An electrical method for detecting while drilling based on an inflatable capsule type wall-adhering electrode

Abstract

The application discloses an electrical method drilling detection method based on an inflation capsule type wall electrode, and relates to the technical field of geophysical detection while drilling. The method presets a measurement point position and a measurement sequence before drilling. After drilling to the preset measurement point, the inflation capsule is pressurized, so that the patch electrode rises radially and tightly adheres to the hole wall. Before measurement, the electrode wall contact effect is judged based on signal stability. If the contact is poor, the pressure is adjusted and re-pressurized until the requirements are met. After the contact effect meets the requirements, the electrical method measurement is implemented according to the preset sequence, and the data stability is verified through repeated collection. After single measurement is completed, the capsule is depressurized and retracted, drilling to the next measurement point is continued, and the above process is repeated until the entire measurement task is completed. The application realizes continuous and collaborative operation of drilling and detection, and through adaptive judgment and adjustment of the contact state, the data collection reliability and detection accuracy under complex hole wall conditions are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of geophysical exploration while drilling technology, and in particular to an electrical exploration while drilling method based on an expanded capsule-type wall-attached electrode. Background Technology

[0002] In practical applications such as underground coal mine exploration, water-bearing anomaly identification, and water-bearing structure detection in the roof and floor, borehole electrical resistivity tomography (BOT) can utilize boreholes as near-field detection channels to investigate changes in the electrical properties of the formation within a certain range around the borehole. It has high spatial specificity and strong response capability to deep anomalies.

[0003] However, most existing borehole electrical resistivity tomography (BOT) methods still rely on post-drilling measurements, single deployment, and fixed-point testing. This means that the testing device or fixed electrode system is lowered into the borehole after drilling is complete. While this approach can accomplish certain borehole electrical resistivity measurement tasks, the testing process is usually separated from the drilling process, making it difficult to meet the needs of phased and continuous testing during drilling.

[0004] Furthermore, the working conditions in the borehole change dynamically during drilling, such as differences in borehole wall condition, borehole diameter, mud adhesion, and local disturbance at different measuring points. This leads to inconsistent contact states of the same set of wall-attached electrodes at different locations. Existing detection methods only perform borehole detection in isolation, failing to accurately grasp environmental changes and lacking optimized strategies for adjusting pressure, re-attaching, and reassessing before resuming formal measurements due to poor contact. Therefore, there is an urgent need for an electrical drilling detection method based on expandable capsule-type wall-attached electrodes to overcome the problems of existing technologies. Summary of the Invention

[0005] The purpose of this invention is to provide an electrical drilling detection method based on an expanded capsule-type wall-mounted electrode, which solves the problems of separation between drilling and detection, inability to adapt to dynamic changes in the borehole wall, and lack of proactive optimization strategies for contact effect in the prior art.

[0006] To achieve the above objectives, the present invention provides an electrical drilling detection method based on an expanded capsule-type wall-attached electrode, comprising the following steps: Step S1: Before drilling, determine the locations of multiple measuring points and the corresponding measurement sequences along the pre-set drilling route for the exploration mission. Step S2: The detection device with the expanded capsule-type wall-mounted electrode is lowered into the borehole along with the drilling system and drilled along the preset route; Step S3: After drilling to any preset measuring point position, pause drilling, pressurize the expansion capsule to expand it and drive the patch electrode to rise radially until it is tightly attached to the hole wall. Step S4: Before the formal measurement, the contact effect between the electrode and the hole wall is judged based on the signal stability. If the judgment result is poor contact, the capsule pressure is adjusted and the wall-attaching action is repeated until the contact effect meets the preset measurement requirements. Step S5: After the contact effect meets the requirements, perform electrical measurement according to the preset measurement sequence, and repeatedly collect the measurement data. The stability of the data is verified by calculating the coefficient of variation of the data. Step S6: After the measurement is completed at the current measuring point, control the expansion capsule to depressurize and retract, so that the electrode is separated from the hole wall; Step S7: Continue drilling to the next preset measuring point, and repeat steps S3 to S6 until the measurement task of all preset measuring points is completed.

[0007] Preferably, the preset parameters in step S1 also include: target pressure for capsule pressurization, pressure adjustment range, contact effect judgment threshold, observation mode, and number of repeated samplings.

[0008] Preferably, in step S4, the judgment of the wall-attaching contact effect based on signal stability specifically includes: S41. Calculate the contact resistance of the emitting electrode circuit, using the following expression: ; in, The detection current between the transmitting electrodes, The voltage between the transmitting electrodes. To calculate the obtained contact resistance; S42. Continuous detection of the same electrode combination Calculate the average contact resistance. and its contact resistance dispersion factor The expression is as follows: ; ; in, Indicates the first The contact resistance was measured once. express Average contact resistance of each test; express The coefficient of variation of contact resistance in the second test; S43, when the average contact resistance Within the preset valid range, and the coefficient of variation If the contact state of the electrode assembly is less than the preset threshold, it is determined that the contact state meets the measurement requirements.

[0009] Preferably, step S4, which involves judging the wall-attachment contact effect based on signal stability, further includes: Monitor the internal pressure of the capsule. When the capsule pressure reaches the target pressure range and the pressure fluctuation within the preset stabilization time does not exceed 2% to 5% of the target pressure, the capsule wall pressure is considered stable. If the pressure continues to drop or the pressure is too high but the contact resistance is still unstable, the contact effect is considered poor.

[0010] Preferably, step S4, adjusting the capsule pressure and re-performing the adhesion action, specifically includes: When the contact resistance is significantly higher than the preset upper limit, the system determines that there may be insufficient contact, local suspension, or mud blockage between the electrode and the hole wall. At this time, the capsule pressure value is increased or the stabilization time is extended to make the conductive electrode press the hole wall more tightly. When the contact resistance fluctuates significantly, the pressure fluctuates significantly, or the detection signal shows intermittent sudden changes, the system determines that there may be local slippage or pore wall breakage in the electrode's adhesion state. In this case, the capsule pressure is first reduced to below the initial pressure, and then the pressure is increased again according to the staged pressurization method to make the capsule and electrode re-adhere to the pore wall.

[0011] Preferably, the graded pressurization method includes three stages executed sequentially: an initial adhesion pressure stage for making initial contact between the capsule and the pore wall, a stable adhesion pressure stage for forming the adhesion state required for formal measurement, and a compensation pressure stage for locally enhanced adhesion when there is local irregularity in the pore wall.

[0012] Preferably, step S5 involves performing electrical measurements according to a preset measurement sequence, including: S51A. Based on the device structure and detection requirements, the excitation type is set to DC resistivity measurement or excitation polarization measurement. S52A, set the receiving type to axial high-density measurement or axial orientation measurement; S53A: The measurement point number, capsule number, electrode number, pressure status, and time information corresponding to each round of measurement are recorded synchronously.

[0013] Preferably, in step S5, the measurement data is repeatedly collected to verify the data stability, specifically as follows: Set the number of repeated collections For the electrical response parameters obtained from repeated sampling, calculate their average value. and the coefficients of variation of its electrical response parameters The formula is: ; ; in, Indicates the first Apparent resistivity data obtained from this measurement express Average apparent resistivity after one measurement; express apparent resistivity dispersion coefficient after the first measurement; when If the apparent resistivity data of the measurement point is less than the preset data stability threshold, it is determined that the data is stable and recorded.

[0014] Preferably, before step S7 is executed, it also includes determining whether the drilling has completed the preset route or reached the termination condition. The termination condition includes: reaching the preset final hole depth, completing all preset measurement points, reaching the target stratum endpoint, receiving a manual termination instruction, or encountering a working condition that is not suitable for continuing the operation.

[0015] Preferably, in step S4, if the wall contact effect still does not meet the measurement requirements after reaching the preset maximum number of adjustments, the measuring point is marked as an abnormal contact measuring point, and operations such as skipping the measuring point, reducing the data weight of the measuring point, activating the backup electrode combination, or prompting manual intervention are performed according to the preset strategy.

[0016] Therefore, the present invention employs the above-mentioned electrical drilling detection method based on an expanded capsule-type wall-attached electrode, which has the following beneficial effects: (1) The detection device is advanced as part of the drilling tool system and the measurement is completed during the drilling pause. This breaks the process barrier of traditional post-drilling measurement and significantly improves the detection efficiency and the timeliness of geological guidance.

[0017] (2) Before formal measurement, a dual judgment mechanism based on contact resistance and contact pressure is introduced, which can quantitatively assess the adhesion state between the electrode and the hole wall and effectively identify poor contact caused by mud skin, hole wall breakage, etc.

[0018] (3) For different causes of poor contact (such as insufficient contact or local slippage), the system can automatically implement differentiated adjustment strategies such as increasing pressure and staged pressurization until the measurement requirements are met, which greatly improves the detection success rate in complex drilling environments.

[0019] (4) By repeatedly collecting and calculating the discrete coefficients of electrical parameters, the data quality is quantitatively verified, effectively filtering out the influence of single accidental noise and instantaneous disturbances, and ensuring the reliability and repeatability of the measurement results.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 This is an overall flowchart of an electrical drilling detection method based on an expanded capsule-type wall-attached electrode according to the present invention. Figure 2This is a schematic diagram of the electrical drilling detection method based on an expanded capsule-type wall-mounted electrode according to an embodiment of the present invention. Detailed Implementation

[0022] The following detailed description of embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] Please see Figures 1-2 An electrical drilling detection method based on an expanded capsule-type wall-attached electrode includes the following steps: Step S1: Before drilling, the locations of multiple measuring points and corresponding measurement sequences on the pre-set drilling route are determined according to the exploration mission. The pre-set parameters also include: capsule pressurization target pressure, pressure adjustment range, contact effect judgment threshold, observation mode, and number of repeated acquisitions.

[0024] Step S2: The detection device with the expanding capsule-type wall-attached electrode is lowered into the borehole along the drilling system and drilled along the preset route; at this time, the capsule is in an unexpanded or retracted state, and the conductive electrode does not form formal measurement contact with the borehole wall.

[0025] Step S3: After drilling reaches any preset measuring point, pause drilling or allow the drill bit to enter a stable state suitable for measurement, creating conditions for subsequent capsule adhesion and electrical resistivity measurement. The system automatically records the current measuring point number, depth position, time information, and current drilling status. After reaching the preset measuring point, initiate the pressurization control process, inputting pressure medium into the expansion capsule to gradually expand it and unfold towards the borehole wall, thereby causing the conductive electrodes mounted on the capsule surface to adhere to the borehole wall. The capsule pressurization and unfolding process adopts staged pressure control. First, a lower pressure is used to initially bring the capsule into contact with the borehole wall. After contact with the borehole wall, the pressure continues to increase to achieve a stable adhesion state for the electrodes. Since multiple expansion capsules are set, a synchronous pressurization method is adopted to form the required measurement array of multiple capsule electrodes.

[0026] Step S4: After the capsule is pressurized and unfolded, the formal measurement is not started immediately. Instead, the contact effect between the electrode and the pore wall is judged based on the signal stability. If the judgment result is poor contact, the capsule pressure is adjusted and the wall-attaching action is repeated until the contact effect meets the preset measurement requirements. Among them, the judgment of the wall-attachment contact effect based on signal stability specifically includes: S41. Calculate the contact resistance of the emitting electrode circuit, using the following expression: ; in, The detection current between the transmitting electrodes, The voltage between the transmitting electrodes. To calculate the obtained contact resistance; S42. Continuous detection of the same electrode combination Calculate the average contact resistance. and its contact resistance dispersion factor The expression is as follows: ; ; in, Indicates the first The contact resistance was measured once. express Average contact resistance of each test; express The coefficient of variation of contact resistance in the second test; S43, when the average contact resistance Within the preset valid range, and the coefficient of variation When the contact resistance is less than the preset threshold, the electrode assembly is deemed to meet the measurement requirements. The preset effective range can be determined by calibration based on the borehole medium, mud resistivity, surrounding rock resistivity, and instrument output capability. In water-bearing or mud-bearing boreholes in coal mines, the effective contact resistance range can be set to 1. Within 5%, the coefficient of variation is set to within 5%.

[0027] Judging the adhesion effect based on signal stability also includes: monitoring the internal pressure of the capsule. When the capsule pressure reaches the target pressure range, and the pressure fluctuation within the preset stabilization time does not exceed 2% to 5% of the target pressure, the capsule adhesion pressure is considered stable. If the pressure continues to drop, it indicates that there may be capsule leakage, pore wall breakage leading to local instability, or insufficient adhesion. If the pressure is too high but the contact resistance is still unstable, it indicates that there may be mud on the pore wall, local suspension, or uneven contact on the electrode surface.

[0028] Adjust the capsule pressure and repeat the adhesion process, specifically including: When the contact resistance is significantly higher than the preset upper limit, the system determines that there may be insufficient contact, local suspension, or mud blockage between the electrode and the hole wall. At this time, the capsule pressure value is increased or the stabilization time is extended to make the conductive electrode press the hole wall more tightly. When contact resistance fluctuates significantly, pressure fluctuates significantly, or the detection signal shows intermittent abrupt changes, the system determines that the electrode's adhesion to the pore wall may be locally slipping or the pore wall may be broken. In this case, the capsule pressure is first reduced to below the initial pressure, and then the pressure is increased again according to the staged pressurization method to make the capsule and electrode re-adhere to the pore wall. After each pressure adjustment, the system re-collects the contact resistance and contact pressure and performs the adhesion contact determination again. If the contact requirements are still not met after reaching the preset maximum number of adjustments, the system marks the measurement point as a contact abnormality measurement point and selects to skip the measurement point, reduce the data weight of the measurement point, activate the backup electrode combination, or prompt manual intervention according to the preset strategy. The staged pressurization method includes three stages: initial adhesion pressure, stable adhesion pressure, and compensation pressure. The initial adhesion pressure is used to make the capsule initially contact the pore wall, the stable adhesion pressure is used to form the adhesion state required for formal measurement, and the compensation pressure is used to locally strengthen the adhesion when there is poor contact or local irregularity of the pore wall.

[0029] Step S5: After the contact effect meets the requirements, perform electrical measurement according to the preset measurement sequence. In order to avoid the influence of accidental noise, local contact disturbance or instantaneous changes in operating conditions on a single measurement, the measurement data is repeatedly collected after the formal measurement is completed, and the data stability is verified by calculating the coefficient of variation of the data. The electrical measurement, performed according to a preset measurement sequence, includes: S51A. Based on the device structure and detection requirements, the excitation type is set to DC resistivity measurement or excitation polarization measurement. S52A, set the receiving type to axial high-density measurement or axial orientation measurement; S53A: The measurement point number, capsule number, electrode number, pressure status, and time information corresponding to each round of measurement are recorded synchronously.

[0030] The measurement data was repeatedly collected to verify data stability, specifically as follows: Set the number of repeated collections The number of repeated samplings can be set according to the required detection accuracy, preferably 3 to 10 times. For the electrical response parameters obtained from repeated samplings, their average value is calculated. and the coefficients of variation of its electrical response parameters The formula is: ; ; in, Indicates the first Apparent resistivity data obtained from this measurement express Average apparent resistivity after one measurement; express apparent resistivity dispersion coefficient after the first measurement; when When the apparent resistivity of the measurement point is less than the preset data stability threshold, it is determined to be stable and recorded. The preset data stability threshold can be determined based on the instrument accuracy, the ambient noise level, and the requirements of the detection target. It is generally set to within 5%, but can be relaxed to 10% in environments with strong interference.

[0031] Step S6: After completing the measurement and repeated acquisition of the current measuring point, control the depressurization of the expansion capsule to restore it from the wall-attached expansion state to the retracted state, thereby reducing the contact interference between the device and the orifice wall and facilitating continued advancement.

[0032] Step S7: After completing the current measurement point, determine whether the borehole has completed the preset route or reached the termination condition. This includes determining whether the preset final borehole depth has been reached, whether all preset measurement points have been completed, whether the target formation endpoint has been reached, whether a manual termination command has been received, or whether any unsuitable conditions for continuing drilling or testing have occurred. If the result is "yes," the testing process ends; if the result is "no," drilling continues to the next measurement point.

[0033] Step S8: Continue drilling to the next preset measuring point, and repeat steps S3 to S6 until the measurement task of all preset measuring points is completed.

[0034] The above method is particularly suitable for drilling-while-drilling scenarios where drilling is not yet complete and it is necessary to simultaneously acquire electrical information of the formation around the borehole during drilling. Unlike traditional borehole electrical resistivity tomography (ERT), which typically involves lowering electrodes, cables, or detection devices after drilling is completed, the expandable capsule-type wall-attached electrode detection device in this invention enters the borehole synchronously with the drilling tool system. When drilling reaches a preset measurement point or near the target stratum, it utilizes the drilling pause or stable drilling conditions to complete electrode wall attachment, contact determination, electrical measurement, and data stability verification. After measurement, the capsule is depressurized and retracted, and the device continues to advance with the drilling tool to the next measurement point, thereby achieving phased, continuous, and multi-point ERT during the drilling process.

[0035] This invention can be used for identifying water-bearing anomalies during underground drilling in coal mines. Drilling proceeds from near the roadway or working face towards the target area, potentially traversing fault fracture zones, collapse column boundaries, water-rich fracture zones, mining-induced disturbance zones, or floor water-conducting channels, among other abnormal areas. Traditional post-drilling detection methods require removing the drilling tools after drilling is completed and then separately deploying the electrode system for testing. This not only separates the construction process but also makes it difficult to obtain timely information on anomalies ahead of or during drilling. The detection device of this invention is integrated into the drilling tool system and advanced during drilling. After reaching each preset depth, drilling is paused and the expansion capsule is deployed, allowing the patch electrode to press firmly against the borehole wall. Once the electrode contact state and signal stability are confirmed to meet requirements, resistivity measurements, induced polarization measurements, or combined electrical resistivity measurements are immediately performed to obtain the electrical response of the formation near the current borehole location.

[0036] In the scenario of identifying water-bearing anomalies during underground coal mine drilling, measurement results are used not only for post-drilling interpretation but also for real-time or just-in-time decision-making during drilling. When a significant low-resistivity anomaly, enhanced polarization anomaly, or abrupt change in response gradient occurs at a single measuring point or multiple consecutive measuring points, it can be determined that there is a water-bearing fractured zone or water-conducting structure ahead of or laterally of the borehole, thereby adjusting the subsequent drilling strategy. This can be achieved by reducing the spacing between measuring points near the anomaly section for more intensive detection or controlling the drilling speed, or by adjusting the borehole extension direction and final borehole position based on changes in the anomaly response.

[0037] Example This embodiment predicts the possible existence of a water-rich fracture zone in the borehole depth range of 150m to 250m. Specifically, the drilling route is designed, with the borehole advancing from the borehole opening towards the predicted anomaly area. The drilling route enters the target detection area according to the azimuth and dip angle determined by the geological design, and the total length of the borehole is designed to be no less than 250m. The preset measuring point spacing is 4m, with a total of 25 measuring points. The target pressure of the capsule is 1.2MPa, the pressure adjustment range is 0.8-1.8MPa, the maximum contact resistance is 1.0KΩ, the contact resistance dispersion coefficient threshold is 5%, the data stability threshold is 5%, and the number of repeated acquisitions is 5.

[0038] When the drill bit reaches the i-th preset measuring point at the hole depth, the system records the current hole depth, drilling parameters, and hole state. Drilling stops and enters the capsule deployment stage. The capsule-type expandable component is pressurized to raise the capsule pressure to 1.2 MPa to ensure that the conductive electrode units are attached to the hole wall. Then, the contact resistance between each conductive electrode unit and the hole wall is detected to ensure that the maximum contact resistance does not exceed 1.0 KΩ and the contact resistance dispersion coefficient does not exceed 5%. When the contact resistance meets the requirements, five electrical resistivity data acquisitions are performed at the current measuring point. If the apparent resistivity of the measuring point is stable after repeated acquisitions and the dispersion coefficient is less than 5%, the data at that point is saved as valid measuring point data. Then, the capsule is depressurized and it is determined whether to continue advancing or terminate until 25 measurements are completed.

[0039] Therefore, this invention employs an electrical resistive drilling (ORD) method based on an expandable capsule-type wall-attached electrode. By integrating the expandable capsule-type wall-attached electrode device into the drilling tool system, measurements can be performed during drilling pauses. Specifically, this includes: pre-setting measurement points and parameters, running the electrode downhole, and pressurizing the capsule upon reaching the measurement point to radially attach the electrode to the borehole wall. The key innovation lies in the introduction of a dual judgment mechanism based on contact resistance calculation and pressure stability before measurement. This mechanism can accurately assess the wall-attaching effect and automatically implement proactive adjustment strategies such as increasing pressure or staged pressurization for poor contact (e.g., high mud skin, borehole wall instability). After successful contact, measurements are taken according to a preset sequence and data acquisition is repeated. Data stability is verified by calculating the coefficient of variation of electrical parameters. Once measurement is complete, the pressure is released and the electrode retracts, and drilling continues. This method achieves drilling-measurement coordination, adaptive contact optimization, and quantitative control of data quality, significantly improving the reliability and success rate of ORD under complex borehole conditions. It is particularly suitable for advanced detection of targets such as water-bearing structures in coal mines.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for electrical drilling detection based on an expandable capsule-type wall-attached electrode, characterized in that, Includes the following steps: Step S1: Before drilling, determine the locations of multiple measuring points and the corresponding measurement sequences along the pre-set drilling route for the exploration mission. Step S2: The detection device with the expanded capsule-type wall-mounted electrode is lowered into the borehole along with the drilling system and drilled along the preset route; Step S3: After drilling to any preset measuring point position, pause drilling, pressurize the expansion capsule to expand it and drive the patch electrode to rise radially until it is tightly attached to the hole wall. Step S4: Before the formal measurement, the contact effect between the electrode and the hole wall is judged based on the signal stability. If the judgment result is poor contact, the capsule pressure is adjusted and the wall-attaching action is repeated until the contact effect meets the preset measurement requirements. Step S5: After the contact effect meets the requirements, perform electrical measurement according to the preset measurement sequence, and repeatedly collect the measurement data. The stability of the data is verified by calculating the coefficient of variation of the data. Step S6: After the measurement is completed at the current measuring point, control the expansion capsule to depressurize and retract, so that the electrode is separated from the hole wall; Step S7: Continue drilling to the next preset measuring point, and repeat steps S3 to S6 until the measurement task of all preset measuring points is completed.

2. The electrical drilling detection method based on an expandable capsule-type wall-attached electrode according to claim 1, characterized in that, The preset parameters in step S1 also include: target pressure for capsule pressurization, pressure adjustment range, contact effect judgment threshold, observation mode, and number of repeated samplings.

3. The electrical drilling detection method based on an expandable capsule-type wall-attached electrode according to claim 2, characterized in that, Step S4 involves judging the wall-attaching contact effect based on signal stability, specifically including: S41. Calculate the contact resistance of the emitting electrode circuit, using the following expression: ； in, The detection current between the transmitting electrodes, The voltage between the transmitting electrodes. To calculate the obtained contact resistance; S42. Continuous detection of the same electrode combination Calculate the average contact resistance. and its contact resistance dispersion factor The expression is as follows: ； ； in, Indicates the first The contact resistance was measured once. express Average contact resistance of each test; express The coefficient of variation of the sub-detection; S43, when the average contact resistance Within the preset valid range, and the coefficient of variation If the contact state of the electrode assembly is less than the preset threshold, it is determined that the contact state meets the measurement requirements.

4. The electrical drilling detection method based on an expandable capsule-type wall-attached electrode according to claim 3, characterized in that, Step S4, which judges the wall-attachment contact effect based on signal stability, also includes: Monitor the internal pressure of the capsule. When the capsule pressure reaches the target pressure range and the pressure fluctuation within the preset stabilization time does not exceed 2% to 5% of the target pressure, the capsule wall pressure is considered stable. If the pressure continues to drop or the pressure is too high but the contact resistance is still unstable, the contact effect is considered poor.

5. The electrical drilling detection method based on an expanded capsule-type wall-attached electrode according to claim 4, characterized in that: Step S4 involves adjusting the capsule pressure and re-performing the adhesion action, specifically including: When the contact resistance is significantly higher than the preset upper limit, the system determines that there is insufficient contact between the electrode and the hole wall, local suspension, or mud blockage. At this time, the capsule pressure value is increased or the stabilization time is extended to make the conductive electrode press the hole wall more tightly. When the contact resistance fluctuates significantly, the pressure fluctuates significantly, or the detection signal shows intermittent sudden changes, the system determines that there is local slippage or pore wall breakage in the electrode's adhesion state. At this time, the capsule pressure is first reduced to below the initial pressure, and then the pressure is increased again according to the staged pressurization method to make the capsule and electrode re-adhere to the pore wall.

6. The electrical drilling detection method based on an expandable capsule-type wall-attached electrode according to claim 5, characterized in that, The graded pressurization method includes three stages executed sequentially: an initial adhesion pressure stage to bring the capsule into initial contact with the pore wall, a stable adhesion pressure stage to form the adhesion state required for formal measurement, and a compensation pressure stage to locally enhance adhesion when there is local irregularity in the pore wall.

7. The electrical drilling detection method based on an expanding capsule-type wall-attached electrode according to claim 6, characterized in that, Step S5 involves performing electrical measurements according to a preset measurement sequence, including: S51A. Based on the device structure and detection requirements, the excitation type is set to DC resistivity measurement or excitation polarization measurement. S52A, set the receiving type to axial high-density measurement or axial orientation measurement; S53A: The measurement point number, capsule number, electrode number, pressure status, and time information corresponding to each round of measurement are recorded synchronously.

8. The electrical drilling detection method based on an expandable capsule-type wall-attached electrode according to claim 7, characterized in that, Step S5 involves repeatedly collecting measurement data to verify data stability, specifically as follows: Set the number of repeated collections For the electrical response parameters obtained from repeated sampling, calculate their average value. and the coefficient of variation of the electrical response parameters The formula is: ； ； in, Indicates the first Apparent resistivity data obtained from this measurement express Average apparent resistivity after one measurement; express apparent resistivity dispersion coefficient after the first measurement; when If the apparent resistivity data of the measurement point is less than the preset data stability threshold, the data is determined to be stable and recorded.

9. The electrical drilling detection method based on an expanded capsule-type wall-attached electrode according to claim 8, characterized in that: Before execution, step S7 also includes determining whether the borehole has completed the preset route or reached the termination condition. The termination conditions include: reaching the preset final borehole depth, completing all preset measurement points, reaching the target formation endpoint, receiving a manual termination instruction, or encountering a working condition that is not suitable for continuing the operation.

10. The electrical drilling detection method based on an expanded capsule-type wall-attached electrode according to claim 9, characterized in that: In step S4, if the wall contact effect still does not meet the measurement requirements after reaching the preset maximum number of adjustments, the measuring point is marked as an abnormal contact measuring point, and operations such as skipping the measuring point, reducing the data weight of the measuring point, activating the backup electrode combination, or prompting manual intervention are performed according to the preset strategy.

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