Spacer Spool Return Line for Closed-BOP MPD Circulation
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Solution Overview
Problem
Conventional pressure management in wellbore drilling is inadequate in narrow drilling windows, particularly in offshore drilling, leading to risks and the inability to maintain controlled circulation when the blowout preventor is closed, necessitating a switch to open-vessel systems that compromise pressure management.
Innovation Solution
A modified drilling spool integrated into the blowout preventor allows for a managed pressure drilling (MPD) alternate flow path from the wellbore annulus to the MPD choke, enabling continued closed-loop circulation even when circulation above the blowout preventor is prevented.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional pressure management is used in narrow drilling window applications, then the system operates with simple open-vessel configuration, but pressure control capability deteriorates and well control risks increase
Solution Approach 1:
The system divides the flow path into multiple segments: a primary flow path through the rotating control device and an alternate flow path through the drilling spool. This segmentation allows the system to maintain pressure control capability by switching between paths, resolving the contradiction between simple configuration and reliable pressure control in narrow drilling window applications
Solution Approach 2:
The system dynamically switches between the primary flow path (when blowout preventor is open) and the alternate flow path (when blowout preventor is closed). This dynamic adaptability maintains pressure control capability throughout different operational states, preventing the reliability deterioration that would occur with a static open-vessel configuration
2Reliability
If the blowout preventor is closed to prevent mud flow, then well control safety improves, but circulation capability deteriorates and MPD operations cannot continue
Solution Approach 1:
The drilling spool acts as an intermediary component that provides an alternate flow path when the blowout preventor is closed. This intermediary structure enables circulation to continue through the alternate path, resolving the contradiction between well control safety (achieved by closing the blowout preventor) and circulation capability (maintained through the alternate path)
3Device complexity
If conventional pressure management is used, then equipment complexity is reduced, but the ability to monitor and control wellbore pressure deteriorates
Solution Approach 1:
The alternate flow path through the drilling spool serves multiple functions: it maintains circulation capability, enables pressure monitoring, and supports MPD operations. This multi-functionality allows the system to achieve precise wellbore pressure monitoring and control without significantly increasing equipment complexity, as the same structural components serve multiple purposes
Data Source
AI summary
A system includes a rotating control device (RCD), a managed pressure drilling (MPD) choke, a blowout preventor (BOP), a component in the blowout preventor (BOP), and a drilling spool. The RCD is installed on the wellbore, seals an annulus of the wellbore, and provides a MPD flow path from the annulus of the wellbore to the MPD choke. The MPD choke is configured to apply a back pressure on the wellbore to drill the wellbore using a MPD technique. The BOP is installed downhole from the RCD on the wellbore. The component located in the BOP is configured to close to prevent mud from flowing to RCD. The drilling spool installed downhole from the component in the BOP has a MPD choke line outlet configured to provide a MPD alternate flow path from the annulus of the wellbore to the MPD choke when the component is closed.