Direct measurement type test method and device for water pressure in drill hole

Abstract

The invention discloses a direct measurement type test method and device for water pressure in a drill hole, a pressure sensor and a flow sensor are installed in a test section in the drill hole, the test pressure in the test section and the seepage flow under the pressure are directly measured, and measurement data are automatically calculated and analyzed to form a test result. Personal errors caused by manual reading errors, pipeline flow loss calculation, pressure correction and the like are avoided, the accuracy and reliability of test results and the working efficiency are effectively improved, and the working cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of hydropower and water conservancy engineering, and in particular, it is a direct-measurement borehole pressure test method and device, which is mainly used for on-site pressure test and data analysis in wireline coring boreholes in hydropower engineering, water conservancy engineering and other engineering exploration. Background Technology

[0002] Water pressure testing is an indispensable routine in-situ testing method in hydropower and water conservancy engineering surveys. It is used to determine the permeability of rock masses and provide basic data for evaluating the permeability characteristics of rock masses and designing seepage control measures.

[0003] The in-situ borehole pressure water test device consists of a water stop plug, a water supply system, and a measurement system. Traditional pressure water tests rely on manual observation and recording of test pressure and flow rate using mechanical pressure gauges and flow meters installed on the ground surface. The test results are then calculated and analyzed manually, which is not only time-consuming, inefficient, and costly, but also prone to significant errors. Summary of the Invention

[0004] The purpose of this invention is to provide a direct-measurement borehole water pressure test method and apparatus, in which a pressure sensor is installed at the midpoint of the test section inside the borehole and a flow sensor is installed at the lower part of the upper plug to directly measure the test pressure of the test section and the seepage flow rate under that pressure, effectively improving the accuracy and reliability of the test results and the work efficiency, thereby solving the aforementioned problems existing in the prior art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a direct-measurement borehole water pressure test method, wherein a pressure sensor is installed at the midpoint of the test section inside the borehole, and a flow sensor is installed at the lower part of the upper plug to directly measure the test pressure of the test section and the seepage flow rate under the pressure. The test data is transmitted to the ground control equipment set on the ground for data processing via a signal transmission cable.

[0006] Furthermore, the ground control equipment includes display, touch operation buttons, data storage and upload functions, automatically calculates the rock permeability and permeability coefficient of the test section, plots the P-Q curve and determines the curve type, automatically generates a pressure test result report and uploads it in real time.

[0007] Furthermore, a pressure sensor was installed at the midpoint of the test section inside the borehole. Before the test, the water level elevation inside the borehole was calculated by converting the pressure value and the atmospheric pressure elevation at the measuring point. After water was injected into the borehole, the pressure values ​​at each stage of the test section were measured according to the specifications, and the measurement data were collected through ground control equipment.

[0008] Furthermore, the ground control equipment measures the test pressure and seepage flow rate Q under the pressure specified in the standard, calculates the rock permeability and permeability coefficient of the test section, and plots...P-Q The system generates a curve, determines the curve type, produces a pressure test results report, and uploads it in real time.

[0009] Furthermore, the pressure sensor is installed in the middle of the water pressure test probe, located 2.5m below the midpoint of the upper plug.

[0010] A direct-measurement borehole water pressure testing device, employing the aforementioned direct-measurement borehole water pressure testing method, includes the following components: Ground control equipment is used to control the test process, signal transmission and data analysis of the borehole pressure water test. It includes display, touch operation buttons, data storage and upload functions, automatic calculation of rock permeability and permeability coefficient of the test section, plotting P-Q curve and determining the curve type, automatic generation of pressure test result report and real-time upload to relevant professionals. A flow sensor, installed at the lower part of the upper plug, is used to measure the flow rate of seepage water entering the test section at a certain pressure, and the measurement data is collected through ground control equipment; The pressure sensor is installed at the midpoint of the test section inside the borehole. When the water pressure test probe is lowered to the measurement position, it measures the atmospheric pressure value at the midpoint of the test section inside the borehole, thereby calculating the elevation of the groundwater level inside the borehole. After water is injected into the borehole, the pressure value at each stage in the test section is measured according to the specifications, and the measurement data is collected through ground control equipment.

[0011] The beneficial effects of this invention are as follows: This invention is based on installing pressure and flow sensors in the test section inside the borehole, directly measuring the test pressure and the seepage flow rate under that pressure in the test section, and automatically calculating and analyzing the measurement data to form test results. It avoids the counting errors of ground-based mechanical pressure gauges, eliminates the need to calculate the water column pressure and pipeline pressure and seepage loss between the pressure gauge's midpoint and the zero line, effectively improving the accuracy and reliability of test results and work efficiency, while reducing operating costs. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the direct-measurement borehole internal pressure water test device of the present invention.

[0013] Figure 2 The pressure flow rate using the method of this invention ( P-Q (Graphic showing curve types and characteristics)

[0014] Figure 3 This is an embodiment of the present invention. P-Q curve. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0016] In the description of this invention, it should be noted that the terms "upper", "middle", "lower", "inner", "outer", "both sides", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the purpose of simplifying the description of this invention 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. Therefore, they should not be construed as limiting this invention.

[0017] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0018] like Figure 1 As shown, the direct-measurement borehole water pressure test method of the present invention involves installing a pressure sensor 1 at the midpoint of the test section inside the borehole and a flow sensor 3 at the lower part of the upper plug 2 to directly measure the test pressure of the test section and the seepage flow rate under that pressure. The test data is then transmitted to the ground control equipment 5 located on the ground for data processing via a signal transmission cable 4.

[0019] Furthermore, the ground control equipment 5 includes display, touch operation buttons, data storage and upload functions, automatically calculates the rock permeability and permeability coefficient of the test section, plots the P-Q curve and determines the curve type, automatically generates a pressure test result report and uploads it to relevant professionals in real time.

[0020] Furthermore, a pressure sensor was installed at the midpoint of the test section inside the borehole. Before the test, the water level elevation inside the borehole was calculated by converting the pressure value and the atmospheric pressure elevation at the measuring point. After water was injected into the borehole, the pressure values ​​at each stage of the test section were measured according to the specifications, and the measurement data were collected through ground control equipment.

[0021] Furthermore, the ground control equipment 5 measures the test pressure and seepage flow rate Q under the pressure specified in the standard, calculates the rock permeability and permeability coefficient of the test section, and plots... P-Q The system generates a curve, determines the curve type, produces a pressure test results report, and uploads it to relevant professionals in real time.

[0022] Furthermore, the pressure sensor 3 is installed in the middle of the water pressure test probe 6, located 2.5m below the midpoint of the upper plug.

[0023] A direct-measurement borehole water pressure testing device, employing the aforementioned direct-measurement borehole water pressure testing method, includes the following components: Ground control equipment 5 is used to control the test process, signal transmission and data analysis of the borehole pressure water test. It includes display, touch operation buttons, data storage and upload functions, automatic calculation of rock permeability and permeability coefficient of the test section, plotting P-Q curve and determining the curve type, automatic generation of pressure test result report and real-time upload to relevant professionals. Flow sensor 3 is installed at the lower part of the upper plug to measure the flow rate of seepage water entering the test section at a certain pressure, and the measurement data is collected through ground control equipment; Pressure sensor 1 is installed at the midpoint of the test section inside the borehole. When the water pressure test probe is lowered to the measurement position, it measures the atmospheric pressure value at the midpoint of the test section inside the borehole, thereby calculating the elevation of the groundwater level inside the borehole. After water is injected into the borehole, the pressure value of each stage in the test section is measured according to the specifications, and the measurement data is collected through ground control equipment.

[0024] Specifically, a pressure sensor is installed at the midpoint of the test section inside the borehole. Before the test, the water level elevation inside the borehole is calculated by converting the pressure value and the atmospheric pressure (elevation) at the measuring point. Measuring and recording the test pressure at the midpoint of the test section avoids the counting error of surface mechanical pressure gauges and eliminates the need to calculate the water column pressure between the midpoint of the pressure gauge and the zero line, as well as pipeline pressure losses. The measured and recorded pressure value is the test pressure. The flow rate at a specific test pressure is measured at the lower part of the upper plug, avoiding the counting error of surface flow meters and pipeline seepage losses. The measured and recorded seepage flow rate is the actual seepage flow rate at a specific test pressure within the test section.

[0025] Ground control and data analysis involve measuring the test pressure and seepage flow rate under the pressure specified in the "Specification for Borehole Pressure Water Test in Hydropower Engineering" (NB / T35113-2018), automatically calculating the rock permeability (formula ①) and permeability coefficient (formula ②) of the test section, and plotting... P-Q Curve and determine curve type (see curve) Figure 2 The system automatically generates pressure test results reports and uploads them to relevant professionals in real time, ensuring that the test results are reliable, authentic, and unmodifiable.

[0026] ① In the formula: To test the permeability of the section, The pressure at the maximum pressure stage of the test section. for Permeation flow rate of the test section under pressure This is the length of the test segment.

[0027] ② In the formula: This is the rock mass permeability coefficient, calculated when the test section is below the groundwater level; To push in the flow rate, according to P-Q The curve type should be selected according to the specifications. To test the water head; The length of the test segment; Where is the borehole radius.

[0028] This invention is based on installing pressure and flow sensors in the test section inside the borehole to directly measure the test pressure and the permeation flow rate under that pressure in the test section, and automatically calculates and analyzes the measurement data to form test results.

[0029] The ground control equipment (ground control and data analysis) is a system used to control the borehole pressure water test process, signal transmission, and data analysis. It includes functions such as display, touch operation buttons, data storage and uploading, and automatically calculates the rock permeability and permeability coefficient of the test section, and plots... P-Q The system calculates and determines the curve type, automatically generates a pressure test results report, and uploads it to relevant professionals in real time. This is standard practice in this field, as exemplified by the use of Lugeotest borehole pressure water testing equipment manufactured by Beijing Oumeidadi Company.

[0030] A flow sensor, installed at the lower part of the (upper) plug, is used to measure the flow rate of permeable water entering the test section at a certain pressure, and the measurement data is collected through ground control equipment.

[0031] The pressure sensor is installed at the midpoint of the water pressure test probe 6 (test section), typically 2.5m below the midpoint of the (upper) plug, and can be adjusted according to the test section length requirements. When the water pressure test probe is lowered to the measurement position (before water injection), the pressure value at the midpoint of the test section inside the borehole is measured. When the water level in the borehole is at or above the midpoint of the test section during the test, the elevation of the groundwater level in the borehole is calculated using formula ③. After water injection into the borehole begins, the pressure values ​​at each stage within the test section are measured according to the specifications, and the measurement data is collected through ground control equipment.

[0032] ( )③ In the formula: This refers to the water level elevation inside the borehole. The ground elevation at the borehole opening; The pressure value before the water pressure test at the midpoint of the test section; The atmospheric pressure value above the ground surface at the borehole or the water level inside the borehole; This represents the density of the fluid inside the borehole. , These represent the starting and ending depths of the test section, respectively.

[0033] This invention installs pressure and flow sensors in the test section inside the borehole to directly measure the test pressure and the permeation flow rate at that pressure, and automatically calculates and analyzes the measurement data to form test results. This avoids human errors caused by manual reading errors, pipeline flow loss calculations, and pressure corrections, effectively improving the accuracy and reliability of test results, increasing work efficiency, and reducing operating costs.

[0034] Examples of field comparative tests: To verify the accuracy and reliability of this invention, a 30-35m conventional pressure test section (5m long) of borehole ZK106 at the lower dam site of a pumped storage power station was selected for comparative testing. To facilitate better comparison, when using traditional equipment (i.e., installing pressure gauges and flow meters on the surface inlet pipe, manually reading each pressure value and corresponding flow value, and then performing calculations and plotting curves), the test pipeline underwent rigorous sealing and inspection to ensure that pipeline pressure and flow losses were negligible, i.e., zero pressure and flow losses. Only the pressure gauge readings and the pressure value from the center of the pressure gauge to the zero line were calculated.

[0035] The ground elevation of borehole ZK106 is 516.32m; the atmospheric pressure at the borehole opening is 1.013 kPa; the water level inside the borehole during the test is 23.7m (manual measurement), which is above the test section, and the calculated zero line is 23.7m; the center of the pressure gauge is 0.6m from the ground, and the pressure value from the center of the pressure gauge to the calculated zero line is 0.243 MPa.

[0036] According to the "Specification for Borehole Pressure Water Test in Hydropower Engineering" (NB / T35113-2018), this comparative test adopted three pressure levels of 0.3MPa, 0.6MPa, and 1.0MPa and five stages (i.e., three pressurization stages and two depressurization stages) to conduct a conventional pressure water test (clear water). The time interval between each test pressure stage was 7 minutes.

[0037] Before drilling and injecting water, the device of this invention was lowered into the test section, and the water level pressure inside the hole was measured to be 1.0221 MPa. According to formula ③, the water level elevation inside the hole during the test was calculated to be 492.62 m (depth of 23.7 m), which is consistent with the value measured manually.

[0038] When using traditional equipment for testing, the test results are as follows:

[0039] The permeability of the 30-35m test section of borehole ZK106, calculated according to formula ③, is: (Lu), with a permeability coefficient of: =0.319. P-Q The curve is laminar (Type A), such as Figure 3 .

[0040] The test results using the device of the present invention are as follows:

[0041] The permeability of the 30-35m test section of borehole ZK106, calculated according to formula ③, is: (Lu), with a permeability coefficient of: =0.318. P-Q The curve is laminar (Type A), such as Figure 3 .

[0042] The comparative test results above show that the test results of the device of the present invention are consistent with those of the traditional device. However, the device of the present invention has more precise test pressure control, and the pressure and flow values ​​are directly measured values ​​of the test section, which are more accurate than manual readings, without the need for calculation or consideration of pipeline pressure and flow loss.

[0043] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A direct-measurement borehole water pressure test method, characterized in that, A pressure sensor (1) is installed at the midpoint of the test section inside the borehole, and a flow sensor (3) is installed at the bottom of the upper plug (2). The test pressure and the permeation flow rate under the pressure are directly measured. The test data are transmitted to the ground control equipment (5) set on the ground through the signal transmission cable (4) for data processing.

2. The direct-measurement borehole water pressure test method according to claim 1, characterized in that, The ground control equipment (5) includes display, touch operation buttons, data storage and upload functions, automatically calculates the rock permeability and permeability coefficient of the test section, draws the P-Q curve and determines the curve type, automatically generates a pressure test result report and uploads it in real time.

3. The direct-measurement borehole water pressure test method according to claim 2, characterized in that, A pressure sensor is installed at the midpoint of the test section inside the borehole. Before the test, the water level elevation inside the borehole is calculated by converting the pressure value and the atmospheric pressure value at the measuring point. After water is injected into the borehole, the pressure value at each stage in the test section is measured according to the specifications, and the measurement data is collected through ground control equipment.

4. The direct-measurement borehole water pressure test method according to claim 3, characterized in that, The ground control equipment (5) measures the test pressure and seepage flow rate Q under the pressure specified in the standard, calculates the rock permeability and permeability coefficient of the test section, and plots... P-Q The system generates a curve, determines the curve type, produces a pressure test results report, and uploads it in real time.

5. The direct-measurement borehole water pressure test method according to claim 1, characterized in that, The pressure sensor (3) is installed in the middle of the water pressure test probe (6), located 2.5m below the midpoint of the upper plug.

6. A direct-measurement borehole water pressure testing device, employing the direct-measurement borehole water pressure testing method according to any one of claims 1-5, characterized in that, Includes the following components: Ground control equipment is used to control the test process, signal transmission and data analysis of the borehole pressure water test. It includes display, touch operation buttons, data storage and upload functions, automatic calculation of rock permeability and permeability coefficient of the test section, plotting P-Q curve and determining the curve type, automatic generation of pressure test result report and real-time upload to relevant professionals. A flow sensor, installed at the lower part of the upper plug, is used to measure the flow rate of seepage water entering the test section at a certain pressure, and the measurement data is collected through ground control equipment; The pressure sensor is installed at the midpoint of the test section inside the borehole. When the water pressure test probe is lowered to the measurement position, it measures the atmospheric pressure value at the midpoint of the test section inside the borehole, thereby calculating the elevation of the groundwater level inside the borehole. After water is injected into the borehole, the pressure value at each stage in the test section is measured according to the specifications, and the measurement data is collected through ground control equipment.

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