Drilling Pressure Control via Bypass Flow and Feedback
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Solution Overview
Problem
Current well drilling operations face challenges in precisely controlling bottom hole pressure and flow, particularly during connections in the drill string, where fluid circulation is interrupted, leading to difficulties in maintaining desired downhole pressures without causing pressure transients or fluid influx/exflux issues.
Innovation Solution
The system employs a pressure and flow control system that includes a rotating control device (RCD) and a hydraulics model, along with sensors and automated control systems, to regulate annulus pressure by varying flow through chokes and bypass lines, ensuring continuous pressure control even during drill string connections, using a combination of sensors and automated control to maintain desired downhole pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fluid circulation is interrupted during drill string connections, then drill string assembly operations can be performed, but bottom hole pressure control is lost and pressure transients occur
Solution Approach 1:
The system performs preliminary actions by establishing a bypass flow path before drill string connections are made. The bypass line is pre-configured with a flow control device that can be activated to maintain fluid circulation through the annulus during connections, preventing pressure control loss before the problem occurs
Solution Approach 2:
A bypass line acts as an intermediary flow path that allows drilling fluid to continue circulating through the annulus during drill string connections. This intermediate pathway transfers the fluid flow function from the blocked drill string interior to the annulus, maintaining pressure control through the choke system
2Reliability
If traditional choke control is used during drill string connections, then some pressure control is maintained, but precise bottom hole pressure control is lost due to flow interruption
Solution Approach 1:
The system uses feedback from bottom hole pressure sensors and annulus pressure sensors to continuously monitor pressure conditions. The controller receives this feedback and automatically adjusts the choke flow control device to maintain precise bottom hole pressure control, creating a closed-loop control system that compensates for connection-induced flow interruptions
Solution Approach 2:
The system replaces manual mechanical choke adjustment with an automated electronic control system. The controller electronically actuates the choke flow control device based on sensor feedback, substituting precise electronic control for traditional mechanical adjustment, enabling accurate pressure control even during flow interruptions
3Device complexity
If manual pressure control methods are used, then system complexity is reduced, but response time to pressure changes is too slow to prevent fluid influx or loss
Solution Approach 1:
The control system performs self-service by automatically monitoring pressure conditions and adjusting choke opening without human intervention. The controller continuously reads sensor data and autonomously actuates the choke flow control device to maintain desired bottom hole pressure, making the system self-regulating and eliminating manual control delays
Solution Approach 2:
Real-time feedback from bottom hole pressure sensors and annulus pressure sensors enables the controller to detect pressure deviations and immediately adjust choke positioning. This continuous feedback loop ensures rapid response to pressure changes, preventing fluid influx or loss by automatically compensating for disturbances as they occur
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
This approach allows for precise control of bottom hole pressure and flow, preventing fluid loss or influx, and maintaining stable drilling conditions by continuously regulating annulus pressure, even when fluid circulation is interrupted, thus enhancing drilling efficiency and safety.
Implementation Method 1
The annulus is typically closed during drilling through use of a rotating control device (RCD, also known as a rotating control head or rotating blowout preventer) which seals about the drill pipe as it rotates
Implementation Method 2
The system employs a pressure and flow control system that includes a rotating control device (RCD) and a hydraulics model, along with sensors and automated control systems, to regulate annulus pressure by varying flow through chokes
Implementation Method 3
utilizing a combination of sensors and automated control to maintain desired downhole pressures
Data Source
AI summary
A well drilling system includes a flow control device regulating flow from a rig pump to a drill string, the flow control device being interconnected between the pump and a standpipe manifold, and another flow control device regulating flow through a line in communication with an annulus. Flow is simultaneously permitted through the flow control devices. A method of maintaining a desired bottom hole pressure includes dividing drilling fluid flow between a line in communication with a drill string interior and a line in communication with an annulus; the flow dividing step including permitting flow through a flow control device interconnected between a pump and a standpipe manifold.