A dynamic liquid level monitoring and control method for well repair operation

Abstract

A method for monitoring and controlling the dynamic liquid level in well repair operations, through sensing pressure signals and timing control of dynamic liquid level monitoring and timely automatic conversion control methods, and a method for selecting and judging abnormal data in the dynamic liquid level detection process, controls the dynamic liquid level monitoring system to adapt to the operation of the entire process of well repair operations. In combination with the particularity and regular characteristics of the well repair operation process, a control method combining sensing pressure signal monitoring control with timing monitoring control and timely automatic conversion is provided to avoid sound velocity interference. Practical application has proved that it can effectively solve the problems faced by downhole dynamic liquid level monitoring during well repair operations, such as the inability to receive dynamic liquid level return waves, sound velocity interference, and the inability to achieve seamless automatic monitoring of dynamic liquid levels throughout the entire operation process.

Description

Technical Field

[0001] The present invention relates to a dynamic liquid level monitoring and control method for well repair operations, and in particular to a dynamic liquid level monitoring and control method for timing control and pressure signal triggering control as well as intelligent selection, switching and data collection in the field of well repair operations. Background Art

[0002] Controlling the dynamic liquid level changes and trends of oil, gas and water wells during production or well repair operations is extremely important for crude oil production, reservoir protection and well control safety. It is the basis for analyzing, judging and formulating relevant process measures, and the most direct and effective means to protect reservoirs. Dynamic liquid level monitoring during well repair operations is an emerging technology. Relying on mature dynamic liquid level monitoring technology and control methods, it is possible to modify the operation well control rules, implement active well control, simplify the current slow and cost-effective operation procedures, effectively protect reservoirs, automatically curb safety hazards, and improve construction quality and efficiency.

[0003] Low-frequency acoustic wave liquid level monitoring technology has been widely used in production wells, but there are many difficulties and no precedents to use this technology for downhole dynamic liquid level monitoring during the process of lifting and lowering the oil pipe in well repair operations. Conventional open operations cannot receive the dynamic liquid surface return wave signal; the speed of sound is the scale of acoustic wave ranging. The piston movement of lifting and lowering the oil pipe causes irregular agitation of the gas pressure in the wellbore, causing the gas density to change, resulting in a change in the speed of sound, and making the detection results inaccurate. If these problems are not solved, even if the dynamic liquid level does not change, different abnormal results will be measured, which will lose the reference significance, and it will be impossible to achieve automatic seamless dynamic liquid level monitoring that is consistent with the entire well repair operation process and does not affect the construction progress. It is even more impossible to realize subsequent processes such as automatic metering and calculation of liquid filling, and to achieve the goal of active well control to protect the safe production of oil and gas layers.

[0004] In view of the special environment of well repair operations, special control and auxiliary methods are needed to create conditions, avoid interference, ensure the detection and accurate detection of the dynamic liquid level, and then realize automatic monitoring of the dynamic liquid level without affecting the progress of the operation. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a dynamic liquid level monitoring and control method for well repair operations. In combination with the particularity and regular characteristics of the well repair operation process, the timing and pressure signal control mode are used to start the dynamic liquid level detection, and automatically switch under specified conditions to achieve dynamic liquid level monitoring of the entire well repair operation process. In the process of lifting and lowering the tubing, an external pressure signal is used to control the timing of starting the dynamic liquid level detection, so as to avoid the influence of the pressure excitation caused by the piston movement of the lifting and lowering tubing on the sound velocity value. In other non-interference operations other than lifting and lowering the tubing, the timing of starting the dynamic liquid level detection is controlled by the timing method, and the detection time interval value is preset to realize automatic timing dynamic liquid level monitoring. By using the pressurized plug installed on the wellhead blowout preventer, during the process of making and unmaking the oil pipe, the wellhead is automatically blocked by the heavy pressure of the pipe string and the elevator, creating a closed dynamic liquid level detection environment to ensure that the dynamic liquid level return wave can be successfully received. At the same time, the sensed pressure signal is transmitted to the dynamic liquid level monitoring and control system as an external pressure signal to start a dynamic liquid level detection. A pressure signal is sent once for each making and unmaking, and according to the alternative preset value, a dynamic liquid level detection is started once a pressure signal is received or a dynamic liquid level detection is started once n pressure signals are received. In this way, the dynamic liquid level in the process of lifting and lowering the pipe string is automatically monitored, and the dynamic liquid level detection is started in the relatively static state of making and unloading the oil pipe string, avoiding the detection during the up and down movement of the oil pipe string, and effectively solving the problem of the oil pipe string movement interfering with the sound velocity.

[0006] One of the inventive points of the present invention is that, no matter in the timing control or pressure signal control mode, the premise of starting detection is that the pressure signal value must be received and maintained unchanged, because only then the wellhead is blocked and detection conditions are met, and it is consistent with the well repair operation operation procedures. After starting detection, the pressure signal value must be maintained unchanged for t≥60s before the test data can be accepted, otherwise it will be judged as disturbed and inaccurate data and abandoned.

[0007] The second inventive point of the present invention is that, in the state of lifting and lowering the tubing or under the pressure signal control mode, if the pressure signal value remains unchanged within the specified time t1 (120s≤t1≤600s optional), it will immediately switch to the timing control mode, and perform dynamic liquid level monitoring according to the preset timing value t2 (60s≤t2≤600s optional); in the timing control mode, if the pressure signal value disappears, it will immediately switch to the pressure signal control mode, and the pressure signal will be detected again within the time period ≤t1, the dynamic liquid level detection will be started, and the dynamic liquid level monitoring will be performed in the pressure signal control mode according to the alternative preset value (1 to 5 roots / time alternative preset), and the switching back and forth will avoid interference, create conditions, carry out dynamic liquid level monitoring covering the entire process of well repair operations, and control automatic filling, etc.

[0008] One of the purposes of the present invention is to improve a pressure plugging sensing system installed on a blowout preventer in combination with the characteristics of well repair operations, plug the wellhead during the period of dynamic liquid level detection under pressure, establish a closed wellbore testing environment, and solve the problem that conventional open operations cannot detect the dynamic liquid level;

[0009] The second purpose of the present invention is to provide a timely and selective control start-up method for monitoring the dynamic liquid level in the well during the well repair operation, in combination with the characteristics of the well repair operation, so as to select a time period without interference with the sound velocity to automatically monitor the dynamic liquid level, avoid interference, and effectively solve the problem of inaccurate monitoring data caused by abnormal changes in the sound velocity due to interference;

[0010] The third purpose of the present invention is to combine the characteristics of well repair operations, adopt a timing monitoring and control method in non-lifting and lowering pipe string working conditions, and realize seamless dynamic liquid level monitoring throughout the well repair operation;

[0011] The fourth purpose of the present invention is to combine the characteristics of well repair operations, based on the changes in the pressure signal of the pressure plugging sensing system installed on the blowout preventer, rely on the system software control system to analyze and judge, realize the pressure signal and timing monitoring control mode, and make corresponding timely automatic adjustments and timely switching according to different working conditions of the well repair operation.

[0012] The fifth purpose of the present invention is to combine the characteristics of well repair operations, based on the changes in the pressure signal of the pressure plugging sensing system installed on the blowout preventer, rely on the system software control system to analyze and judge, avoid system conflicts or erroneous operations, identify and avoid erroneous data acceptance and storage, and ensure the authenticity and accuracy of the monitoring data.

[0013] The beneficial effects of the present invention are:

[0014] 1. The pressure plugging sensing system automatically senses the pressure signal and combines it with the timing control and timely conversion method to monitor the dynamic liquid level during the process of lifting and lowering the pipe string in the well repair operation, avoiding interference and breaking through the technical bottleneck of the inability to automatically and accurately monitor the dynamic liquid level during the well repair operation. Without this method, it is impossible to achieve automatic and accurate monitoring of the dynamic liquid level during the well repair operation and subsequent automatic filling;

[0015] 2. By combining pressure signals with timing monitoring control and automatically switching with different working conditions, the dynamic liquid level automatic monitoring covers the entire process of well repair operations. The dynamic liquid level monitoring and well repair operations do not interfere with each other, which better meets actual needs.

[0016] 3. The present invention utilizes a pressure plugging induction system to solve the problem of the escape of the dynamic liquid surface reflection wave during the well repair operation, and provides the system with an induction pressure signal corresponding to the working condition, thus solving the problem that the dynamic liquid surface cannot be automatically detected during the well repair operation;

[0017] 4. By using the inductive pressure signal control method, the problem of interference of the lifting and lowering of the pipe in the well repair operation on the sound velocity is successfully avoided, and the accuracy and reliability of the automatic dynamic liquid level monitoring data in the well repair operation process are improved to a level that can meet actual needs;

[0018] 5. The method of sensing pressure signal and timing control and timely switching is based on the change of the pressure signal. Under the constraint of the system control software, the monitoring data is converted and judged whether to be accepted or not in a timely and organic manner, so as to realize the uninterrupted automatic dynamic liquid level monitoring and error correction in the whole process of well repair operation. It complements the operation process and does not interfere with each other, laying a reliable foundation for automatic calculation and metering of liquid filling, protection of oil and gas layers and realization of active well control; BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a logic block diagram of the dynamic liquid level monitoring and control method for well repair operations. DETAILED DESCRIPTION

[0020] A dynamic liquid level monitoring and control method for well repair operations, through sensing pressure signals and timing control of dynamic liquid level monitoring and timely automatic conversion control methods, and dynamic liquid level detection process abnormal data selection and discrimination methods, controls the dynamic liquid level monitoring system to adapt to the operation of the entire process of well repair operations. In combination with the particularity and regular characteristics of the well repair operation process, a sensing pressure signal control method that avoids sound speed interference is provided, which is combined with a timing control method and a timely automatic conversion control method to effectively solve the problems faced by downhole dynamic liquid level monitoring during well repair operations.

[0021] By using the pressure plugging sensing system installed on the wellhead blowout preventer, the wellhead is quickly plugged and a pressure-induced signal is formed by the heavy pressure during the period when the oil pipe string is sitting on the wellhead and unbuckling. The system software control system analyzes and judges, and serves as the timing of dynamic liquid level monitoring and the control basis for the conversion of the pressure signal monitoring control mode and the start-up command. During other operations of the oil pipe completion and unbuckling, the dynamic liquid level monitoring system does not receive the pressure signal of the pressure plugging sensing system and is in a waiting state. The waiting time is set to t1 (120s≤t1≤600s optional). The dynamic liquid level monitoring system receives the pressure signal within the t1 period, starts monitoring, and runs in the self-sensing pressure signal control dynamic liquid level monitoring mode; if there is no change in the pressure signal value > t1, it will immediately switch to the timing control mode and perform dynamic liquid level monitoring according to the preset timing value;

[0022] In the case of lifting and lowering the pipe string or the pressure signal control mode, if the pressure signal value remains unchanged within the specified time t1 (120s≤t1≤600s optional), it will immediately switch to the timing control mode and perform dynamic liquid level monitoring according to the preset timing value t2 (60s≤t2≤600s optional); in the timing control mode, if the pressure signal value disappears, it will immediately switch to the pressure signal control mode, detect the pressure signal again within the time period ≤t1, start the dynamic liquid level detection, and perform dynamic liquid level monitoring in the pressure signal control mode according to the alternative preset value (1 to 5 roots / time, alternative preset), so as to switch back and forth, avoid interference, create conditions, perform dynamic liquid level monitoring covering the entire process of well repair operations, and control automatic filling, etc. Regardless of the timing control or pressure signal control mode, the premise for starting detection is that the pressure signal value must be received and maintained unchanged, because only then the wellhead is blocked, detection conditions are available, and it is consistent with the well repair operation operating procedures. After starting the detection, the pressure signal value must be maintained unchanged for t≥60s before the test data can be accepted. Otherwise, it will be judged as disturbed and inaccurate data and will not be accepted.

[0023] Example 1

[0024] The present invention is further described below in conjunction with the accompanying drawings:

[0025] A dynamic liquid level monitoring and control method for well repair operations, through the sensing of pressure signals and timing control of dynamic liquid level monitoring and timely automatic conversion control method, and the dynamic liquid level detection process abnormal data selection and judgment method, controls the dynamic liquid level monitoring system to adapt to the operation of the whole process of well repair operations. In combination with the particularity and regular characteristics of the well repair operation process, a control method combining sensing pressure signal monitoring control with timing monitoring control and timely automatic conversion is provided to avoid sound speed interference, effectively solving the problems of inability to receive dynamic liquid level return waves and sound speed interference faced by downhole dynamic liquid level monitoring during well repair operations.

[0026] When the well repair operation enters the pipe lifting and lowering condition, it is necessary to carry out the single-piece oil pipe buckling and unbuckling operations. At this time, the pressure-sealing sensing system installed on the wellhead blowout preventer bears the gravity of the oil pipe string and the elevator, and seals the wellhead after being pressurized to create a closed test environment for the wellbore, and at the same time forms a corresponding induced pressure signal. The appearance of this pressure signal at different time periods represents the corresponding operation process content. The system software control system detects this induced pressure signal and combines it with the set time t1 as the basis for analysis and judgment to select the corresponding control mode and switch it in time. During other operations of completing the buckling and unbuckling of the oil pipe, the dynamic liquid level monitoring system does not receive the pressure signal of the pressure-sealing sensing system and is in a waiting state. The waiting time is set to t1. (120s≤t1≤600s optional preset), the dynamic liquid level monitoring system receives the pressure signal within the t1 period, starts monitoring, and operates in the self-sensing pressure signal control dynamic liquid level monitoring mode; if there is no pressure signal value change > t1, it will immediately switch to the timing control mode and perform dynamic liquid level monitoring according to the preset timing value t2 (60s≤t2≤600s optional preset); in the case of lifting and lowering the pipe string or the pressure signal control mode, if the pressure signal value remains unchanged within the specified time t1 (120s≤t 1≤600s alternative preset), immediately switch to the timing control mode, and monitor the dynamic liquid level according to the preset timing value; in the timing control mode, if the pressure signal value disappears, immediately switch to the pressure signal control mode, detect the pressure signal again within the time period ≤t1, start the dynamic liquid level detection, and monitor the dynamic liquid level in the pressure signal control mode according to the alternative preset value, and switch back and forth in this way to avoid interference, create conditions, conduct dynamic liquid level monitoring covering the entire process of well repair operations, and control automatic filling, etc. Regardless of whether it is in the timing control or pressure signal control mode, the premise for starting detection is that the pressure signal value must be received and maintained unchanged, because only then the wellhead is blocked, the detection conditions are met, and it is consistent with the well repair operation operating procedures. After starting detection, the pressure signal value must be maintained unchanged for t≥60s before the test data can be accepted, otherwise it will be judged as interference-inaccurate data and abandoned.

Claims

1. A method for monitoring and controlling the dynamic liquid level in a well repair operation, which controls the dynamic liquid level monitoring system to operate in the whole process of the well repair operation by sensing the pressure signal and timing control of the dynamic liquid level monitoring and timely automatic conversion control method, and a method for selecting and judging abnormal data in the dynamic liquid level detection process, and is characterized in that: The pressure plugging sensing system is installed on the wellhead blowout preventer. It plugs the wellbore to establish a closed detection environment during the period of making and breaking the oil pipe string, senses whether the oil pipe string is in a relatively static state of making and breaking the oil pipe string, and forms a corresponding induced pressure signal. This induced pressure signal and its changes are used as the basis for selecting the control dynamic liquid level monitoring mode and switching in coordination with the corresponding working conditions. The control method combines the induced pressure signal control mode with the timing control mode and automatically switches at the right time. The pressure sensing signal comes from the pressure plugging sensing system. During the other operations of the tubing string making and breaking, the dynamic liquid level monitoring system does not receive the pressure signal from the pressure plugging sensing system and is in a waiting state. The waiting time is set to t1. If the dynamic liquid level monitoring system receives the pressure signal within the t1 period, the monitoring is started and the system operates in the dynamic liquid level monitoring mode controlled by the self-sensing pressure signal. If there is no change in the pressure signal value during the period > t1, it will immediately switch to the timing control mode and perform dynamic liquid level monitoring according to the preset timing value t2; The waiting time t1 is 120s≤t1≤600s; The preset timing value t2 is 60s≤t2≤600s.

2. A method for monitoring and controlling the dynamic liquid level in a well repair operation according to claim 1, characterized in that: In the sensing pressure signal control mode, if the pressure signal value remains unchanged within the specified time t1, it will immediately switch to the timing control mode and perform dynamic liquid level monitoring according to the preset timing value t2.

3. A method for monitoring and controlling the dynamic liquid level in a well repair operation according to claim 1, characterized in that: In the timing control mode, if the pressure signal value disappears, it will immediately switch to the inductive pressure signal control mode. If the pressure signal is detected again within the time period ≤t1, the dynamic liquid level detection will be started, and the dynamic liquid level monitoring will be performed in the inductive pressure signal control mode according to the alternative preset value.

4. A method for monitoring and controlling the dynamic liquid level in a well repair operation according to claim 1, characterized in that: No matter it is in timing control or pressure signal sensing control mode, dynamic liquid level detection can only be started after receiving the pressure signal and maintaining the pressure signal value unchanged. After starting the detection, the pressure signal value must be maintained unchanged for t≥60s before the test data can be accepted. Otherwise, it will be judged as disturbed and inaccurate data and will not be accepted.

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