External Sensor Choke Pressure Control for Noisy Drilling Fluids
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Solution Overview
Problem
Conventional managed pressure drilling systems face challenges in accurately measuring fluid pressure due to compressible fluids and suspended cuttings, leading to noisy pressure readings and delayed choke control, which limits fine-tuned pressure management.
Innovation Solution
A choke system with an actuator, choke plunger, and a sensor external to the choke that measures actuator parameters such as force, torque, or current to determine fluid pressure, allowing for real-time control of fluid pressure without direct fluid communication, thereby reducing lag time and noise issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is placed in line with the choke to measure fluid pressure, then pressure measurement is possible, but the measurement becomes noisy and inaccurate due to compressible fluid and suspended cuttings
Solution Approach 1:
The patent extracts the pressure measurement function from direct fluid contact by using a force sensor on the choke plunger instead of a pressure sensor in the fluid line. This removes the measurement device from the harmful fluid environment, eliminating noise from compressible fluid and suspended cuttings while maintaining accurate pressure measurement capability through force measurement on the plunger.
2Reliability
If the choke is closed slowly to compensate for inaccurate pressure measurement, then measurement inaccuracies are mitigated, but the controllability and response time of the choke deteriorates
Solution Approach 1:
The patent implements real-time feedback control by measuring the force on the choke plunger with a force sensor and using this measurement to control choke movement. The control system receives real-time force data, determines actual fluid pressure, and adjusts choke position dynamically to maintain desired pressure, enabling both reliable control and fast response without the need for slow closure compensation.
3Loss of time
If a force sensor is used to measure force on the choking member, then real-time pressure determination becomes possible, but the device complexity increases
Solution Approach 1:
The patent uses the choke plunger as an intermediary element that transmits fluid pressure to a force sensor. Instead of placing a pressure sensor directly in the fluid path, the plunger acts as a mediator that converts fluid pressure into mechanical force that can be measured by the force sensor, eliminating lag time while keeping the overall system complexity manageable through a well-defined mechanical interface.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables faster and more precise control of fluid pressure by eliminating delays from fluid compressibility and noise, enhancing the controllability of the choke system.
Implementation Method 1
a force sensor disposed between the actuator and the choking member, the force sensor configured to measure a force exerted on the choking member by the fluid; and a control system configured to control the pressure of the fluid by: determining the pressure of the fluid based on the force measured by the force sensor, and wherein the force is proportional to the pressure of the fluid
Data Source
AI summary
A choke system for oilfield operations including an actuator; a choke including: a housing defining an interior flow path; a choke plunger coupled to and movable by the actuator; and a choking member coupled to and movable by the choke plunger within the interior flow path to adjust a pressure of a fluid in the interior flow path; a sensor external to the choke, the sensor configured to measure an actuator parameter; and a control system configured to control the pressure of the fluid by: determining the pressure of the fluid based on the actuator parameter measured by the sensor, and wherein the actuator parameter is proportional to the pressure of the fluid; and actuating the actuator to cause the choking member to move within the interior flow path until the pressure of the fluid reaches a desired pressure.