Adjustable Orifice Choke Valve Control for Stable MPD Pressure
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Solution Overview
Problem
Existing well drilling systems face challenges in quickly responding to pressure variations during Managed Pressure Drilling (MPD) due to the slow response of iterative control valve systems, which can lead to uncontrolled pressure fluctuations and potential blowouts.
Innovation Solution
A well drilling system incorporating a choke manifold with adjustable orifice choke valves and a controller that determines the appropriate choke position based on pressure differences, fluid density, and flow rates, allowing for rapid adjustment of annular fluid pressure to maintain a stable pressure window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If iterative control valve systems are used to control annular fluid pressure, then the system can adjust pressure, but the response time is slow
Solution Approach 1:
The patent replaces the iterative mechanical control valve system with an automated electronic control system that uses a controller to directly actuate the choke valve based on pressure sensor feedback. This substitution of mechanical iterative adjustment with electronic automated control dramatically improves response time while reducing operational complexity.
Solution Approach 2:
The patent implements a feedback control system where pressure sensors continuously monitor annular fluid pressure and feed this information back to the controller. The controller then automatically adjusts the choke valve position to maintain pressure within the desired window, eliminating the slow iterative manual adjustment process.
2Reliability
If pressure control is not sufficient, then the system is simple, but blowouts may occur
Solution Approach 1:
The patent employs feedback control through pressure sensors positioned at critical locations (annulus, drill string, surface) that continuously monitor pressure conditions and provide real-time data to the controller. This enables the system to detect pressure deviations and automatically adjust the choke valve to prevent blowouts, significantly improving reliability.
Solution Approach 2:
The control system is designed to automatically regulate annular fluid pressure without requiring constant manual intervention. The controller receives pressure feedback, calculates the required choke valve adjustment, and executes the control action autonomously, making the system self-regulating and highly reliable for preventing blowouts.
3Ease of operation
If iterative adjustment process is used, then the system is easier to operate, but the response to pressure variation is slow
Solution Approach 1:
The patent makes the choke control system self-operating by implementing automated feedback control. The controller automatically monitors pressure conditions through sensors and adjusts the choke valve position without requiring manual iterative adjustment by operators. This maintains ease of operation while dramatically improving response speed to pressure variations.
Solution Approach 2:
The patent replaces manual mechanical iterative adjustment with automated electronic control. The system uses electronic sensors and controllers to automatically regulate pressure, eliminating the need for operators to manually iterate through choke positions. This substitution maintains operational simplicity while achieving rapid response to pressure changes.
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
The system enables rapid and precise control of annular fluid pressure, enhancing safety and efficiency by avoiding pressure fluctuations and maintaining the pressure within the desired window, thus preventing blowouts and optimizing drilling operations.
Implementation Method 1
determine a difference in pressure (ΔP) between a set point annular pressure and a second fluid pressure at a position downstream of the choke manifold
Implementation Method 2
The choke valve has a flow coefficient value (Cv) for each choke position. The instructions relate Cv values to choke positions for the choke valve
Data Source
AI summary
A well drilling system is provided that includes a choke manifold and a controller. The choke manifold includes at least one choke valve. The choke valve is actuable between fully open and closed choke positions. The choke valve has a Cv value for each choke position. The controller is in communication with the choke valve and a non-transitory memory storing instructions. The instructions relate Cv values to choke positions for the choke valve. The instructions when executed cause the controller to: a) determine a difference in pressure (ΔP); b) input or determine a density value; c) input or determine a Q value; d) determine a first Cv value using the ΔP, the density value, and the Q value; and e) actuate the choke valve to a first choke position associated with the first Cv value.