Choke Cv Curve Pressure Control Drilling
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Solution Overview
Problem
Current methods for controlling wellbore pressure in drilling operations lack precision and efficiency, particularly when fluid circulation is interrupted during connections, leading to potential instability and inaccurate pressure regulation.
Innovation Solution
A system utilizing a Cv curve to determine the optimal choke position, which allows for continuous pressure control by varying the backpressure applied to the annulus through a choke manifold, even when fluid is not circulating, using a combination of sensors and automated control systems to maintain desired downhole pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional pressure control methods are used during drilling operations, then pressure regulation is possible, but precision and stability are insufficient especially when fluid circulation is interrupted
Solution Approach 1:
The system employs a feedback control mechanism where a pressure sensor continuously monitors wellbore pressure and feeds this information to a controller. The controller compares the measured pressure with the desired pressure setpoint and automatically adjusts the choke position via an actuator to maintain precise pressure control, resolving the contradiction between precision and stability during circulation interruptions.
Solution Approach 2:
The patent replaces traditional manual or incremental mechanical pressure control methods with an automated electronic control system that uses a Cv curve model. The controller calculates the optimal choke position based on the desired pressure and the pre-determined Cv curve characteristics, then directly actuates the choke without requiring incremental manual adjustments, thereby improving both precision and reliability.
2Ease of operation
If incremental choke adjustments are made to control pressure, then pressure regulation is achieved, but the process is time-consuming and requires continuous manual intervention
Solution Approach 1:
The system implements self-service automated pressure control where the controller autonomously determines the optimal choke position using the Cv curve and automatically actuates the choke via an actuator. This eliminates the need for continuous manual intervention and incremental adjustments, allowing the system to self-regulate pressure rapidly and efficiently, thereby reducing operational time and effort.
3Productivity
If fluid circulation is interrupted during connections, then drilling operations can proceed, but pressure control becomes unstable and imprecise
Solution Approach 1:
The system performs preliminary action by pre-determining the Cv curve characteristics for the choke and storing them in the controller. This allows the controller to rapidly calculate the optimal choke position even when fluid circulation is interrupted during connections, maintaining pressure control stability without requiring continuous fluid flow. The pre-stored Cv curve data enables immediate pressure regulation responses.
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 precise and stable wellbore pressure control, preventing fluid loss and fracturing, while allowing for uninterrupted pressure regulation during connections, thereby enhancing drilling operations by maintaining optimal pressure conditions without the need for incremental adjustments.
Implementation Method 1
backpressure applied by a choke in a mud return line
Implementation Method 2
pressure applied by a dedicated backpressure pump
Data Source
AI summary
A method of controlling pressure in a wellbore can include determining a desired position for a choke, the determining being based on a Cv curve for the choke, and adjusting the choke to the desired position, thereby producing a desired backpressure. A wellbore drilling system can include a choke which variably restricts flow of fluid from the wellbore, and a control system which compares actual and desired wellbore pressures and, in response to a difference between the actual and desired wellbore pressures, adjusts the choke to a predetermined position which corresponds to a desired Cv of the choke. A method of controlling pressure in a wellbore can include comparing an actual wellbore pressure to a desired wellbore pressure and, in response to a difference between the actual and desired wellbore pressures, adjusting a choke to a predetermined position, the predetermined position corresponding to a desired Cv of the choke.