Small-aperture integrated hydraulic fracturing ground stress testing equipment
By designing a small-aperture integrated hydraulic fracturing ground stress test equipment, the new push-pull switch and new central pipe are used to separate the fracturing water flow and the impression water flow, the problems of repeated lifting and disassembly of traditional equipment are solved, and a more efficient and safer testing process is achieved.
Patent Information
- Application Number
- CN202421770759.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-25
- Publication Date
- 2025-05-27
- Estimated Expiration
- 2034-07-25
AI Technical Summary
Traditional hydraulic fracturing geodesic stress equipment requires repeated lifting, release and disassembly, resulting in a long test time. The collapse of the hole wall during equipment replacement may lead to a greater risk of testing failure and the equipment being buried.
A small-aperture integrated hydraulic fracturing ground stress testing equipment was designed. The fracturing water flow was separated from the impression water flow through a new push-pull switch and a new central tube, so that the equipment can be lowered in one go to complete the fracturing and impression operations.
It significantly reduces the number of equipment assembled during testing, improves work efficiency, reduces the possibility of hole wall collapse and the risk of equipment being buried.
Smart Images
Figure CN222913356U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of hydraulic fracturing in-situ stress testing, in particular to a small-aperture integrated hydraulic fracturing in-situ stress testing device. Background Art
[0002] The sizes of traditional hydraulic fracturing in-situ stress testing devices are mostly designed with a 65-mm aperture. The testing steps are mainly divided into two steps: fracturing test and impression test. The fracturing test is used to determine the value of the in-situ stress borne by the rock in this area, and two methods, namely double-loop and single-loop, can be adopted. Among them, the double-loop is applicable to relatively shallow strata, and the single-loop can be used for both shallow and deep strata. The impression test is used to determine the direction of the in-situ stress borne by the rock in this area, and a special water-inflatable rubber impression device is used for determination. However, at present, all hydraulic fracturing in-situ stress testing devices separate the fracturing test and the impression test. It is necessary to reassemble the device after the fracturing test is completed to perform the impression operation. The sizes of traditional hydraulic fracturing in-situ stress testing devices are mostly designed with a 65-mm aperture. Therefore, the length of the commonly used fracturing test section is nearly 0.4 m, and the length of the complete core is required to be more than 2 m. At the same time, traditional hydraulic fracturing in-situ stress testing devices need to be repeatedly lifted and lowered and disassembled and assembled during the in-situ stress test, resulting in a long testing time. During the equipment replacement period, there is a high risk that the hole wall may collapse, leading to the failure of the in-situ stress test and the equipment being buried.
[0003] According to the provisions of the Standard for Test Methods of Engineering Rock Masses GB / T 50266-2013, the water permeability rate of the rock mass in the pressurized section and the packer section of hydraulic fracturing should not be greater than 1 Lu. This means that the selected hydraulic fracturing test section and the water sealing section must be intact or without through-going fractures. However, in actual engineering boreholes, it is extremely difficult to select a complete core with a length of 2-2.4 m (0.4 m for the test section and 1 m for each of the upper and lower rubber packers).
[0004] Traditional hydraulic fracturing methods completely separate the fracturing test and the impression test, that is, after the fracturing test is completed, the device is lifted out of the borehole, the fracturing structure is removed, and the impression structure is reinstalled. Then the device is lowered again for the impression test, and finally the entire operation process of hydraulic fracturing in-situ stress testing is completed. This method requires repeated lifting and lowering and disassembling and assembling of the device, seriously affecting the work efficiency. Moreover, since the liquid pressure applied to the formation during the first fracturing test is greater than the tensile strength of the rock in the fracturing area, the repeated hydraulic pressure loading and unloading cause the fractures to continuously open and close, which may lead to the collapse of the hole wall in the fracturing area during the process of lifting the device to replace the impression structure, affecting the subsequent impression operation, and even may cause the device to be buried underground during the impression test and unable to be lifted out, resulting in economic losses.
[0005] Among them, the requirement for the length of the intact core section can be optimized by reducing the borehole diameter. At the same time, in view of the low-efficiency and high-risk repeated lifting and disassembly operations of traditional hydraulic fracturing in-situ stress measurement equipment during in-situ stress measurement, it is necessary to improve the testing equipment and methods to improve efficiency and reduce risks. Summary of the Invention
[0006] In order to overcome the above technical problems, the purpose of the present utility model is to provide a small-bore integrated hydraulic fracturing in-situ stress testing device to solve the problems in the above background technology that traditional hydraulic fracturing in-situ stress measurement equipment requires repeated lifting and disassembly operations during in-situ stress measurement, resulting in a long time-consuming hydraulic fracturing in-situ stress test, and during the equipment replacement period, the risk of borehole wall collapse may lead to the failure of in-situ stress measurement and the equipment being buried.
[0007] To achieve the above purpose, the present utility model provides the following technical solutions: A small-bore integrated hydraulic fracturing in-situ stress testing device, including: a lower rubber packer, with a locator and a fracturing test section arranged at both ends of the lower rubber packer. At the end of the fracturing test section away from the lower rubber packer, there are an upper rubber packer, a new push-pull switch, a rubber impression maker, a high-pressure hose connector, a double-circuit water inlet end, and a drill pipe. Inside the upper rubber packer, there is an original central pipe, and inside the rubber impression maker, there is a new central pipe. Fracturing water flow and impression water flow circulate in the double-circuit water inlet end.
[0008] Preferably: The lower rubber packer, the fracturing test section, the upper rubber packer, the original central pipe, and the new push-pull switch form a fracturing module. The fracturing module adopts a complete traditional single-circuit fracturing system, and the fracturing water flow directly circulates in the drill pipe.
[0009] Preferably: The water flow in the drill pipe reaches the new push-pull switch through the double-circuit water inlet end and the new central pipe. First, the lower rubber packer and the upper rubber packer are inflated, and then by rotating and pushing and pulling the new push-pull switch, different water flow delivery circuits in the new push-pull switch are opened to achieve the fracturing effect of the fracturing test section.
[0010] Preferably: The locator, the rubber impression maker, the new central pipe, and the high-pressure hose connector form an impression module. The impression module separates the fracturing water flow and the impression water flow by the new central pipe and supplies water to the rubber impression maker through the high-pressure hose connector. After the rubber impression maker expands, the position and shape of the rock fracture in the fracturing area are engraved on its surface, and finally, the fracture orientation is determined by the locator.
[0011] Preferably, the high-pressure hose connector, the double-loop water inlet end, and the new central tube separate the fracturing water flow and the impression water flow in the double-loop water inlet end. The new push-pull switch and the new central tube allow the fracturing water flow to directly enter the new push-pull switch through the new central tube. The impression water flow will be blocked in the rubber impression device and cannot enter the new push-pull switch, providing a prerequisite for completing the fracturing and impression operations in one lowering of the device.
[0012] Preferably, the locator, the lower rubber packer, the fracturing test section, the upper rubber packer, the original central tube, the new push-pull switch, the rubber impression device, the new central tube, the high-pressure hose connector, the double-loop water inlet end, and the drill pipe are assembled in sequence.
[0013] Compared with the prior art, the beneficial effects of the present utility model are as follows:
[0014] 1. Compared with the traditional hydraulic fracturing method, by selecting a 45-mm drill bit, the length of the fracturing test section is reduced to 0.27 m, and the requirement for the intact core section can be shortened to 1.8 - 2.2 m, reducing the requirement for the length of the intact core section under limited conditions.
[0015] 2. The assembly sequence of the original equipment parts is rearranged, and the interfaces of the original push-pull switch and the original central tube are slightly improved to obtain a new type of hydraulic fracturing in-situ stress measurement device integrating a fracturing structure and an impression structure and related usage methods. The integrated hydraulic fracturing in-situ stress measurement device combines the advantages of the traditional single-loop fracturing structure and the traditional double-loop fracturing structure. While separating the fracturing water flow and the impression water flow by means of the new central tube, the new push-pull switch is used to further separate the fracturing water flow into two water flow circuits for the expansion of the rubber packer and the fracturing of the fracturing test section. Based on the three subdivided water flow circuits, the dual operations of fracturing and impression are finally completed during one lowering of the device.
[0016] 3. Compared with the traditional hydraulic fracturing in-situ stress measurement device, the integrated hydraulic fracturing in-situ stress measurement device can significantly reduce the number of equipment assembly times during testing, reduce waste of human resources and improve work efficiency. At the same time, since the integrated hydraulic fracturing in-situ stress measurement device does not require the device to be lifted to replace the impression structure after the fracturing operation is completed, the time interval from fracturing to impression in the fracturing test area is reduced, and the time for the rock in the fracturing test area to be exposed to the atmosphere after undergoing repeated high hydraulic pressure loading and unloading is shortened. It can reduce the possibility of borehole wall collapse during the process from fracturing to impression, creating favorable conditions for subsequent impression operations and also reducing the risk of the device being buried. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 It is a schematic diagram of a traditional double-loop fracturing structure;
[0018] Figure 2Schematic diagram of traditional single-loop fracturing structure;
[0019] Figure 3 Schematic diagram of traditional impression structure;
[0020] Figure 4 Schematic diagram of integrated fracturing impression structure;
[0021] Figure 5 Schematic diagram of input circuits for fracturing water flow and impression water flow in integrated fracturing impression structure;
[0022] Figure 6 Schematic diagram of original connection method between push-pull switch and drill pipe;
[0023] Figure 7 Schematic diagram of connection method between new push-pull switch, rubber impression device and new central pipe.
[0024] In the figure: 1. Lower rubber packer; 2. Fracturing test section; 3. Upper rubber packer; 4. Original central pipe; 5. High-pressure hose joint; 6. Double-loop water inlet end; 7. Drill pipe; 9. Locator; 10. Rubber impression device; 12. New push-pull switch; 13. New central pipe. Specific implementation mode
[0025] Please refer to Figure 1-7 and refer to Figure 1 and Figure 2 For traditional hydraulic fracturing in-situ stress measurement equipment, the fracturing system can be divided into two types: double-loop and single-loop. The double-loop fracturing system consists of a lower rubber packer 1, a fracturing test section 2, an upper rubber packer 3, an original central pipe 4, a high-pressure hose joint 5, a double-loop water inlet end 6, and a drill pipe 7. Among them, the water flow of the upper rubber packer 3 is directly supplied by the high-pressure hose through the high-pressure hose joint 5. The water flow passes through a special circuit in the fracturing test section 2 and reaches the lower rubber packer 1 after passing through the fracturing test section 2, realizing the simultaneous expansion of the rubber packers. The water flow of the fracturing test section 2 is input through the drill pipe 7, passes through the double-loop water inlet end 6 and the original central pipe 4, and passes through the upper rubber packer 3 to reach the fracturing test section 2, realizing the fracturing effect. The single-loop fracturing system consists of a lower rubber packer 1, a fracturing test section 2, an upper rubber packer 3, an original central pipe 4, an original push-pull switch. Refer to Figure 2 and Figure 6 In the figure, the label 8 is the original push-pull switch, and a drill pipe 7. The water flows of the lower rubber packer 1, the upper rubber packer 3 and the fracturing test section 2 are all transported by the drill pipe 7. When the water flow reaches the original push-pull switch, different water flow transportation circuits in the original push-pull switch are opened through the rotation and push-pull operations of the original push-pull switch, first realizing the expansion of the lower rubber packer 1 and the upper rubber packer 3 of the rubber packer, and then realizing the fracturing effect of the fracturing test section 2. Refer to Figure 3, the impression system of traditional hydraulic fracturing in-situ stress measurement equipment defaults to a single loop: This impression system consists of a locator 9, a rubber impression device 10, a single-loop water inlet end, and a drill pipe 7. Refer to Figure 3 In the figure, the number 11 is the single-loop water inlet pipe. The external water flow conveyed by the drill pipe 7 directly enters the rubber impression device 10 through the single-loop water inlet end, realizing the expansion of the rubber impression device 10. After the rubber impression device 10 expands, the soft rubber on its surface engraves the position and shape of the rock fracture in the fracturing area. Finally, the locator 9 determines the fracture orientation. Refer to Figure 5 , the traditional hydraulic fracturing method does not have the function of completing both fracturing tests and impression tests with a single lowering of the equipment. By reinstalling and improving the components in the traditional single-loop fracturing system and impression system, two independent water flow circuits, namely the fracturing water flow and the impression water flow, are separated in the integrated hydraulic fracturing impression system; Refer to Figure 4 , the fracturing water flow is input through the drill pipe 7, passes through the new central pipe 13 through the rubber impression device 10, enters the new push-pull switch 12, and enters the lower rubber packer 1, the upper rubber packer 3, and the fracturing test section 2 through the rotation and lifting operations of the push-pull switch, realizing the expansion of the rubber packer and the fracturing operation; The impression water flow is directly input into the rubber impression device 10 through the high-pressure hose through the high-pressure hose connector 5, realizing the expansion of the rubber impression device 10 and the impression operation. Refer to Figure 6 and Figure 7 , after reorganizing the order of the components of the traditional equipment, it is necessary to improve the interfaces of the original push-pull switch and the original central pipe 4. In the traditional single-loop fracturing system, the upper interface of the original push-pull switch is connected to the drill pipe 7 using a taper thread. In the integrated fracturing impression system, the upper interface of the new push-pull switch 12 needs to be connected to the lower interfaces of both the rubber impression device 10 and the new central pipe 13 through a new thread. Although both are thread connections, the lower interface of the rubber impression device 10 is different from the lower interface of the drill pipe 7. At the same time, considering the connection between the upper interface of the new push-pull switch 12 and the lower interface of the new central pipe 13, it is necessary to improve the upper interface of the original push-pull switch and the lower interface of the original central pipe 4 according to Figure 7 shown in the figure to realize the assembly of the integrated fracturing impression system.
[0026] An embodiment provided by the present utility model: A small-aperture integrated hydraulic fracturing in-situ stress measurement device includes: a lower rubber packer 1, with a locator 9 and a fracturing test section 2 provided at both ends of the lower rubber packer 1. At the end of the fracturing test section 2 far from the lower rubber packer 1, there are an upper rubber packer 3, a new push-pull switch 12, a rubber impression device 10, a high-pressure hose connector 5, a double-loop water inlet end 6, and a drill pipe 7. Inside the upper rubber packer 3, there is an original central pipe 4, and inside the rubber impression device 10, there is a new central pipe 13. The double-loop water inlet end 6 has a fracturing water flow and an impression water flow flowing through it. In the appendix Figure 5 a represents the fracturing water flow, and b represents the impression water flow.
[0027] The lower rubber packer 1, the fracturing test section 2, the upper rubber packer 3, the original central pipe 4 and the new push-pull switch 12 form a fracturing module. The fracturing module adopts a complete traditional single-loop fracturing system, and the fracturing water flow directly circulates in the drill pipe 7. Based on the standard of the test method for engineering rock mass GB / T 50266-2013, the pressurized test section length of the water pressure fracturing in-situ stress measurement point should be greater than 6.0 times the diameter of the test hole. As long as a drill bit with a diameter of 45mm or even smaller is selected, the test section length can be reduced to less than 0.27m, and the requirement for the intact core section can be reduced to 1.8 - 2.3m.
[0028] The water flow in the drill pipe 7 reaches the new push-pull switch 12 through the double-loop water inlet end 6 and the new central pipe 13. First, the lower rubber packer 1 and the upper rubber packer 3 are expanded, and then different water flow delivery circuits in the new push-pull switch 12 are opened by rotating and pushing / pulling the new push-pull switch 12, realizing the fracturing effect of the fracturing test section 2.
[0029] The locator 9, the rubber impression device 10, the new central pipe 13, the double-loop water inlet end 6 and the high-pressure hose connector 5 form an impression module. The impression module separates the fracturing water flow from the impression water flow by using the double-loop water inlet end 6 and the new central pipe 13, and then directly supplies the impression water flow to the rubber impression device 10 through the high-pressure hose connector 5. After the rubber impression device 10 expands, the position and shape of the rock fracture in the fracturing area are engraved on its surface, and finally the fracture orientation is determined by the locator 9.
[0030] The combination of the high-pressure hose connector 5, the double-loop water inlet end 6 and the new central pipe 13 separates the fracturing water flow from the impression water flow in the double-loop water inlet end 6. The new push-pull switch 12 and the new central pipe 13 enable the fracturing water flow to directly enter the new push-pull switch 12 through the new central pipe 13, and the impression water flow will be blocked in the rubber impression device 10 and cannot enter the new push-pull switch 12, providing a prerequisite for completing the fracturing and impression operations in one lowering of the equipment.
[0031] The locator 9, the lower rubber packer 1, the fracturing test section 2, the upper rubber packer 3, the original central pipe 4, the new push-pull switch 12, the rubber impression device 10, the new central pipe 13, the high-pressure hose connector 5, the double-loop water inlet end 6 and the drill pipe 7 are assembled in sequence, and the integrated fracturing and impression system can complete the fracturing and impression operations in one lowering of the equipment.
[0032] Working principle: According to Figure 4Assemble the fittings as shown. After setting the working time of the locator 9, lower the fracturing module of the integrated fracturing impression system to the target position using the drill pipe 7. First, perform the fracturing operation: inject water into the new push-pull switch 12 using the drill pipe 7. The water flow passes through the double-loop water inlet end 6 and the new central pipe 13, causing the lower rubber packer 1 and the upper rubber packer 3 to expand. After the rubber packers expand and squeeze against the hole wall, they provide resistance to adjust the switches of different water flow delivery circuits in the new push-pull switch 12. Then, rotate and lower the drill pipe 7 to change the water flow delivery circuit in the new push-pull switch 12, provide water flow to the fracturing test section 2, fracture the rock of the hole wall, and obtain relevant data on rock fracture using the sensor. After that, drain the water flow in the fracturing test section 2 to relieve the water pressure in the fracturing area. Rotate and lift the drill pipe 7 to change the water flow circuit in the new push-pull switch 12 to drain the water flow in the lower rubber packer 1 and the upper rubber packer 3. The rubber packers contract, and the fracturing operation is completed.
[0033] Since the rubber packers have contracted to their original size, lower the drill pipe 7 at this time to place the rubber impression device 10 in the previously fractured rock area and start the impression operation: supply water flow to the rubber impression device 10 through the high-pressure hose connector 5. The rubber impression device 10 expands to record the position and shape of the fractured rock on the hole wall. Then, drain the water flow in the rubber impression device 10, and the rubber impression device 10 contracts to its original size. Lift the drill pipe 7 to lift all the equipment out of the borehole. The fracture orientation is finally determined by the locator 9, and the impression operation is completed.
Claims
1. Small-aperture integrated hydraulic fracturing ground stress testing equipment, characterized in that: include: A lower rubber packer, wherein both ends of the lower rubber packer are provided with a locator and a fracturing test section, an upper rubber packer, a new push-pull switch, a rubber mold, a high-pressure hose connector, a dual-circuit water inlet and a drill pipe are provided at one end of the fracturing test section away from the lower rubber packer, an original center pipe is provided inside the upper rubber packer, a new center pipe is provided inside the rubber mold, and fracturing water flow and mold water flow flow through the dual-circuit water inlet.
2. The small-aperture integrated hydraulic fracturing ground stress testing device according to claim 1 is characterized in that: The lower rubber packer, the fracturing test section, the upper rubber packer, the original central pipe and the new push-pull switch constitute a fracturing module. The fracturing module adopts a complete traditional single-loop fracturing system, and the fracturing water flows directly in the drill pipe.
3. The small-aperture integrated hydraulic fracturing in-situ stress testing device according to claim 2 is characterized in that: The fracturing water flow in the drill pipe reaches the new push-pull switch through the dual-circuit water inlet end and the new center pipe, first achieving the expansion of the lower rubber packer and the upper rubber packer, and then opening the different water flow conveying circuits in the new push-pull switch by rotating and pushing and pulling the new push-pull switch, thereby achieving the fracturing effect of the fracturing test section.
4. The small-aperture integrated hydraulic fracturing in-situ stress testing device according to claim 1 is characterized in that: The locator, rubber mold, new center tube, dual-circuit water inlet and high-pressure hose connector form a mold module. The mold module uses the dual-circuit water inlet and the new center tube to separate the fracturing water flow from the mold water flow. The high-pressure hose connector directly supplies the mold water flow to the rubber mold. After the rubber mold expands, the surface will record the position and shape of the rock fracture in the fracturing area. Finally, the locator determines the fracture orientation.
5. The small-aperture integrated hydraulic fracturing in-situ stress testing device according to claim 1, characterized in that: The high-pressure hose connector, dual-circuit water inlet and new center pipe combination separate the fracturing water flow and the impression water flow in the dual-circuit water inlet, and the new push-pull switch and new center pipe allow the fracturing water flow to directly enter the new push-pull switch through the new center pipe, while the impression water flow will be blocked in the rubber impression device and cannot enter the new push-pull switch, thereby providing the prerequisite for the equipment to complete the fracturing and impression operations in one go.
6. The small-aperture integrated hydraulic fracturing in-situ stress testing device according to claim 1, characterized in that: The locator, lower rubber packer, fracturing test section, upper rubber packer, original central tube, new push-pull switch, rubber impression device, new central tube, high-pressure hose connector, dual-circuit water inlet end and drill pipe are assembled in sequence.