Search

CN-121976768-A - Control method for cutting off and salvaging underground tubular column based on real-time working condition sensing

CN121976768ACN 121976768 ACN121976768 ACN 121976768ACN-121976768-A

Abstract

The invention relates to the field of pipe string salvage, in particular to a control method for cutting off and salvaging a downhole pipe string based on real-time working condition sensing. The method comprises the steps of designing a multi-stage pulling force scheme based on an operation log database, carrying out step-by-step loading operation based on the multi-stage pulling force scheme, collecting effective stress parameters based on a sensor array, carrying out positioning tracing and well depth coordinate conversion based on the effective stress parameters, marking underground clamping column coordinates, carrying out multi-position stress calculation on the effective stress parameters to generate a plurality of segmented stress state vector sets, carrying out multi-constraint solving based on the stress state vector sets and the underground clamping column coordinates to obtain optimal cutting position points, and driving a cutting tool to carry out cutting operation according to the optimal cutting position points to complete underground pipe string cutting and salvaging operation. According to the invention, through real-time salvage working condition parameter analysis, the optimal pipe column cutting point is accurately calculated, and the efficiency and safety of cutting and salvage are improved.

Inventors

  • LI XIANG
  • LI HONGWEI

Assignees

  • 天津广志技术服务有限公司

Dates

Publication Date
20260505
Application Date
20260206

Claims (9)

  1. 1. A control method for cutting off and salvaging a downhole tubular column based on real-time working condition sensing is characterized by comprising the following steps: Step S1, designing a multi-stage pulling force scheme based on a job log database, carrying out step-by-step loading operation based on the multi-stage pulling force scheme, and acquiring effective stress parameters based on a sensor array; s2, performing positioning tracing and well depth coordinate conversion based on effective stress parameters, and marking underground card column coordinates; s3, carrying out multi-position stress calculation on the effective stress parameters to generate a plurality of segmented stress state vector sets; S4, carrying out multi-constraint solving based on the stress state vector set and the underground clamping column coordinates to obtain an optimal cutting position point; and S5, driving a cutting tool to perform cutting operation according to the optimal cutting position point, and completing cutting and salvaging operation of the underground pipe column.
  2. 2. The method for controlling cutting and fishing of a down-hole string based on real-time working condition sensing as claimed in claim 1, wherein the step S1 specifically comprises the following steps: extracting operation parameters and tubular column basic parameters corresponding to the target well based on the operation log database; Determining yield strength and tensile strength parameters based on the pipe column foundation parameters, calculating operation depth and downhole corrosion coefficient based on the operation parameters; Performing fatigue damage prediction according to the operation depth and the downhole corrosion coefficient to obtain a pipe column material performance attenuation value; carrying out safety constraint calculation on the yield strength and the tensile strength parameters according to the pipe column material performance attenuation value to obtain the maximum allowable over-lifting force; Gradient division is carried out based on the maximum allowable lifting force, and a multi-stage lifting force scheme is generated; And carrying out step-by-step loading operation based on a multi-stage lifting force scheme, and acquiring effective stress parameters based on the sensor array.
  3. 3. The method for controlling cutting and fishing of a down-hole string based on real-time working condition sensing according to claim 2, wherein the string base parameters comprise string outer diameter, wall thickness, steel grade index, joint thread type and maximum running depth.
  4. 4. The method for controlling the cutting and fishing of the down-hole tubular column based on the real-time working condition sensing according to claim 2, wherein the step-by-step loading operation is performed based on a multi-stage pulling force scheme, and the specific steps for acquiring the effective stress parameters based on the sensor array are as follows: Performing step-by-step loading operation based on a multi-stage pulling force scheme, and collecting real-time working conditions based on a sensor array to obtain underground pipe column stress parameters, wherein the underground pipe column stress parameters comprise axial load change, instantaneous rebound characteristics and loading hysteresis characteristics; carrying out sensor self-noise identification on the stress parameters of the underground pipe column to obtain self-noise parameters; and carrying out multi-scale noise separation processing according to the self-noise parameters, and extracting effective stress parameters.
  5. 5. The method for controlling cutting and fishing of a down-hole pipe string based on real-time working condition sensing according to claim 4, wherein the step-by-step loading operation is performed based on a multi-stage pulling force scheme, real-time working condition acquisition is performed based on a sensor array, and the specific steps of obtaining the stress parameters of the down-hole pipe string are as follows: Generating a plurality of lifting force instructions based on a multi-stage lifting force scheme; Configuring initial parameters of a force control system according to the plurality of force lifting operation instructions; Step-by-step pulling force is applied according to the initial parameters of the force control system, and the lifting, holding, lowering and holding execution operation is executed at each pulling force stage; Deploying multi-type sensor arrays at a wellhead and a key well section, wherein the sensors comprise a high-precision tension sensor, an axial displacement sensor, a torque sensor and a vibration acceleration sensor; and acquiring multidimensional stress parameters of step-by-step loading operation according to the multi-type sensor array, and fitting to obtain the stress parameters of the underground tubular column.
  6. 6. The method for controlling cutting and fishing of a down-hole string based on real-time working condition sensing as claimed in claim 1, wherein the step S2 specifically comprises the following steps: Carrying out stress response nonlinear variation analysis based on the effective stress parameters to obtain a nonlinear stress response curve; According to the nonlinear stress response curve, calculating the blocking resistance from stage to stage, and extracting the blocking resistance at different stages; carrying out stress abnormality calculation according to the clamping resistance, and identifying a stress abnormality concentration area; inversion calculation is carried out on the stress abnormal concentrated area, and the maximum stress peak value position is determined; And carrying out positioning tracing and well depth coordinate conversion based on the maximum stress peak position, and marking the underground clamping column coordinates.
  7. 7. The control method for cutting off and fishing a down-hole pipe string based on real-time working condition sensing as claimed in claim 1, wherein the specific steps of the step S3 are as follows: Carrying out multi-position stress calculation on the effective stress parameters to obtain stress values of different positions; carrying out vertical axis stress distribution analysis on the pipe column according to the stress value to obtain a vertical axis stress distribution diagram; Performing tubular column virtual segmentation based on the vertical axis stress distribution diagram to obtain a plurality of stress analysis sections; and calculating the stress concentration degree, the well wall friction locking probability and the local buckling sensitivity of the stress analysis sections to generate a plurality of segmented stress state vector sets.
  8. 8. The control method for cutting off and fishing a down-hole pipe string based on real-time working condition sensing as claimed in claim 1, wherein the specific steps of the step S4 are as follows: performing decoupling analysis of cut-off risks based on the stress state vector set to obtain the overall limited risk and the local structure fragile risk of each segment; performing comprehensive cut-off risk assessment according to the whole limited risk and the local structure fragile risk to obtain cut-off risk estimation values of different sections; and carrying out multi-constraint solving based on the underground card column coordinates and the cutting risk estimation value to obtain an optimal cutting position point.
  9. 9. The control method for cutting off and fishing a down-hole pipe string based on real-time working condition sensing as claimed in claim 1, wherein the specific steps of the step S5 are as follows: performing actual depth calculation of the tubular column according to the optimal cutting position point, and outputting a target depth position; driving a cutting tool to perform cutting operation based on the target depth position, and completing controlled cutting of the tubular column; and after the cutting operation is detected, the multi-stage pulling force scheme is called again, step-by-step pulling attempt is carried out on the upper part of the cut pipe column, and when the stress response of the pipe column in any pulling process of the pulling force scheme is monitored to be recovered to be normal, the pipe column is judged to be successfully fished, and the underground pipe column cutting and salvaging operation is completed.

Description

Control method for cutting off and salvaging underground tubular column based on real-time working condition sensing Technical Field The invention relates to the field of pipe string salvage, in particular to a control method for cutting off and salvaging a downhole pipe string based on real-time working condition sensing. Background In the long-term running process of the underground pipe column, the pipe column is easy to block, bend or concentrate stress due to friction and load change of the pipe column, the well wall and underground equipment, and external interference, misoperation or sudden geological conditions can cause failure of cutting operation, so that equipment damage, operation delay and even underground accidents are caused. These factors make the real-time sensing capability and intelligent control level of the cutting-off and fishing operation of the lifting pipe column a problem to be solved urgently. Traditional downhole cutting control methods rely primarily on job logs, limited sensor data, and manual experience judgment. Although the method can basically monitor the overall condition of the pipe column, the method often lacks the capability of real-time analysis of stress distribution, blocking positions and cutting dynamic working conditions, and is difficult to realize accurate control on complex underground environments. The existing method has the defects of low operation efficiency and insufficient operation safety due to insufficient capabilities in the aspects of abnormality early warning, cutting optimization and automatic control. Disclosure of Invention The invention provides a control method for cutting off and salvaging a downhole string based on real-time working condition sensing to solve at least one technical problem. In order to achieve the above purpose, the invention provides a control method for cutting off and salvaging a down-hole tubular column based on real-time working condition sensing, which comprises the following steps: Step S1, designing a multi-stage pulling force scheme based on a job log database, carrying out step-by-step loading operation based on the multi-stage pulling force scheme, and acquiring effective stress parameters based on a sensor array; s2, performing positioning tracing and well depth coordinate conversion based on effective stress parameters, and marking underground card column coordinates; s3, carrying out multi-position stress calculation on the effective stress parameters to generate a plurality of segmented stress state vector sets; S4, carrying out multi-constraint solving based on the stress state vector set and the underground clamping column coordinates to obtain an optimal cutting position point; and S5, driving a cutting tool to perform cutting operation according to the optimal cutting position point, and completing cutting and salvaging operation of the underground pipe column. The method has the advantages that the data of the historical pulling operation is analyzed through the operation log database, a multi-stage pulling force scheme is designed, the situation that underground clamping columns are broken suddenly or sleeves are damaged due to excessive load at one time can be avoided, and the accident risk is reduced. The step-by-step loading operation can accurately control the pulling force applied by each step, so that the underground pipe column is in a controllable stress state, and overload is prevented. The effective stress parameters acquired by the sensor array provide a reliable data basis for subsequent analysis and a scientific basis for positioning the clamping column and judging the stress state. By utilizing the transformation of the stress parameters and the well depth coordinates, the position of the clamping column can be accurately determined, the cutting deviation from the target is avoided, and the cutting success rate is improved. By the positioning tracing method, the length and the position distribution of the clamping column can be clearly identified, and the interference to other underground equipment or the pipe column is reduced. The stress data and the position information are marked, so that a complete operation record can be formed, a vector set is generated by multi-position stress calculation, the stress state of the pipe column in each section is visually displayed, and the analysis of key stress points is facilitated. The sectional stress state is helpful for judging which positions are most suitable for cutting, and secondary blocking or tool damage caused by cutting at a high stress point is avoided. Through vector set analysis, the selection of the cutting points is more scientific, the cutting precision is high, and the success rate is greatly improved. Through multi-constraint solving, factors such as stress state, clamping column position, tool capacity and the like are comprehensively considered, an optimal cutting point is determined, and empirical or blind selection is avoid