Downhole Coupling With Catcher for Fluid Separation and Rotation Control
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Solution Overview
Problem
Existing cementing methods for tubulars in bores face challenges in efficiently delivering and separating fluids, preventing cross-contamination, and managing differential rotation between inner and bore-lining tubings, which can lead to connection issues and fluid leakage.
Innovation Solution
A coupling system is introduced that connects an inner string to a bore-lining tubing, featuring a catcher and occluding members like balls or plugs, allowing fluid separation and pressure equalization, while preventing relative rotation through helical buckling or offsetting, and providing buoyancy with lower density materials in the annulus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an inner string is provided within the bore-lining tubing for cementing operations, then fluid delivery efficiency is improved, but differential rotation between the inner string and bore-lining tubing causes connection issues and fluid leakage
Solution Approach 1:
A coupling device is introduced as an intermediary component between the inner string and bore-lining tubing. This coupling includes a catcher mechanism that actively prevents differential rotation by capturing and restraining the inner string relative to the bore-lining tubing, thereby maintaining connection integrity while allowing the inner string to remain in place for fluid delivery operations.
2Productivity
If fluids are pumped through the inner string into the annular space, then cementing operation productivity is improved, but cross-contamination between fluids occurs without proper separation mechanisms
Solution Approach 1:
The coupling device is segmented into distinct functional zones: an occluding member section that seals against the inner string, a catcher section that prevents rotation, and flow path sections that guide different fluids. This segmentation creates physical barriers and dedicated flow channels that prevent cross-contamination between cement slurry, displacement fluid, and annular space fluids while maintaining efficient cementing operations.
3Device complexity
If the inner string is retained in the cemented tubing after cementing, then device complexity is reduced, but retrieval operations become difficult without a release mechanism
Solution Approach 1:
The coupling device incorporates a dynamic catcher mechanism that can transition between engaged and disengaged states. During cementing operations, the catcher is engaged to prevent rotation and maintain connection integrity. After cementing, the catcher can be disengaged through a release mechanism, allowing the inner string to be freely retrieved from the cemented tubing without damaging the coupling or bore-lining tubing.
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 ensures efficient fluid delivery, minimizes cross-contamination, maintains connection integrity, and reduces friction, enabling seamless cementing operations in various bore configurations.
Implementation Method 1
The member may be displaceable from an occluding position, for example the member may be held in an occluding position to occlude the inner string to allow the inner string above the member to be pressurized
Implementation Method 2
The coupling or inner string may include an open equalizing port to balance pressure between the inside of the inner-string and an inner annulus formed between the inner-string and the bore-lining tubing
Implementation Method 3
provides the assembly with a degree of buoyancy. This may reduce the friction between the assembly and a surrounding bore wall
Data Source
AI summary
A coupling connects an inner string to a lower end of a bore-lining tubing, such as a liner. The coupling includes a catcher and may be provided in combination with at least one member for translating through the inner string and landing in the catcher. The member may be an occluding member, such as a ball for occluding a flow passage through the coupling.