Water exploration and drainage drilling operation parameter real-time optimization and safety constraint control method

Abstract

The invention relates to a real-time optimization and safety constraint control method for water exploration and drainage drilling operation parameters. The real-time optimization and safety constraint control method comprises the steps that bit pressure, torque, rotating speed, footage speed and water parameters including in-hole backwater flow or in-hole water pressure are collected in real time; in the continuous sampling window, when the water parameter is monotonically increased or monotonically decreased and the change amplitude exceeds a first threshold value, it is judged that the water content approaching to-be-confirmed state is entered; a perturbation detection action is inserted in the to-be-confirmed state; judging in a recovery window after the action is finished: if the water parameter returns to the reference interval, determining that the risk is reduced, and if the water parameter does not return to the reference interval or continuously monotonically changes and the change amplitude exceeds a second threshold value, determining that the risk is increased; when the risk rises, a safety constraint control state is started, and at least one of the bit pressure set value, the rotating speed and the footage speed is limited to be up-regulated or down-regulated; and when the risk is reduced, exiting the to-be-confirmed state and allowing updating according to a preset up-regulation step length.

Description

Technical Field

[0001] This invention relates to the field of mining engineering technology, specifically a method for real-time optimization and safety constraint control of drilling operation parameters for water exploration and drainage. Background Technology

[0002] Based on the existing patent document CN114016912A, it can be seen that the core of this technical solution lies in adding a detection sub to the drill string assembly and using a quick-connect connector to switch the circuit polarity by reverse connection. It determines whether water accumulation exists at the detection sub by monitoring whether the circuit current is conducting. Essentially, it is a drilling water level detection device and method based on the principle of circuit continuity. While structurally this solution does achieve the function of determining the presence of water accumulation in the borehole without lifting the drill string, it still has significant shortcomings and limitations from the perspective of real-time optimization of drilling operation parameters and safety constraint control. Firstly, the core issue this solution focuses on is the presence and location of water accumulation. Its technical purpose is water level detection, but it does not involve the dynamic adjustment and optimization control of drilling operation parameters. It lacks a real-time control mechanism for key construction parameters such as drill pressure, rotation speed, and drilling speed, and cannot proactively intervene in construction behavior during the identification of risk trends. Therefore, it cannot achieve true real-time optimization and safety closed-loop control.

[0003] Secondly, this method's logic for identifying water hazard risks is based on a binary judgment of whether the circuit is conducting or not, which is a discrete state discrimination. It can only determine whether the probe section is connected by water accumulation, but cannot identify the gradual hydraulic response changes during the approach of the water-bearing body, nor can it continuously analyze the trends of water pressure fluctuations and return flow changes in the borehole. It lacks a trend judgment mechanism and cannot provide early warning in the early stage of water inrush. Thirdly, this technology requires manual reversal of the quick-connect fitting to enter the water level detection state. Its detection behavior is a manual trigger operation and cannot operate continuously and automatically during drilling. It is difficult to form a continuous monitoring and dynamic response system. When changes in drilling parameters cause abnormalities in the hydraulic environment, the device cannot automatically adjust the construction parameters, resulting in a risk of response lag. Furthermore, this scheme relies on current on / off and stable connection states for water level determination. When the conductivity of the drilling mud changes, contact points become contaminated, or the local conductive environment becomes abnormal, misjudgments or missed judgments may occur. It lacks multi-parameter cross-validation and error suppression mechanisms, and it has not established stability determination structures such as benchmark intervals, recovery windows, and continuous sampling counting, resulting in limited anti-interference capabilities. From a safety control perspective, this technology does not set up safety constraint control states, latching control states, or graded suppression and adjustment mechanisms. When water accumulation is confirmed, it does not provide corresponding drilling pressure, rotation speed, or advance speed adjustment strategies, nor does it establish direction-priority adjustment or parameter gradual reduction logic. Therefore, it cannot avoid the risk of secondary disturbance caused by continuing to advance at the original construction intensity in high-risk areas.

[0004] Furthermore, while the structural design of this scheme is centered on the circuit structure and involves minimal modifications to the existing drilling tools, it remains a hardware-based functional extension solution. It lacks real-time optimization algorithms or control strategies at the software level, and adjustments to construction parameters still rely on manual experience, resulting in limited intelligence. In summary, while existing water level detection devices and methods based on the principle of drilling circuit continuity have solved the problem of difficult drilling detection, they exhibit significant shortcomings in risk pre-identification, continuous trend analysis, automated linkage parameter adjustment, and safety constraint closed-loop control capabilities. These deficiencies make it difficult to meet the requirements of real-time optimization and coordinated safety constraint control in water exploration and drainage drilling operations. Summary of the Invention

[0005] The purpose of this invention is to provide a method for real-time optimization and safety constraint control of drilling parameters for water exploration and drainage operations, thereby solving some of the drawbacks and shortcomings pointed out in the background art.

[0006] The present invention addresses the aforementioned technical problems by employing the following technical solution: a method for real-time optimization and safety constraint control of drilling parameters for water exploration and drainage, comprising: real-time acquisition of drilling pressure, torque, rotational speed, drilling speed, and borehole return water flow rate or borehole water pressure, wherein the borehole return water flow rate or borehole water pressure are water parameters; within a continuous sampling window, when the water parameter monotonically increases or monotonically decreases and the change amplitude exceeds a first threshold, it is determined to enter a state of near-water content awaiting confirmation, wherein the change amplitude is the absolute value of the difference between the maximum and minimum values ​​within the window or the difference between the first and last values ​​of the window;

[0007] In the pending confirmation state, a perturbation detection action is inserted. The action is selected from one of the following: reducing the drilling pressure setting value, reducing the rotation speed, stopping and maintaining rotation before resuming propulsion, and stopping and resuming rotation. After the action is completed, a judgment is made in the recovery window: if the water parameters return to the reference range, the risk is confirmed to have decreased; if they do not return to the reference range or continue to change monotonically and the change exceeds the second threshold, the risk is confirmed to have increased. The reference range is taken from the range of water parameter values ​​in the reference window before the perturbation detection action.

[0008] When the risk increases, the system enters a safety constraint control state, restricting at least one of the following: drilling pressure setting, rotation speed, and feed rate, from being increased or decreased; when the risk decreases, the system exits the pending confirmation state and allows updates according to preset increments.

[0009] Furthermore, the continuous sampling window includes a short window and a long window; when the water parameter satisfies monotonic change within the short window and the change amplitude exceeds the first threshold, it enters the pre-judgment state, and only when the condition is met again within the long window is it determined to enter the near water content confirmation state; otherwise, it exits the pre-judgment state and maintains the operating parameters.

[0010] Furthermore, the determination of returning to the reference interval is that multiple consecutive samples within the recovery window fall into the reference interval; if the water parameter does not return to the reference interval, risk suppression adjustment is performed according to the monotonic change direction of the water parameter: if the water parameter increases monotonically, at least one of the drilling pressure setting value or the rotation speed is reduced; if the water parameter decreases monotonically, at least the advance speed is reduced or the advance is stopped and kept rotating before resuming advance.

[0011] Furthermore, once the risk is confirmed to be elevated, the system enters a latching control state. During the latching period, the drilling pressure setting, rotation speed, and feed rate are prohibited from being increased and are instead reduced in stages according to a preset reduction step size. When the water parameters return to the baseline range within at least two consecutive recovery windows and the change is less than the third threshold, the latching is released. After release, the system is allowed to update according to a preset increase step size.

[0012] Furthermore, the reference interval is determined by the upper and lower quantile values ​​of the water parameter within the reference window and remains unchanged during the perturbation detection operation; when any sample within the recovery window exceeds the reference interval, the counting of the consecutive multiple samples restarts.

[0013] Furthermore, the adjustment is performed in stages, first gently and then forcefully: first, the rotational speed or drilling pressure setting is reduced by a preset step size; if the speed and drilling pressure setting are not returned to the reference range in the next recovery window, both the rotational speed and drilling pressure setting are reduced simultaneously; if the speed and drilling pressure are still not returned to the reference range, the rotation is stopped and then resumed.

[0014] Furthermore, when the water parameter increases monotonically and does not return to the reference range, the drilling pressure setting value is reduced first; when the water parameter decreases monotonically and does not return to the reference range, the advance speed is reduced first; and when the water parameter fails to return to the reference range a predetermined number of times in the same monotonous direction, the advance is stopped, the rotation is maintained, and then the advance is resumed as the adjustment.

[0015] Furthermore, the rotation is maintained for a preset duration without changing the speed setting value; if the water parameters do not return to the reference range within the recovery window after the preset duration ends, the speed is reduced by a preset step size in the next cycle and the stop-and-keep rotation is repeated before resuming propulsion.

[0016] Furthermore, the preset duration is divided into at least two sub-periods. In the first sub-period, the rotation is maintained while the vehicle stops. In the second sub-period, the water parameters are sampled and judged while the vehicle stops and rotates. If the water parameters show a regression trend in the second sub-period, the vehicle stops and resumes driving. The regression trend is that the deviation of the water parameters from the reference interval decreases continuously.

[0017] Furthermore, the number of times the rotational speed is reduced by a preset step size is set to a preset upper limit K, and the number of reductions is the cumulative number within the same latching control state cycle; when the number of reductions reaches K and the water parameter has not yet returned to the reference range, the rotational speed is kept from being reduced further and the drilling pressure setting value is reduced by a preset step size, and then the stop-and-keep-rotation process is repeated before resuming propulsion, where K is a preset positive integer determined by the drilling operation safety level or drilling stage.

[0018] The beneficial effects of this invention are as follows: By constructing a continuous sampling window monotonicity determination mechanism and a dual-window prediction mechanism, this invention achieves pre-identification of abnormal trends in water parameters. It enters a near-water-bearing confirmation state before significant water outflow or sudden water inrush, and actively verifies risks through perturbation detection. Combining baseline interval regression determination, quantile value determination methods, and a continuous sampling count reset mechanism, it effectively reduces the impact of occasional fluctuations and noise interference on the determination results, improving the accuracy and stability of risk identification. Compared to traditional methods relying on fixed threshold alarms, this invention can distinguish between recoverable fluctuations and continuously reinforcing risks, avoiding false shutdowns or misjudgments, and enhancing the reliability of water exploration and release operations.

[0019] Upon confirming an increased risk, this invention introduces a safety constraint control state and latching control mechanism. Through progressive control strategies such as prohibiting parameter increases, tiered decreases, priority directional adjustment, and stop-and-hold rotation, a memory-based suppression closed loop is formed, effectively preventing repeated fluctuations near the risk boundary. Simultaneously, a preset step-by-step recovery and decrease count limit mechanism achieves stable parameter optimization under safety constraints, balancing operational efficiency with water hazard prevention requirements. The overall solution transforms water exploration and drainage drilling operations from passive response to proactive identification and tiered control, significantly improving operational safety, control accuracy, and field adaptability. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the logic for real-time optimization and safety constraint control of drilling operation parameters for water exploration in this invention.

[0021] Figure 2 This is an overview of the return water flow rate and key stages in the ten-minute operation of Embodiment 1 of the present invention.

[0022] Figure 3 This is a schematic diagram of the monotonicity and amplitude determination of the dual-window system in Embodiment 1 of the present invention.

[0023] Figure 4 This is a schematic diagram of the determination of the quantile reference interval and the recovery counter in Embodiment 1 of the present invention.

[0024] Figure 5 This is a graph showing the water pressure changes within the three continuously recoverable window holes and the baseline range in Embodiment 2 of the present invention.

[0025] Figure 6 This is a fitting verification graph for the monotonically increasing trend of the recovery window in Embodiment 2 of the present invention.

[0026] Figure 7 This is a schematic diagram illustrating the regression trend determination of the second sub-period of rotation during the stop-and-go phase in Embodiment 2 of the present invention. Detailed Implementation

[0027] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0028] Combined with appendix Figure 1 This invention discloses a method for real-time optimization and safety constraint control of drilling parameters for water exploration and drainage operations, applicable to advanced water exploration and drainage drilling operations in coal mines or tunnel excavation. During the operation, sensors installed on the drilling rig control system and the borehole pipe collect data in real time, including drilling pressure, torque, rotational speed, drilling speed, and borehole return water flow rate or borehole water pressure. The borehole return water flow rate or borehole water pressure, as water parameters, characterize the hydraulic response state of the water-bearing body ahead of the borehole. These parameters are continuously acquired at a fixed sampling period and input to the control unit for online processing.

[0029] The control unit constructs a continuous sampling window on the time axis, which is a data interval that is updated continuously according to a set length. Within each continuous sampling window, the monotonicity of the water parameters is determined. When the water parameters show a continuous increasing or decreasing trend within the window, and the magnitude of the change in the water parameters within the window exceeds a first threshold, the drilling operation is determined to have entered a state of pending confirmation of near-water aquifer. The magnitude of change is calculated using the difference between the maximum and minimum values ​​within the window, or the absolute value of the difference between the starting and ending values ​​of the window, to reflect the overall intensity of change within the window. The first threshold is a preset parameter used to distinguish between normal fluctuations and abnormal hydraulic responses.

[0030] After entering the near-water-bearing confirmation state, the control unit sends a disturbance detection command to the drilling rig to obtain the response characteristics of the water-bearing body ahead to operational disturbances. The disturbance detection action is a controlled adjustment based on the current operating parameters, specifically selected from one of the following: reducing the drilling pressure setpoint, reducing the rotation speed, stopping and maintaining rotation before resuming advance, or stopping and resuming rotation. The duration of the action is a preset duration, completed under the premise of ensuring borehole stability and equipment safety, without changing the overall drilling operation process.

[0031] Before performing a perturbation detection action, the control unit extracts a reference window from the current operating data. The reference window is the interval of continuous sampled data immediately preceding the perturbation detection action. A reference interval is determined based on the range of water parameter values ​​within this reference window to characterize the steady hydraulic state before the perturbation.

[0032] After the perturbation detection action concludes, the system enters a recovery window. The recovery window is a continuous sampling interval following the end of the action. Water parameters are continuously collected within the recovery window and compared with a baseline interval. When the water parameters return to the baseline interval within the recovery window, the risk is confirmed to have decreased, and the aforementioned abnormal changes are determined to be recoverable fluctuations. When the water parameters do not return to the baseline interval, or continue to monotonically increase or decrease within the recovery window with a change exceeding a second threshold, the risk is confirmed to have increased. The second threshold is used to distinguish between residual fluctuations during the recovery process and a continuously enhanced hydraulic response.

[0033] When an increased risk is confirmed based on the water parameters assessed within the recovery window, the control unit switches the drilling operation to a safety constraint control state. In this state, constraints are implemented on the drill pressure setpoint, rotation speed, and drilling footage rate. The control unit prohibits any further increase in at least one of these parameters and performs a downward adjustment on the corresponding parameter according to the current risk level. The downward adjustment is implemented in stages according to a preset step size, gradually reducing the intensity of operational disturbance and thus mitigating further stimulation of the aquifer ahead. The adjustment sequence and combination of parameters are determined based on the direction of water parameter changes to achieve targeted suppression of hydraulic anomalies. The safety constraint control state remains in effect until the risk relief conditions are met.

[0034] When the water parameters within the recovery window return to the baseline range and no longer meet the risk increase judgment criteria, the risk is confirmed to have decreased. The control unit exits the pending confirmation state and simultaneously releases the safety constraint control state. Subsequently, the drilling pressure setpoint, rotational speed, or advance speed is allowed to be updated incrementally according to a preset increment. The increment is a pre-set value used to ensure a smooth parameter recovery process and avoid new disturbances caused by sudden large adjustments.

[0035] To improve the stability and anti-interference capability of adjacent water-bearing risk assessment, a tiered continuous sampling window is set. The continuous sampling window includes a short window and a long window, which differ in time length and are both updated on a rolling basis at a fixed sampling period. The short window is used to quickly capture instantaneous trend changes in water parameters, while the long window is used to verify whether the trend is persistent.

[0036] During drilling operations, the control unit first determines the monotonicity and magnitude of change of water parameters within a short window. When the water parameters show a monotonically increasing or decreasing trend within the short window, and the magnitude of the change exceeds a first threshold, the system enters a pre-judgment state. The pre-judgment state indicates the existence of a potential water-bearing anomaly trend, but it has not yet been confirmed. After entering the pre-judgment state, the control unit continues to determine the monotonicity and magnitude of change of water parameters within a long window.

[0037] When water parameters again exhibit monotonic changes within a long window and the magnitude of these changes exceeds the first threshold, the trend is determined to be persistent and stable. The system then enters a near-water-bearing confirmation state and triggers subsequent micro-perturbation detection procedures. If the conditions are not met again within the long window, the anomaly within the short window is considered a transient fluctuation or local disturbance. The system exits the prediction state, maintains the current drilling pressure setpoint, rotation speed, and advance rate unchanged, and continues real-time monitoring.

[0038] After completing the perturbation detection, the system enters the recovery window phase. The recovery window is a continuous sampling interval used to observe the stability of water parameters after a disturbance. The control unit compares the sampled data within the recovery window point by point with the reference interval. The criterion for returning to the reference interval is that multiple consecutive sampled values ​​within the recovery window fall within the reference interval, and there are no instances of values ​​exceeding the reference interval during this continuous sampling period. Only when both of these conditions are met is it confirmed that the water parameters have recovered to a stable state.

[0039] If the water parameters within the recovery window do not meet the condition of falling into the reference range multiple times consecutively, it is determined that the water has not returned to the reference range. At this time, the control unit performs risk mitigation adjustments based on the monotonic change direction of the water parameters. If the water parameters show a monotonic increase, indicating an enhanced hydraulic response in the hole, the control unit will at least reduce either the drill pressure setpoint or the rotation speed to reduce the disturbance intensity to the aquifer ahead. If the water parameters show a monotonic decrease, indicating a rapid change in the hydraulic environment in the hole or a tendency for unstable release, the control unit will at least reduce the advance speed or perform a stop-and-hold rotation before resuming advance to slow the advance rate and maintain stability in the hole. These adjustment measures are evaluated at the end of each recovery window until the water parameters meet the criteria for returning to the reference range.

[0040] Once the risk is confirmed to have increased based on the recovery window assessment, the control unit switches the drilling operation status to latching control status. Latching control status is an enhanced phase of safety constraint control, used to prevent parameters from fluctuating repeatedly near the risk boundary. During latching, upward adjustments to the drill pressure setpoint, rotation speed, and feed rate are prohibited. Simultaneously, parameters are adjusted in stages according to preset downward adjustment step sizes. The downward adjustment process is executed cyclically, with only one preset step size adjusted per cycle to ensure that the disturbance intensity gradually decreases and avoids sudden, drastic changes.

[0041] In latched control mode, the system continuously performs recovery window determinations on water parameters. When water parameters return to the baseline range within at least two consecutive recovery windows, and the variation during this period is below a third threshold, the hydraulic state is considered stable. The third threshold is used to limit the residual fluctuation amplitude during the recovery process to ensure that stability reaches the set standard before latching is released.

[0042] Once the release conditions are met, the control unit exits the latching control state. After release, the drill pressure setpoint, rotational speed, or advance rate can be updated incrementally according to the preset increment. The adjustment process is implemented in a graded incremental manner, and a new sampling window is entered for monitoring after each update to avoid triggering the risk again during the recovery process.

[0043] Before entering the perturbation detection process, the control unit selects continuous sampling data immediately preceding the perturbation detection action as a reference window. This reference window contains a sequence of water parameters from the stable operation phase. To mitigate the impact of occasional outliers on the judgment results, the reference interval is determined by the upper and lower quantile values ​​of the water parameters within this reference window. The upper quantile value serves as the upper boundary of the interval, and the lower quantile value as the lower boundary. The quantile values ​​are calculated according to a preset ratio to reflect the stable distribution range of the parameters.

[0044] During the perturbation detection operation, the reference interval remains unchanged and is not updated with real-time sampling data to ensure consistency of the comparison benchmark before and after the perturbation. After the perturbation detection operation ends, the recovery window phase begins. The control unit samples the water parameters within the recovery window sequentially and compares them with the reference interval. During the recovery determination process, a continuous sampling counter is set to count the number of consecutive samplings falling within the reference interval.

[0045] When any sampled value within the recovery window exceeds the baseline range, the control unit immediately resets the counter and restarts counting the consecutive occurrences from the next sample. Only when the consecutive sample count reaches a preset threshold is it confirmed that the water parameter has returned to the baseline range.

[0046] If the system determines that the hole has not returned to the reference range within the recovery window, the control unit implements suppression adjustments in a tiered manner. The adjustment process adopts a strategy of gradual reduction, starting with gentle adjustments and then increasing them to progressively reduce the disturbance intensity to the aquifer ahead. In the first stage, the system reduces either the rotational speed or the drilling pressure setting by a preset step size, with the reduction target determined based on the direction of change in the current water parameters. After completing one adjustment, the system proceeds to the next recovery window for further assessment. If the conditions for returning to the reference range are still not met within the next recovery window, the system enters the second stage, simultaneously reducing both the rotational speed and drilling pressure setting by a preset step size. If the system again determines that the hole has not returned to the reference range, the system enters the third stage, performing a stop-and-hold rotation followed by a resumption of propulsion to further reduce propulsion disturbance and maintain a stable state within the hole.

[0047] During execution, when water parameters monotonically increase and fail to return to the reference range, the drilling pressure setting is preferentially reduced to decrease the pressure effect on the water-bearing body ahead. When water parameters monotonically decrease and fail to return to the reference range, the drilling speed is preferentially reduced to slow down the advance rate and control changes in the borehole condition. These priority rules are used to achieve targeted adjustments corresponding to the direction of monotonic change. When the reference range is not returned after a preset number of consecutive attempts in the same monotonic direction, the control unit consistently uses a stop-and-hold rotation followed by resumption of advance as the adjustment method, maintaining this method until the recovery judgment condition is met.

[0048] During the adjustment phase of resuming advance after a stop-and-hold rotation, the control unit stops the advance action while maintaining the drilling rig's rotation. The principle of maintaining the rotation phase is to keep the current speed setting constant, without adjusting the speed upwards or downwards, allowing the borehole fluid and drill pipe system to release or redistribute stress under stable rotation conditions. This rotation-holding phase lasts for a preset duration, a fixed time parameter pre-set according to the operating conditions, to ensure sufficient response time for water parameters.

[0049] After the preset time period ends, the system enters a recovery window to continuously sample and judge water parameters. If the water parameters still do not return to the reference range within this recovery window, the current disturbance intensity is determined to be too high. In the next cycle, the control unit reduces the rotational speed by a preset step size and executes the stop-and-hold rotation-and-resume propulsion process again. The preset step size is a fixed reduction in rotational speed to achieve graded adjustment and avoid large one-time changes affecting the stability of the borehole wall. The above process continuously monitors changes in water parameters between cycles until the judgment condition of returning to the reference range is met.

[0050] During the stop-and-hold rotation adjustment phase, the preset duration is divided into at least two consecutive sub-periods. The first sub-period only involves stop-and-hold rotation without risk assessment, allowing the hydraulic state within the borehole to be fully released and adjusted under stable rotation conditions. In the second sub-period, while continuing stop-and-hold rotation, water parameters are continuously sampled and analyzed in real time. The control unit calculates the deviation of the water parameters from the reference range during the second sub-period and tracks the trend of this deviation. When the deviation continuously decreases and the direction of change points towards the reference range, a regression trend is identified. Upon confirmation of the regression trend, the stop-and-hold state is immediately terminated and propulsion resumes to avoid unnecessary efficiency losses.

[0051] Within the latching control cycle, a cumulative limit is set for the number of times the rotational speed is reduced. The number of times the rotational speed is reduced by a preset step size is set to a preset number K, which is the cumulative number of executions within the same latching control cycle. After each reduction, a new recovery window is entered for judgment. If the cumulative reduction number reaches K and the water parameter has not returned to the baseline range, the rotational speed reduction is stopped, and the drilling pressure setting value is reduced by a preset step size instead. After the drilling pressure setting value is reduced, the stop-and-hold rotation and then resume propulsion process is executed again. K is a preset positive integer that can be set according to the drilling operation safety level or the drilling stage to limit the number of consecutive adjustments of a single parameter and avoid excessive reduction of rotational speed affecting hole stability. By combining sub-period judgment and the reduction number limit, dynamic balance and orderly control are achieved in the risk suppression process.

[0052] Example 1:

[0053] In this embodiment, a water exploration and drainage borehole operation is conducted at a coal mine tunneling face. The target borehole depth is 100m. A hydraulic water exploration and drainage drilling rig is used. The drilling rig control system is connected to a flow meter and pressure sensor in the borehole inlet pipeline. The return water flow rate Q in the borehole is used as a water parameter to characterize the hydraulic response of the aquifer ahead. The control unit collects drilling pressure (WOB), torque (T), rotational speed (RPM), advance rate (ROP), and Q in real time with a sampling period of 1 second. The sampled flow is processed online using a rolling window to achieve real-time optimization of operation parameters and safety constraint control.

[0054] The system consists of a drilling rig actuator, a data acquisition module, and a control unit. The data acquisition module acquires WOB, T, RPM, and ROP in the main circuit of the drilling rig, and Q in the borehole pipe. The control unit has built-in continuous sampling windows of 30s (short window) and 120s (long window), both of which are updated every 1s. It also has a 20s duration for perturbation detection and a 60s recovery window for stability determination after perturbation.

[0055] This embodiment provides a continuous 10-minute running record. The values ​​in Table 1 are average values ​​per minute or representative values ​​for each stage, used to illustrate the state transitions throughout the entire process. The original sampled sequence is continuously stored by the control unit at a 1-second resolution and used for calculations described later. This data corresponds to the generated... Figure 2 The chart marks the abnormal trend segments (relative to 6-8 minutes) and provides a baseline horizontal line. =19.3L / min.

[0056]

[0057] Depend on Figure 2It can be seen that Q is stable at around 19.0 L / min within the relative minutes 0–5, with an average value of about 19.00 L / min; a significant increase occurs in the relative minutes 6–7, rising from 24.0 L / min to 28.5 L / min, which is much higher than the stable average value of the first 6 minutes, forming an abnormal trend segment; subsequently, it falls back to around 19.2 L / min in the perturbation and recovery phase, completing the state transition closed loop.

[0058] The first threshold is set at 6.0 L / min to distinguish between normal fluctuations and abnormal hydraulic response trends. The second threshold is set at 4.0 L / min to distinguish between residual fluctuations and continuous strengthening trends during the recovery process. The step size for parameter recovery is set to increase WOB by 0.5 kN, RPM by 10 r / min, and ROP by 0.01 m / min each time, and each increase is followed by at least one short window before the next update.

[0059] Around 6 minutes past the hour, Q within a short window of 30 seconds shows a monotonically increasing trend with a change exceeding the first threshold, triggering the control unit to enter a predictive state. Monotonicity is determined using linear regression within the short window, with the time series set as follows: And measured in seconds, the water parameters are The fitted model is:

[0060]

[0061] During this 30-second window, Q continuously increased from 22.00 L / min to 28.38 L / min, yielding...

[0062]

[0063] satisfy and The criterion of monotonous increase.

[0064] The range of change within the same short window is calculated as the difference between the maximum and minimum values:

[0065]

[0066] Since 6.38 L / min is greater than the first threshold of 6.0 L / min, the short window condition is met.

[0067] The control unit then continued to verify trend stability within a long window of 120 seconds. During this window, Q increased from 20.00 L / min to 28.92 L / min, and regression analysis yielded...

[0068]

[0069] and

[0070]

[0071] Therefore, the prediction status was switched to the near-water content confirmation status. Figure 3 The system simultaneously overlays short-window and long-window samples and regression lines, allowing for a direct comparison of the dual-layer judgment logic that enables rapid capture and continuous verification.

[0072] After entering the pending confirmation state, the control unit inserts a perturbation detection action to obtain the response characteristics of the aquifer to the disturbance. In this embodiment, reducing the drilling pressure setting value is selected as the perturbation method. Before the perturbation, a reference window is constructed from the data of the 30 seconds immediately preceding the action, and a reference interval is determined accordingly. The 30 sampled values ​​of Q within the reference window are:

[0073] 19.64, 19.30, 19.44, 19.76, 19.67, 18.96, 19.44, 19.16, 19.17, 19.30, 19.24, 19.56, 19.39, 19.23, 19.31, 19.28, 19.57, 19.15, 19.28, 18.99, 18.56, 19.36, 19.42, 19.01, 19.77, 18.84, 19.21, 19.18, 19.58, 19.64.

[0074] The baseline interval was determined using the quantile method, taking the lower quantile (10%) and the upper quantile (90%). The sample size was n=30, and the empirical quantile position formula was used:

[0075]

[0076] calculate:

[0077] The 10th percentile position is Corresponding to the 3rd and 4th ordered values ​​of 18.96 and 18.99, linear interpolation yields...

[0078]

[0079] The 90th percentile position is Corresponding to the 27th and 28th ordered values ​​of 19.64 and 19.67, respectively, linear interpolation yields:

[0080]

[0081] Therefore, the reference range is set to 19.00 L / min to 19.64 L / min and remains unchanged during the perturbation detection operation to avoid reference drift caused by perturbation.

[0082] The above quantile intervals correspond to the distribution of the benchmark sample. Figure 4 . Figure 4 The left side shows the box plot of the baseline window and the q10 and q90 quantile lines; the right side shows the Q curve of the recovery window segment and the step change of the continuous counter.

[0083] The perturbation detection action lasts for 20 seconds, during which the WOB is reduced from 18.0 kN to 16.0 kN, the RPM is maintained at 240 r / min, and the ROP is slightly reduced from 0.35 m / min to 0.33 m / min. After the action ends, a 60-second recovery window is entered. The recovery determination uses a continuous sampling counter with a counting threshold set to N=10. This means that Q must fall within the reference interval for 10 consecutive samples to be considered back to the reference interval, and if any sample exceeds the limit, the count is reset to zero and re-accumulated.

[0084] The recovery window provides a key sampling segment as shown in Table 2 below, in units of seconds and L / min, with a baseline range of 19.00–19.64 L / min.

[0085]

[0086] like Figure 4 As shown, a sampling rate of 19.82 L / min exceeding the upper limit occurred in the 8th second of the recovery window. This point is marked as "over-limit reset" in the figure, and the counter is immediately reset to zero. Subsequently, the accumulation resumes from the 9th second, and by the 18th second, the requirement of falling into the baseline range for 10 consecutive times is met, confirming that the water parameter has returned to the baseline range, thus confirming a reduction in risk. In this embodiment, risk outcome scenario A is selected, and the control unit exits the near-water content confirmation state without entering the safety constraint control state.

[0087] To further illustrate the difference in hydraulic response before and after the disturbance using data, the sliding window area index was used to assess the trend intensity, with a baseline level as the reference:

[0088]

[0089] The discrete integral is approximated as

[0090]

[0091] in .

[0092] The calculation was performed within the 30-second exception window before confirmation:

[0093]

[0094] Within the recovery window, due to Q rapidly regressing to the baseline, the following calculations were performed:

[0095]

[0096] The area index decreased significantly, indicating that the deviation of water parameters was significantly reduced after the perturbation, which is consistent with... Figure 4 The recovery counter results shown are consistent, supporting the conclusion that the risk has been reduced.

[0097] After the risk is reduced, the control unit allows the parameters to recover step by step according to a preset increment. To avoid further disturbances, a strategy of updating once after each short window is crossed is adopted. The WOB is recovered from 16.0kN to 18.0kN in 0.5kN increments, the RPM is recovered from 240r / min to 250r / min in 10r / min increments, and the ROP is recovered to 0.35m / min. After each update, the monotonicity and amplitude conditions of the short and long windows are continuously monitored to ensure a smooth recovery process. Compared with the threshold direct triggering strategy that does not use this method, this embodiment suppresses instantaneous noise triggering through short window prediction and long window verification. At the same time, it identifies an abnormal trend as a recoverable fluctuation by perturbation detection and recovery counting, thus avoiding efficiency loss caused by direct and large parameter reduction.

[0098] Example 2:

[0099] In this embodiment, advance exploratory drilling is conducted at a tunnel excavation face. The target hole depth is 80m. A hydraulic top-drive exploratory drilling rig is used, and a pressure sensor is installed inside the hole. The water pressure P inside the hole is used as a water parameter to characterize the hydraulic response of the water-bearing body ahead after disturbance. The tunneling team is responsible for advancing the borehole, while the on-duty electrical controller is responsible for monitoring and executing the control unit's commands. The control unit records WOB, RPM, ROP, and P at a 1-second sampling period and enters a latching control state after the risk increase is confirmed, which serves as the starting point of this embodiment.

[0100] Before entering latching control mode, the system has confirmed increased risk through short-window and long-window trend verification and perturbation detection. In latching control mode, WOB, RPM, and ROP are prohibited from being increased and are instead adjusted downwards in preset steps. Initial operating parameters are set as follows: WOB 20kN, RPM 220r / min, and ROP 0.30m / min. The baseline interval is obtained from statistics of the previous stabilization phase. It is 0.80 MPa. It is 0.95 MPa, used for window recovery determination.

[0101] This embodiment selects a risk pattern where P increases monotonically, representing a continuous increase in orifice water pressure and a deviation from the baseline range. To represent at least three consecutive recovery windows, a sampling sequence for the three recovery windows is given, with a sampling interval of 10 seconds and each window lasting 60 seconds. Window 1 is the initial assessment after entering latching, window 2 is the assessment after stage 1 adjustment, and window 3 is the assessment after stage 2 adjustment. The orifice water pressure curves for the three windows are compared with the baseline range as follows: Figure 5 As shown in the figure, it is also marked and Used to intuitively determine whether or not the price has returned to the baseline range.

[0102] The recovery window corresponds to the following parameters: WOB 20kN, RPM 220r / min, ROP 0.30m / min, and P sequence 0.96, 0.98, 1.01, 1.03, 1.06, 1.08, 1.10MPa. Within this window, P is consistently higher than... And it continues to rise, indicating that it has not returned to the benchmark range and the risk has not been eliminated. Figure 5 As can be seen, the peak value of window 1 is 1.10 MPa, which provides a benchmark for subsequent comparison of graded inhibition effects.

[0103] To quantify the trend, the control unit performs a linear fit between P and time within the recovery window, denoted by a slope of s (in MPa per second). Least squares fitting is then performed using 10-s sampling points to obtain...

[0104]

[0105] Furthermore, the slope is positive, satisfying the monotonically increasing trend criterion. The fitting process and residuals are illustrated below. Figure 6 As shown, Figure 6 The given goodness of fit is R²=0.996670, indicating that the upward trend of this window is stable and can be used to trigger subsequent control decisions. Since this risk pattern is monotonically increasing, according to the priority rule, the WOB should be reduced first to weaken the pressure-injection effect and the rise in intra-orifice pressure. Therefore, the adjustment enters the first stage of adjustment, which is first gentle and then strong.

[0106] In Phase 1, the WOB was reduced by only 1 kN in increments, decreasing it from 20 kN to 19 kN, while RPM and ROP remained unchanged. Subsequently, the system entered Recovery Window 2 for evaluation. Window 2 parameters were: WOB 19 kN, RPM 220 r / min, ROP 0.30 m / min, and P-series values ​​of 0.99, 1.00, 1.02, 1.03, 1.05, 1.06, and 1.07 MPa. Figure 5 It can be seen that the window curve is still generally higher than And it continues to rise, and it is determined that it has not returned to the benchmark range, so it enters the second stage of adjustment.

[0107] Phase two adjustment simultaneously reduced RPM and WOB, decreasing RPM from 220 r / min to 210 r / min in increments, and WOB from 19 kN to 18 kN, while ROP remained at 0.30 m / min. Subsequently, the recovery window three was evaluated, with parameters corresponding to WOB of 18 kN, RPM of 210 r / min, ROP of 0.30 m / min, and P-series values ​​of 0.97, 0.99, 1.00, 1.01, 1.02, 1.02, and 1.03 MPa. The latter part of this window tended to plateau but remained generally higher than [the target value]. The judgment indicates that the price has not yet returned to the benchmark range, and therefore enters Phase Three adjustment. Figure 5As can be seen, the peak value of window three is 1.03 MPa, which is 0.07 MPa lower than the peak value of window one (1.10 MPa). This reflects the suppression effect of stage one and stage two graded inhibition on the peak water pressure, but it is still not enough to bring P back to the reference range.

[0108] Phase Three involves adjusting the drill bit to maintain rotation after a stop, then resuming propulsion. The control unit reduces the ROP to 0 and maintains the drill bit's rotation for a total duration of 90 seconds. The first 30-second sub-period only involves maintaining rotation without any judgment, while the second 60-second sub-period continues maintaining rotation while making judgments. This phase strictly adheres to the principle of maintaining rotation without changing the RPM setpoint; the RPM is maintained at 210 r / min without further adjustment, allowing the borehole fluid and drill pipe system to release and redistribute stress under stable rotation conditions.

[0109] In the second sub-period, the deviation is defined as:

[0110]

[0111] When P is higher At that time, the deviation is equal to P minus The sequence of P and deviation for every 10 seconds in the second sub-period is given. P values ​​are 1.02, 1.01, 1.00, 0.99, 0.98, 0.97, and 0.96 MPa, with corresponding deviations d of 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, and 0.01 MPa. The P curve and deviation step curve for this process are shown below. Figure 7 As shown, the deviation difference sequence is -0.01, -0.01, -0.01, -0.01, -0.01, -0.01 MPa, with negative differences appearing 6 times, satisfying the regression trend criterion of continuous decrease. Therefore, the control unit can terminate the stop state and resume propulsion before the end of the total 90s duration, thereby reducing unnecessary efficiency losses.

[0112] To reflect the upper limit of the number of speed reductions within the same latching cycle, the upper limit K for the number of speed reductions is set to 3 times, and a new recovery window must be entered for evaluation after each reduction. If the cumulative reduction reaches 3 times and the speed still has not returned to the baseline range, the RPM reduction is stopped and the WOB is reduced before the stop-and-go rotation process is executed again. In this embodiment, a stronger disturbance occurred before stage two, resulting in three RPM reductions during the latching cycle without recovery. Specifically, after the RPM was successively reduced from 240 r / min to 230 r / min, 220 r / min, and 210 r / min, P was still higher than 3. At this point, the control unit no longer lowers the RPM but instead lowers the WOB1kN and enters the three-stop-keep rotation process of this stage, thereby avoiding the risk of hole formation instability caused by excessive reduction in speed and meeting the number of times limit strategy.

[0113] To compare the intensity of disturbances that are initially gentle and then become stronger, the discrete disturbance energy index is defined as follows:

[0114]

[0115] Take weight =1, It is 0.02. The time step is 1 second, and the value is 25. In Phase 1, only WOB 1 kN is reduced and maintained for 60 seconds for evaluation, resulting in J1 of 60. In Phase 2, both WOB 1 kN and RPM 10 r / min are reduced and maintained for 60 seconds for evaluation, resulting in J2 of 180. Phase 3 includes a 90-second pause during which ROP decreases from 0.30 m / min to 0, resulting in J3 of 202.5. The values ​​of J1, J2, and J3 and their increasing relationship are already shown in [the original text]. Figure 7 The calculation results show that the control intensity increases gradually, from gentle to strong, rather than decreasing abruptly. After the regression trend in stage three triggers early recovery, the control unit enters a new recovery window, and P falls back and stabilizes within the baseline range over the next 60 seconds. Because upward adjustments are prohibited during latch-up and a hysteresis strategy of limiting the number of adjustments and maintaining rotation during pauses is employed, repeated increases and frequent parameter adjustments near the risk boundary are avoided, ensuring orderly suppression and controllable recovery of the tunnel's advanced exploration boreholes under increased risk conditions.

Claims

1. A method for real-time optimization and safety constraint control of drilling operation parameters for water exploration and drainage, characterized in that... include: Real-time data collection includes drilling pressure, torque, rotational speed, drilling speed, and borehole return water flow rate or borehole water pressure, where the borehole return water flow rate or borehole water pressure are water parameters. Within a continuous sampling window, if the water parameter monotonically increases or monotonically decreases and the change exceeds a first threshold, it is determined to enter a state of pending confirmation of near-water content. The change is the absolute value of the difference between the maximum and minimum values ​​within the window or the difference between the first and last values ​​of the window. In the pending confirmation state, a perturbation detection action is inserted. The action is selected from one of the following: reducing the drilling pressure setting value, reducing the rotation speed, stopping and maintaining rotation before resuming propulsion, and stopping and resuming rotation. After the action is completed, a judgment is made in the recovery window: if the water parameters return to the reference range, the risk is confirmed to have decreased; if they do not return to the reference range or continue to change monotonically and the change exceeds the second threshold, the risk is confirmed to have increased. The reference range is taken from the range of water parameter values ​​in the reference window before the perturbation detection action. When the risk increases, the system enters a safety constraint control state, restricting at least one of the following: drilling pressure setting, rotation speed, and feed rate, from being increased or decreased; when the risk decreases, the system exits the pending confirmation state and allows updates according to preset increments.

2. The method for real-time optimization and safety constraint control of water exploration and drainage drilling operation parameters according to claim 1, characterized in that... The continuous sampling window includes a short window and a long window; when the water parameter satisfies the condition of monotonic change and the change amplitude exceeds the first threshold in the short window, it enters the pre-judgment state, and only when the condition is met again in the long window is it determined to enter the near water content confirmation state; otherwise, it exits the pre-judgment state and maintains the operating parameters.

3. The method for real-time optimization and safety constraint control of water exploration and drainage drilling operation parameters according to claim 1, characterized in that... The determination of returning to the reference interval is that multiple consecutive samples within the recovery window all fall within the reference interval; When the water parameters do not return to the baseline range, risk suppression adjustment is performed according to the monotonic change direction of the water parameters: if the monotonic increase is followed by a reduction of at least one of the drilling pressure setting or the rotation speed, and if the monotonic decrease is followed by a reduction of at least the advance speed or a stop-and-hold rotation is performed before resuming advance.

4. A method for real-time optimization and safety constraint control of drilling operation parameters for water exploration and drainage according to any one of claims 1-3, characterized in that... Once the risk is confirmed to be increased, the system enters a latching control state. During the latching period, the drilling pressure setting, rotation speed, and footage speed are prohibited from being increased and are instead adjusted in stages according to a preset downward adjustment step size. When the water parameters return to the baseline range within at least two consecutive recovery windows and the change is less than the third threshold, the latching is released. After release, the system is allowed to update according to a preset upward adjustment step size.

5. The method for real-time optimization and safety constraint control of water exploration and drainage drilling operation parameters according to claim 3, characterized in that... The reference interval is determined by the upper and lower quantile values ​​of the water parameter within the reference window and remains unchanged during the perturbation detection operation; when any sample within the recovery window exceeds the reference interval, the counting of the consecutive multiple samples restarts.

6. The method for real-time optimization and safety constraint control of drilling operation parameters for water exploration and drainage according to claim 3, characterized in that... The adjustment is performed in stages, first gently and then strongly: first, reduce one of the rotation speed or drilling pressure setting by a preset step size; if the speed and drilling pressure setting are not returned to the reference range in the next recovery window, reduce both the rotation speed and drilling pressure setting simultaneously; if the speed and drilling pressure are still not returned to the reference range, stop the advance to maintain rotation and then resume the advance.

7. The method for real-time optimization and safety constraint control of water exploration and drainage drilling operation parameters according to claim 3, characterized in that... When the water parameter increases monotonically and does not return to the reference range, the drilling pressure setting value is reduced first; when the water parameter decreases monotonically and does not return to the reference range, the advance speed is reduced first; and when the water parameter fails to return to the reference range a predetermined number of times in the same monotonous direction, the advance is stopped, the rotation is maintained, and then the advance is resumed as the adjustment.

8. The method for real-time optimization and safety constraint control of drilling operation parameters for water exploration and drainage according to claim 7, characterized in that... The rotation is maintained for a preset duration without changing the speed setting. If the water parameters do not return to the reference range within the recovery window after the preset duration ends, the speed is reduced by a preset step size in the next cycle, and the stop-and-keep-rotation process is repeated before resuming propulsion.

9. The method for real-time optimization and safety constraint control of drilling operation parameters for water exploration and drainage according to claim 8, characterized in that... The preset duration is divided into at least two sub-periods. In the first sub-period, the movement is stopped while the rotation is maintained. In the second sub-period, the water parameters are sampled and judged while the movement is stopped and the rotation is maintained. If the water parameters show a regression trend in the second sub-period, the movement is stopped and the movement is resumed. The regression trend is that the deviation of the water parameters from the reference interval decreases continuously.

10. The method for real-time optimization and safety constraint control of water exploration and drainage drilling operation parameters according to claim 8, characterized in that... The number of times the rotation speed is reduced by a preset step size is set to a preset upper limit K. The number of reductions is the cumulative number within the same latching control state cycle. When the number of reductions reaches K and the water parameter has not returned to the reference range, the rotation speed is kept from being reduced further and the drilling pressure setting value is reduced by a preset step size. Then, the stop-and-keep-rotate sequence is repeated and the advance is resumed. K is a preset positive integer, determined by the drilling operation safety level or drilling stage.

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