Integrated hydraulic fracturing and ultrasonic imaging of fracture geostress testing device and method

Abstract

The application discloses an integrated water pressure fracturing and fractured fissure ultrasonic imaging geostress testing device and method, which comprises a downhole high-pressure waterway switching switch, a bridging packer, a pressure trigger device and an ultrasonic imaging device. The downhole high-pressure waterway switching switch can realize high-pressure waterway switching through push-pull operation. The bridging packer has a middle position as a geostress testing section. The pressure trigger device is connected with the bottom of the bridging packer. The ultrasonic imaging device comprises a data acquisition unit, a battery compartment unit, an ultrasonic transducer and a rotating mechanism. After water pressure fracturing geostress testing, the pressure trigger starts the ultrasonic imaging device, and the lifting motion controlled by the ground is matched to realize the detection of the occurrence and orientation information of the fractured fissure, thereby significantly improving the geostress direction detection efficiency and result reliability. The application is suitable for deep hole in-situ geostress measurement and solves the problems of difficult fractured fissure direction detection, poor reliability and low efficiency.

Description

Technical Field

[0001] This invention belongs to the field of in-situ geostress testing technology in the deep crust, specifically relating to an integrated ultrasonic imaging geostress testing device and method for hydraulic fracturing and pressure fracturing. Background Technology

[0002] With the implementation of my country's national strategy of seeking resources, security, and space from the Earth's depths, the depth at which humans have entered the Earth's depths has been increasing year by year. Disasters and resource and environmental problems caused by the high geostress environment in the deep crust have become increasingly prominent. Exploring the current stress environment in deep underground rock masses is of great significance for basic research in geodynamics, efficient development of deep resources, and safe utilization of underground space.

[0003] Hydraulic fracturing is a recognized effective method for probing the deep stress environment of the Earth's crust. It primarily involves sealing the test section within the borehole using a cross-type packer, injecting high-pressure water into the surface to fracture the rock mass within the test section, and determining the minimum and maximum horizontal principal stresses based on the pressure-time curves. The direction of the horizontal principal stresses is then determined based on the direction of the fracturing. Currently, there are two main methods for determining the direction of the fracturing: the first is the impression-oriented method, and the second is imaging logging. The first method involves lowering a vulcanized rubber impression device into the hydraulic fracturing stress test depth after the test. High-pressure water is injected from the surface, causing the impression device to expand and make close contact with the borehole wall. Combined with a downhole electronic compass, the location of the hydraulic fractures in the borehole wall is obtained, thus determining the direction of the horizontal principal stress. This method is suitable for boreholes shallower than 1000m. However, in deeper holes, the impression device rubs against the borehole wall during lifting, easily causing the loss of the fracture information acquired by the impression. The second method involves lowering an imaging logging device via cable after the hydraulic fracturing stress test. By detecting images of the borehole wall in the hydraulic fracturing stress test section, the location of the hydraulic fractures in the borehole wall is obtained, thus determining the direction of the horizontal principal stress. The imaging logging method requires a separate testing system, has low testing efficiency, and due to the long interval between the hydraulic fracturing stress test and the imaging logging, fractures are prone to healing, making it impossible to detect effective information. Therefore, the existing methods for detecting the direction of hydraulic fractures in deep-hole hydraulic fracturing in-situ stress testing can no longer fully meet the requirements. It is urgent to improve the reliability of the detection results of the direction of hydraulic fractures (i.e., in-situ stress) through technological breakthroughs. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an integrated ultrasonic imaging geostress testing device and method for hydraulic fracturing and pressure fracturing.

[0005] To achieve the above objectives, the present invention provides the following solution: An integrated hydraulic fracturing and in-situ stress testing device with ultrasonic imaging includes: a downhole high-pressure water circuit switching switch, a bridging packer, a pressure triggering device, and an ultrasonic imaging device. The downhole high-pressure water circuit switching switch allows for switching of the high-pressure water circuit via a push-pull operation. The middle section of the bridging packer is the in-situ stress testing section, and the top of the pressure triggering device is connected to the bottom of the bridging packer. After hydraulic fracturing and in-situ stress testing, the ultrasonic imaging device is activated via pressure triggering, and, in conjunction with surface-controlled lifting and lowering movements, the occurrence and azimuth information of the in-situ fractures are detected.

[0006] Preferably, the downhole high-pressure water circuit switching switch is located on the upper part of the bridging packer and is used for water circuit switching control during the injection of high-pressure fluid into the bridging packer or test section. The bridging packer is installed on the lower part of the high-pressure water circuit switching switch and is used for sealing the test section and testing the water-induced fracturing stress during the water-induced fracturing stress test. The pressure triggering device is installed on the lower part of the bridging packer and controls the start and stop of the ultrasonic imaging device through the pressure signal. The ultrasonic imaging device is connected to the bottom of the pressure triggering device and is powered by the downhole battery to realize rapid imaging detection of the test section after water-induced fracturing.

[0007] Preferably, a pressure triggering device is provided between the lower packer and the ultrasonic imaging device. The pressure triggering device is connected to the water sealing channel of the packer expansion seat. By pressurizing the packer with 5MPa through the ground and continuing for more than 5 minutes, the downhole step pressure can trigger the ultrasonic imaging device to start. After imaging detection, the device is stopped using a delay function.

[0008] As a preferred method, after the ultrasonic imaging device is started, the pressure inside the packer is released, and the device is raised from the ground to the ground stress test section and moves up and down 2-3 times to achieve imaging of the borehole wall of the water pressure fracturing ground stress test section.

[0009] Preferably, the ultrasonic imaging device has a data acquisition unit at the top, a battery compartment unit in the middle, and an ultrasonic transducer and a rotating mechanism at the bottom, with each unit rigidly connected.

[0010] Preferably, the ultrasonic transducer and rotating mechanism are filled with silicone oil and are equipped with a self-emitting and self-receiving ultrasonic transducer, an emitting surface, a rotating mechanism and a pressure balancing mechanism. The ultrasonic waves emitted by the transducer pass through the rotating reflective surface driven by the motor, through the Peek material acoustic window, hit the well wall and return along the same path to be received by the transducer, realizing ultrasonic detection and imaging around the well wall. The pressure balancing mechanism at the bottom is used to keep the pressure of the transducer and the well barrel balanced.

[0011] Preferably, the integrated hydraulic fracturing and pressure fracture ultrasonic imaging geostress testing device has a temperature resistance index of 150℃ and a pressure resistance index of better than 50MPa. The PEEK material part of the sound-transmitting window adopts the balanced pressure technology to meet the geostress testing requirements of shallower than 5km.

[0012] Preferably, the integrated hydraulic fracturing and indentation fracture ultrasonic imaging geostress testing device has an outer diameter range of 70-200 mm to meet the requirements for hydraulic fracturing geostress testing in open-hole sections with a borehole diameter of 76-230 mm.

[0013] This invention also provides an integrated ultrasonic imaging method for testing in-situ stress in hydraulic fracturing and pressure fracturing, comprising: After completing the conventional hydraulic fracturing stress test at the selected depth, the surface pressurizes the packer by 5 MPa for more than 5 minutes. The downhole step pressure triggers the ultrasonic imaging device to start. The pressure inside the packer is released, and the surface controls the downhole equipment to move back and forth 2-3 times to achieve ultrasonic imaging logging of the hydraulic fracturing stress test section. After the ultrasonic imaging device works continuously for 30 minutes, it is stopped using the delay function, thus completing the stress test of one depth section. Repeat the above process to measure the water pressure fracturing stress in the next test section. After all tests are completed and the downhole equipment is taken out to the surface, the wellbore imaging results are obtained through data revisit.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: Improving testing efficiency: An integrated ultrasonic imaging geostress testing device and method for hydraulic fracturing and pressure fracture can measure both the magnitude and direction of geostress in a single drilling run; Maintaining the opening of the hydraulic fracture: Ultrasonic imaging logging is carried out immediately after hydraulic fracturing, which reduces the healing time of the hydraulic fracture and is expected to ensure the detection effect of the hydraulic fracture.

[0015] Reduced technical complexity: The downhole high-pressure water circuit conversion switch, cross-connect packer, pressure triggering device and ultrasonic imaging device are existing technologies. After integrated development, only downhole power supply and data acquisition modules were added, ensuring the applicability of the technology. Attached Figure Description

[0016] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the integrated hydraulic fracturing and in-situ stress testing device using ultrasonic imaging, according to an embodiment of the present invention. Figure 2 This is a schematic diagram of a bridging packer according to an embodiment of the present invention; Figure 3 This is a schematic diagram of an ultrasound imaging device according to an embodiment of the present invention; The components include: 1. Water tank; 2. High-pressure pump; 3. Ground data acquisition unit; 4. Pressure control device; 5. High-pressure pipeline; 6. Drill rod; 7. Water circuit conversion switch; 8. Upper packer; 9. High-pressure water outlet; 10. Test section; 11. Lower packer; 12. Pressure triggering device; 13. Data acquisition unit; 14. Acquisition circuit; 15. Battery compartment; 16. High-temperature battery; 17. Ultrasonic transducer and rotating mechanism; 18. Ultrasonic transducer; 19. Sound-transmitting window; 20. Reflecting surface; 21. Drive motor; 22. Pressure balancing mechanism. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] Example 1 like Figures 1 to 3 As shown, this invention provides an integrated ultrasonic imaging geostress testing device for hydraulic fracturing and hydraulic fractures, comprising a downhole high-pressure water circuit switching switch, a bridging packer, a pressure triggering device, and an ultrasonic imaging device. The downhole high-pressure water circuit switching switch is located on the upper part of the bridging packer and is used for water circuit switching control during the injection of high-pressure fluid into the bridging packer or test section. The bridging packer is installed below the high-pressure water circuit switching switch and is used for sealing the test section and testing the hydraulic fracturing geostress during the hydraulic fracturing geostress testing process. The pressure triggering device is installed below the bridging packer and controls the start and stop of the ultrasonic imaging device through a pressure signal. The ultrasonic imaging device is connected to the bottom of the pressure triggering device and is powered by a downhole battery to achieve rapid imaging detection of the test section after hydraulic fracturing.

[0021] As one embodiment of the present invention, a combination of traditional hydraulic fracturing stress measurement and storage-type ultrasonic imaging logging technology is used to perform ultrasonic imaging detection of hydraulic fractures within minutes after hydraulic fracturing stress testing.

[0022] As one embodiment of the present invention, a pressure triggering device is provided between the lower packer and the ultrasonic imaging device. The pressure triggering device is connected to the packer expansion seat sealing water passage. By applying 5MPa pressure to the packer through the ground and continuing for more than 5 minutes, the downhole step pressure can trigger the ultrasonic imaging device to start. After imaging detection, the device is stopped using a delay function.

[0023] As one embodiment of the present invention, after the ultrasonic imaging device is started, the pressure inside the packer is released, and the device is raised to the ground stress test section by the ground lifting equipment, and then performs 2-3 up-and-down reciprocating movements to achieve imaging of the borehole wall of the water pressure fracturing stress test section.

[0024] As one embodiment of the present invention, the ultrasonic imaging device is provided with a data acquisition unit at the top, a battery compartment unit in the middle, and an ultrasonic transducer and a rotating mechanism at the bottom, with each unit rigidly connected to the other.

[0025] As one embodiment of the present invention, the ultrasonic imaging device is powered by a downhole battery, wherein the data acquisition unit has functions of setting acquisition parameters, acquiring data, storing and playing back data.

[0026] As one embodiment of the present invention, the ultrasonic transducer and rotating mechanism are filled with silicone oil and are equipped with a self-emitting and self-receiving ultrasonic transducer, an emitting surface, a rotating mechanism and a pressure balancing mechanism. The ultrasonic waves emitted by the transducer pass through the rotating reflective surface driven by the motor, through the Peek material acoustic window, hit the well wall and return along the original path to be received by the transducer, realizing ultrasonic detection and imaging around the well wall. The pressure balancing mechanism at the bottom is used to keep the pressure of the transducer and the well barrel balanced.

[0027] As one embodiment of the present invention, the ultrasonic imaging device has a power supply and storage space that meets the requirements for 8 hours of continuous operation. Based on the pressure-triggered switch and delayed shutdown function, the existing power supply and storage capacity can meet the needs of most borehole stress measurement.

[0028] As one embodiment of the present invention, the integrated hydraulic fracturing and pressure fracture ultrasonic imaging geostress testing device has an overall temperature resistance index of 150℃ and a pressure resistance index of better than 50MPa. The PEEK material of the sound-transmitting window adopts the balanced pressure technology, which can basically meet the geostress testing requirements of shallower than 5km.

[0029] As one embodiment of the present invention, the integrated hydraulic fracturing and indentation fracture ultrasonic imaging geostress testing device has an outer diameter range of 70-200 mm, which can meet the requirements for hydraulic fracturing geostress testing of open-hole sections with a borehole diameter of 76-230 mm.

[0030] An integrated ultrasonic imaging geostress testing device for hydraulic fracturing and hydraulic fracture is used. After completing conventional hydraulic fracturing geostress testing at a predetermined depth, the surface pressurizes the packer at 5 MPa for at least 5 minutes. The downhole step pressure triggers the ultrasonic imaging device to start. After releasing the pressure inside the packer, the surface controls the downhole equipment to reciprocate up and down 2-3 times to achieve ultrasonic imaging logging of the hydraulic fracturing geostress testing section (3-5m). The ultrasonic imaging device operates continuously for 30 minutes and then stops using a time-delay function, thus completing the geostress testing for one depth segment. The above process is repeated to measure the hydraulic fracturing geostress of the next segment. After all tests are completed, the downhole equipment is retrieved to the surface, and the wellbore imaging results are obtained through data replay.

[0031] The integrated hydraulic fracturing and hydraulic fracture ultrasonic imaging geostress testing device and method provided by this invention can be applied to at least the following scenarios: 1) In the deep mining exploration stage, it is used to obtain the magnitude and direction of geostress in deep holes to assess the geological safety risks of roadways during mine construction or production. 2) In the construction of major deep-buried engineering projects, it is used to obtain the magnitude and direction of geostress in vertical deep holes or horizontal directional holes, serving the efficiency and safety of engineering construction. 3) In the oil and gas development process, it obtains reliable geostress direction to serve the selection of horizontal well azimuth and hydraulic fracturing design.

[0032] Example 2 This invention also provides an integrated ultrasonic imaging method for testing in-situ stress in hydraulic fracturing and pressure fracturing, comprising the following steps: Step 1, Select the test section Based on borehole core observations or other logging data, the depth range for in-situ stress testing is determined. Then, using a drilling rig and drill pipe, the integrated hydraulic fracturing and ultrasonic imaging in-situ stress testing device is lowered to the predetermined depth to begin in-situ hydraulic fracturing stress testing.

[0033] Step 2, packer expansion seat High-pressure fluid, usually clean water, is injected into the bridging packer through the drill pipe and water circuit switching switch to complete the bridging packer setting.

[0034] Here, the bridging packer includes an upper packer, a lower packer, a test section between the upper and lower packers, and a high-pressure water outlet within the test section. There is a water channel connecting the upper packer and the lower packer.

[0035] Step 3, Water pressure-induced fracturing stress test By lowering the drill pipe from the ground and switching the water circuit conversion switch to the test water circuit, high-pressure fluid is injected into the test section through the high-pressure water outlet on the test section between the bridging packers. The water-pressure fractured ground stress test is carried out in accordance with the relevant procedures for water-pressure fractured ground stress measurement.

[0036] Step 4: Depressurize and unseal the packer. By switching the water circuit conversion switch to the sealing water circuit through the ground lifting drill pipe, the packer is connected to the ground atmosphere, the pressure inside the packer is released, and the bridging packer is unsealed.

[0037] Step 5, start the ultrasound imaging device. Pressurize the unsealed packer with 5 MPa for more than 5 minutes, then activate the ultrasonic imaging device via the pressure triggering device, and finally release the pressure inside the packer.

[0038] Step 6, Ultrasonic Imaging Logging After the ultrasonic imaging device is started, the high-temperature battery in the battery compartment supplies power to the acquisition circuit, ultrasonic transducer, ultrasonic transducer in the rotating mechanism, and drive motor in the data acquisition unit. The ultrasonic waves emitted by the transducer pass through the rotating reflector driven by the motor, through the sound-transmitting window, hit the well wall, and return along the same path to be received by the transducer, realizing ultrasonic imaging logging around the borehole wall. By raising and lowering the drill pipe on the ground, the device performs 2-3 up-and-down reciprocating movements centered on the test section, realizing imaging logging of the borehole wall of the water-pressure fracture stress test section, and obtaining the occurrence and orientation information of the pressure fracture generated during the water-pressure fracture stress measurement process. The ultrasonic imaging device stops using the delay function 30 minutes after startup.

[0039] Step 7: Repeat the above process to conduct the next section of ground stress test.

[0040] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An integrated ultrasonic imaging geostress testing device for hydraulic fracturing and pressure fracture, characterized in that, include: The system includes a downhole high-pressure water circuit switching switch, a cross-connect packer, a pressure triggering device, and an ultrasonic imaging device. The downhole high-pressure water circuit switching switch allows for switching of the high-pressure water circuit via a push-pull operation. The cross-connect packer has a geostress testing section in its middle position, and the top of the pressure triggering device is connected to the bottom of the cross-connect packer. After the hydraulic fracturing geostress test, the ultrasonic imaging device is activated by pressure triggering, and in conjunction with surface-controlled lifting and lowering movements, it detects the fracture orientation and azimuth information.

2. The integrated hydraulic fracturing and intensified fracture ultrasonic imaging geostress testing device as described in claim 1, characterized in that, The downhole high-pressure water circuit switching switch is located on the upper part of the bridging packer and is used for water circuit switching control during the injection of high-pressure fluid into the bridging packer or test section. The bridging packer is installed below the high-pressure water circuit switching switch and is used for sealing the test section and testing the water-induced fracturing stress during the water-induced fracturing stress test. The pressure triggering device is installed below the bridging packer and controls the start and stop of the ultrasonic imaging device through the pressure signal. The ultrasonic imaging device is connected to the bottom of the pressure triggering device and is powered by the downhole battery to realize rapid imaging detection of the test section after water-induced fracturing.

3. The integrated ultrasonic imaging geostress testing device for hydraulic fracturing and pressure fracture as described in claim 2, characterized in that, A pressure triggering device is installed between the packer and the ultrasonic imaging device. The pressure triggering device is connected to the packer expansion seat water sealing channel. By pressurizing the packer with 5MPa through the ground and continuing for more than 5 minutes, the downhole step pressure can trigger the ultrasonic imaging device to start. After imaging detection, the device is stopped using a delay function.

4. The integrated hydraulic fracturing and intensified fracture ultrasonic imaging geostress testing device as described in claim 3, characterized in that, After the ultrasonic imaging device is started, the pressure inside the packer is released, and the equipment is lifted from the ground to the ground stress test section. It then performs 2-3 up-and-down reciprocating movements to achieve imaging of the borehole wall of the water pressure-induced fracturing ground stress test section.

5. The integrated hydraulic fracturing and intensified fracture ultrasonic imaging geostress testing device as described in claim 4, characterized in that, The ultrasonic imaging device has a data acquisition unit at the top, a battery compartment unit in the middle, and an ultrasonic transducer and a rotating mechanism at the bottom, with each unit rigidly connected.

6. The integrated hydraulic fracturing and intensified fracture ultrasonic imaging geostress testing device as described in claim 5, characterized in that, The ultrasonic transducer and rotating mechanism are filled with silicone oil and are equipped with a self-emitting and self-receiving ultrasonic transducer, a emitting surface, a rotating mechanism, and a pressure balancing mechanism. The ultrasonic waves emitted by the transducer pass through the rotating reflective surface driven by the motor, through the Peek material acoustic window, hit the well wall, and return along the same path to be received by the transducer, realizing ultrasonic detection and imaging around the well wall. The pressure balancing mechanism at the bottom is used to keep the pressure of the transducer and the well barrel balanced.

7. The integrated ultrasonic imaging geostress testing device for hydraulic fracturing and intensified fractures as described in claim 6, characterized in that, The integrated hydraulic fracturing and pressure fracture ultrasonic imaging geostress testing device has a temperature resistance index of 150℃ and a pressure resistance index of better than 50MPa. The PEEK material part of the sound-transmitting window adopts the balanced pressure technology to meet the geostress testing requirements of shallower than 5km.

8. The integrated ultrasonic imaging geostress testing device for hydraulic fracturing and intensified fracture as described in claim 7, characterized in that, The integrated hydraulic fracturing and indentation fracture ultrasonic imaging geostress testing device has an outer diameter range of 70-200 mm to meet the requirements for hydraulic fracturing geostress testing in open-hole sections with a borehole diameter of 76-230 mm.

9. A method for testing in-situ stress using the integrated hydraulic fracturing and intensified fracturing ultrasonic imaging in-situ stress testing device as described in claim 1, characterized in that, include: After completing the conventional hydraulic fracturing stress test at the selected depth, the surface pressurizes the packer by 5 MPa for more than 5 minutes. The downhole step pressure triggers the ultrasonic imaging device to start. The pressure inside the packer is released, and the surface controls the downhole equipment to move back and forth 2-3 times to achieve ultrasonic imaging logging of the hydraulic fracturing stress test section. After the ultrasonic imaging device works continuously for 30 minutes, it is stopped using the delay function, thus completing the stress test of one depth section. Repeat the above process to measure the water pressure fracturing stress in the next test section. After all tests are completed and the downhole equipment is taken out to the surface, the wellbore imaging results are obtained through data revisit.

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