Frac injection apparatus and method for microfracture network

Abstract

The application discloses a pressure drive injection device and method for micro-fracture network. The pressure drive injection device for micro-fracture network comprises a speed control assembly, a first liquid outlet pipe and a second liquid outlet pipe which are sequentially arranged and communicated, the first liquid outlet pipe is used for receiving fracturing fluid, a detection part is arranged on the first liquid outlet pipe, and the detection part is used for detecting the flow rate of the fracturing fluid; the second liquid outlet pipe is used for communicating with a downhole pipe column; the speed control assembly is arranged and communicated between the first liquid outlet pipe and the second liquid outlet pipe, the speed control assembly can be deformed along a first direction, so that the speed control assembly can be deformed along the first direction according to the detection result of the detection part to adjust the flow guiding length of the speed control assembly along the first direction; wherein the first direction is the direction in which the first liquid outlet pipe points to the second liquid outlet pipe.

Description

Technical Field

[0001] This application relates to the field of oil and gas development technology, and in particular to a pressure-driven injection device and method for microfracture networks. Background Technology

[0002] The low-permeability reservoir microfracture network hydraulic injection equipment is a specialized hydraulic hydraulic injection system for oil and gas reservoir stimulation. Primarily designed for unconventional oil and gas reservoirs with low or ultra-low permeability, such as tight sandstone, shale, and carbonate rocks, it utilizes a plunger pump as its power source. Employing a low-pressure, low-flow injection mode, it smoothly introduces low-viscosity fracturing fluid into the reservoir's natural microfractures. Through precise induction, the microfractures expand and interconnect, forming a three-dimensional fracture network. This opens up seepage channels between the reservoir matrix and fractures, overcoming the industry challenges of small pore throats, high seepage resistance, and the tendency for conventional hydraulic injection to form a single main fracture in low-permeability reservoirs. Suitable for refined hydraulic injection operations in deep wells, ultra-deep wells, thin interbedded layers, and reservoirs with well-developed natural fractures, it is a key piece of equipment for improving the utilization efficiency and production capacity of low-permeability oil and gas reservoirs.

[0003] Existing microfracture network injection equipment for low-permeability reservoirs mostly adopts a simple injection structure with a plunger pump directly connected to the pipeline. Due to the inherent characteristics of the plunger pump's reciprocating suction and discharge, the fracturing fluid in the outlet pipe will experience periodic instantaneous increases and decreases in flow velocity. Furthermore, the sudden changes in injection back pressure caused by reservoir heterogeneity will further aggravate the flow velocity fluctuations. Therefore, it is very easy for microfractures to be eroded and collapsed when the flow velocity increases suddenly, and for microfractures to close when the flow velocity decreases suddenly, as well as for formation fluid backflow and blockage. This leads to fracturing fluid channeling loss, uneven formation of the microfracture network, and low injection efficiency, which directly affects the stability of the pressure drive operation, fracture conductivity, and reservoir stimulation effect. Summary of the Invention

[0004] This application provides a pressure-driven injection device for microcrack networks, comprising:

[0005] Valve body assembly, the valve body assembly comprising:

[0006] A first outlet pipe and a second outlet pipe are sequentially arranged and connected. The first outlet pipe is used to receive fracturing fluid and is equipped with a detection unit for detecting the flow rate of the fracturing fluid. The second outlet pipe is used to connect to the downhole tubing string.

[0007] A speed control component is disposed and connected between the first liquid outlet pipe and the second liquid outlet pipe. The speed control component is deformable along a first direction so that the speed control component can adjust its guiding length along the first direction according to the detection result of the detection unit.

[0008] Wherein, the first direction is the direction from the first outlet pipe to the second outlet pipe.

[0009] In some modified embodiments of the first aspect of this application, the aforementioned pressure-driven injection device for microcrack networks includes a flow-stabilizing grid;

[0010] The flow stabilizing grid is disposed inside the second liquid outlet pipe. The flow stabilizing grid is deformable along the first direction so that the flow stabilizing grid can be deformed along the first direction according to the detection result of the detection unit to adjust its flow stabilizing length along the first direction.

[0011] In some modified embodiments of the first aspect of this application, the aforementioned pressure-driven injection device for microcrack networks includes a drive assembly and a controller.

[0012] The controller is signal-connected to the detection unit to generate a first control signal and a second control signal based on the detection result of the detection unit;

[0013] The drive assembly has a first drive end and a second drive end on both sides along the first direction. The first drive end and the second drive end are respectively connected to the speed control assembly and the flow stabilizing grille. The drive assembly is signal connected to the controller. The drive assembly can drive the first drive end and the second drive end to extend or retract along the first direction according to the first control signal and the second control signal, respectively.

[0014] In some modified embodiments of the first aspect of this application, the aforementioned pressure-driven injection device for microcrack networks, wherein

[0015] The speed control component includes a first tapered tube, a first corrugated tube, and a second tapered tube connected sequentially along the first direction.

[0016] The first tapered tube is used to connect to the first liquid outlet tube;

[0017] The second conical tube is used to connect to the second liquid outlet tube;

[0018] The first bellows can deform along the first direction to adjust its flow guiding length along the first direction.

[0019] In some modified embodiments of the first aspect of this application, the aforementioned pressure-driven injection device for microcrack networks, wherein the speed control component further includes a second bellows;

[0020] The two ends of the second corrugated pipe are respectively connected to the second tapered pipe and the second liquid outlet pipe.

[0021] In some modified embodiments of the first aspect of this application, the aforementioned pressure-driven injection device for microcrack networks, wherein the flow-stabilizing grid includes a first grid cylinder and a second grid cylinder coaxially sleeved.

[0022] The first grid tube is fixedly connected to the second liquid outlet pipe;

[0023] The second grid cylinder is slidably connected to the first grid cylinder along the first direction, and the second grid cylinder can reciprocate relative to the first grid cylinder along the first direction in response to the drive of the second drive end;

[0024] The second grid cylinder reciprocates along the first direction to adjust the flow stabilizing length of the flow stabilizing grid along the first direction.

[0025] In some modified embodiments of the first aspect of this application, the aforementioned pressure-driven injection device for microcrack networks, wherein the driving component includes a moving ring, a first adsorption element, and a second adsorption element.

[0026] The movable ring is arranged around the first grid cylinder axially for one revolution outside the first grid cylinder, the movable ring is connected to the second drive end, and the inner wall of the movable ring is provided with a first adsorption element;

[0027] The second grid cylinder is provided with the second adsorption element, which can adsorb each other with the first adsorption element;

[0028] The second driving end can drive the moving ring to reciprocate along the first direction, so that the second grid cylinder responds to the first adsorption member by reciprocating along the first direction with the moving ring through the second adsorption member.

[0029] In some modified embodiments of the first aspect of this application, the aforementioned pressure-driven injection device for microcrack networks, wherein the drive assembly further includes a mounting ring;

[0030] The mounting ring is arranged around the second liquid outlet pipe axially for one revolution outside the second liquid outlet pipe, and the mounting ring is fixedly connected to the second liquid outlet pipe;

[0031] Both the first driving end and the second driving end are connected to the mounting ring.

[0032] In some modified embodiments of the first aspect of this application, the aforementioned pressure-driven injection device for microcrack networks, wherein the driving assembly further includes a plurality of guide rods;

[0033] A plurality of the guide rods are spaced apart around the axial direction of the second liquid outlet pipe, and the guide rods extend along the first direction;

[0034] The first end of the guide rod is fixed to the speed control component, and the second end of the guide rod passes through the mounting ring and is connected to the moving ring.

[0035] The second aspect of this application provides a pressure-driven injection method for microfracture networks based on the aforementioned pressure-driven injection device for microfracture networks, which includes the following steps:

[0036] Inject fracturing fluid and monitor the flow rate of the fracturing fluid;

[0037] If the flow rate is greater than the target flow rate, the flow path of the fracturing fluid is extended.

[0038] If the flow rate is less than the target flow rate, the flow path of the fracturing fluid is shortened.

[0039] If the fluctuation amplitude of the flow rate increases, the steady flow path of the fracturing fluid will be extended;

[0040] If the fluctuation amplitude of the flow rate decreases, the steady flow path of the fracturing fluid will be shortened.

[0041] Compared to existing technologies, the pressure-driven injection device for microfracture networks provided in this embodiment adjusts the length of the speed control component in real time by setting a variable-length speed control component between the first and second outlet pipes, in conjunction with the real-time detection of the fracturing fluid flow rate by the detection unit. This adjusts the friction during the fracturing fluid flow process, thereby adjusting the flow rate of the fracturing fluid. This effectively eliminates sudden increases or decreases in the flow rate of the fracturing fluid downhole, thus avoiding problems such as erosion, collapse, or closure of microfractures, or even backflow of formation fluid, and ensuring the continuous and stable injection operation. Attached Figure Description

[0042] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application are illustrated by way of example and not limitation, with the same or corresponding reference numerals denoteing the same or corresponding parts, wherein:

[0043] Figure 1 A schematic diagram of the pressure-driven injection device using a microcrack network as described in this embodiment is shown.

[0044] Figure 2 The diagram illustrates the cooperative structure of the drive assembly and the two outlet pipes in the pressure-driven injection device for the microcrack network provided in this embodiment.

[0045] Figure 3 The diagram illustrates the cooperative structure of the flow stabilizing grid and the second outlet pipe in the pressure-driven injection device of the microcrack network provided in this embodiment.

[0046] Figure 4 schematically shown Figure 3 Enlarged view of point A in the middle;

[0047] Figure 5 This schematically illustrates a flow-stabilizing grid in an extended state within the pressure-driven injection device for the microcrack network provided in this embodiment.

[0048] Figure 6 A schematic diagram of the pressure-driven injection device for the microcrack network provided in this embodiment is shown.

[0049] Figure 7 A schematic diagram illustrating the flow of the pressure-driven injection method for the microcrack network provided in this embodiment is shown.

[0050] Reference numerals: 1. First outlet pipe; 11. Connecting flange; 2. Second outlet pipe; 3. Speed ​​control assembly; 31. First conical pipe; 32. First corrugated pipe; 33. Second conical pipe; 34. Second corrugated pipe; 4. Detection unit; 5. Injection assembly; 6. Inlet assembly; 61. First connecting pipe; 62. Second connecting pipe; 63. Third connecting pipe; 64. Fourth connecting pipe; 65. Pressure gauge; 66. Electrically controlled valve; 7. Support base; 71. Fixing plate; 72. Support frame; 8. Flow stabilizer; 81. First grid cylinder; 811. Cylindrical cylinder; 812. Grid tube; 82. Second grid cylinder; 82. Outer flange; 821. Drive assembly; 9. Dual-axis cylinder; 91. Moving ring; 92. Through hole; 921. First adsorption element; 93. Second adsorption element; 94. Mounting ring; 95. Guide rod; 96. Controller; 10. First direction a. Detailed Implementation

[0051] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0052] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application shall have the ordinary meaning as understood by one of ordinary skill in the art to which this application pertains.

[0053] It should be noted that in the description of this specification, the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention; the terms "connection," "installation," "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present invention can be understood according to the specific circumstances.

[0054] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0055] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships, such as A and / or B. Specifically, it can be understood as: A and B can be included at the same time, A can exist alone, or B can exist alone, and any of the above three situations can be met.

[0056] Existing hydraulic fracturing injection equipment for microfracture networks in low-permeability reservoirs mostly employs a simple injection structure with a plunger pump directly connected to the pipeline. Due to the inherent characteristics of the plunger pump's reciprocating suction and discharge, the fracturing fluid in the outlet pipe experiences periodic instantaneous velocity surges and drops. Furthermore, the low permeability, strong reservoir heterogeneity, and fragile and easily damaged microfractures in low-permeability reservoirs also contribute to fluctuations in injection velocity. Therefore, during fracturing fluid injection, sudden velocity surges can easily lead to microfracture erosion and collapse, while sudden velocity drops can cause microfracture closure and formation fluid backflow blockage. This results in fracturing fluid channeling losses, uneven microfracture network formation, and low injection efficiency, directly affecting the stability of hydraulic fracturing operations, fracture conductivity, and reservoir stimulation effects.

[0057] In response, the microfracture network pressure injection device provided in this embodiment can detect the fracturing fluid flow rate in the first outlet pipe in real time through the detection unit, and adjust the guide length of the speed control component accordingly based on the detection results, thereby achieving the purpose of stabilizing the flow rate on the ground.

[0058] The technical solution of this application embodiment is to solve the above-mentioned technical problems, and the general idea is as follows:

[0059] Example 1

[0060] Reference Appendix Figure 1The pressure-driven injection device for microfracture networks provided in this application includes a velocity control component 3 and a first outlet pipe 1 and a second outlet pipe 2 arranged sequentially and connected to each other. The first outlet pipe 1 is used to receive fracturing fluid, and the first outlet pipe 2 is provided with a detection unit 4 for detecting the flow rate of the fracturing fluid. The second outlet pipe 2 is used to connect to the downhole tubing string (not shown in the figure). The velocity control component 3 is arranged and connected between the first outlet pipe 1 and the second outlet pipe 2. The velocity control component 3 can deform along a first direction a so that the velocity control component 3 can adjust its guiding length along the first direction a according to the detection result of the detection unit 4. Wherein, the first direction a is the direction from the first outlet pipe 1 to the second outlet pipe 2.

[0061] Understandably, to address the issue of poor fracturing performance in low-permeability reservoirs, the fracturing fluid injection device for microfracture networks provided in this embodiment can detect the fracturing fluid flow rate in the first outlet pipe 1 in real time via the detection unit 4. If the flow rate does not meet the requirements, the flow control component 3 can be adjusted along the guiding length in the first direction a to regulate the flow rate. When the flow rate is greater than the target flow rate, the length of the flow control component 3 can be extended to increase the friction during the fracturing fluid flow, thereby reducing the flow rate. The same applies to the opposite. Thus, the design of this embodiment allows for the adjustment of the fracturing fluid flow rate on the surface, preventing sudden increases or decreases in flow rate from causing microfracture erosion and collapse, microfracture closure, and formation fluid backflow blockage downhole. This effectively avoids fracturing fluid channeling losses, uneven microfracture network formation, and low injection efficiency, directly improving the stability of fracturing operations, fracture conductivity, and reservoir stimulation effect.

[0062] The pressure-driven injection device for microfracture networks provided in this embodiment is a surface-mounted device that provides power for injecting fracturing fluid downhole. This pressure-driven injection device for microfracture networks can be, but is not limited to, applied in low-permeability reservoirs.

[0063] Among them, reference appendix Figure 1 The pressure-driven injection device for microfracture networks provided in this embodiment may include an injection component 5 and a fluid inlet component 6. The injection component 5 may include a plunger pump, specifically a low-pressure, low-displacement, explosion-proof reciprocating plunger pump, which can deliver fracturing fluid under stable low-pressure, low-displacement conditions, reduce basic flow pulsation, and provide reliable power for precise injection into microfractures. The number of plunger pumps can be set and adjusted according to actual needs, and may include, but is not limited to, [a specific number of pumps]. Figure 1The two plunger pumps are shown. The inlet assembly 6 can be a pipeline structure, with its inlet end connected to a fracturing fluid storage device and its outlet end connected to the injection assembly 5, which can be the outlet end of the injection assembly 5. Accordingly, the outlet end of the injection assembly 5 needs to be connected to the first outlet pipe 1, so that the fracturing fluid introduced by the inlet assembly 6 can be pumped into the first outlet pipe 1 under the power of the injection assembly 5. Accordingly, the inlet assembly 6 can be configured to include two branch pipelines in conjunction with two plunger pumps, i.e. Figure 1 As shown, the fluid inlet assembly 6 may include two first connecting pipes 61, which can respectively connect to two plunger pumps radially. The two first connecting pipes 61 converge to a second connecting pipe 62, which can be used to connect to a fracturing fluid storage device. Corresponding to the two plunger pumps, two third connecting pipes 63 can also be arranged axially, corresponding to the outlets of the two plunger pumps. The two third connecting pipes 63 can converge to a fourth connecting pipe 64, which can be detachably connected to the first outlet pipe 1. It is understood that a pressure gauge 65 can be installed on the first connecting pipe 61, and a connecting flange can be installed on the fourth connecting pipe 64 to adapt to the connecting flange 11 on the first outlet pipe 1. The above settings are easily understood by those skilled in the art and will not be elaborated further here.

[0064] In this embodiment, a support base 7 can be provided. The support base 7 can be a rigid structure, and can be made of stainless steel, and can be a frame structure, table structure, machine tool structure, etc., as long as it can provide stable support and mounting position for the injection component 5, the liquid inlet component 6, the first liquid outlet pipe 1, and the second liquid outlet pipe 2. The support base 7 can be stably placed on the ground area of ​​the wellhead accessories such as the mounting platform or the ground. In this embodiment, a fixing plate 71 can be provided on the support base 7 corresponding to the plunger pump, and the plunger pump can be fixed on the fixing plate 71 by bolts.

[0065] In this design, the first outlet pipe 1 and the second outlet pipe 2 can be rigid pipe structures, serving as the final containment or flow area for the fracturing fluid on the surface. The fracturing fluid flows out of the second outlet pipe 2 and enters the wellhead area. Therefore, it is easy to understand that the outlet end of the second outlet pipe 2 can be connected to the downhole tubing. In this embodiment, a support frame 72 can be installed upwards on the support base 7, along with a pipe clamp, to fix the first outlet pipe 1 and the second outlet pipe 2, maintaining the stability of the overall injection equipment.

[0066] The detection unit 4 can detect the flow rate of the fracturing fluid in the first outlet pipe 1. In this embodiment, for the fracturing fluid, the detection unit 4 can be, but is not limited to, an ultrasonic flow meter, an electromagnetic flow meter, etc. The number of detection units 4 can be adjusted according to actual needs, for example, only one can be set to simplify the structure; or, for example... Figure 1 and Figure 2 As shown, two detectors are set up. In this setting, the results of the two detectors 4 can be combined and adjusted. For example, the average can be used as a reference to effectively improve the accuracy. Subsequent adjustments can be made based on, but are not limited to, the average of the two detection results.

[0067] The speed control component 3 is set between the first outlet pipe 1 and the second outlet pipe 2 to adjust the flow rate of the fracturing fluid. The speed control component 3 can be a pipe structure, and the speed control component 3 can deform in the first direction a. The speed control component 3 can be in the form of a telescopic sleeve or a bellows. When the detection unit 4 detects that the flow velocity of the fracturing fluid in the first outlet pipe 1 is greater than the target flow velocity, it indicates a sudden increase in the fracturing fluid flow velocity. This allows the length of the velocity control component 3 along the first direction a to be extended, thus lengthening the flow path of the fracturing fluid from the first outlet pipe 1 to the second outlet pipe 2. This process increases the frictional resistance of the fracturing fluid, thereby reducing its velocity. Conversely, when the detection unit 4 detects that the flow velocity of the fracturing fluid in the first outlet pipe 1 is less than the target flow velocity, it indicates a sudden decrease in the fracturing fluid flow velocity. This allows the length of the velocity control component 3 along the first direction a to be shortened, thus shortening the flow path of the fracturing fluid from the first outlet pipe 1 to the second outlet pipe 2. This process reduces the frictional resistance of the fracturing fluid, thereby increasing its velocity. This ensures that the flow velocity of the fracturing fluid reaching or exiting the second outlet pipe 2 meets the target flow velocity requirement. The target flow velocity can be designed and adjusted according to the actual well conditions, which will not be elaborated here.

[0068] As described above, the hydraulic injection device for microfracture networks provided in this embodiment uses a variable-length speed control component 3 between the first outlet pipe 1 and the second outlet pipe 2. The detection unit 4 monitors the fracturing fluid flow rate in real time and adjusts the length of the speed control component 3 accordingly. This effectively eliminates sudden increases or decreases in fracturing fluid flow rate downhole, thus preventing microfractures from being eroded, collapsed, or closed, and even causing formation fluid backflow, ensuring continuous and stable injection operations.

[0069] Further, see attached document. Figure 2 The pressure-driven injection device for microcrack networks provided in this embodiment includes a flow-stabilizing grid 8 in a specific implementation. The flow-stabilizing grid 8 is disposed in the second outlet pipe 2. The flow-stabilizing grid 8 can deform along the first direction a so that the flow-stabilizing grid 8 can be adjusted along the first direction a according to the detection result of the detection unit 4.

[0070] Understandably, in order to stabilize the flow of fracturing fluid regulated by the velocity control component 3 and prevent turbulence, eddies, or pulsations from eroding microfractures or causing blockages, a flow stabilizing grid 8 is installed in the second outlet pipe 2 in this embodiment. The flow stabilizing grid 8 can be a rigid grid structure, such as a cylindrical or plate-shaped grid structure. It can eliminate turbulence, eddies, or pulsations, regulate the fracturing fluid into a stable laminar flow, and ensure the stability of the flow state of the fracturing fluid finally injected into the microfractures. In this embodiment, the flow stabilizing grid 8 can be set to a deformable form along the first direction a, for example, it can be a telescopic grid cylinder or a cylindrical structure formed by X-shaped cross-hinged structures. In this embodiment, the adjustment of the flow stabilizing grid 8 can be adjusted according to the amplitude of the flow velocity change. For example, a mapping table of the flow velocity change amplitude and the length change of the flow stabilizing grid 8 can be formed based on experiments to achieve adaptive adjustment; wherein the flow velocity change amplitude is the difference between the current flow velocity and the aforementioned target flow velocity. In this embodiment, the regulation of the speed control component 3 and the regulation of the flow stabilizing grid 8 can be synchronized, and their adjustment actions do not interfere with each other. This can immediately eliminate residual turbulence and pulsation caused by sudden changes in flow rate while regulating the flow rate, ensuring the stability of both flow rate and flow state throughout the fracturing fluid injection process.

[0071] Further, see attached document. Figure 2 and attached Figure 6 The pressure-driven injection device for microcrack networks provided in this embodiment may further include a drive component 9 and a controller 10 in a specific implementation. The controller 10 is signal-connected to the detection unit 4 to generate a first control signal and a second control signal based on the detection result of the detection unit 4. The drive component 9 has a first drive end and a second drive end on both sides along the first direction a, respectively. The first drive end and the second drive end are respectively connected to the speed control component 3 and the flow stabilizing grid 8. The drive component 9 is signal-connected to the controller 10. The drive component 9 can drive the first drive end and the second drive end to extend or retract along the first direction a according to the first control signal and the second control signal, respectively.

[0072] It is understandable that, in order to achieve automated control and adjustment of the speed control component 3 and the flow stabilizing grid 8, a drive component 9 and a controller 10 are provided in this embodiment. The controller 10 can be a PLC controller capable of data transmission, reception, storage, analysis, comparison, and program editing. It can pre-store the aforementioned target flow rate and the mapping table between the aforementioned flow rate change amplitude and the length change of the flow stabilizing grid 8. The controller 10 is connected to the detection unit 4 via signal, which can be wireless or wired. It can then compare the real-time flow rate of the fracturing fluid detected by the detection unit 4 with the aforementioned target flow rate and generate a first control signal. It can also calculate the flow rate change amplitude based on the real-time flow rate of the fracturing fluid detected by the detection unit 4 and the aforementioned target flow rate and generate a second control signal. For example, when the real-time flow rate of the fracturing fluid detected by the detection unit 4 is greater than the target flow rate, the first control signal can be a control signal for the first... The drive end contracts towards the second outlet pipe 2 to stretch the speed control component 3. When the real-time flow rate of the fracturing fluid detected by the detection unit 4 is less than the target flow rate, the second control signal can control the first drive end to push out towards the first outlet pipe 1 to compress the speed control component 3. It is also easy to understand that in this embodiment, the degree of deformation of the speed control component 3 and the difference between the real-time flow rate and the target flow rate of the fracturing fluid can be pre-stored in the controller 10 to form a mapping table. The difference here includes positive difference and negative difference. A positive difference indicates a sudden increase in flow rate, and a negative difference indicates a sudden decrease in flow rate. The first control signal corresponding to the positive difference is to control the first drive end to contract towards the second outlet pipe 2, and the first control signal corresponding to the negative difference is to control the first drive end to push out towards the first outlet pipe 1. The velocity change amplitude corresponding to the flow stabilizing grid 8 is not positive or negative, but only large or small. A large velocity change amplitude (which can be a sudden increase or a sudden decrease) lengthens the flow stabilizing grid 8 to increase its stabilizing effect, while a small velocity change amplitude shortens the flow stabilizing grid 8 to reduce its stabilizing effect. Accordingly, when the velocity change amplitude calculated based on the detection result of the detection unit 4 increases, the second control signal can control the second drive end to contract towards the first outlet pipe 1 to stretch the flow stabilizing grid 8. When the velocity change amplitude calculated based on the detection result of the detection unit 4 decreases, the second control signal can control the second drive end to push out towards the second outlet pipe 2 to shorten the flow stabilizing grid 8. It is also understood that in this embodiment, the injection component 5 can be connected to the controller 10 to achieve automatic control of its start and stop pumping; an electrically controlled valve 66 can also be installed on the inlet component 6, especially the second connecting pipe 62, and the controller 10 can be connected to the electrically controlled valve 66 to achieve automatic control of whether the pressurized fluid is injected; this setting is easily understood by those skilled in the art and will not be elaborated here.

[0073] Accordingly, in this embodiment, the drive assembly 9 can be configured as a dual-axis cylinder 91, and the first drive end and the second drive end can respectively correspond to the two piston rods of the dual-axis cylinder 91; in this embodiment, the drive assembly 9 can also be configured as two independent cylinders, and the first drive end and the second drive end can respectively correspond to the piston rods of the two cylinders.

[0074] Further, see attached document. Figure 2 The pressure-driven injection device for microcrack networks provided in this embodiment, in a specific implementation, includes a speed control component 3 comprising a first tapered tube 31, a first corrugated tube 32, and a second tapered tube 33 connected sequentially along the first direction a; the first tapered tube 31 is used to connect to the first outlet tube 1; the second tapered tube 33 is used to connect to the second outlet tube 2; the first corrugated tube 32 can deform along the first direction a to adjust its guiding length along the first direction a.

[0075] Understandably, in order to achieve the scalability and simplified structural design of the speed control component 3, in this embodiment, the speed control component 3 can be configured to include a first tapered tube 31, a first corrugated tube 32, and a second tapered tube 33. The first tapered tube 31, the first corrugated tube 32, and the second tapered tube 33 can all be metal tube structures. For scenarios involving low-pressure fracturing fluid transportation, corrugated tube structures made of rubber or plastic can also be selected. The first tapered tube 31 can achieve a smooth transition between the first outlet tube 1 and the first corrugated tube 32, avoiding fluid turbulence and pressure loss caused by sudden changes in tube diameter. The second tapered tube 33 can serve as a core motion actuator, connecting to the first drive end and receiving the driving force from the first drive end to drive the first corrugated tube 32 to reciprocate and extend. The first bellows 32 can not only adjust the frictional resistance to the fracturing fluid by deforming along the first direction a, but also change the flow area of ​​the fracturing fluid within it, thereby further playing the role of slowing down and accelerating the flow. For example, when the first bellows 32 is stretched, its effective flow area for the fracturing fluid increases, thereby reducing the flow velocity of the fracturing fluid, and vice versa. It is easy to understand that the first drive end can be connected to the position where the second tapered pipe 33 connects to the first bellows 32.

[0076] Further, see attached document. Figure 2 In the specific implementation of the pressure-driven injection device for microcrack networks provided in this embodiment, the speed control component 3 further includes a second bellows 34; the two ends of the second bellows 34 are respectively connected to the second tapered tube 33 and the second outlet tube 2.

[0077] It is understandable that, in order to ensure the overall sealing of the device after the second conical tube 33 shifts in the first direction a, this embodiment can provide a second bellows 34 between the second conical tube 33 and the second outlet pipe 2. The configuration of the second bellows 34 can refer to the first bellows 32, and will not be elaborated here. While the first bellows 32 is deformed by the second conical tube 33 at the first drive end, the second bellows 34 will expand and contract synchronously. For example, when the first bellows 32 is stretched, the second bellows 34 will be compressed, and when the first bellows 32 is compressed, the second bellows 34 will be stretched to compensate for the displacement of the second conical tube 33 and the first bellows 32 in the first direction a; that is, the second bellows 34 and the first bellows 32 form a complementary volume adjustment mechanism of tension and compression, jointly realizing rapid dynamic control of the flow rate; in addition, the position where the second bellows 34 is connected to the second outlet pipe 2 will not change displacement, thereby effectively ensuring the sealing effect of the overall device. Meanwhile, the second tapered tube 33 can also achieve a smooth connection of the flow channels between the two corrugated tubes. It should also be noted that in this embodiment, the initial state of the first corrugated tube 32 and the second corrugated tube 34, that is, the state after the equipment is installed but not yet put into use, is that both are in a naturally extended state. Specifically, the first corrugated tube 32 and the second corrugated tube 34 are in their original length without any axial external force. All their crests and troughs maintain the original height designed by the factory. There is no reduction in crest and increase in wave pitch caused by axial tension, nor is there an increase in crest and decrease in wave pitch caused by axial compression. This initial state setting can ensure that there is a maximum bidirectional extension stroke margin when the flow rate is controlled, while avoiding fatigue damage caused by long-term prestress of the corrugated tube, ensuring the stability of the initial flow area and the reliability of the flow rate control accuracy.

[0078] Further, see attached document. Figure 3 The pressure-driven injection device for microcrack networks provided in this embodiment includes, in a specific implementation, a flow-stabilizing grid 8 comprising a first grid cylinder 81 and a second grid cylinder 82 coaxially sleeved; the first grid cylinder 81 is fixedly connected inside the second outlet pipe 2; the second grid cylinder 82 is slidably connected inside the first grid cylinder 81 along the first direction a, and the second grid cylinder 82 is capable of reciprocating relative to the first grid cylinder 81 along the first direction a in response to the drive of the second drive end; wherein, the reciprocating motion of the second grid cylinder 82 along the first direction a adjusts the flow-stabilizing length of the flow-stabilizing grid 8 along the first direction a.

[0079] It is understandable that, in order to achieve the retractable flow stabilization effect of the flow stabilizing grid 8, this embodiment can configure the flow stabilizing grid 8 to include a first grid cylinder 81 and a second grid cylinder 82 that are coaxially sleeved and slidably connected along the first direction a; see attached figure. Figure 5The first grid cylinder 81 may be in the form of a cylindrical cylinder 811 and an internal grid tube 812. The cylindrical cylinder 811 may be a rigid structure, and may be, but is not limited to, made of stainless steel. It can be fixed to the inner wall of the second outlet pipe 2 by screwing or welding. The grid tube 812 may be a matrix of interconnected thin tubes. Figure 5 The rectangular tube shown can also be a thin tube of other shapes, such as a circular tube, a triangular tube, or other polygonal thin tubes. It can also be multiple axial flow channels formed by parallel and intersecting grid ribs. The grid tube 812 extends along the first direction a and is the same length as the cylinder 811. The second grid cylinder 82 can be fitted to the grid tube 812. It is easy to understand that the second grid cylinder 82 has the same structural form as the grid tube 812, but its size is smaller than the grid tube 812. Therefore, the second grid cylinder 82 can slide back and forth within the grid tube 812 along the first direction a. Appropriately, an outward flange 821 can be provided at the inlet end of the second grid cylinder 82. This not only limits the retraction direction of the second grid 82 but also allows it to be configured to have the same radial dimension as the cylinder 811, thereby improving the overall consistency of the flow stabilizing grid 8. Of course, the second grid cylinder 82 is located within the grid tube 811. A limiting structure can also be provided at one end of the 12 to prevent the second grid tube 82 from coming out of the first grid tube 81. The limiting structure can be a combination of a retractable limiting protrusion and a limiting groove. For example, a limiting groove can be provided on the inner wall of the grid tube 812, and a limiting protrusion that can extend and retract radially can be provided on the outer wall of the second grid tube 82. When the limiting protrusion corresponds to the limiting groove, it can be inserted into it to complete the limiting. Conversely, when the second grid tube 82 needs to retract, a larger driving force can be used to push the second grid tube 82 into the first grid tube 81 to overcome the obstruction of the limiting protrusion. In this setting, the limiting protrusion can be hemispherical.

[0080] Further, see attached document. Figure 4 The pressure-driven injection device for microcrack networks provided in this embodiment includes, in a specific implementation, a driving component 9 comprising a moving ring 92, a first adsorption element 93, and a second adsorption element 94. The moving ring 92 is arranged axially around the first grid cylinder 81 outside the first grid cylinder 81. The moving ring 92 is connected to the second driving end, and the first adsorption element 93 is provided on the inner wall of the moving ring 92. The second adsorption element 94 is provided on the second grid cylinder 82, and the second adsorption element 94 can adsorb with the first adsorption element 93. The second driving end can drive the moving ring 92 to reciprocate along the first direction a, so that the second grid cylinder 82 reciprocates along the first direction a in response to the first adsorption element 93 via the second adsorption element 94.

[0081] It is understandable that, since the flow stabilizing grid 8 is located inside the second outlet pipe 2, the second driving end cannot enter the second outlet pipe 2 to connect with it. Therefore, in order to realize the driving of the second grid cylinder 82 by the second driving end, a moving ring 92, a first adsorption member 93, and a second adsorption member 94 can be provided in this embodiment. The moving ring 92 can be a rigid ring structure, made of metal or plastic, etc. It can be a circular ring or a ring structure of other shapes, which is not limited here. The moving ring 92 is wrapped around the outside of the second outlet pipe 2, and the first adsorption member 93 is provided on its inner wall. The first adsorption member 93 can be a magnet or a magnetically adsorbable metal. Correspondingly, the second adsorption element 94 can also be a magnet. The first adsorption element 93 and the second adsorption element 94 only need to be able to cooperate and adsorb each other; preferably, two strong magnets are used. In this embodiment, the first adsorption element 93 can be continuously arranged around the inner wall of the moving ring 92 or multiple elements can be arranged intermittently. Similarly, the second adsorption element 94 can be arranged on the outer wall of the outer flange 821 of the second grid cylinder 82. Furthermore, when the second driving end drives the moving ring 92 to reciprocate along the first direction a according to the second control signal, the first adsorption element 93 can drive the second grid cylinder 82 by adsorbing the second adsorption element 94. Also, refer to the attached... Figure 2 and attached Figure 3 In this embodiment, several through holes 921 can be provided on the moving ring 92 to reduce the overall weight of the moving ring 92, thereby reducing the driving load on the second driving end and reducing energy consumption. Correspondingly, in order to improve the smoothness of the moving ring 92 moving along the first direction a, in this embodiment, sliding components can be provided in cooperation on the outer wall of the second outlet pipe 2 and the inner wall of the moving ring 92. For example, a continuous guide groove (not shown in the figure) can be provided on the outer wall of the second outlet pipe 2 along the first direction a, and several sliders (not shown in the figure) can be evenly distributed on the inner wall of the moving ring 92 so that the sliders can slide stably in the guide groove.

[0082] Further, see attached document. Figure 2 In the specific implementation of the pressure-driven injection device for microcrack networks provided in this embodiment, the driving component 9 further includes a mounting ring 95; the mounting ring 95 is arranged axially around the second outlet pipe 2 outside the second outlet pipe 2, and the mounting ring 95 is fixedly connected to the second outlet pipe 2; the first driving end and the second driving end are both connected to the mounting ring 95.

[0083] Understandably, in order to achieve relative fixation of the dual-axis cylinder 91, this embodiment can use a mounting ring 95 as its mounting carrier. The mounting ring 95 can be a rigid ring structure, made of metal, plastic, or other materials, and can be circular or other ring shapes, without limitation. The mounting ring 95 can be fixed to the outer wall of the second liquid outlet pipe 2 by screwing or welding to maintain fixation. Alternatively, it can be fixed to the support base 7 in conjunction with the support frame 71. The dual-axis cylinder 91 can be mounted on the mounting ring 95, with its first driving end and second driving end located on opposite sides of the mounting ring 92 along the first direction a, providing a stable mounting position for the dual-axis cylinder 91 and a fixed contact position for the movement of the first driving end and the second driving end along the first direction a.

[0084] Further, see attached document. Figure 2 In the specific implementation of the pressure-driven injection device for microcrack networks provided in this embodiment, the driving component 9 further includes a plurality of guide rods 96; the plurality of guide rods 96 are distributed at intervals around the axial direction of the second liquid outlet pipe 2, and the guide rods 96 extend along the first direction a; the first end of the guide rod 96 is fixed to the speed control component 3, and the second end of the guide rod 96 passes through the mounting ring 95 and is connected to the moving ring 92.

[0085] Understandably, to ensure the stable movement of the two bellows and the moving ring 92, this embodiment can be equipped with guide rods 96. The guide rods 96 are rigid rod structures and can be, but are not limited to, made of stainless steel. The number of guide rods 96 can be set and adjusted according to actual needs, but at least three rods are evenly distributed around the first direction a. The first end of the guide rod 96 can be fixedly connected to the connection between the second tapered tube 33 and the first bellows 32, and the second end can be fixedly connected to the moving ring 92. When the dual-axis cylinder 91 drives the first bellows 32 and the moving ring 92 to move, the guide rod 96 can slide back and forth relative to the mounting ring 95 along the first direction a. This can constrain the second tapered tube 33, i.e. the first bellows 32, to only move in a straight line along the first direction a, preventing radial offset and sway, and avoiding the first bellows 32 from twisting, jamming, or prematurely damaging due to uneven force. It should also be noted that, in order to avoid the first bellows 32 and the moving ring 92 from interfering with each other due to the guide rod 96, in this embodiment, guide rods can be provided for the first bellows 32 and the moving ring 92 respectively. That is, the mounting ring 95 has two types of guide rods on both sides along the first direction a. The first type is fixed to the second tapered tube 33 and slidably connected to the mounting ring 95, and the second type is fixed to the moving ring 92 and slidably connected to the mounting ring 95. In this embodiment, the length of the guide rod 96 can be set to strictly match the maximum extension stroke of the first bellows 32, thereby limiting the limit of the action range of the dual-axis cylinder 91 and preventing the first bellows 32 from being overstretched or compressed, causing permanent deformation. In this embodiment, the guide rod 96 can be configured to have a clearance fit with the mounting ring 95, improving the ease of sliding of the guide rod 96 relative to the mounting ring 95. Furthermore, in this configuration, no additional sliding components are needed between the moving ring 92 and the second outlet pipe 2. The moving ring 92 can be installed using several guide rods 96 and can maintain a distance from the outer wall of the second outlet pipe 2. Thus, the moving ring 92 will not come into contact with the second outlet pipe 2 during operation, which not only simplifies the structural design but also effectively reduces friction during movement, thereby reducing the load on the second drive end and further reducing energy consumption and cost.

[0086] Example 2

[0087] Reference Appendix Figure 7 This embodiment provides a pressure-driven injection method for microcrack networks based on the pressure-driven injection device for microcrack networks described in Embodiment 1, which may include the following steps:

[0088] S1. Inject fracturing fluid and detect the flow rate of the fracturing fluid;

[0089] This step can involve using the injection component 5 and the fluid inlet component 6 to inject fracturing fluid into the first outlet pipe 1, allowing the fracturing fluid to flow downhole through the first outlet pipe 1, the speed control component 3, and the second outlet pipe 2. The specific structures of the injection component 5 and the fluid inlet component 6, and their structural coordination with the first outlet pipe 1, can be found in the detailed description of Embodiment 1, and will not be repeated here.

[0090] S2. If the flow rate is greater than the target flow rate, then the flow path of the fracturing fluid is extended;

[0091] This step involves the detection unit 4 monitoring the flow velocity in the first outlet pipe 1 in real time and transmitting the results to the controller 10. The controller 10 compares and judges the flow velocity with the pre-stored target flow velocity. When the detection unit 4 detects that the flow velocity of the fracturing fluid in the first outlet pipe 1 is greater than the target flow velocity, it indicates a sudden increase in the flow velocity of the fracturing fluid. In this case, the length of the speed control component 3 along the first direction a can be extended, thus extending the flow path of the fracturing fluid from the first outlet pipe 1 to the second outlet pipe 2. This process increases the frictional resistance of the fracturing fluid, thereby reducing its speed. Specifically, the controller 10 generates a first control signal and sends it to the first drive end of the dual-axis cylinder 91, driving the second tapered pipe 33 and the first bellows pipe 32 to stretch towards the second outlet pipe 2.

[0092] Furthermore, in this embodiment, the deformation degree of the speed control component 3 and the difference between the real-time flow rate and the target flow rate of the fracturing fluid can be pre-stored in the controller 10 to form a mapping table. The difference here includes positive and negative difference values. A positive difference value indicates a sudden increase in flow rate, and a negative difference value indicates a sudden decrease in flow rate. The first control signal corresponding to the positive difference value controls the first drive end to contract towards the second outlet pipe 2, and the first control signal corresponding to the negative difference value controls the first drive end to push out towards the first outlet pipe 1.

[0093] S3. If the flow velocity is less than the target flow velocity, then the flow path of the fracturing fluid is shortened.

[0094] This step can also be performed based on the detection results of the detection unit 4. When the detection unit 4 detects that the flow rate of the fracturing fluid in the first outlet pipe 1 is less than the target flow rate, it indicates that the flow rate of the fracturing fluid has suddenly dropped. In this case, the length of the speed control component 3 along the first direction a can be shortened, that is, the flow path of the fracturing fluid from the first outlet pipe 1 to the second outlet pipe 2 is shortened. This process can reduce the friction on the fracturing fluid, thereby increasing its speed. Specifically, the controller 10 can generate a second control signal and send it to the second drive end of the dual-axis cylinder 91 to drive the second tapered pipe 33 and the first bellows 32 to compress towards the first outlet pipe 1.

[0095] S4. If the fluctuation amplitude of the flow rate increases, the steady flow path of the fracturing fluid will be extended.

[0096] This step can be performed simultaneously with step S2 or S3;

[0097] This step can involve the detection unit 4 detecting the flow velocity in the first outlet pipe 1 in real time and transmitting the detection result to the controller 10. The controller 10 calculates the difference between the flow velocity and the target flow velocity to obtain the flow velocity change amplitude. The flow velocity change amplitude here can be either positive or negative, only large or small. An increase in the flow velocity change amplitude (either a sudden increase or a sudden decrease) can lengthen the flow stabilizing grid 8 to enhance its flow stabilizing effect, while a decrease in the flow velocity change amplitude can shorten the flow stabilizing grid 8 to reduce its flow stabilizing effect. Specifically, when the flow velocity change amplitude calculated by the detection unit 4 increases, the second control signal can control the second drive end to retract towards the first outlet pipe 1 to pull out the second grid cylinder 82 relative to the first grid cylinder 81.

[0098] S5. If the fluctuation amplitude of the flow rate decreases, the steady flow path of the fracturing fluid is shortened.

[0099] This step can be achieved by the detection unit 4 detecting the flow velocity in the first outlet pipe 1 in real time and transmitting the detection result to the controller 10. The controller 10 then calculates the difference between the flow velocity and the target flow velocity to obtain the flow velocity change amplitude. When the flow velocity change amplitude calculated by the detection unit 4 decreases, the second control signal can control the second drive end to push out towards the second outlet pipe 2 to push the second grid cylinder 82 relative to the first grid cylinder 81.

[0100] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A pressure-driven injection device for microcrack networks, characterized in that, It includes: A first outlet pipe and a second outlet pipe are arranged sequentially and connected. The first outlet pipe is used to receive fracturing fluid. The first outlet pipe is equipped with a detection unit for detecting the flow rate of the fracturing fluid. The second outlet pipe is used to connect to the downhole tubing string; A speed control component is disposed and connected between the first liquid outlet pipe and the second liquid outlet pipe. The speed control component is deformable along a first direction so that the speed control component can adjust its guiding length along the first direction according to the detection result of the detection unit. Wherein, the first direction is the direction from the first outlet pipe to the second outlet pipe.

2. The pressure-driven injection device for microcrack networks according to claim 1, characterized in that: Including flow-stabilizing grilles; The flow stabilizing grid is disposed inside the second liquid outlet pipe. The flow stabilizing grid is deformable along the first direction so that the flow stabilizing grid can be deformed along the first direction according to the detection result of the detection unit to adjust its flow stabilizing length along the first direction.

3. The pressure-driven injection device for microcrack networks according to claim 2, characterized in that: Includes drive components and controllers; The controller is signal-connected to the detection unit to generate a first control signal and a second control signal based on the detection result of the detection unit; The drive assembly has a first drive end and a second drive end on both sides along the first direction. The first drive end and the second drive end are respectively connected to the speed control assembly and the flow stabilizing grille. The drive assembly is signal connected to the controller. The drive assembly can drive the first drive end and the second drive end to extend or retract along the first direction according to the first control signal and the second control signal, respectively.

4. The pressure-driven injection device for microcrack networks according to claim 1, characterized in that: The speed control component includes a first tapered tube, a first corrugated tube, and a second tapered tube connected sequentially along the first direction. The first tapered tube is used to connect to the first liquid outlet tube; The second conical tube is used to connect to the second liquid outlet tube; The first bellows can deform along the first direction to adjust its flow guiding length along the first direction.

5. The pressure-driven injection device for microcrack networks according to claim 4, characterized in that: The speed control component also includes a second bellows; The two ends of the second corrugated pipe are respectively connected to the second tapered pipe and the second liquid outlet pipe.

6. The pressure-driven injection device for microcrack networks according to claim 3, characterized in that: The flow stabilizing grid includes a first grid cylinder and a second grid cylinder coaxially sleeved together. The first grid tube is fixedly connected to the second liquid outlet pipe; The second grid cylinder is slidably connected to the first grid cylinder along the first direction, and the second grid cylinder can reciprocate relative to the first grid cylinder along the first direction in response to the drive of the second drive end; The second grid cylinder reciprocates along the first direction to adjust the flow stabilizing length of the flow stabilizing grid along the first direction.

7. The pressure-driven injection device for microcrack networks according to claim 6, characterized in that: The driving component includes a moving ring, a first adsorption element, and a second adsorption element; The movable ring is arranged around the first grid cylinder axially for one revolution outside the first grid cylinder, the movable ring is connected to the second drive end, and the inner wall of the movable ring is provided with a first adsorption element; The second grid cylinder is provided with the second adsorption element, which can adsorb each other with the first adsorption element; The second driving end can drive the moving ring to reciprocate along the first direction, so that the second grid cylinder responds to the first adsorption member by reciprocating along the first direction with the moving ring through the second adsorption member.

8. The pressure-driven injection device for microcrack networks according to claim 7, characterized in that: The drive assembly also includes a mounting ring; The mounting ring is arranged around the second liquid outlet pipe axially for one revolution outside the second liquid outlet pipe, and the mounting ring is fixedly connected to the second liquid outlet pipe; Both the first driving end and the second driving end are connected to the mounting ring.

9. The pressure-driven injection device for microcrack networks according to claim 8, characterized in that: The drive assembly also includes several guide rods; A plurality of the guide rods are spaced apart around the axial direction of the second liquid outlet pipe, and the guide rods extend along the first direction; The first end of the guide rod is fixed to the speed control component, and the second end of the guide rod passes through the mounting ring and is connected to the moving ring.

10. A pressure-driven injection method for microfracture networks based on the pressure-driven injection device for microfracture networks according to any one of claims 1-9, characterized in that, It includes the following steps: Inject fracturing fluid and monitor the flow rate of the fracturing fluid; If the flow rate is greater than the target flow rate, the flow path of the fracturing fluid is extended. If the flow rate is less than the target flow rate, the flow path of the fracturing fluid is shortened. If the fluctuation amplitude of the flow rate increases, the steady flow path of the fracturing fluid will be extended; If the fluctuation amplitude of the flow rate decreases, the steady flow path of the fracturing fluid will be shortened.

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