Directional perforation-pulsation fracturing cooperative crack control device and perforation method

Abstract

The invention relates to a directional perforation-pulsation fracturing cooperative crack control device and a perforation method. The directional perforation-pulsation fracturing cooperative crack control device can achieve cooperative crack control operation of directional perforation and well bottom pulsation fracturing by descending a well once. The device comprises an upper tool connector, a directional perforation assembly, a connecting short section, a pulse generator, a packer assembly and a lower tool connector. The directional perforation assembly comprises an outer shell, a gun barrel, a detonating and detonating system connected with the gun barrel and an orientation measuring and guiding mechanism, a plurality of perforations are formed in the outer shell in the circumferential direction, and perforation channels are matched with a targeted crack plane so that a weak plane zone facilitating crack initiation along the target plane can be constructed near a shaft; the pulse generator comprises a stepping motor, a rotary valve, a frequency converter and a flow stabilizing section. The problems that in the prior art, the shale oil horizontal well crack initiation orientation is difficult to control, the crack form is single, fracturing section transformation is not uniform, and multiple times of tubular column tripping are needed in perforation and fracturing operation are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of perforation and fracturing equipment, in particular to a directional perforation-pulsating fracturing coordinated fracture control device suitable for shale oil reservoir horizontal wells and a directional perforation-pulsating fracturing coordinated fracture control method. BACKGROUND

[0002] Shale oil reservoirs are mostly buried in medium-deep to deep layers, with extremely low porosity and permeability, dense matrix, and uneven development of natural fractures and bedding. It is difficult to obtain economic production by relying solely on formation energy. In order to achieve effective development, large-scale fracturing is usually implemented in horizontal wells to form complex fracture networks, thereby improving the flow conductivity and producing degree. The volume fracturing process of this type usually adopts high-displacement and large-sand injection methods, which puts forward higher requirements for fracturing equipment, surface manifold and wellbore integrity.

[0003] At present, conventional fracturing technologies such as slickwater fracturing and alternating injection are mainly used for shale oil fracturing development. In the prior art, conventional perforation or uniform perforation is usually used for hole arrangement in most well sections, and the operation parameters are determined according to the regional stress direction and empirical formula. Due to the influences of well trajectory deflection, interlayer heterogeneity and natural fracture orientation difference, the stress field near the wellbore is often very complex, which leads to problems such as high fracturing initiation pressure, late initiation of some perforations, fracture deflection and significant difference in the degree of transformation between different clusters during fracturing, thereby affecting the volume of fracturing transformation and the production capacity.

[0004] The directional perforation technology controls the azimuth of the perforation hole in the wellbore circumference, usually matches the perforation inclination with the maximum horizontal principal stress or the target fracture direction, thereby forming a favorable stress concentration area near the wellbore, reducing the fracture initiation pressure and improving the initiation direction. The existing directional perforation technology has been applied in conventional oil and gas reservoirs and some unconventional reservoirs, but it mainly controls the initiation direction, and the perforation disturbance range is limited. After the fracture expands to the far field, the fracture direction is still mainly controlled by the regional stress and natural fractures, and the regulation ability of the fracture morphology and network structure is limited.

[0005] The pulsating fracturing technology is a technology that superimposes periodic pressure or displacement fluctuation on the basis of conventional fracturing injection. The alternating opening and closing of the fracture under dynamic load is beneficial to the activation of potential fractures, the improvement of fracture complexity and the volume of transformation. The existing pulsating fracturing technology is usually realized by frequency control of the surface pump truck. The pulsating frequency and amplitude are usually selected according to experience or single-well test, and the main concern is to reduce the initiation pressure and improve the fracturing effect. There is a lack of coordinated design with the downhole perforation direction and the near-wellbore stress field, and the fracture propagation direction is still largely uncontrollable. SUMMARY

[0006] The present application aims to provide a directional perforation-pulsating fracturing collaborative fracture control device, which is used to solve the problems of difficult control of fracture initiation direction, single fracture shape, insufficient reconstruction volume and dispersed operation process in the fracturing reconstruction of horizontal wells in shale oil reservoirs.

[0007] The present application solves the technical problems by the technical scheme that the directional perforation-pulsating fracturing collaborative fracture control device can realize the collaborative fracture control operation of directional perforation and bottom pulsating fracturing in one trip, which comprises an upper tool joint, a directional perforation assembly, a connecting pup joint, a pulsation generator, a packer assembly and a lower tool joint; the directional perforation assembly comprises an outer shell, a gun barrel, an initiation and propagation system connected with the gun barrel and an azimuth measurement and guiding mechanism, a plurality of perforations are arranged on the outer shell in the circumferential direction, the perforation channels are matched with the target fracture plane to construct a weak plane zone in the near wellbore which is beneficial to the fracture initiation along the target plane; the azimuth measurement and guiding mechanism is used to obtain the wellbore attitude and geographical azimuth and control the circumferential attitude of the gun barrel so that the perforations are arranged on one side or in a predetermined angle range of the wellbore circumferential direction; the pulsation generator comprises a stepping motor, a rotary valve, a frequency converter and a flow stabilizing section, the stepping motor is drivingly connected with the rotary valve, the stepping motor is electrically connected with the frequency converter, the flow stabilizing sections are arranged at both ends of the pulsation generator shell respectively, the frequency converter provides a control signal with adjustable frequency and duty cycle to the stepping motor to drive the rotary valve to rotate or reciprocate according to the set rule, and the rotary valve realizes the periodic throttling of the fracturing fluid by changing the flow passage area.

[0008] In the above scheme, the pulsation frequency generated by the pulsation generator is adjustable in the range of 0.1-10 Hz, and the pulsation amplitude is adjusted by the size of the throttling groove, the valve opening and the pump injection displacement.

[0009] In the above scheme, the inlet flow stabilizing section is arranged at the upper end of the pulsation generator shell, the outlet flow stabilizing section is arranged at the lower end of the shell, the inlet flow stabilizing section is in communication with the internal flow passage of the upper tool joint, and the outlet flow stabilizing section is in communication with the internal flow passage of the lower tool joint, which is used to stabilize the flow of the incoming and outgoing fracturing fluid.

[0010] In the above scheme, the inner diameters of the upper tool joint, the connecting pup joint and the lower tool joint are matched with the inner diameters of the directional perforation assembly and the pulsation generator to form a fluid passage through from top to bottom, the upper tool joint is connected with the directional perforation assembly, and the directional perforation assembly is connected with the pulsation generator through the connecting pup joint; the internal fluid passage of the upper tool joint is in communication with the wellbore, which is used to connect with the upper pipe string and guide the fracturing fluid injected from the ground into the device.

[0011] The packer assembly is sleeved on the outer periphery of the pulsation generator and is arranged at intervals along the axial direction, and is used to fluidly isolate the pulsation generator and the adjacent well section from the upper and lower well sections after setting, so as to form an independent fracturing chamber.

[0012] The packer assembly includes a plurality of packers, each of which includes a rubber sleeve, an upper compression ring, a lower compression ring and a sliding tooth structure, and the rubber sleeve is radially expanded and tightly pressed against the inner wall of the casing by internal pressure setting or mechanical pressure setting, so as to form upper and lower packer seals in the wellbore and constitute an independent fracturing chamber.

[0013] The lower tool joint is connected with the lower pipe string or the liner and is in communication with the lower end flow passage of the pulsation generator, and is used to deliver the fracturing fluid modulated by the pulsation generator to the lower well section and the target reservoir; the lower tool joint and the lower pipe string or the liner are connected by threads, a quick connector or a coupling.

[0014] The directional perforation-pulsation fracturing synergic fracture control device has the directional perforation-pulsation fracturing synergic fracture control method. Step one: determining the target fracture distribution direction and the segmented position according to the formation stress and the reservoir characteristics; Step two: lowering the synergic fracture control device into the horizontal well to the target fracturing section, and performing directional perforation in a predetermined range of direction by the directional perforation assembly to form a weak plane zone consistent with the target fracture plane; Step three: setting the packer isolation assembly to form an independent fracturing chamber; Step four: during the fracturing process, injecting the fracturing fluid into the independent fracturing chamber, so that the fracturing fluid flows through the directional perforation assembly and the pulsation generator in sequence, and the stepping motor, the rotary valve and the frequency converter in the pulsation generator cooperate to apply the fluid velocity and pressure pulsation with adjustable frequency, amplitude and duty cycle to the passing fracturing fluid, so that the fracture along the weak plane zone formed by the directional perforation generates periodic opening and closing and shear slip under the pulsation load, promotes the branching, deflection and interconnection of the fracture, and forms a complex fracture network under the condition that the average bottom hole pressure is slightly higher than the formation breakdown pressure; Step five: moving the synergic fracture control device to the subsequent fracturing section in sequence to repeat steps one to four, and after each fracturing section, adjusting and optimizing the perforation density, the pulsation frequency and the pulsation amplitude of the subsequent fracturing section according to the pump pressure curve, the displacement change and the microseismic monitoring results obtained during the construction process of each fracturing section, so as to improve the balanced degree and the overall stimulation effect of each cluster fracturing reconstruction, and complete the whole-well multi-section synergic fracture control fracturing reconstruction.

[0015] Step one of the above scheme is as follows: Based on seismic data, well logging data, measured in-situ stress and reservoir heterogeneity, the target layer is jointly analyzed to determine the target fracture propagation direction and the location of each fracturing segment, and based on this, the perforation azimuth angle range matching the target fracture propagation direction is determined, so that subsequent directional perforation and pulse fracturing are constrained by the target fracture propagation direction.

[0016] Step two in the above scheme is as follows: the collaborative fracture control device is lowered into the horizontal well to the target fracturing section. The azimuth measurement and mechanical guidance functions of the directional perforation assembly are used to adjust the circumferential attitude of the tool so that the perforations are concentrated within the perforation azimuth angle range. Single-sided or narrow sector directional perforation is carried out in the predetermined azimuth to form a near-wellbore weak surface zone that is basically consistent with the direction of the target fracture propagation. Beneficial effects

[0017] 1. The directional perforation-pulsating fracturing synergistic fracture control device and perforation method provided by this invention solves the problems in existing technologies such as difficulty in controlling the fracture initiation direction in shale oil horizontal wells, uniform fracture morphology, uneven fracturing section modification, and the need for multiple tubing trips during perforation and fracturing operations. This invention combines directional perforation components with geostress analysis results. First, unilateral or narrow-sector directional perforation is performed on the target fracture plane to form a weak zone near the wellbore that is conducive to fracture initiation along the target plane. Then, the pulse fracturing component applies adjustable pressure / displacement pulses during fracturing, causing periodic opening and closing and shear slip of the fracture during initiation and propagation stages. This promotes fracture branching and the formation of complex fracture networks, achieving precise control over the fracture orientation and propagation range.

[0018] 2. The directional perforation-pulsating fracturing synergistic controlled perforation method of the present invention enables the directional perforation and bottom hole pulsating fracturing process to work together, further optimizing the fracture initiation conditions and propagation path, and improving the overall stimulation effect of horizontal wells in shale oil reservoirs.

[0019] 3. By using the device and perforation method of the present invention, directional perforation and pulsed fracturing can be completed in a single well run, which can improve the fracturing efficiency and fracturing control accuracy, increase the effective stimulation volume, improve the balance of fracturing stimulation of each cluster, and reduce construction time and wellbore risk, thereby significantly improving the production capacity and development benefits of horizontal wells in shale oil reservoirs.

[0020] 4. This invention can continuously complete multi-stage directional perforation-pulsating fracturing coordinated fracturing transformation by depressurizing and unsealing the device and moving it to the next fracturing stage for repeated joint fracturing control. This reduces the time and risk caused by multiple tripping of tubing strings and achieves the balance of fracturing transformation of each cluster throughout the well and improves the overall efficiency.

[0021] 5. While continuously injecting fracturing fluid, this invention utilizes a pulsating fracturing assembly to apply bottom hole pressure or displacement pulsations with adjustable frequency, amplitude, and duty cycle. This introduces periodic opening and closing and shear slip in the weak zone and natural fracture network formed by directional perforation, causing fractures to initiate in a predetermined direction and generate branches and turns, forming a complex fracture network, which significantly increases the volumetric modification range and conductivity.

[0022] 6. This invention uses a packer isolation assembly to set and seal the target section, forming an independent fracturing chamber isolated from the fluid in the upstream and downstream well sections. Its advantages are that it can improve the pressure-bearing capacity and sealing integrity of the section, prevent fracturing fluid from crossing sections and energy diffusion, and help control the effective length of the stimulated section and improve the utilization efficiency of a single section of reservoir.

[0023] 7. After the collaborative crack control device is lowered into the target section, the present invention utilizes the orientation measurement and mechanical guidance function of the directional perforation component to carry out unilateral or narrow sector perforation within a predetermined orientation range. The perforation holes are strictly placed near the target crack plane, constructing a continuous weak surface zone, thereby achieving precise control of the crack initiation orientation from the source.

[0024] 8. This invention optimizes the target fracture propagation direction and the location of each fracturing section by jointly analyzing the in-situ stress, reservoir heterogeneity and horizontal well trajectory. This ensures that subsequent directional perforation and pulsating fracturing are constrained by the target plane, avoiding the randomness of fracture initiation direction caused by "fracturing along the well trajectory" in traditional processes, and improving the pertinence and effectiveness of the overall stimulation design. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a directional perforation-pulsating fracturing synergistic fracturing control device according to the present invention.

[0026] Figure 2 This is a structural diagram of the fluid velocity pulsation generator assembly.

[0027] In the diagram: 1 Upper tool connector; 2 Directional perforation assembly; 3 Perforation; 4 Connecting short section; 5 Pulse generator; 6 Packer assembly; 7 Lower tool connector; 8 Stepper motor; 9 Rotary valve; 10 Frequency converter; 11 Packer; 12 Outlet flow stabilization section. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings: like Figure 1 , Figure 2As shown, this directional perforation-pulsation fracturing co-control device is suitable for horizontal wells in shale oil reservoirs. The device includes, from top to bottom, an upper tool joint 1, an upper directional perforation assembly 2, a connecting short section 4, a pulsation generator 5, and a lower tool joint 7 along the wellbore axis. Multiple packers 11 are axially spaced around the outer periphery of the pulsation generator 5, forming a packer assembly 6.

[0029] The upper tool connector 1 is used to connect to the upper tubing string and has an internal fluid channel communicating with the wellbore for introducing fracturing fluid injected from the surface into the device. The upper directional perforation assembly 2 has several perforations 3 arranged circumferentially on its shell. The directional structure can concentrate the perforations 3 within a predetermined azimuth angle range based on geostress analysis or geological design results, ensuring that the formed perforation channels match the target fracture plane and creating a weak zone near the wellbore that facilitates fracturing initiation along the target plane. The connecting section 4 reliably connects the upper directional perforation assembly 2 to the pulse generator 5 and forms a continuous fluid channel within it.

[0030] The pulsation generator 5 is a fluid velocity pulsation fracturing assembly located in the middle of the tool, and its internal structure is as follows: Figure 2 As shown, the system includes a stepper motor 8, a rotary valve 9 connected to the stepper motor 8, a frequency converter 10 that provides adjustable control signals to the stepper motor 8, and inlet and outlet flow stabilization sections 12 arranged at both ends of the housing. The inlet and outlet flow stabilization sections 12 are connected to the upper tool connector 1 and the lower tool connector 7, respectively, and are used to rectify and stabilize the incoming and outgoing fracturing fluid. The rotary valve 9 is located in the middle flow channel and achieves periodic throttling of the fluid by changing the flow cross-sectional area. Driven by the adjustable frequency and duty cycle electrical signals output by the frequency converter 10, the stepper motor 8 causes the rotary valve 9 to rotate or reciprocate according to a set pattern, thereby superimposing fluid velocity and pressure pulsations with adjustable frequency and amplitude in the continuously injected fracturing fluid, which are transmitted to the lower part of the wellbore and the reservoir through the lower tool connector 7.

[0031] The packer assembly 6 includes multiple packers 11 arranged at intervals along the axial direction. The packers 11 are sleeved on the outer periphery of the pulsation generator 5. The rubber sleeve is radially expanded and pressed against the well wall by internal pressure setting or mechanical pressurization, forming upper and lower packer seals in the wellbore. This isolates the well section where the pulsation generator 5 and the upper directional perforation assembly 2 are located from the fluid in the upper and lower well sections, forming an independent fracturing chamber. This chamber is used to withstand the fracturing fluid pressure and ensure that the pulsation load is effective within the target interval.

[0032] The lower tool connector 7 is located at the bottom of the device and is used to connect to the lower tubing string or tailpipe. It also forms an internal fluid channel, allowing the fracturing fluid modulated by the pulsation generator 5 to smoothly enter the lower well section and the target reservoir connected by the perforation 3. Through the integrated series arrangement of the above components, the device of this invention can achieve coordinated fracturing control of directional perforation and fluid velocity pulsation fracturing in a single well run, providing a foundation for subsequent methodological steps.

[0033] The directional perforation-pulsating fracturing co-control method of the above-mentioned directional perforation-pulsating fracturing co-control device is as follows: S1. Based on seismic data, well logging data, measured geostress and reservoir heterogeneity, the target section is jointly analyzed to determine the target fracture propagation direction and the location of each fracturing section, and the perforation azimuth angle range matching the target fracture propagation direction is determined accordingly, so that subsequent directional perforation and pulsed fracturing are constrained by the target fracture propagation direction. S2. The collaborative fracture control device is lowered into the horizontal well to the target fracturing section. Using the azimuth measurement and mechanical guidance function of the directional perforation assembly (2), the circumferential attitude of the tool is adjusted so that the perforations (3) are concentrated within the azimuth angle range of the perforation. Single-sided or narrow sector directional perforation is carried out in the predetermined azimuth to form a near-wellbore weak surface zone that is basically consistent with the direction of the target fracture. S3. The packer assembly (6) is set by internal pressure or mechanical pressure, so that multiple packers (11) form upper and lower sealing ports in the wellbore, which isolate the target fracturing section from the fluid in the upper and lower well sections, and form an independent fracturing chamber with pressure bearing capacity that meets the fracturing requirements. S4. Fracturing fluid is injected into the independent fracturing chamber, and the fracturing fluid flows through the directional perforation assembly 2 and the pulsation generator 5 in sequence. The stepper motor 8, rotary valve 9 and frequency converter (10) in the pulsation generator 5 work together to apply fluid velocity and pressure pulsation with adjustable frequency, amplitude and duty cycle to the passing fracturing fluid. Under the condition that the average pressure at the bottom of the well is slightly higher than the formation fracturing pressure, the fractures that start along the weak surface zone will generate periodic opening and closing and shear slip under the action of pulsation load, which will cause the fractures to branch, deflect and interconnect, forming a complex fracture network, thereby increasing the effective stimulation volume and conductivity. S5. After completing the current fracturing section construction, reduce the pressure inside the pipe to release the setting state of the packer assembly (6), move the collaborative fracturing control device to the next target fracturing section, and repeat steps S2 to S4; and adjust and optimize the perforation density, pulsation frequency and pulsation amplitude of the subsequent fracturing sections according to the pump pressure curve, displacement change and microseismic monitoring results obtained during the construction of each fracturing section, so as to improve the balance of fracturing transformation of each cluster and the overall production increase effect. Example

[0034] like Figure 1As shown, this directional perforation-pulsed fracturing co-control fracturing device, arranged from top to bottom along the wellbore axis, includes an upper tool joint 1, a directional perforation assembly 2, a connecting sub 4, a pulse generator 5, and a lower tool joint 7. Multiple packers 11 are axially spaced around the outer periphery of the pulse generator 5, forming a packer assembly 6. The entire device is connected to the upper and lower tubing strings via threads or other conventional connections, allowing for both perforation and fracturing operations to be completed in a single run in a horizontal well.

[0035] The upper tool connector 1 is located at the top of the device and is used for reliable connection with the upper tubing string such as tubing, casing, or coiled tubing. The upper tool connector 1 forms a through fluid channel inside, allowing fracturing fluid injected from the surface to enter the device; its shape can be a conventional cylinder or a guide structure with an outer conical surface to facilitate smooth passage through the curved section of the wellbore.

[0036] The directional perforation assembly 2 is located below the upper tool joint 1. Its housing is preferably a multi-prism structure with several perforations 3 arranged circumferentially around the housing. The directional perforation assembly 2 internally includes a barrel, perforation projectile, guide sleeve, azimuth measurement unit, and detonation transmission mechanism. The azimuth measurement unit may include sensors such as gyroscopes, accelerometers, or magnetometers to acquire wellbore attitude and geographic azimuth information. The guide sleeve and mechanical limiting structure control the circumferential azimuth of the barrel relative to the wellbore, ensuring that the perforations 3 are concentrated within a predetermined azimuth angle range, such as on one side near the direction of maximum horizontal principal stress or within a narrow sector of 30°–90°. During construction, the detonation system triggers the perforation projectile, and the jet forms perforations 3 through preset holes in the housing, creating a set of perforation channels distributed along the wellbore axis at the target azimuth, constructing a continuous weak zone near the wellbore to facilitate subsequent fracture initiation and propagation along the target fracture plane.

[0037] The connecting section 4 is positioned between the directional perforation assembly 2 and the pulsation generator 5, and also forms a continuous fluid channel inside to ensure the continuity of fracturing fluid flow within the tool. The connecting section 4 can be equipped with external reinforcing ribs or a thickened structure as needed to meet axial tensile and compressive strength requirements and external pressure requirements.

[0038] The pulsation generator 5 is a fluid velocity pulsation fracturing assembly, and its internal structure is as follows: Figure 2As shown. The pulsation generator 5 includes a housing, a stepper motor 8, a rotary valve 9, a frequency converter 10, and inlet / outlet flow stabilizing sections 12 arranged at both ends of the housing. The inlet / outlet flow stabilizing sections 12 are respectively located at the upper and lower ends of the pulsation generator 5, and are connected to the internal flow channels of the upper tool connector 1 and the lower tool connector 7. A flow rectifier or guide vanes can be arranged inside the flow stabilizing section 12 to reduce fluid turbulence and ensure a stable flow field before and after entering the rotary valve 9, thereby improving the pulsation control accuracy. The rotary valve 9 is installed in the flow channel in the middle of the housing of the pulsation generator 5 and is a throttling element that periodically adjusts the flow cross-sectional area. The rotary valve 9 has multiple throttling grooves or channels, and by changing the effective overlapping area of ​​the throttling grooves, the periodic change of the fracturing fluid channel cross-section is achieved. The stepper motor 8 is located at one end of the housing or in an external sealed cavity, and its output shaft is connected to the rotary valve 9 via a sealed drive shaft. The frequency converter 10 is electrically connected to the stepper motor 8 and is used to provide the stepper motor 8 with control signals that are adjustable in frequency and duty cycle, so that the stepper motor 8 drives the rotary valve 9 to perform periodic rotation or reciprocating motion according to the set speed and angle.

[0039] With the above-described structural arrangement, when fracturing fluid is continuously injected into the ground, the fracturing fluid enters the pulsation generator 5 through the inlet and outlet stabilization section 12. Under the periodic throttling action of the rotary valve 9, the fluid velocity and pressure change periodically over time, thereby superimposing a pulsating load with adjustable frequency and amplitude in the fracturing fluid. The pulsation frequency can be set according to the reservoir response characteristics, preferably in the range of 0.1–10 Hz, and the pulsation amplitude can be adjusted by the throttling groove size, valve opening, and pump injection rate.

[0040] The packer assembly 6 consists of multiple packers 11, which are spaced apart along the tool axis around the periphery of the pulsation generator 5. Each packer 11 includes a conventional packing structure such as a rubber sleeve, upper pressure ring, lower pressure ring, and sliding teeth. Through internal pressure setting, mechanical pressurization, or a combination of hydraulic and mechanical methods, the rubber sleeve expands radially and adheres tightly to the inner wall of the casing, thereby forming two or more upper and lower packer seals outside the tool. After setting, the packer assembly 6 isolates the pulsation generator 5 and its adjacent well section from the fluids of the upper and lower well sections, forming an independent fracturing chamber. The pulsating load generated by the pulsation generator 5 acts on the formation within this fracturing chamber, causing fractures to initiate and propagate within a defined well section, preventing fracturing fluid cross-contamination and energy diffusion.

[0041] The lower tool connector 7 is located at the bottom of the device and connects to the lower tubing or tailpipe. It also forms an internal fluid channel, allowing the fracturing fluid modulated by the pulsation generator 5 to be delivered to the lower well section and the fracture initiation zone. Depending on site requirements, the lower tool connector 7 can also connect to a ball dropper, sand plugging tool, or other completion tools.

[0042] Through the integrated series arrangement of the above components, directional perforation, isolation segmentation, and bottom hole fluid velocity pulsation fracturing can be completed in a single well run, providing a hardware foundation for subsequent collaborative fracturing control methods.

[0043] The directional perforation-pulsating fracturing co-control method of the above-mentioned directional perforation-pulsating fracturing co-control device is as follows: Step 1: Based on seismic data, well logging interpretation, and measured in-situ stress data, conduct in-situ stress analysis and reservoir heterogeneity evaluation of the target shale oil section to determine the direction of the maximum horizontal principal stress and a suitable fracture propagation plane. Combined with the horizontal well trajectory and segmentation scheme, optimize the location of each fracturing segment and the corresponding perforation azimuth range. The aforementioned targeted fracture plane and perforation azimuth serve as control conditions for directional perforation and pulsed fracturing.

[0044] Step 2: The coordinated fracture control device is lowered into a horizontal well via tubing or coiled tubing, positioning the directional perforation assembly 2 in the predetermined target fracturing section. Using the azimuth measurement and guidance mechanism within the directional perforation assembly 2, the circumferential orientation of the tool is adjusted so that the sector containing the perforation 3 is substantially aligned with the target fracture plane determined in Step 1. Subsequently, the directional perforation assembly 2 is detonated, forming multiple perforations 3 distributed along the wellbore axis on one side of the wellbore or in a narrow sector, thereby constructing a continuous weak zone near the wellbore that aligns with the target fracture plane.

[0045] Step 3: After completing the directional perforation, the packer assembly 6 is set by increasing the internal pressure, adding weight, or using a special setting tool. This causes the rubber sleeves of each packer 11 to expand radially and press against the inner wall of the casing, forming upper and lower packer seals within the wellbore. This isolates the target fracturing section from the fluids in the upper and lower well sections, creating an independent fracturing chamber. After setting, a pressure test can be conducted to verify the packer integrity and pressure-bearing capacity.

[0046] Step 4: In the isolated state, start the surface fracturing pump to inject fracturing fluid into the tubing string. The fracturing fluid passes sequentially through the upper tool joint 1, the directional perforation assembly 2, and the connecting short section 4 into the pulsation generator 5. The frequency converter 10 outputs control signals with a set frequency and duty cycle to the stepper motor 8, driving the rotary valve 9 to rotate or reciprocate according to a predetermined pattern, causing the flowing fracturing fluid to undergo periodic throttling in time, forming fluid velocity and pressure pulsations of a certain frequency and amplitude.

[0047] Under the condition that the average pressure at the bottom of the well is slightly higher than the formation fracture pressure, by adjusting the pulsation frequency, amplitude and drilling flow rate, the weak zone formed by directional perforation and the natural fractures around it are alternately opened and closed and sheared under the action of pulsating load, thereby causing the fractures to initiate along the target plane and generate branches, deflections and interconnections during the propagation process, forming a complex fracture network.

[0048] Step 5: After completing the current fracturing section, reduce the pressure inside the tubing, release the packer assembly 6 from its seated state, and move the coordinated fracturing control device to the next target fracturing section. Repeat steps 2 to 4 to achieve multi-segment directional perforation-pulsating fracturing coordinated fracturing stimulation throughout the well. Based on the pump pressure curves, displacement changes, and microseismic monitoring results recorded during the construction of each segment, the perforation density, pulsation frequency, and amplitude of subsequent segments can be optimized and adjusted to further improve the balance of fracturing stimulation in each cluster and the overall stimulation volume.

[0049] This invention organically combines directional perforation technology with downhole fluid velocity pulsating fracturing technology: the directional perforation assembly 2 controls the fracture initiation direction, while the pulsation generator 5 outputs adjustable pulsating loads. This enables coordinated fracture control throughout the entire process of fracture initiation and propagation within the independent fracturing chamber formed by the packer assembly 6. Perforation, fracturing, and pulsating fracturing operations can be completed in a single well run, significantly improving fracture initiation efficiency and control accuracy. Furthermore, it increases the effective stimulation volume, improves the balance of fracturing across different clusters, and enhances the productivity and development benefits of horizontal wells in shale oil reservoirs.

Claims

1. A directional perforation-pulsating fracturing synergistic fracturing control device, characterized in that: This directional perforation-pulsed fracturing co-control fracturing device can achieve coordinated fracturing operations of directional perforation and bottom hole pulsed fracturing in a single well run. It includes an upper tool joint, a directional perforation assembly, a connecting sub, a pulse generator, a packer assembly, and a lower tool joint. The directional perforation assembly includes an outer shell, a barrel, an initiation and detonation transmission system connected to the barrel, and an azimuth measurement and guidance mechanism. Several perforations are arranged circumferentially on the outer shell, with the perforation channels matching the target fracture plane to create a weak zone near the wellbore that facilitates fracturing initiation along the target plane. The azimuth measurement and guidance mechanism is used to obtain the wellbore attitude. Based on geographical location and controlling the circumferential attitude of the gun barrel, the perforations are concentrated on one side of the wellbore circumference or within a predetermined angle range; the pulse generator includes a stepper motor, a rotary valve, a frequency converter, and a flow stabilization section. The stepper motor is driven and connected to the rotary valve, and the stepper motor is electrically connected to the frequency converter. Flow stabilization sections are set at both ends of the pulse generator housing. The frequency converter provides the stepper motor with control signals that can adjust the frequency and duty cycle, driving the rotary valve to rotate or reciprocate according to a set pattern. Fluid velocity and pressure pulsations are superimposed in the continuously injected fracturing fluid. The rotary valve achieves periodic throttling of the fracturing fluid by changing the flow cross-sectional area.

2. The directional perforation-pulsating fracturing synergistic fracturing control device according to claim 1, characterized in that: The pulse frequency generated by the pulse generator is adjustable in the range of 0.1 to 10 Hz.

3. The directional perforation-pulsating fracturing synergistic fracturing control device according to claim 2, characterized in that: The upper end of the pulsation generator housing is provided with an inlet flow stabilization section, and the lower end of the housing is provided with an outlet flow stabilization section. The inlet flow stabilization section is connected to the internal flow channel of the upper tool joint, and the outlet flow stabilization section is connected to the internal flow channel of the lower tool joint, which is used to rectify and stabilize the incoming and outgoing fracturing fluid.

4. The directional perforation-pulsating fracturing synergistic fracturing control device according to claim 3, characterized in that: The inner diameters of the upper tool joint, connecting sub, and lower tool joint are matched with the inner diameters of the directional perforation assembly and the pulsation generator to form a fluid channel that runs from top to bottom. The upper tool joint is connected to the directional perforation assembly, and the directional perforation assembly is connected to the pulsation generator through the connecting sub. The upper tool joint has a fluid channel that communicates with the wellbore inside.

5. The directional perforation-pulsating fracturing synergistic fracturing control device according to claim 4, characterized in that: The packer assembly is sleeved on the outer periphery of the pulsation generator and arranged at intervals along the axial direction. It is used to isolate the pulsation generator and its adjacent well sections from the fluid in the upper and lower well sections after setting, forming an independent fracturing chamber.

6. The directional perforation-pulsating fracturing synergistic fracturing control device according to claim 5, characterized in that: The packer assembly includes multiple packers, each packer comprising a rubber sleeve, an upper pressure ring, a lower pressure ring, and a sliding tooth structure. The rubber sleeve is radially expanded and pressed against the inner wall of the casing by internal pressure setting or mechanical pressurization, forming upper and lower packer seals in the wellbore, constituting an independent fracturing chamber.

7. The directional perforation-pulsating fracturing synergistic fracturing control device according to claim 6, characterized in that: The lower tool connector is connected to the lower tubing or tailpipe and communicates with the lower flow channel of the pulsation generator, used to deliver the fracturing fluid modulated by the pulsation generator to the lower well section and the target reservoir; the lower tool connector is connected to the lower tubing or tailpipe by a threaded connection, a quick connector, or a coupling.

8. A method for coordinated fracturing and directional perforation-pulsating fracturing using the coordinated fracturing device of claim 7, characterized in that... Includes the following steps: Step 1: Determine the target fracture propagation direction and segment location based on the formation stress and reservoir characteristics; Step 2: The collaborative fracture control device is lowered into the horizontal well to the target fracturing section, and directional perforation is carried out within a predetermined azimuth range using the directional perforation assembly to form a weak surface zone consistent with the plane of the target fracture. Step 3: Use the packer isolation assembly to set and seal, forming an independent fracturing chamber; Step 4: During the fracturing process, fracturing fluid is injected into the independent fracturing chamber, allowing the fracturing fluid to flow sequentially through the directional perforation assembly and the pulsation generator. The stepper motor, rotary valve, and frequency converter in the pulsation generator work together to apply fluid velocity and pressure pulsations with adjustable frequency, amplitude, and duty cycle to the passing fracturing fluid. Under the condition that the average bottom hole pressure is controlled to be slightly higher than the formation fracturing pressure, the fractures that initiate along the weak surface zone formed by the directional perforation will undergo periodic opening and closing and shear slip under the action of pulsating load, causing the fractures to branch, deflect, and interconnect, forming a complex fracture network. Step 5: Move the coordinated fracture control device sequentially to the subsequent fracturing sections and repeat steps 1 to 4. After each fracturing section, adjust and optimize the perforation density, pulsation frequency, and pulsation amplitude of the subsequent fracturing sections based on the pump pressure curve, displacement change, and microseismic monitoring results obtained during the construction of each fracturing section, so as to improve the balance of fracturing stimulation of each cluster and the overall production enhancement effect, and complete the multi-stage coordinated fracture control fracturing stimulation of the whole well.

9. The method for coordinated fracturing and directional perforation-pulsating fracturing according to claim 8, characterized in that: Step one specifically involves: conducting a joint analysis of the target formation based on seismic data, well logging data, measured geostress, and reservoir heterogeneity to determine the target fracture propagation direction and the location of each fracturing segment, and accordingly determining the perforation azimuth range that matches the target fracture propagation direction, so that subsequent directional perforation and pulsed fracturing are constrained by the target fracture propagation direction.

10. The method for coordinated fracturing and directional perforation-pulsating fracturing according to claim 9, characterized in that: Step two specifically involves: lowering the collaborative fracture control device into the horizontal well to the target fracturing section; using the azimuth measurement and mechanical guidance functions of the directional perforation assembly, adjusting the circumferential attitude of the tool to concentrate the perforations within the perforation azimuth angle range; and performing unilateral or narrow sector directional perforation in a predetermined azimuth to form a near-wellbore weak surface zone that is basically consistent with the direction of the target fracture propagation.

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