Inflatable Packer Motor Control via Pressure Derivative Feedback
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Solution Overview
Problem
Inflatable packers used in oil and gas drilling experience pressure overshoots during inflation, which can damage and deform packer elements, due to the inability to accurately control motor speed and timing, leading to prolonged inflation times and increased pressure beyond the desired level.
Innovation Solution
A method and system that utilize a pressure sensor and motor controller with a processor-executable algorithm to measure pressure derivatives, detecting the onset of packer restraint and adjusting motor speed to prevent overshoots by using a Savitzky-Golay polynomial filter to calculate pressure derivatives and control the motor speed in real-time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If motor speed is reduced to prevent pressure overshoot, then packer element damage is prevented, but inflation time is prolonged
Solution Approach 1:
The system continuously monitors packer pressure and uses this feedback to dynamically adjust motor speed. When pressure approaches the target value, the system automatically reduces motor speed to prevent overshoot, eliminating the need for conservative pre-setting of motor speed. This resolves the contradiction by enabling both fast inflation (through high initial motor speed) and precise pressure control (through real-time feedback-based speed adjustment).
Solution Approach 2:
The motor speed is made dynamic rather than static, transitioning from a fixed pre-determined speed to a variable speed that adapts to real-time pressure conditions. The system operates at high speed during early inflation and automatically slows down as pressure approaches the target, enabling both rapid inflation and precise pressure control without compromising packer element integrity.
2Productivity
If motor speed is increased to reduce inflation time, then productivity is improved, but pressure overshoot increases causing packer element damage
Solution Approach 1:
Real-time pressure monitoring provides feedback that enables the system to operate at high motor speeds during early inflation when overshoot is not yet a concern, then automatically reduce speed when pressure approaches the target. This feedback mechanism allows the system to achieve both high productivity and prevent harmful pressure overshoots that would damage packer elements.
Solution Approach 2:
The system takes preliminary action by continuously monitoring pressure and preparing to reduce motor speed before pressure overshoot can occur. By detecting the approach to target pressure and preemptively slowing the motor, the system prevents the harmful effect of overshoot while maintaining high productivity during the main inflation phase.
3Reliability
If motor ramp-down time is extended to reduce overshoot, then packer element damage is prevented, but inflation time is prolonged
Solution Approach 1:
The feedback-based control system dynamically determines the optimal ramp-down timing based on real-time pressure measurements rather than using a fixed extended ramp-down period. The system reduces motor speed precisely when pressure approaches the target value, achieving both element integrity protection and minimized total inflation time by eliminating unnecessary extended ramp-down periods.
Solution Approach 2:
The motor speed profile is made dynamic, with the ramp-down phase automatically adjusted based on real-time pressure conditions. Rather than using a static extended ramp-down period, the system adapts the deceleration timing and rate to the actual inflation state, achieving both element protection and time optimization through continuous adaptation.
Data Source
AI summary
The disclosure provides for a method for setting an inflatable packer. The method includes positioning an inflatable packer within a borehole, and pumping fluid into an inflatable element of the inflatable packer using a pump that is driven by a motor. The method includes measuring pressure of the inflatable element, determining a derivative of the measured pressure with respect to time, and determining onset of restraining of the inflatable element has occurred. Upon or after determining the onset of restraining, the method includes turning off the motor or slowing down an rpm of the motor. The disclosure also provides for a system, including a computer readable medium with processor-executable instructions stored thereon that are configured to instruct a processor to execute a pressure control algorithm to control a speed of the motor in response to pressure measurement data from the pressure sensor.