimulation technology for general acid fracturing, targeted acid fracturing with coiled tubing, or localized acid fracturing. In recent years, breakthroughs in staged completion and injection tools have led to rapid development of horizontal well staged stimulation technology. Generally speaking, these techniques can be categorized into five types: flow restriction stimulation, mechanical isolation, coiled tubing, hydraulic injection, and chemical isolation. Mechanical isolation staged acid fracturing is currently the mainstream technology for horizontal well staged acid fracturing. Because carbonate reservoirs differ from sandstone reservoirs in their greater thickness and heterogeneity, acid preferentially enters high-permeability zones during stimulation, preventing the effective utilization of low-permeability zones. Furthermore, wormholes created during stimulation further increase the permeability difference between high- and low-permeability zones, preventing the effective stimulation of low-permeability zones, which are crucial for oil well production. Therefore, the most important thing about acid fracturing to increase production of tight oil and gas resources such as carbonate rocks is to promote the formation of complex fracture networks while ensuring the extension of fractures.

[0005] The pulse acid fracturing process, combining hydraulic pulses with acid fracturing, is highly effective. The hydraulic pulses generate continuous pulsating stress waves that act on the fracture surface, reflecting and superimposing each other. The alternating loads of the hydraulic pulses cause fatigue damage to the formation rock, significantly reducing its strength. This reduces formation fracturing and fractures; furthermore, the pulses alter the stress state on the formation rock surface, contributing to the formation of a complex fracture network. Furthermore, pulse acid fracturing can further dissolve existing fractures, increasing their conductivity and promoting the formation of a complex fracture network.

[0006] At present, conventional pulse acid fracturing includes two methods. One method is to create a pulse effect by changing the displacement and pump pressure of the ground fracturing pump, which acts on the production-increasing layer. That is, by controlling the displacement to change alternately during acid injection, the acid generates a hydraulic shock wave at the wellhead, forcing water hammer to occur in the liquid (that is, the liquid flow rate increases or decreases sharply in a short period of time); due to the sudden change in the acid flow rate, the injection pressure suddenly increases or decreases, thereby generating alternating pressure in the oil pipe. The shock wave propagates and acts on the rock wall of the oil layer, and performs alternating disturbance and oscillating shear, which can cause microcracks in the reservoir rock; at the same time, the hydraulic shock pressure can make the fluid flow rapidly, which plays a role in flushing the pores and carrying blockages out of the pores, forming a "dynamic unblocking" process, thereby achieving the purpose of deep unblocking or pulse acid fracturing.

[0007] Another method involves lowering a hydraulic pulse generator downhole to generate hydraulic pulses that act on the formation rock. One type of oscillator consists of a multi-stage rupture disc, steel balls, a rupture chamber, and a check valve. During operation, a pump truck pumps pressure into the tubing at the wellhead. When the wellhead pressure, combined with the pressure generated by the fluid column within the tubing, exceeds the rupture pressure of the rupture disc, the rupture disc explodes. The high-pressure fluid in the wellbore is then converted into a high-velocity fluid, entering the rupture chamber. It then flows out through the check valve, completing a single hydraulic vibration of the formation. Because the hydraulic pressure exceeds the fracture pressure of the formation, multiple irregular cracks are created at the moment of hydraulic vibration. Multiple steel balls are then added sequentially to the formation for repeated hydraulic vibration treatments, deepening the cracks. After the hydraulic vibration is complete, acid is injected to complete the acid fracturing of the formation.

[0008] However, the two aforementioned pulse acid fracturing methods each have their own drawbacks: When pulse acid fracturing is performed by regulating the construction pressure through a surface fracturing pump, the pulse pressure is generated by ground excitation, and the energy of the pressure wave is significantly attenuated when it reaches the formation rock. Furthermore, frequent changes in pump displacement place higher demands on the life and performance of the fracturing pump. Furthermore, research has shown that pulse acid fracturing is more effective when the pulse frequency is within a certain range (e.g., 18-20 Hz), but it is difficult to achieve pressure fluctuations within this frequency range simply by regulating the surface pump group. Downhole ram oscillators use a ball-throwing method to excite hydraulic pulses, and the ball-throwing step size limits the number of hydraulic pulses. Furthermore, after construction, the tool is difficult to remove, and the necking of the sleeve hinders the subsequent insertion of tools into the well, making later production and maintenance of the well difficult.

[0009] Therefore, the applicant, relying on many years of experience and practice in related industries, has proposed a hydraulic pulse soluble segmented acid fracturing sleeve and a pulse acid fracturing construction method to overcome the defects of the existing technology.

[0010] Summary of the Invention

[0011] The purpose of the present application is to provide a hydraulic pulse soluble segmented acid fracturing sleeve and a pulse acid fracturing construction method, which can ensure that hydraulic pulses of appropriate frequency are excited at the bottom of the well during the carbonate rock acid fracturing process, reduce energy attenuation, increase the proportion of effective energy, promote the formation of complex fracture networks in the formation, and at the same time simplify the construction process and shorten the construction period; at the same time, after the acid fracturing construction is completed, a full-diameter wellbore environment can be created to provide good wellbore conditions for subsequent downhole operations.

[0012] The purpose of this application can be achieved by the following scheme:

[0013] The present application provides a hydraulic pulse type soluble segmented acid fracturing sleeve, which is used to output acid fracturing working fluid in the form of hydraulic pulses. The hydraulic pulse type soluble segmented acid fracturing sleeve includes:

[0014] The outer sleeve tube is provided with a flow hole communicating with the interior of the outer sleeve tube;

[0015] The rotary valve assembly includes a valve core, a valve ball, and a guide ring. The valve core is cylindrical with two ends open. The valve core has a cavity connecting the two ends of the opening. The valve core and the guide ring are both located in the outer sleeve of the sliding sleeve. The valve ball is located in the cavity and can block the cavity.

[0016] The guide ring is provided with a plurality of guide holes. The guide ring is located upstream of the valve core along the flow direction of the acid-pressing working fluid. A guide flow channel and a diversion flow channel are formed between the outer wall of the valve core and the inner wall of the outer sleeve tube. The guide flow channel is spiral. The outer sleeve tube has at least a first position and a second position in the axial direction. When the valve core is in the first position, the outer wall of the valve core blocks the flow hole. The guide hole is used to change the flow direction of the acid-pressing working fluid fed into the outer sleeve tube and to guide the acid-pressing working fluid to the guide flow channel. The acid-pressing working fluid flowing through the guide flow channel can push the valve core to move along the outer sleeve tube from the first position to the second position, and push the valve core to rotate continuously for a preset time at the second position, so that when the valve core is in the second position, the diversion flow channel is connected to the flow hole at intervals, and the acid-pressing working fluid flowing from the guide flow channel to the diversion flow channel is ejected from the flow hole in the form of hydraulic pulses.

[0017] The valve ball is a soluble sphere whose entirety or surface can be dissolved in the acid fracturing working fluid. The valve ball is used to dissolve at least part of its position after the acid fracturing construction is completed to make the cavity conductive.

[0018] In a preferred embodiment of the present application, a plurality of spiral guide ribs are provided on the outer wall of the valve core, and the plurality of guide ribs are distributed along the circumference of the valve core to form a guide channel between two adjacent guide ribs and the inner wall of the outer tube of the sliding sleeve.

[0019] In a preferred embodiment of the present application, a plurality of block-shaped or strip-shaped diverter ribs are provided on the outer wall of the valve core. The plurality of diverter ribs are spaced apart along the circumference of the valve core to form diverter channels between two adjacent diverter ribs and the inner wall of the outer tube of the sliding sleeve.

[0020] The width of the diverter rib in the circumferential direction of the valve core is greater than the width of the flow hole in the circumferential direction of the sliding sleeve outer cylinder, and the length of the diverter rib in the axial direction of the valve core is greater than the length of the flow hole in the axial direction of the sliding sleeve outer cylinder.

[0021] In a preferred embodiment of the present application, the number of the flow-guiding ribs is greater than the number of the flow-diverting ribs.

[0022] In a preferred embodiment of the present application, there are multiple flow holes, and the multiple flow holes are arranged at intervals along the circumference of the outer cylinder of the sliding sleeve.

[0023] In a preferred embodiment of the present application, the guide ring is movably disposed above the valve core along the axial direction of the outer sleeve, and the plurality of guide holes are arranged along the circumference of the guide ring.

[0024] In a preferred embodiment of the present application, the guide hole is an inclined hole, and a first inflow angle α is formed between the central axis of the guide hole and the radial direction of the outer cylinder of the sliding sleeve;

[0025] A second inflow angle β is formed between the extension direction of the guide rib and the radial direction of the outer cylinder of the sliding sleeve;

[0026] The first inflow angle α and / or the second inflow angle β are used to adjust the driving force of the acid fracturing working fluid on the valve core, so as to change the rotation speed of the valve core.

[0027] In a preferred embodiment of the present application, the guide ring includes a trumpet-shaped guide portion and a straight-cylindrical connecting portion, the necked end of the guide portion is connected to the connecting portion, a plurality of guide holes are arranged along the circumference of the guide portion, and adjacent guide holes are separated by connecting ribs.

[0028] In a preferred embodiment of the present application, a mounting groove is defined along the circumference of the bottom of the connecting portion, an annular first receiving groove is defined on the bottom wall of the mounting groove, and a plurality of first balls are rotatably embedded in one end of the valve core near the guide ring, and at least some of the plurality of first balls are rollably embedded in the first receiving groove;

[0029] A needle roller assembly is provided in the assembly groove, and the guide ring is connected to the valve core through the first ball and the needle roller assembly, so that the valve core can rotate along the circumference of the sliding sleeve outer cylinder relative to the guide ring.

[0030] In a preferred embodiment of the present application, a conical transition step is provided on the inner wall of the cavity, and the valve ball is seated at the transition step.

[0031] In a preferred embodiment of the present application, at least two dynamic sealing assemblies are arranged between the outer wall of the valve core and the inner wall of the sliding sleeve outer tube. When the valve core is in the first position, the two dynamic sealing assemblies are respectively located on both sides of the flow hole in the axial direction of the sliding sleeve outer tube.

[0032] In a preferred embodiment of the present application, at least two sealing grooves are spaced apart along the axial direction of the valve core, the dynamic sealing assembly is arranged in the corresponding sealing groove, and the dynamic sealing assembly is sealed to the outer wall of the sliding sleeve outer tube.

[0033] In a preferred embodiment of the present application, when the valve core is in the first position, the outer tube of the sliding sleeve and the valve core are connected by a positioning screw, and the acid pressure working fluid flowing through the diversion channel can push the valve core to cut off the positioning screw and move from the first position to the second position.

[0034] In a preferred embodiment of the present application, the hydraulic pulse type soluble segmented acid fracturing sleeve also includes a support ring fixed in the outer tube of the sleeve, and a valve core is provided with an annular second accommodating groove at one end close to the support ring, and a plurality of second balls are rotatably embedded on the end surface of the support ring facing the valve core. When the valve core is in the second position, at least part of the second balls can be rollingly embedded in the second accommodating groove, so that the valve core can rotate relative to the support ring along the circumferential direction of the outer tube of the sleeve.

[0035] In a preferred embodiment of the present application, the hydraulic pulse soluble segmented acid fracturing sleeve further includes a first joint and a second joint, and both ends of the sleeve outer tube are respectively connected to the first joint and the second joint to connect the sleeve outer tube to the oil pipe.

[0036] In a preferred embodiment of the present application, both ends of the sliding sleeve outer tube are threadedly connected to the first joint and the second joint respectively, and at least one sealing ring is provided at the connection position between the sliding sleeve outer tube and the first joint and the second joint respectively.

[0037] In a preferred embodiment of the present application, the sliding sleeve outer tube, the first joint and the second joint are all made of corrosion-resistant, high-strength metal materials, and the inner walls of the sliding sleeve outer tube, the first joint and / or the second joint are provided with an anti-corrosion layer.

[0038] In a preferred embodiment of the present application, the valve core, guide ring and support ring are all made of metal materials that can be dissolved or corroded in the acid fracturing working fluid, and the rate at which the valve core, guide ring and support ring dissolve or are corroded in the acid fracturing working fluid is lower than the rate at which the valve ball dissolves in the acid fracturing working fluid.

[0039] In a preferred embodiment of the present application, the surfaces of the valve core, the guide ring and the support ring are provided with an anti-corrosion layer.

[0040] The present application provides a pulse acid fracturing construction method, which uses the above-mentioned hydraulic pulse soluble segmented acid fracturing sleeve to fracture the oil and gas reservoir by pulse output of acid fracturing working fluid. The construction method includes the following steps:

[0041] Step S1: multiple hydraulic pulse type soluble segmented acid fracturing sleeves are connected in series through oil pipes and lowered into a preset position in the well, and a packer is provided on the oil pipe between two adjacent hydraulic pulse type soluble segmented acid fracturing sleeves;

[0042] Step S2: placing a valve ball to seal the internal cavity of the valve core in the hydraulic pulse type soluble segmented acid fracturing sleeve;

[0043] Step S3: injecting acid fracturing working fluid into the well and increasing the pump pressure, the acid fracturing working fluid drives the valve core in the hydraulic pulse type soluble segmented acid fracturing sliding sleeve to disconnect from the sliding sleeve outer tube, and the valve core moves from the first position in the sliding sleeve outer tube of the hydraulic pulse type soluble segmented acid fracturing sliding sleeve to the second position;

[0044] Step S4: the valve core rotates continuously at the second position for a preset time, and causes the acid fracturing working fluid to be ejected from the flow holes on the outer cylinder of the sliding sleeve to the oil and gas reservoir in the form of hydraulic pulses.

[0045] In a preferred embodiment of the present application, multiple hydraulic pulse type soluble segmented acid fracturing sleeves, multiple packers and oil pipes are connected to form a tool string. From the wellhead to the bottom of the well, the inner diameter of the cavity in the multiple hydraulic pulse type soluble segmented acid fracturing sleeves decreases successively, so that the multiple hydraulic pulse type soluble segmented acid fracturing sleeves correspond to valve balls of different diameters respectively.

[0046] In a preferred embodiment of the present application, before step S1, the sleeve outer tube, valve core and guide ring in the hydraulic pulse soluble segmented acid fracturing sleeve are assembled, the valve core is located in the first position in the sleeve outer tube and the flow hole is blocked.

[0047] In a preferred embodiment of the present application, in step S2, if the pressure in the well is detected to continue to rise by the pump pressure detection equipment, the valve ball has been sealed in place.

[0048] In a preferred embodiment of the present application, after step S4, at least a portion of the valve ball is dissolved, and the transition step in the cavity of the hydraulic pulse soluble segmented acid fracturing sleeve is dissolved to make the cavity conductive.

[0049] From the above, the characteristics and advantages of the hydraulic pulse soluble segmented acid fracturing sleeve and pulse acid fracturing construction method of this application are:

[0050] When the spool is in the first position, the outer wall of the valve core blocks the flow hole, and the acid fracturing working fluid fed into the outer tube of the sliding sleeve flows through the diversion flow channel. The acid fracturing working fluid can push the valve core to move from the first position to the second position along the axial direction of the sliding sleeve outer tube after the valve core reaches the second position. After the valve core reaches the second position, the acid fracturing working fluid can push the valve core to rotate continuously for a preset time at the second position. When the valve core continues to rotate, the diversion flow channel can be connected to the flow hole interval, thereby making the acid fracturing working fluid ejected from the flow hole in the form of hydraulic pulses, thereby achieving fracturing of the oil and gas reservoir and promoting the formation of a complex fracture network in the stratum.

[0051] Along the flow direction of the acid fracturing working fluid, since a guide ring is provided upstream of the valve core and multiple guide holes are provided on the guide ring, when the cavity is blocked by the valve ball, the guide holes, the guide flow channel and the diversion flow channel form the only channel for the acid fracturing working fluid to flow to the flow hole. Therefore, in the actual construction process, the frequency of the hydraulic pulse can be changed by the guide ring and / or the pump pressure of the acid fracturing working fluid to ensure that a hydraulic pulse of appropriate frequency can be excited. Since the hydraulic pulse is excited by the target layer in the well, it can reduce energy attenuation, increase the effective energy ratio, and enhance the fracturing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The following figures are intended only to illustrate and explain the present application and are not intended to limit the scope of the present application.

[0053] Figure 1: Schematic diagram of the structure of the hydraulic pulse soluble segmented acid fracturing sleeve of this application.

[0054] Figure 2: is a schematic diagram of the structure of the hydraulic pulse soluble segmented acid fracturing sleeve in the working state of this application.

[0055] Figure 3: Axonometric view of the hydraulic pulse soluble segmented acid fracturing sleeve of this application.

[0056] Figure 4: A cross-sectional view taken at position AA in Figure 1.

[0057] Figure 5: A cross-sectional view of the BB position in Figure 2.

[0058] Figure 6: is one of the structural schematic diagrams of the guide ring in the hydraulic pulse type soluble segmented acid fracturing sliding sleeve of this application.

[0059] FIG7 is the second structural diagram of the guide ring in the hydraulic pulse type soluble segmented acid fracturing sleeve of this application.

[0060] Figure 8: A partial enlarged view of the connection position between the guide ring and the valve core in the hydraulic pulse type soluble segmented acid fracturing sleeve of this application.

[0061] Figure 9: An exploded view of the rotary valve assembly in the hydraulic pulse soluble segmented acid fracturing sleeve of this application.

[0062] Figure 10: Schematic diagram of the structure of the sheath in the hydraulic pulse soluble segmented acid fracturing sliding sleeve of this application.

[0063] FIG11 is an exploded view of the outer sleeve, the first joint and the second joint of the hydraulic pulse soluble segmented acid fracturing sleeve of the present application.

[0064] Figure 12: Schematic diagram of the assembly of the hydraulic pulse soluble segmented acid fracturing sleeve in the construction state of this application.

[0065] Figure 13: Schematic diagram of the structure of the hydraulic pulse soluble segmented acid fracturing sleeve in the construction completed state of this application.

[0066] Figure 14 is a schematic diagram of the inflow angle of the hydraulic pulse soluble segmented acid fracturing sleeve in the construction state of this application.

[0067] Figure 15: Schematic diagram of the speed regulation of the rotary valve assembly in the hydraulic pulse soluble segmented acid fracturing sleeve of this application.

[0068] The figures in the present application are as follows: 1. outer sleeve of sliding sleeve; 101. flow hole; 2. valve core; 201. flow guide rib; 202. flow diverter rib; 203. cavity; 204. transition step; 205. second accommodating groove; 206. flow guide channel; 207. flow diverter channel; 208. sealing groove; 3. first joint; 4. second joint; 5. flow guide ring; 501. flow guide hole; 502. connecting rib; 503. flow guide portion; 504. connecting portion; 6. positioning screw; 7. dynamic sealing assembly; 8. second ball bearing; 9. support ring; 901. second accommodating groove; 10. sheath; 1001. limiting hole; 1002. boss; 11. fastening screw; 12. soluble screw; 13. valve ball; 14. Needle roller assembly; 15. Limit sleeve; 16. First ball; 100. Hydraulic pulse soluble segmented acid fracturing sleeve; 200. Oil pipe; 300. Packer; 400. Oil and gas reservoir. DETAILED DESCRIPTION

[0069] In order to have a clearer understanding of the technical features, purposes and effects of this application, the specific implementation methods of this application are now described with reference to the accompanying drawings.

[0070] The directional words such as up, down, top, bottom, inside, outside, etc. mentioned in this application are based on the up, down, top, bottom, inside, outside, etc. directions in Figure 1, and are intended to illustrate the positional relationship between the various structural members, and do not limit their specific directions, which are explained here.

[0071] Implementation Method 1

[0072] As shown in FIG. 1 to FIG. 12 , the present application provides a hydraulic pulse type soluble segmented acid fracturing sleeve, which is used to output acidic acid fracturing working fluid in the form of hydraulic pulses.

[0073] The hydraulic pulse type soluble segmented acid fracturing sleeve includes a sleeve outer tube 1 and a rotary valve assembly. The sleeve outer tube 1 is a tube with openings at both ends (i.e., a straight tube shape). A flow hole 101 communicating with the interior of the sleeve outer tube 1 is provided on the tube wall of the sleeve outer tube 1. The two ends of the sleeve outer tube 1 are respectively used to be connected with the oil pipe 200; the rotary valve assembly includes a valve core 2, a valve ball 13 and a guide ring 5. The valve core 2 is a tube with openings at both ends (i.e., a straight tube shape). The valve core 2 has a cavity 203 communicating with the openings at both ends. The valve core 2 and the guide ring 5 are both located in the sleeve outer tube 1. The valve ball 13 is located in the cavity 203 and can seal the cavity 203. The guide ring 5 has a plurality of holes. A plurality of guide holes 501 are provided. Along the flow direction of the acid-pressing working fluid, the guide ring 5 is located upstream of the valve core 2. The acid-pressing working fluid needs to flow through the guide holes 501 on the guide ring 5 before reaching the valve core 2. Along the axial direction of the sleeve outer tube 1, a guide flow channel 206 and a diversion flow channel 207 are formed between the outer wall of the valve core 2 and the inner wall of the sleeve outer tube 1. Along the flow direction of the acid-pressing working fluid, the guide flow channel 206 is located upstream of the diversion flow channel 207. The acid-pressing working fluid must first flow through the guide flow channel 206 before flowing to the diversion flow channel 207. The guide flow channel 206 is spiral, and the sleeve outer tube 1 has at least a first position and a second position in the axial direction ( Along the flow direction of the acid-pressing working fluid, the first position is located upstream of the second position). When the valve core 2 is in the first position, the outer wall of the valve core 2 blocks the flow hole 101, and the interior of the sleeve outer tube 1 is blocked; when the acid-pressing working fluid is pumped into the sleeve outer tube 1, the diversion hole 501 can change the flow direction of the acid-pressing working fluid and guide the acid-pressing working fluid to the diversion flow channel 206. The acid-pressing working fluid flowing through the diversion flow channel 206 can push the valve core 2 to move from the first position to the second position, and push the valve core 2 to rotate continuously for a preset time at the second position, so that when the valve core 2 is in the second position, the diversion flow channel 207 and the flow hole 101 are connected. Interval communication (i.e., during the rotation of the valve core 2, the diverter channel 207 is periodically connected to the flow hole 101. When the diverter channel 207 is connected to the flow hole 101, the acid fracturing working fluid is ejected from the flow hole 101, thereby forming a hydraulic pulse). The acid fracturing working fluid flowing from the diverter channel 206 to the diverter channel 207 is ejected from the flow hole 101 in the form of a hydraulic pulse. The valve ball 13 is a soluble sphere that can be dissolved in the acid fracturing working fluid as a whole or on the surface. The valve ball 13 is used to dissolve at least partially after the acid fracturing construction is completed to make the cavity 203 conductive, thereby increasing the size of the production channel and helping to improve the acid fracturing effect.

[0074] In this application, the valve ball 13 is used during the acid-pressing process. Before the acid-pressing process begins, the valve ball 13 is placed into the cavity 203 and seals the cavity 203, thereby maintaining pressure within the cavity 203. After the acid-pressing working fluid is pumped in, the pressure pushes the valve core 2 to cut off the positioning screw 6 connecting the valve core 2 and the outer sleeve 1, and the valve core 2 moves from the first position to the second position. During this process and subsequent acid-pressing processes, the valve ball 13 remains in the cavity 203. After the acid-pressing process is completed, the valve ball 13 dissolves.

[0075] In the present application, the preset time for the valve core 2 to continuously rotate in the second position is the time for fracturing the oil and gas reservoir 400 in the form of hydraulic pulses. This time can be set according to the type of the oil and gas reservoir 400 and the actual fracturing conditions of the oil and gas reservoir 400. The preset time is not specifically limited in the present application.

[0076] In this application, the acid fracturing working fluid can be a conventional acid that can dissolve the cracks in the formation. After stopping the pump and releasing the pressure, the dissolved cracks will not be completely closed. The specific type of the acid fracturing working fluid is not limited in this application.

[0077] In the present application, a valve core 2 and a guide ring 5 are arranged in the outer sleeve tube 1, and a valve ball 13 is arranged in the cavity 203 of the valve core 2. The cavity 203 is blocked by the valve ball 13, and a guide flow channel 206 and a diversion flow channel 207 are formed between the outer wall of the valve core 2 and the inner wall of the outer sleeve tube 1. When the valve core 2 is located in the first position in the outer sleeve tube 1, the outer wall of the valve core 2 blocks the flow hole 101, and the acid-pressing working fluid fed into the outer sleeve tube 1 flows through the guide flow channel 20 6, the acid fracturing working fluid can push the valve core 2 to move from the first position to the second position along the axial direction of the sliding sleeve outer tube 1. After the valve core 2 reaches the second position, the acid fracturing working fluid can push the valve core 2 to rotate continuously at the second position for a preset time. When the valve core 2 continues to rotate, the diversion flow channel 207 can be connected to the flow hole 101 at intervals, thereby allowing the acid fracturing working fluid to be ejected from the flow hole 101 in the form of hydraulic pulses, thereby achieving fracturing of the oil and gas reservoir and promoting the formation of a complex fracture network in the formation.

[0078] Along the flow direction of the acid fracturing working fluid, since a guide ring 5 is provided upstream of the valve core 2, and a plurality of guide holes 501 are provided on the guide ring 5, when the cavity 203 is blocked by the valve ball 13, the guide holes 501, the guide flow channel 206 and the diversion flow channel 207 form the only channel for the acid fracturing working fluid to flow to the flow hole 101. Therefore, in the actual construction process, the frequency of the hydraulic pulse can be changed by the guide ring 5 and / or the ground pumping pressure of the acid fracturing working fluid to ensure that a hydraulic pulse of appropriate frequency can be excited. Since the hydraulic pulse is excited by the target layer in the well, it can reduce energy attenuation, increase the proportion of effective energy, and enhance the fracturing effect.

[0079] In an optional embodiment of the present application, as shown in Figures 1 to 3 and 11, the hydraulic pulse soluble segmented acid fracturing sleeve also includes a first joint 3 and a second joint 4. The top end of the sleeve outer tube 1 is connected to the first joint 3, and the bottom end of the sleeve outer tube 1 is connected to the second joint 4. The sleeve outer tube 1 is connected to the oil pipe 200 through the first joint 3 and the second joint 4.

[0080] Furthermore, as shown in Figures 1 and 2, the ends of the sliding sleeve outer cylinder 1 are threadedly connected to the first joint 3 and the second joint 4, respectively. At least one sealing ring is provided at each of the connection points between the sliding sleeve outer cylinder 1 and the first and second joints 3 and 4 to achieve a sealed connection surface. Specifically, the sliding sleeve outer cylinder 1 is generally elongated and cylindrical, with short trapezoidal straight threads and sealing surfaces provided on the top and bottom inner walls, respectively. A tapered internal oil pipe thread is provided on the upper inner wall of the first joint 3 for connection with the oil pipe 200 located upstream of the sliding sleeve outer cylinder 1. The lower outer wall of the first joint 3 is provided with short trapezoidal straight threads and two or more sealing grooves. The short trapezoidal straight threads of the first joint 3 are used to connect with the internal threads at the top of the sliding sleeve outer cylinder 1. Sealing rings are provided in the sealing grooves to achieve a sealed connection surface between the first joint 3 and the sliding sleeve outer cylinder 1. The structure of the second joint 4 is similar to that of the first joint 3 and is threadedly connected to the oil pipe 200 located downstream of the sliding sleeve outer cylinder 1.

[0081] In an optional embodiment of the present application, the outer sleeve tube 1, the first joint 3, and the second joint 4 are all made of corrosion-resistant, high-strength metal materials. The inner walls of the outer sleeve tube 1, the first joint 3, and / or the second joint 4, as well as surfaces that come into contact with the acid fracturing fluid, are provided with an anti-corrosion layer. The anti-corrosion layer can be produced using processes such as chrome plating, tungsten carbide spraying, or carbonitriding to enhance its resistance to acid corrosion, thereby extending the service life of the outer sleeve tube 1, the first joint 3, and the second joint 4 during the acid fracturing process and preventing them from premature failure or damage due to corrosion from the acid fracturing fluid, thereby preventing them from affecting the effectiveness of the acid fracturing operation.

[0082] Furthermore, the sliding sleeve outer tube 1, the first joint 3 and the second joint 4 can be made of, but not limited to, alloy steel such as 40CrMnMoA, 42CrMo or 4330V, which has been subjected to quenching and tempering treatment.

[0083] In an optional embodiment of the present application, as shown in Figures 1 to 3 and 9, a plurality of spiral guide ribs 201 are provided on the outer wall of the valve core 2. The plurality of guide ribs 201 are distributed along the circumference of the valve core 2 to form a guide channel 206 between two adjacent guide ribs 201 and the inner wall of the sliding sleeve outer tube 1. Specifically, the guide ribs 201 are spirally shaped with a certain angle (clockwise). Along the flow direction of the acid fracturing working fluid, the angle between the tangent direction of the initial point on the guide rib 201 and the radial direction of the sliding sleeve outer tube 1 (the horizontal direction in Figure 14) is used as the spiral angle of the guide rib 201, as shown in Figure 14. This angle β is also the inflow angle of the guide channel 206. The angle β can be adjusted according to actual needs to achieve the purpose of adjusting the driving force and speed of the acid fracturing working fluid on the valve core 2. Due to the provision of the guide ribs 201 , the acid fracturing working fluid can generate radial force under the impact to drive the valve core 2 to rotate along the circumferential direction of the sliding sleeve outer cylinder 1 .

[0084] In an optional embodiment of the present application, as shown in Figures 3 to 5 and 9, a plurality of block-shaped or strip-shaped diverter ribs 202 are provided on the outer wall of the valve core 2. The diverter ribs 202 extend along the axial direction of the valve core 2. The plurality of diverter ribs 202 are spaced and evenly distributed along the circumference of the valve core 2 to form diverter channels 207 between two adjacent diverter ribs 202 and the inner wall of the sliding sleeve outer tube 1. The width of the diverter ribs 202 in the circumferential direction of the valve core 2 needs to be greater than the width of the flow hole 101 in the circumferential direction of the sliding sleeve outer tube 1, and the length of the diverter ribs 202 in the axial direction of the valve core 2 needs to be greater than the length of the flow hole 101 in the axial direction of the sliding sleeve outer tube 1, to ensure that the diverter ribs 202 can effectively and instantaneously block the flow hole 101 on the sliding sleeve outer tube 1 during continuous rotation of the valve core 2.

[0085] Furthermore, the number of the guide ribs 201 is greater than the number of the diverter ribs 202. Preferably, the number of the guide ribs 201 is twice the number of the diverter ribs 202. This helps increase the driving force of the acid fracturing working fluid on the valve core 2 and improves the effect of the pulsed ejection of the acid fracturing working fluid.

[0086] In an optional embodiment of the present application, as shown in Figures 1, 5, and 11, there are multiple flow holes 101, and the flow holes 101 are located in the middle of the sleeve outer tube 1. The multiple flow holes 101 are spaced and evenly arranged along the circumference of the sleeve outer tube 1. The flow holes 101 are oblong through holes extending axially along the sleeve outer tube 1. The number of flow holes 101 can be, but is not limited to, 5-10. In a specific embodiment of the present application, the number of flow holes 101 is 6, which is used to ensure that when the sleeve is in working condition, a unique channel can be formed for the acid fracturing working fluid to flow to the flow holes 101, so as to ensure that the acid (acid fracturing working fluid) sent from the ground can enter the annulus and oil and gas reservoir 400 in the well.

[0087] In an optional embodiment of the present application, as shown in Figures 1, 2, 6 and 7, the guide ring 5 can be axially moved along the sliding sleeve outer tube 1 and is arranged above the valve core 2, and multiple guide holes 501 are arranged along the circumference of the guide ring 5.

[0088] Furthermore, as shown in Figures 7 and 14, the guide hole 501 can be an inclined hole, the number of the guide holes 501 is the same as the number of the guide ribs 201, and there is a first inflow angle α between the central axis of the guide hole 501 and the radial direction of the sliding sleeve outer cylinder 1 (such as the horizontal direction in Figure 14); there is a second inflow angle β between the extension direction of the guide rib 201 and the radial direction of the sliding sleeve outer cylinder 1 (such as the horizontal direction in Figure 14); the first inflow angle α and / or the second inflow angle β are used to adjust the driving force of the acid fracturing working fluid on the valve core 2, so as to change the driving force on the valve core 2, and thereby change the rotational speed of the valve core 2.

[0089] During actual construction, the rotational characteristics of the valve core 2 can be adjusted by adjusting the first inflow angle α of the guide hole 501, thereby regulating the outflow angle of the fluid flowing out of the guide ring 5. This, combined with the second inflow angle β of the guide rib 201 on the valve core 2 at different angles, can be used to adjust the rotational characteristics of the valve core 2. As shown in Figure 15, for different construction conditions and formation conditions, the appropriate ratio of inflow angle parameters for the rotary valve assembly (i.e., the first inflow angle α of the guide hole 501 and the second inflow angle β of the guide rib 201) can be selected based on the previously obtained rotational characteristic curve of the rotary valve assembly to obtain a rotational speed and hydraulic pulse frequency that match the actual working conditions. The output speed of the valve core 2 under different displacement and inflow angle conditions, combined with corresponding theoretical calculations, finite element simulations, and experimental data, can be used to derive a relationship curve between the fluid displacement, inflow angle, and valve core 2 rotational speed, thereby determining the optimal parameter range. During the construction process, the construction displacement of the ground fracturing pump truck can also be adjusted within an appropriate range to achieve secondary adjustment of the rotation speed of the valve core 2 and the hydraulic pulse frequency, thereby obtaining the optimal hydraulic pulse frequency.

[0090] In this embodiment, as shown in Figures 6 and 7, the guide ring 5 includes a bell-shaped guide portion 503 and a straight cylindrical connecting portion 504. The constricted end of the guide portion 503 is connected to the connecting portion 504. A plurality of guide holes 501 are arranged circumferentially along the guide portion 503, with adjacent guide holes 501 separated by connecting ribs 502. This structure not only improves the connection strength and erosion resistance between the guide portion 503 and the connecting portion 504, but also allows the angle of the inclined hole to change the first inflow angle α of the fluid after passing through the guide ring 5, thereby increasing the impact force of the fluid on the guide ribs 201 on the valve core 2 and improving the hydraulic pulse output capability. The number of guide holes 501 and connecting ribs 502 can be 3-5, respectively.

[0091] Furthermore, as shown in Figure 8, an assembly groove is provided on the inner side wall of the bottom of the connecting portion 504 along its circumference, and an annular first accommodating groove is provided on the bottom wall of the assembly groove along the circumference of the assembly groove. The valve core 2 and one end close to the guide ring 5 are provided with multiple semicircular grooves with cross sections along the circumference of the valve core 2, and first balls 16 are rotatably embedded in the multiple semicircular grooves, and at least part of the multiple first balls 16 can be rollingly embedded in the first accommodating groove; and a needle roller assembly 14 is provided in the assembly groove, and the guide ring 5 is connected to the valve core 2 through the first balls 16 and the needle roller assembly 14, and the multiple first balls 16 and the needle roller assembly 14 act as bearings, so that the valve core 2 can rotate relative to the guide ring 5 along the circumference of the sliding sleeve outer tube 1.

[0092] Furthermore, as shown in FIG8 , a limiting sleeve 15 is provided in the assembly groove, the outer wall of the limiting sleeve 15 being connected to the side wall of the assembly groove, and an annular needle roller assembly 14 is provided between the inner wall of the limiting sleeve 15 and the upper outer wall of the valve core 2 to limit the needle roller assembly 14. The needle roller assembly 14 is composed of a plurality of needle rollers evenly arranged along the circumference and is integrally mounted on the top of the valve core 2 to ensure smooth rotation of the valve core 2. The needle roller assembly 14 is limited by the limiting sleeve 15 to ensure that during the rotation of the valve core 2, the needle roller assembly 14 does not rotate with the valve core 2 and does not separate from the valve core 2.

[0093] In an optional embodiment of the present application, as shown in Figures 1 and 2, a conical transition step 204 is provided on the inner wall of the cavity 203 along its circumference, so that the cavity 203 forms a vertical cavity structure with a large diameter at the top and a small diameter at the bottom, and a transition connection in the middle through the transition step 204. The valve ball 13 is sealed at the transition step 204, and the outer wall of the valve ball 13 fits and abuts against the wall surface of the transition step 204.

[0094] In a specific embodiment of the present application, the transition step 204 and the valve core 2 can be made into a separate structure, and the two are connected after molding. The transition step 204 uses the same material as the valve ball 13, so that after the acid fracturing construction is completed, the valve ball 13 and the transition step 204 are both dissolved to achieve the purpose of conducting the cavity 203, and at this time the valve core 2 and other structural parts are in an undissolved state.

[0095] Furthermore, each hydraulic pulse type soluble segmented acid fracturing sleeve 100 is a fracturing tool. Along the flow direction of the acid fracturing working fluid, multiple hydraulic pulse type soluble segmented acid fracturing sleeves 100, multiple packers 300 and oil pipes 200 are connected to form a tool string. From the wellhead to the bottom of the well, the inner diameter of the cavity 203 corresponding to the valve core 2 in the multiple hydraulic pulse type soluble segmented acid fracturing sleeves 100 is successively reduced, so that the multiple hydraulic pulse type soluble segmented acid fracturing sleeves 100 correspond to valve balls of different diameters, which are used to achieve staged fracturing of the rock. Among them, the number of hydraulic pulse type soluble segmented acid fracturing sleeves 100 and the diameter of the corresponding cavity 203 can be selected according to the actual staged fracturing working conditions. Generally, the diameter difference (step difference) of the valve ball 13 can be selected to be 1 / 4 inch, 1 / 8 inch, etc.

[0096] Furthermore, the angle between the wall surface of the transition step 204 and the horizontal direction is preferably 30° to 60°, so as to ensure that the valve ball 13 can form an effective seal when it is seated on the transition step 204 .

[0097] In an optional embodiment of the present application, as shown in Figures 1 and 2, at least two dynamic seal assemblies 7 are disposed between the outer wall of the valve core 2 and the inner wall of the sliding sleeve outer tube 1. When the valve core 2 is in the first position, the two dynamic seal assemblies 7 are located on either side of the flow hole 101 in the axial direction of the sliding sleeve outer tube 1 (i.e., the axial distance between the two dynamic seal assemblies 7 in the sliding sleeve outer tube 1 is greater than the axial length of the flow hole 101 in the sliding sleeve outer tube 1), thereby ensuring that the flow hole 101 can be blocked. When the valve core 2 moves to the second position, as shown in Figure 2, the two dynamic seal assemblies 7 move to the same side of the flow hole 101.

[0098] Specifically, as shown in Figures 1, 2, and 9, sealing grooves 208 corresponding to the dynamic seal assemblies 7 are provided at intervals along the axial direction of the valve core 2. The dynamic seal assemblies 7 are disposed within the corresponding sealing grooves 208 and are in sealing contact with the outer wall of the sliding sleeve outer tube 1. The dynamic seal assemblies 7 can employ existing dynamic sealing mechanisms, such as a frame disposed within the sealing grooves 208 and an O-ring disposed thereon, to ensure sealing between the outer wall of the valve core 2 and the inner wall of the sliding sleeve outer tube 1 without affecting the movement of the valve core 2 during its rotation. The specific structure of the dynamic seal assemblies 7 is not limited herein.

[0099] In an optional embodiment of the present application, as shown in Figures 1 and 2, when the valve core 2 is in the first position, the sleeve outer tube 1 and the valve core 2 are connected by a positioning screw 6, and the acid-pressing working fluid flowing through the guide channel 206 can push the valve core 2 to cut off the positioning screw 6 and push the valve core 2 to rotate circumferentially along the sleeve outer tube 1.

[0100] Specifically, there are multiple positioning screws 6, and the multiple positioning screws 6 are arranged at intervals along the circumference of the valve core 2, and the multiple positioning screws 6 respectively connect the tube wall of the sliding sleeve outer tube 1 with the corresponding diversion ribs 202 on the valve core 2 to ensure that the valve core 2 and the sliding sleeve outer tube 1 are firmly fixed in the initial state.

[0101] In an optional embodiment of the present application, as shown in Figures 1, 2, 9 and 10, the hydraulic pulse soluble segmented acid fracturing sleeve also includes a support ring 9 located in the sleeve outer tube 1, the support ring 9 is connected to the sleeve outer tube 1 by a soluble screw 12, and the valve core 2 is provided with an annular second accommodating groove 205 at one end close to the support ring 9, and a plurality of second balls 8 are rotatably embedded on the end surface of the support ring 9 facing the valve core 2. When the valve core 2 is in the second position, at least part of the second balls 8 can be rollingly embedded in the second accommodating groove 205, so that the valve core 2 can rotate relative to the support ring 9 along the circumferential direction of the sleeve outer tube 1.

[0102] Specifically, as shown in Figures 1, 2, 9, and 10, the hydraulic pulse type soluble segmented acid fracturing sleeve also includes an annular sleeve 10 located in the sleeve outer tube 1, a support ring 9, and a plurality of semicircular grooves are provided on the end surface facing the valve core 2 along the circumference of the support ring 9. Second balls 8 are rotatably provided in the plurality of semicircular grooves. A plurality of limiting holes 1001 are provided on the sleeve 10 along its circumference. The aperture of the limiting hole 1001 is smaller than the diameter of the second ball 8. The sleeve 10 is covered on the top of the support ring 9 and is connected by a fastening screw 11. , multiple limiting holes 1001 correspond one-to-one to multiple semicircular grooves, at least part of the upper part of the second ball 8 extends out from the limiting hole 1001, and the valve core 2 is close to the end of the support ring 9 and is provided with a second accommodating groove 205 along the circumference of the valve core 2. The cross-section of the second accommodating groove 205 is semicircular. When the valve core 2 is in the second position, at least part of the upper part of the second ball 8 is rolled and embedded in the second accommodating groove 205. The second ball 8 is limited by the sleeve 10, and it is ensured that the second ball 8 can rotate freely without being compacted.

[0103] In this application, the valve ball 13 is a soluble sphere that is soluble in the acid fracturing fluid, either in its entirety or on its surface. After the acid fracturing operation is completed, at least a portion of the valve ball 13 dissolves into the cavity 203, leaving it open. The valve ball 13 is spherical in shape and made of a metal material (which may be, but is not limited to, a magnesium alloy) that dissolves rapidly in the acid fracturing fluid. The diameter of the valve ball 13 is determined by the inner diameter of the transition step 204 within the cavity 203 and by the number of sliding sleeve stages in the staged fracturing operation. Typically, the diameter difference (step difference) of the valve ball 13 can be selected to be 1 / 4 inch, 1 / 8 inch, etc. When the valve ball 13 is deployed, it falls into the cavity 203 of the valve core 2 under the action of the fluid, ultimately sealing the cavity 203. Among them, the valve ball 13 can be a solid ball, a hollow ball or a sphere with a soluble rubber outer layer. The setting of the valve ball 13 only needs to ensure the temporary (such as 3-4 hours) sealing of the cavity 203 during the acid fracturing operation. After the short-term acid fracturing construction is completed, the valve ball 13 disintegrates and restores the conduction of the cavity 203.

[0104] The surface of the valve ball 13 can be surface treated (for example, an anti-corrosion layer can be formed by using surface treatment processes such as electroplating, micro-arc oxidation, and electrostatic powder spraying). Different surface treatments can allow the valve ball 13 to withstand different periods of time in the acid-pressing working fluid. In actual construction, different surface treatment methods can be selected according to the construction time to achieve the purpose of blocking the contact between the soluble material of the valve ball 13 and the acid-pressing working fluid, and prevent the main body of the valve ball 13 (i.e., the soluble material part) from dissolving during the acid-pressing process. Instead, the surface of the valve ball 13 is damaged or dissolved in the acid-pressing working fluid some time after the acid-pressing construction is completed, so that the main body of the valve ball 13 can come into contact with the acid-pressing working fluid and dissolve quickly.

[0105] In an optional embodiment of the present application, the valve core 2, the guide ring 5, the support ring 9, the first ball 16, the needle roller assembly 14, the limit sleeve 15, the sleeve 10, the second ball 8, the soluble screw 12 and other structural components are all made of metal materials (such as magnesium alloy or aluminum alloy, etc.) that can dissolve in the acid-pressing working fluid or corrode in low-concentration acid. Since it is necessary to ensure that the valve ball 13 dissolves first, and the rotary valve assembly can remain in the sliding sleeve outer tube 1 for a certain period of time, it is necessary to ensure that the valve core 2, the guide ring 5, the support ring 9, the first ball 16, the needle roller assembly 14, the limit sleeve 15, the sleeve 10, the second ball 8, the soluble screw 12 and other structural components dissolve in the acid-pressing working fluid or corrode in the low-concentration acid at a rate lower than the rate at which the valve ball 13 dissolves in the acid-pressing working fluid.

[0106] Furthermore, an anti-corrosion layer can be provided on the surface of the valve core 2, the guide ring 5, the support ring 9, the first ball 16, the needle assembly 14, the limit sleeve 15, the sleeve 10, the second ball 8, the soluble screw 12 and other structural parts. Specifically, the anti-corrosion layer can be formed by surface treatment processes such as electroplating, micro-arc oxidation, and electrostatic powder spraying to enhance the ability to resist acid corrosion and ensure that under a certain temperature and acid fracturing working fluid concentration, the various structural parts are prevented from being corroded by the acid fracturing working fluid during the acid fracturing construction process and premature failure, thereby affecting the construction effect. However, after the acid fracturing construction operation, the various structural parts can be completely dissolved or corroded by adjusting the conditions such as the concentration and / or immersion time of the acid fracturing working fluid, thereby restoring the maximum internal diameter of the sleeve. Therefore, the installation thickness and process of the surface anti-corrosion layer of the rotary valve assembly and its related structural parts can be selected in combination with the working conditions. In general, the requirements for the surface acid corrosion resistance of each structural part are: in 80°C, 20% acid solution (such as HCl), the effective working time should be ≥ 72 hours; the requirements for the solubility or corrosion ability of each structural part are: in 80°C, 1% acid solution (such as HCl), the time for complete dissolution or corrosion should be ≤ 720 hours.

[0107] In an optional embodiment of the present application, as shown in Figure 12, packers 300 are respectively provided on the oil pipes 200 connected to the upstream and downstream of the hydraulic pulse soluble segmented acid fracturing sliding sleeve 100. The packers 300 may be, but are not limited to, open hole packers.

[0108] The hydraulic pulse soluble segmented acid fracturing sleeve of this application can ensure that hydraulic pulses of appropriate frequency can be stimulated in the well during carbonate rock acid fracturing, reduce energy attenuation, increase the proportion of effective energy, promote the formation of complex fracture networks in the formation, simplify the construction process, and shorten the construction period. Compared with pulse acid fracturing methods that use surface fracturing pumps to change the displacement and pump pressure and punch oscillators to create pulse effects, this application has the following characteristics and advantages:

[0109] 1. The hydraulic pulse type soluble segmented acid fracturing sleeve can generate hydraulic pulses near the target layer in the well, avoiding the energy loss of hydraulic pulses during long-distance transmission;

[0110] Second, the hydraulic pulse type soluble segmented acid fracturing sleeve can cause the flow hole 101 on the sleeve outer tube 1 to open and close at intervals through the rotation of the valve core 2, so that the flow area of ​​the flow hole 101 changes periodically, thereby stimulating hydraulic pulses. Since the valve core 2 can rotate at a relatively high speed, the present application can form a high-efficiency hydraulic pulse of 18-20Hz at an appropriate displacement.

[0111] Third, in this hydraulic pulse type soluble segmented acid fracturing sliding sleeve, the angle between the guide hole 501 on the guide ring 5 and the spiral guide rib 201 on the valve core 2 and the horizontal direction can be adjusted to change the outflow angle and inflow angle of the acid fracturing working fluid, thereby adjusting the rotation characteristics of the valve core 2 and realizing the adjustment of the hydraulic pulse frequency under different working conditions to adapt to different working conditions;

[0112] Fourth, in the hydraulic pulse type soluble segmented acid fracturing sliding sleeve, the rotary valve assembly can continuously rotate within the construction displacement range during the acid fracturing process and generate hydraulic pulses. The hydraulic pulse action time is not limited;

[0113] 5. In the hydraulic pulse soluble segmented acid fracturing sliding sleeve, all the structural parts that make up the rotary valve assembly are made of soluble materials and can dissolve themselves within a period of time after the completion of fracturing, thereby increasing the size of the production channel and helping to improve the acid fracturing effect.

[0114] Implementation Method 2

[0115] The present application provides a pulse acid fracturing construction method, which uses the above-mentioned hydraulic pulse soluble segmented acid fracturing sleeve 100 to fracture the oil and gas reservoir 400 by pulse output of acid fracturing working fluid. The pulse acid fracturing construction method includes:

[0116] Step S1: As shown in FIG12 , multiple hydraulic pulse type soluble segmented acid fracturing sleeves 100 are connected in series through tubing 200 and lowered into a preset position in the well. A packer 300 is provided on the tubing 200 between two adjacent hydraulic pulse type soluble segmented acid fracturing sleeves 100;

[0117] Step S2: placing the valve ball 13 to seal the internal cavity 203 of the valve core 2 in the hydraulic pulse soluble segmented acid fracturing sleeve 100;

[0118] Step S3: injecting acid fracturing working fluid into the well and increasing the pump pressure, the acid fracturing working fluid drives the valve core 2 in the hydraulic pulse type soluble segmented acid fracturing sleeve 100 to disconnect from the sleeve outer tube 1, and the valve core 2 moves from the first position in the sleeve outer tube 1 of the hydraulic pulse type soluble segmented acid fracturing sleeve 100 to the second position;

[0119] Step S4: the valve core 2 rotates continuously at the second position for a preset time, and causes the acid fracturing working fluid to be ejected from the flow holes 101 on the outer tube of the sliding sleeve 1 to the oil and gas reservoir 400 in the form of hydraulic pulses.

[0120] In an optional embodiment of the present application, multiple hydraulic pulse soluble segmented acid fracturing sleeves 100, multiple packers 300, and tubing 200 are connected to form a tool string. From the wellhead to the bottomhole, the inner diameters of the cavities 203 in the multiple hydraulic pulse soluble segmented acid fracturing sleeves 100 decrease sequentially, so that the multiple hydraulic pulse soluble segmented acid fracturing sleeves 100 correspond to valve balls of different diameters. The number of hydraulic pulse soluble segmented acid fracturing sleeves 100 and the corresponding cavity 203 diameters can be selected based on the actual staged fracturing operating conditions. Typically, the diameter difference (step difference) of the valve balls 13 can be selected to be 1 / 4 inch, 1 / 8 inch, etc.

[0121] In an optional embodiment of the present application, before step S1, the sleeve outer tube 1, valve core 2 and guide ring 5 in the hydraulic pulse soluble segmented acid fracturing sleeve 100 are assembled, the valve core 2 is located in the first position in the sleeve outer tube 1 and the flow hole 101 is blocked, and at this time, the valve ball 13 is not released.

[0122] In an optional embodiment of the present application, in step S2, the pump pressure detection equipment detects that the pressure in the well continues to increase, indicating that the valve ball 13 has been sealed in place.

[0123] In an optional embodiment of the present application, after step S4, at least a portion of the valve ball 13 is dissolved, and the transition step in the cavity of the hydraulic pulse soluble segmented acid fracturing sleeve is dissolved to make the cavity 203 conductive.

[0124] The specific construction process of this application is as follows:

[0125] The hydraulic pulse soluble segmented acid fracturing sleeve 100 is assembled, with only the valve ball 13 remaining. Initially, the valve core 2 is fixedly connected to the sleeve outer tube 1 via set screws 6. The valve core 2 cannot rotate relative to the sleeve outer tube 1, and the flow hole 101 on the sleeve outer tube 1 is blocked by the valve core 2. During construction, the two ends of the hydraulic pulse soluble segmented acid fracturing sleeve 100 are respectively connected to the oil pipe 200 and a packer 300 is set on the oil pipe 200. The hydraulic pulse soluble segmented acid fracturing sleeve 100 is lowered into a preset position in the well through the wellhead equipment. Then, the valve ball 13 is dropped at the wellhead, and the valve ball 13 is pushed into the cavity 203 of the valve core 2 by pumping liquid on the ground to seal the cavity 203. Since a dynamic sealing assembly 7 is provided between the outer wall of the valve core 2 and the inner wall of the sleeve outer tube 1, after the valve ball 13 seals the cavity 203, a complete seal is established upstream and downstream of the valve core 2. At this time, the ground pump pressure detection equipment shows that the pump pressure has increased, and it can be determined that the valve ball 13 is in the sealing position.

[0126] When it is detected that the valve ball 13 is in the blocking position, the displacement of the ground pump group can be increased to drive the fluid pressure inside the oil pipe 200 to increase. Under the action of pressure, the positioning screw 6 connected between the valve core 2 and the sleeve outer tube 1 is cut off, and the valve core 2 moves downward axially while rotating circumferentially from the initial position, and moves downward to a position where the diverter channel 207 on the valve core 2 can be connected with the flow hole 101 on the sleeve outer tube 1; at the same time, due to the action of the fluid (acid fracturing working fluid), the valve core 2 continues to rotate, and the diverter rib 202 can periodically block the flow hole 101 during the process, thereby producing a hydraulic pulse effect, and then during the acid fracturing process, a hydraulic pulse of a certain frequency can be excited at the bottom of the well to achieve the purpose of reducing energy attenuation and increasing the proportion of effective energy, which can promote the formation of a complex fracture network in the formation.

[0127] After the acid fracturing operation, since the various components that make up the rotary valve assembly are all made of soluble metal materials, they can dissolve on their own over time; or if the various components that make up the rotary valve assembly are all made of metal materials that can be quickly corroded in low-concentration acid, after the operation, the various components that make up the rotary valve assembly can be quickly dissolved by injecting low-concentration acid and soaking for a certain period of time; as shown in Figure 13, after the various components that make up the rotary valve assembly have dissolved, the sliding sleeve completely restores its original internal diameter, allowing the sliding sleeve to remain unobstructed, forming a flow channel for oil, gas and water at the bottom of the well.

[0128] It should be noted that, during the construction process, the frequency of the hydraulic pulses generated by the pulse-type soluble segmented acid fracturing sleeve can be adjusted by adjusting the first inlet angle α of the guide hole 501 on the guide ring 5, the second inlet angle β of the guide rib 201, the number of diversion ribs 202, the wellhead discharge volume and other parameters. During the construction process, the dual effects of regulating the surface pump group to excite the pressure wave and the hydraulic pulse-type soluble segmented acid fracturing sleeve 100 located in the well to excite the hydraulic pulse can also be combined to improve the construction effect of the pulse acid fracturing.

[0129] The pulse acid fracturing construction method of the present application has the same technical effect as the above-mentioned hydraulic pulse soluble segmented acid fracturing sleeve 100, and will not be described in detail here.

[0130] The above description is only an illustrative embodiment of the present application and is not intended to limit the scope of the present application. Any equivalent changes and modifications made by any person skilled in the art without departing from the concept and principle of the present application shall fall within the scope of protection of the present application.

Claims

1. A hydraulic pulse soluble segmented acid fracturing sleeve, which is used to output acid fracturing working fluid in the form of hydraulic pulses, characterized in that: The hydraulic pulse soluble segmented acid fracturing sliding sleeve comprises: A sliding sleeve outer cylinder, wherein the sliding sleeve outer cylinder is provided with a flow hole communicating with the interior thereof; A rotary valve assembly, the rotary valve assembly comprising a valve core, a valve ball and a guide ring, the valve core being in the shape of a cylinder with openings at both ends, the valve core having a cavity communicating with the openings at both ends, the valve core and the guide ring being both located in the outer cylinder of the sliding sleeve, the valve ball being located in the cavity and being capable of blocking the cavity; The guide ring is provided with a plurality of guide holes, and the guide ring is located upstream of the valve core along the flow direction of the acid fracturing working fluid; a guide flow channel and a diversion flow channel are formed between the outer wall of the valve core and the inner wall of the outer sleeve tube, the guide flow channel is spiral, and the outer sleeve tube has at least a first position and a second position in the axial direction, and when the valve core is located at the first position, the outer wall of the valve core blocks the flow hole; the guide hole is used to change the flow direction of the acid fracturing working fluid fed into the outer sleeve tube and guide the acid fracturing working fluid to the guide flow channel, and the acid fracturing working fluid flowing through the guide flow channel can push the valve core to move from the first position to the second position along the outer sleeve tube, and push the valve core to rotate continuously at the second position for a preset time, so that when the valve core is located at the second position, the diversion flow channel is connected with the flow hole at intervals, and the acid fracturing working fluid flowing from the guide flow channel to the diversion flow channel is ejected from the flow hole in the form of hydraulic pulses; The valve ball is a soluble sphere whose entirety or surface can be dissolved in the acid fracturing working fluid. The valve ball is used to dissolve at least partially after the acid fracturing construction is completed to make the cavity conductive.

2. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 1, characterized in that: A plurality of spiral guide ribs are arranged on the outer wall of the valve core, and the plurality of guide ribs are distributed along the circumference of the valve core to form a guide channel between two adjacent guide ribs and the inner wall of the outer tube of the sliding sleeve.

3. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 2 is characterized in that: A plurality of block-shaped or strip-shaped diverter ribs are provided on the outer wall of the valve core, and the plurality of diverter ribs are spaced apart along the circumference of the valve core to form a diverter channel between two adjacent diverter ribs and the inner wall of the outer tube of the sliding sleeve; The width of the diverter rib in the circumferential direction of the valve core is greater than the width of the flow hole in the circumferential direction of the sliding sleeve outer tube, and the length of the diverter rib in the axial direction of the valve core is greater than the length of the flow hole in the axial direction of the sliding sleeve outer tube.

4. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 3 is characterized in that: The number of the flow-guiding ribs is greater than the number of the flow-dividing ribs.

5. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 3, characterized in that: There are multiple flow holes, and the multiple flow holes are arranged at intervals along the circumference of the outer cylinder of the sliding sleeve.

6. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 2, characterized in that: The guide ring is movably arranged above the valve core along the axial direction of the outer tube of the sliding sleeve, and a plurality of the guide holes are arranged along the circumference of the guide ring.

7. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 6, characterized in that: The guide hole is an inclined hole, and a first inflow angle α is formed between the central axis of the guide hole and the radial direction of the outer cylinder of the sliding sleeve; There is a second inflow angle β between the extension direction of the guide rib and the radial direction of the outer cylinder of the sliding sleeve; The first inflow angle α and / or the second inflow angle β are used to adjust the driving force of the acid fracturing working fluid on the valve core to change the rotation speed of the valve core.

8. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 6 or 7, characterized in that: The guide ring includes a bell-shaped guide portion and a straight-cylindrical connecting portion, the constricted end of the guide portion is connected to the connecting portion, a plurality of guide holes are arranged along the circumference of the guide portion, and two adjacent guide holes are separated by connecting ribs.

9. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 8, characterized in that: The bottom of the connecting portion is provided with an assembly groove along its circumference, and the bottom wall of the assembly groove is provided with an annular first accommodating groove, and a plurality of first balls are rotatably embedded in one end of the valve core close to the guide ring, and at least part of the plurality of first balls can be rotatably embedded in the first accommodating groove; A needle roller assembly is arranged in the assembly groove, and the guide ring is connected to the valve core through the first ball and the needle roller assembly, so that the valve core can rotate along the circumference of the sliding sleeve outer cylinder relative to the guide ring.

10. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 1, characterized in that: The inner wall of the cavity is provided with a conical transition step, and the valve ball is seated at the transition step.

11. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 1, characterized in that: At least two dynamic sealing assemblies are arranged between the outer wall of the valve core and the inner wall of the sliding sleeve outer tube. When the valve core is located at the first position, the two dynamic sealing assemblies are respectively located on both sides of the flow hole in the axial direction of the sliding sleeve outer tube.

12. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 11, characterized in that: At least two sealing grooves are arranged at intervals along the axial direction of the valve core, the dynamic sealing assembly is arranged in the corresponding sealing grooves, and the dynamic sealing assembly is sealedly connected to the outer wall of the sliding sleeve outer cylinder.

13. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 1, characterized in that: When the valve core is located at the first position, the sliding sleeve outer tube is connected to the valve core via a positioning screw, and the acid-pressure working fluid flowing through the diversion channel can push the valve core to cut off the positioning screw and move from the first position to the second position.

14. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 1, characterized in that: The hydraulic pulse type soluble segmented acid fracturing sleeve also includes a support ring fixed in the sleeve outer tube, an annular second accommodating groove is provided at one end of the valve core close to the support ring, and a plurality of second balls are rotatably embedded on the end surface of the support ring facing the valve core. When the valve core is located at the second position, at least part of the second balls can be rollingly embedded in the second accommodating groove, so that the valve core can rotate relative to the support ring along the circumferential direction of the sleeve outer tube.

15. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 1, characterized in that: The hydraulic pulse soluble segmented acid fracturing sleeve also includes a first joint and a second joint, and the two ends of the sleeve outer tube are respectively connected to the first joint and the second joint to connect the sleeve outer tube to the oil pipe.

16. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 15, characterized in that: Two ends of the sliding sleeve outer tube are respectively threadedly connected to the first joint and the second joint, and at least one sealing ring is respectively provided at the connection positions between the sliding sleeve outer tube and the first joint and the second joint.

17. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 15 or 16, characterized in that: The sliding sleeve outer cylinder, the first joint and the second joint are all made of corrosion-resistant, high-strength metal materials, and the inner walls of the sliding sleeve outer cylinder, the first joint and / or the second joint are provided with an anti-corrosion layer.

18. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 14, characterized in that: The valve core, the guide ring and the support ring are all made of metal materials that can be dissolved or corroded in the acid fracturing working fluid, and the dissolution or corrosion rate of the valve core, the guide ring and the support ring in the acid fracturing working fluid is lower than the dissolution rate of the valve ball in the acid fracturing working fluid.

19. The hydraulic pulse soluble segmented acid fracturing sleeve according to claim 18, characterized in that: The surfaces of the valve core, the guide ring and the support ring are provided with an anti-corrosion layer.

20. A pulse acid fracturing construction method, characterized in that: It adopts the hydraulic pulse soluble segmented acid fracturing sleeve described in any one of claims 1 to 19 to fractur e the oil and gas reservoir by pulse output of acid fracturing working fluid. The construction method comprises the following steps: Step S1: connecting a plurality of hydraulic pulse type soluble segmented acid fracturing sleeves in series through oil pipes and lowering them into a preset position in the well, and a packer is provided on the oil pipe between two adjacent hydraulic pulse type soluble segmented acid fracturing sleeves; Step S2: placing a valve ball to seal the internal cavity of the valve core in the hydraulic pulse soluble segmented acid fracturing sleeve; Step S3: injecting acid fracturing working fluid into the well and increasing the pump pressure, the acid fracturing working fluid drives the valve core in the hydraulic pulse type soluble segmented acid fracturing sliding sleeve to disconnect from the sliding sleeve outer tube, and the valve core moves from the first position in the sliding sleeve outer tube of the hydraulic pulse type soluble segmented acid fracturing sliding sleeve to the second position; Step S4: the valve core rotates continuously at the second position for a preset time, and the acid fracturing working fluid is ejected from the flow holes on the outer cylinder of the sliding sleeve to the oil and gas reservoir in the form of hydraulic pulses.

21. The pulse acid fracturing construction method according to claim 20, characterized in that: A plurality of the hydraulic pulse type soluble segmented acid fracturing sleeves, a plurality of packers and an oil pipe are connected to form a tool string. From the wellhead to the bottom of the well, the inner diameters of the cavities in the plurality of the hydraulic pulse type soluble segmented acid fracturing sleeves decrease successively, so that the plurality of the hydraulic pulse type soluble segmented acid fracturing sleeves correspond to valve balls of different diameters respectively.

22. The pulse acid fracturing construction method according to claim 20, characterized in that: Before the step S1, the sleeve outer tube, valve core and guide ring in the hydraulic pulse soluble segmented acid fracturing sleeve are assembled, and the valve core is located at the first position in the sleeve outer tube and blocks the flow hole.

23. The pulse acid fracturing construction method according to claim 20, characterized in that: In the step S2, if the pressure in the well continues to increase as detected by the pump pressure detection device, the valve ball has been sealed in place.

24. The pulse acid fracturing construction method according to claim 20, characterized in that: After step S4, at least part of the valve ball is dissolved, and the transition step in the cavity of the hydraulic pulse soluble segmented acid fracturing sleeve is dissolved, so that the cavity is conductive.

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