Wellbore Pump-Down Control for Wireline Tension Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wellbore operations, pump-down systems face challenges in maintaining optimal wireline cable tension during the conveyance of tools in inclined sections, leading to potential tool separation and costly recovery processes due to imbalances between hydraulic pressure and wireline speed, resulting in inefficiencies and increased operational time.
Innovation Solution
A closed-loop control system is implemented to simultaneously manage wireline speed and pump flowrate, using sensors and control algorithms to maintain target downhole tension and recommended job speed, dynamically adjusting gains based on operating conditions and geometry to prevent tool separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wireline speed and pump flowrate are controlled manually by different operators, then operational flexibility is maintained, but coordination accuracy deteriorates leading to cable tension instability
Solution Approach 1:
The patent merges the control of wireline speed and pump flowrate into a single automated control system that coordinates both parameters simultaneously. This integration eliminates the coordination errors that occur when different operators manually control each parameter, thereby maintaining cable tension within the specified range while preserving operational flexibility through programmable control sequences.
Solution Approach 2:
The system implements feedback control by continuously monitoring cable tension and using this information to dynamically adjust wireline speed and pump flowrate. Sensors measure the actual tension and feed this data back to the controller, which automatically modifies operational parameters to maintain tension within the specified range, resolving the instability caused by manual coordination errors.
2Productivity
If wireline speed is increased to improve conveyance efficiency, then productivity increases, but cable tension control becomes more difficult leading to potential slack and cable damage
Solution Approach 1:
The control system dynamically adjusts wireline speed based on real-time cable tension feedback and operational conditions. Rather than using a fixed high speed that could cause tension loss, the system continuously adapts the speed parameter to maintain optimal tension levels, enabling high productivity while preventing cable damage through automated dynamic control.
Solution Approach 2:
The system automatically changes operational parameters including wireline speed, pump flowrate, and tension setpoints based on real-time conditions. When approaching inclined sections or detecting tension trends, the controller modifies these parameters proactively to maintain safe tension levels throughout the conveyance operation, allowing efficient high-speed operation without compromising cable safety.
3Speed
If pump flowrate is increased to push wireline tools through inclined sections faster, then conveyance speed improves, but wireline cable tension may be lost causing tool separation
Solution Approach 1:
The control system performs preliminary actions by detecting upcoming inclined sections and proactively adjusting pump flowrate and wireline speed before the tool enters these challenging sections. This anticipatory control prevents tension loss and tool separation by preparing the system in advance, allowing faster conveyance through inclined sections while maintaining safe tension levels throughout the operation.
Data Source
AI summary
A method for controlling a pump-down operation in a wellbore includes selecting a target value for downhole tension of a support cable and a recommended job speed to convey a wireline tool string down a section of the wellbore, generating a line speed signal for controlling a line speed of the support cable and a pumprate signal to control a pumprate of a hydraulic fluid in the wellbore, determining a first error between the target value for downhole tension and a measured value of the downhole tension, determining a second error between the recommended job speed and an actual line speed, and maintaining the target value for the downhole tension by simultaneously controlling the line speed and the pumprate using a value for the line speed signal and a value for the pumprate signal generated based on the first and second errors.