Drainable high-pressure air test device and method suitable for deep borehole test section
By using a drainable high-pressure air-pressure testing device in the deep borehole test section, the accumulated water is dynamically discharged and the air tightness test is conducted in a dry state, which solves the problem of water accumulation in the deep borehole test section affecting the test results and achieves efficient and accurate evaluation of rock mass air tightness.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHANGJIANG RIVER SCI RES INST CHANGJIANG WATER RESOURCES COMMISSION
- Filing Date
- 2026-03-15
- Publication Date
- 2026-07-24
AI Technical Summary
The failure to effectively drain water from the deep borehole test section led to distorted test results, affecting the accuracy of rock mass airtightness evaluation and increasing test costs and time.
A drainable high-pressure air compression testing device is adopted, including drill rod, borehole sealing unit, ground supply unit, dynamic drainage unit and data acquisition unit. The dynamic discharge and temporary storage of accumulated water are achieved through drainage valve and pressure limiting valve to ensure that the air tightness test is carried out in a dry state.
It enables real airtightness testing of rock masses in a dry state, improving testing efficiency and accuracy, reducing construction difficulty and cost, and providing accurate gas permeability parameters.
Smart Images
Figure CN122448702A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of geotechnical engineering investigation and in-situ testing, specifically relating to a drainable high-pressure compressed air testing device and method suitable for deep borehole test sections. Background Technology
[0002] In deep rock mass air tightness evaluation (such as compressed air energy storage and underground gas storage site selection), high-pressure borehole gas compression testing is a key in-situ testing method for obtaining rock mass gas permeability. However, water accumulation is common after the completion of deep boreholes. The sealing process at the beginning of the test will seal off a certain amount of water in the test section. During the test, groundwater will also seep out from the borehole wall of the test section. If this accumulated water and groundwater cannot be drained, it will seriously interfere with the test results. Tests with water accumulation in the sealed test section that cannot be drained have the following problems: 1. The test results obtained before the water has completely infiltrated are two-phase high-pressure gas-water tests, not true high-pressure gas compression tests; 2. The measured pressure-flow-time curves are severely distorted, and the gas permeability calculated based on them is significantly lower, failing to reflect the true air tightness of the rock mass under dry or low-water-content conditions. Existing technologies have the following problems: 1. They ignore the water accumulation in the test section, failing to actively and thoroughly remove the water in the test section before the test, and failing to manage water seepage in the test section during the test, resulting in low reliability of the test results and affecting the engineering safety evaluation. 2. Three pipelines are used to connect the ground to the test section, with one pipeline used to drain seepage water from the test section. This testing method requires additional pipelines and other testing equipment, which greatly increases the testing cost; moreover, the equipment installation procedure during drilling is cumbersome, which greatly prolongs the testing time. Summary of the Invention
[0003] One objective of this invention is to address the shortcomings of existing technologies by providing a drainable high-pressure compressed air testing device suitable for deep borehole test sections. This device can not only effectively drain and temporarily store the accumulated water in the test section, allowing the rock mass to undergo airtightness testing in a "dry" state, but also safely discharge the temporarily stored water after the test, enabling continuous, efficient, and accurate testing of multiple test sections within a single borehole.
[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A drainable high-pressure compressed air testing device suitable for deep borehole test sections, comprising: Drill rod, which is installed in the borehole; The in-hole packer unit includes an upper packer and a lower packer fitted on the drill pipe. The upper and lower packers are sealed in the borehole by air pressure, thereby forming a test section between them. The ground supply unit includes a high-pressure air pump and a ground control pipeline connected to the high-pressure air pump. The high-pressure air pump is used to fill the test section with high-pressure gas for drainage and airtightness tests. The high-pressure air pump also pressurizes and seals the upper and lower packers. The ground control pipeline is used for gas flow and direction control and to feed the gas into the drill pipe. A dynamic drainage unit is used to dynamically discharge high-pressure water in the test section according to the water pressure and air pressure. The dynamic drainage unit includes a water storage tank located at the bottom of the lower packer and connected to the test section, a drain valve located at the bottom of the test section and used to drain water from the test section, and a one-way air inlet valve located on the pipeline connecting the high-pressure air pump and the test section. The outlet of the drain valve is connected to the water storage tank. The data acquisition unit includes a pressure sensor and a flow sensor connected to the high-pressure air pump, as well as a data acquisition device electrically connected to the pressure sensor and the flow sensor. The pressure sensor is used to acquire air pressure data in the test section during the high-pressure air compression test, and the flow sensor is used to acquire gas flow rate during the high-pressure air compression test.
[0005] Furthermore, the end of the drill rod closest to the ground is fixed to the ground by a tripod, thereby suspending the drill rod in the borehole.
[0006] Furthermore, a switching valve is installed on the drill pipe. The switching valve includes two unconnected passages, one of which is connected to the upper and lower packers, and the other is connected to the test section.
[0007] Furthermore, the drain valve is configured to open when the pressure in the test section reaches a first preset pressure threshold, so as to force the water accumulated in the test section into the water storage tank.
[0008] Furthermore, the dynamic drainage unit also includes a pressure limiting valve located at the bottom of the water storage tank. The pressure limiting valve is configured to open when the pressure inside the water storage tank reaches a level higher than a second preset pressure threshold, so as to discharge the water temporarily stored in the water storage tank into the borehole.
[0009] Furthermore, the dynamic drainage unit also includes a water outlet pipe, which passes through the lower packer and is connected at one end to the test section and at the other end to the water storage tank. A one-way vent valve is also provided at the end of the water outlet pipe located in the test section to release the gas in the water storage tank when the water is drained into the water storage tank.
[0010] Furthermore, the drainage test device also includes a regulating valve, which is installed on the ground control pipeline for precisely controlling the gas pressure delivered into the drill pipe.
[0011] Furthermore, the upper packer and the lower packer are connected by a connecting pipe, but neither of them is connected to the test section.
[0012] The present invention also provides a method for using the above-described drainable high-pressure compressed air testing device suitable for deep borehole test sections, comprising the following steps: S1. Install the upper packer and lower packer on the drill pipe, and install a dynamic drainage unit between the upper and lower packers. Then lower the assembled drainage test device into the borehole to the predetermined test depth. S2. Start the high-pressure air pump to supply pressure to the upper and lower packers, so that the upper and lower packers expand and set in the borehole to form a sealed test section between them. S3. Stop pressurizing the upper and lower packers, and then inject air into the test section through the drill rod and one-way air inlet valve. When the pressure rises to the first preset pressure threshold, the drain valve opens, and the water in the test section is discharged into the water storage tank under the pressure drive. Continue to supply pressure until the flow sensor shows that the gas flow rate tends to be stable. S4. Maintain or gradually increase the air pressure in the test section, record the pressure and flow rate changes in real time through the data acquisition device, conduct a high-pressure air compression test, and evaluate the air tightness of the rock mass under the air pressure. S5. After the air pressure test is completed, continue to increase the air pressure to the second preset pressure threshold. At this time, the pressure relief valve opens, and the water temporarily stored in the water tank is discharged into the lower part of the borehole under the drive of high pressure gas. S6. After the water tank is emptied, the pressure in the drainage test device is released, the upper and lower packers are retracted, and the sealing of the test section is lifted. S7: Raise or lower the test drainage device to the next test depth, and repeat steps S2 to S6 to perform continuous stratification tests.
[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Eliminates interference from water accumulation in the test section: This invention sets up a drainage valve and opens it when the air pressure in the test section reaches a first preset pressure threshold, thereby forcing the accumulated water into the storage tank. This ensures that the rock mass is in a "dry rock mass" state, realizing the process of actively draining water before testing. This ensures that the air tightness test is carried out in a "dry" state of the rock mass, thus obtaining real and reliable gas permeability parameters. 2. Achieves closed-loop and self-cleaning of the testing process: This invention sets up an original "drainage-storage-controllable discharge" dynamic unit, which automatically drains water through a drain valve and collects it in a storage tank. The water in the storage tank is then automatically discharged through a pressure relief valve, so that the discharged water is properly managed and safely transferred after the test. The device itself does not accumulate water, which makes continuous and multi-stage testing possible and greatly improves the efficiency of airtightness testing.
[0014] 3. High system integration and strong operability: This invention seamlessly integrates drainage function with standard compressed air test, eliminating the need to pull up the drill rod or add extra complicated pumping operations, simplifying the operation process and reducing construction difficulty and cost; 4. Providing key data for major projects: The precise rock mass air tightness parameters obtained by this invention can be directly used for safety and stability assessment of projects such as compressed air energy storage (CAES) caves, underground gas storage facilities, and high-level radioactive waste geological disposal facilities, and have important engineering application value. Attached Figure Description
[0015] Figure 1 This is a schematic diagram of the structure of a drainable high-pressure compressed air testing device applicable to deep borehole test sections according to an embodiment of the present invention. Detailed Implementation
[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0017] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.
[0018] The present invention will be further described below with reference to specific embodiments, but these are not intended to limit the scope of the invention.
[0019] like Figure 1 As shown in the figure, this invention discloses a drainable high-pressure compressed air testing device suitable for deep borehole test sections, including a drill rod 1, an in-hole packing unit, a ground supply unit, a dynamic drainage unit, and a data acquisition unit. For ease of testing, one end of the drill rod 1 is suspended on the ground using a tripod 2, and the other end extends into the borehole 3. Additionally, to facilitate pipeline switching, a switching valve 4 is installed on the drill rod, comprising two non-interconnected passages. The in-hole packing unit includes an upper packer 51 fitted onto the drill rod and a lower packer 52 connected to the upper packer via a connecting pipe. The upper packer 51 and lower packer 52 are sealed within the borehole by air pressure, thus forming a test section 6. The upper and lower packers are connected to one of the passages in the switching valve 4.
[0020] The surface supply unit includes a high-pressure air pump 71 and a surface control pipeline connected to the high-pressure air pump 71. The high-pressure air pump pressurizes the upper and lower packers through one of the pathways of the surface control pipeline and the switching valve 4, causing them to expand and seal within the borehole to form a test section. In addition, the high-pressure air pump 71 is also used to fill the test section with high-pressure gas for drainage and airtightness tests. Specifically, the other pathway of the switching valve 4 is connected to the test section, and the high-pressure air pump 71 pumps high-pressure gas into the test section 6 through the other pathway of the surface control pipeline and the switching valve 4. To facilitate better gas pressurization in the test section 6, a one-way inlet valve 73 is installed on the high-pressure pipe wall joint near the test section 6, allowing gas only to enter the test section 6. Furthermore, a regulating valve 74 is also installed on the surface control pipeline to precisely control the gas pressure delivered downhole.
[0021] The dynamic drainage unit includes a water storage tank 81 located at the bottom of the lower packer 52 and connected to the test section 6, and a drain valve 82 located at the bottom of the test section 6 for draining water according to the pressure of the test section 6. The water storage tank 81 is connected to the test section 6 via an outlet pipe 83 for collecting and temporarily storing water discharged from the test section 6. The outlet pipe 83 passes through the lower packer 52, with one end connected to the test section 6 and the other end connected to the water storage tank 81. To facilitate water drainage into the water storage tank 81, a one-way vent valve 84 is installed at the end of the outlet pipe 83 located in the test section to release any gas released when water is drained into the water storage tank 81. The outlet of the drain valve 82 is connected to the water storage tank 81, allowing water from the test section to be drained into the water storage tank 81 through the drain valve 82. To ensure effective drainage and temporary storage of accumulated water within the test section during the test, allowing the rock mass to undergo airtightness testing in a "dry" state, the drainage valve 82 is configured to open when the air pressure within the test section 6 reaches a first preset pressure threshold, at which point the accumulated water is forced into the water storage tank 81 for temporary storage. To ensure safe drainage of the water in the water storage tank 81 after the test, a pressure limiting valve 85 is also installed at the bottom of the water storage tank 81. In this embodiment, the pressure limiting valve 85 is configured to open when the pressure inside the water storage tank 81 reaches a level higher than a second preset pressure threshold, thereby draining the temporarily stored water in the water storage tank 81 into the borehole 3.
[0022] In this embodiment, the data acquisition unit includes a pressure sensor 91 and a flow sensor 92 connected to the test section 6, and a data acquisition device 93 electrically connected to the pressure sensor 91 and the flow sensor 92. Specifically, in this embodiment, the pressure sensor 91 and the flow sensor 92 are installed on the ground control pipeline. The pressure sensor 91 is used to collect the air pressure data in the test section 6 during the high-pressure air compression test, and the flow sensor 92 is used to collect the gas flow rate during the high-pressure air compression test.
[0023] The method for conducting high-pressure air compression tests using the deep borehole high-pressure air compression test section drainage test device of this embodiment includes the following steps: S1. Equipment connection and lowering: Lower the drainage test device equipped with upper packer 51, lower packer 52, high pressure pipe and dynamic drainage unit into the borehole 3 to the predetermined test depth, and then hang the drill rod 1 near the ground on the ground through the tripod 2, thereby fixing the drill rod 1 in the borehole 3. S2, Test Section Sealing: Open the passage in the switching valve 4 that connects to the upper and lower packers, close the passage in the switching valve 4 that connects to the test section, and supply pressure to the cavity of the upper and lower packers through the high-pressure air pump so that the upper packer 51 and the lower packer 52 expand and seal in the borehole 3, thereby forming a sealed test section 6 between them. S3. Active Drainage Stage: Close the passage in the switching valve 4 that connects to the upper and lower packers, open the passage in the switching valve 4 that connects to the test section, start the high-pressure air pump 71, and slowly inject air and pressurize it into the test section 6 through the regulating valve 72. The gas enters the test section 6 through the passage in the switching valve 4 and the one-way air inlet valve 73. When the pressure in the test section 6 rises to the first preset pressure threshold of the drain valve 82, the drain valve 82 opens, and the water in the test section is discharged into the water storage tank 81 for temporary storage through the drain valve 82 and the water storage tank 83 under the drive of air pressure. Continue to supply pressure until the flow sensor 92 shows that the gas flow rate tends to be stable, indicating that the water in the test section 6 has been basically drained and the rock mass is in a "dry rock mass" state. S4. Compressed air test stage: Maintain or gradually increase the air pressure in the test section, record the pressure and flow rate changes in real time through the data acquisition device 93, conduct high-pressure compressed air test, and evaluate the air tightness of the rock mass under the air pressure; tests under multiple pressure levels can be performed. S5, Water tank drainage stage: After the air pressure test is completed, the high pressure air pump 71 continues to supply pressure to the test section 6 to increase the air pressure until the second preset pressure threshold is reached. At this time, the pressure limiting valve 85 opens under the action of pressure, and the water temporarily stored in the water tank 81 is discharged into the lower part of the borehole through the pressure limiting valve 84 under the drive of high pressure gas. S6. Depressurization and Unsealing: After confirming that the water tank 81 is emptied, slowly release the pressure in the test device, retract the upper and lower packers, and release the seal on the test section 6. S7: Repeat test or relocation: Raise or lower the drainage test device to the next test depth and repeat steps S2 to S6 to perform continuous stratification tests.
[0024] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the content of this specification should be included within the protection scope of the present invention.
Claims
1. A drainable high-pressure compressed air testing device suitable for deep borehole test sections, characterized in that, include: Drill rod, which is installed in the borehole; The in-hole packer unit includes an upper packer and a lower packer fitted on the drill pipe. The upper and lower packers are sealed in the borehole by air pressure, thereby forming a test section between them. The ground supply unit includes a high-pressure air pump and a ground control pipeline connected to the high-pressure air pump. The high-pressure air pump is used to fill the test section with high-pressure gas for drainage and airtightness tests. The high-pressure air pump also pressurizes the upper and lower packers to seal them in the borehole. The ground control pipeline is used for gas flow rate and direction control and to feed the gas into the drill pipe. A dynamic drainage unit is used to dynamically discharge high-pressure water in the test section according to the water pressure and air pressure. The dynamic drainage unit includes a water storage tank located at the bottom of the lower packer and connected to the test section, a drain valve located at the bottom of the test section and used to drain water from the test section, and a one-way air inlet valve located on the pipeline connecting the high-pressure air pump and the test section. The outlet of the drain valve is connected to the water storage tank. The data acquisition unit includes a pressure sensor and a flow sensor connected to the test section, as well as a data acquisition device electrically connected to the pressure sensor and the flow sensor. The pressure sensor is used to acquire the gas pressure data in the test section during the high-pressure gas compression test, and the flow sensor is used to acquire the gas flow rate during the high-pressure gas compression test.
2. The drainable high-pressure compressed air testing device suitable for deep borehole test sections according to claim 1, characterized in that, The end of the drill rod closest to the ground is fixed to the ground by a tripod, thus suspending the drill rod in the borehole.
3. The drainable high-pressure compressed air testing device suitable for deep borehole test sections according to claim 1, characterized in that, A switching valve is installed on the drill pipe. The switching valve includes two unconnected passages. One passage is connected to the upper and lower packers, and the other passage is connected to the test section.
4. The drainable high-pressure compressed air testing device suitable for deep borehole test sections according to claim 1, characterized in that, The drain valve is configured to open when the pressure in the test section reaches a first preset pressure threshold, so as to force the water accumulated in the test section into the water storage tank.
5. The drainable high-pressure compressed air testing device suitable for deep borehole test sections according to claim 1, characterized in that, The dynamic drainage unit also includes a pressure limiting valve located at the bottom of the water storage tank. The pressure limiting valve is configured to open when the pressure inside the water storage tank reaches a level higher than a second preset pressure threshold, so as to discharge the water temporarily stored in the water storage tank into the borehole.
6. The drainable high-pressure compressed air testing device suitable for deep borehole test sections according to claim 1, characterized in that, The dynamic drainage unit also includes a water outlet pipe, which passes through the lower packer and is connected at one end to the test section and at the other end to the water storage tank. A one-way vent valve is also provided at the end of the water outlet pipe located in the test section to release the gas in the water storage tank when the water is drained into the water storage tank.
7. The drainable high-pressure compressed air testing device suitable for deep borehole test sections according to claim 1, characterized in that, The drainage test device also includes a regulating valve, which is installed on the ground control pipeline to precisely control the gas pressure delivered in the drill pipe.
8. The drainable high-pressure compressed air testing device suitable for deep borehole test sections according to claim 1, characterized in that, The upper packer and the lower packer are connected by a connecting pipe, but neither of them is connected to the test section.
9. A method using the drainable high-pressure compressed air testing device suitable for deep borehole test sections as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Install the upper packer and lower packer on the drill pipe, and install a dynamic drainage unit between the upper and lower packers. Then lower the assembled drainage test device into the borehole to the predetermined test depth. S2. Start the high-pressure air pump to supply pressure to the upper and lower packers, so that the upper and lower packers expand and set in the borehole to form a sealed test section between them. S3. Stop pressurizing the upper and lower packers, and then inject air into the test section through the drill rod and one-way air inlet valve. When the pressure rises to the first preset pressure threshold, the drain valve opens, and the water in the test section is discharged into the water storage tank under the pressure drive. Continue to supply pressure until the flow sensor shows that the gas flow rate tends to be stable. S4. Maintain or gradually increase the air pressure in the test section, record the pressure and flow rate changes in real time through the data acquisition device, conduct a high-pressure air compression test, and evaluate the air tightness of the rock mass under the air pressure. S5. After the air pressure test is completed, continue to increase the air pressure to the second preset pressure threshold. At this time, the pressure relief valve opens, and the water temporarily stored in the water tank is discharged into the lower part of the borehole under the drive of high pressure gas. S6. After the water tank is emptied, the pressure in the drainage test device is released, the upper and lower packers are retracted, and the sealing of the test section is lifted. S7: Raise or lower the test drainage device to the next test depth, and repeat steps S2 to S6 to perform continuous stratification tests.