Choke Valve Flow Measurement via Position Sensing
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Solution Overview
Problem
Conventional flow measurement techniques, such as Coriolis flowmeters, are expensive and have pressure limitations, making them unsuitable for some drilling equipment applications, and occupy valuable space in choke manifolds, necessitating a more efficient and space-effective method for measuring fluid flow rates in well drilling operations.
Innovation Solution
A choke valve system with a valve position sensor and controller that determines and adjusts the flow rate of return fluid, allowing for precise control of fluid flow and detection of kicks or losses in the wellbore, utilizing a choke valve with a linearly translatable gate and seat configuration that maintains a choke minimum passage area of at least 30% of the seat orifice area, enabling accurate flow rate measurement and pressure control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Coriolis flowmeters are used to measure return fluid flow rate, then measurement accuracy is improved, but cost and device complexity increase
Solution Approach 1:
The patent extracts the flow measurement function from the choke manifold system by using a separate, dedicated flowmeter positioned in the return fluid line downstream from the choke valve. This separates the measurement function from the pressure control function, allowing each to be optimized independently. The flowmeter is removed from the high-pressure choke manifold environment and placed in a lower-pressure return line, reducing complexity requirements.
Solution Approach 2:
The patent introduces an intermediary computational approach where the controller calculates flow rate based on measured choke valve position and pressure differential data, rather than relying solely on a complex mechanical flowmeter. This computational mediation allows for accurate flow measurement using simpler, less expensive sensors combined with mathematical modeling of fluid flow through the choke valve.
2Measurement precision
If Coriolis flowmeters are installed in the choke manifold, then flow measurement capability is improved, but available rig space is reduced
Solution Approach 1:
The flow measurement function is extracted from the choke manifold assembly and relocated to the return fluid line. This physical separation removes the flowmeter from the space-constrained choke manifold environment, allowing the manifold to maintain its compact configuration while still providing accurate flow measurement capabilities in the return line where space is more abundant.
3Manufacturing precision
If choke valve position is adjusted frequently to maintain constant bottom hole pressure, then pressure control accuracy is improved, but response time and operational complexity increase
Solution Approach 1:
The patent implements a feedback control system where the controller continuously monitors bottom hole pressure (through differential pressure measurements across the choke valve) and automatically adjusts choke valve position to maintain constant pressure. This closed-loop feedback eliminates manual intervention delays and provides rapid, precise pressure control by automatically responding to pressure changes and adjusting valve position accordingly.
Solution Approach 2:
The patent replaces manual mechanical pressure control with an automated electromechanical system. The controller uses electronic sensors to monitor pressure and position, then actuates the choke valve through an automated mechanism rather than manual operation. This substitution of manual mechanical control with automated electromechanical control significantly reduces response time and improves pressure control accuracy.
Data Source
AI summary
A drilling system includes a choke valve system in fluid communication with a wellbore via a fluid return line. The choke valve system is configured to receive a return fluid from the wellbore. The choke valve system includes a choke valve through which the return fluid flows and a valve position sensor configured to determine a position of the choke valve. The drilling system further includes a controller in signal communication with the valve position sensor. The controller is programmed to determine a flow rate of the return fluid through the fluid return line based on the determined position of the choke valve. The controller is further programmed to adjust the position of the choke valve in response to the determined flow rate of the return fluid.