Buoyant Chamber Casing String Friction Reduction
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Solution Overview
Problem
In extended reach wells or wells with complex trajectories, operators face difficulties in running a liner/casing due to drag forces, which can cause the liner to become stuck or prematurely set in the wellbore, leading to hole downsizing.
Innovation Solution
A sealing device with a frangible sealing element and a buoyant chamber filled with a fluid of lower specific gravity than the wellbore fluid is used, allowing the casing string to reduce friction and facilitate easier installation by increasing buoyancy and reducing contact forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If further downward force is applied to run the liner deeper, then the liner can reach greater depth, but the liner may be pushed into the sidewall of the wellbore and become stuck or threaded connections may be negatively impacted
Solution Approach 1:
The patent introduces a buoyant chamber filled with a fluid of lower specific gravity than the wellbore fluid, creating an upward buoyant force that counteracts the downward drag forces and weight of the liner. This buoyant force reduces the contact forces between the liner and wellbore sidewall, preventing the liner from being pushed into the sidewall while allowing it to reach greater depths.
2Ease of operation
If special low friction centralizers or special fluid additives are used to reduce effective friction coefficient, then the liner running ability is improved, but the device complexity and cost increase
Solution Approach 1:
The patent introduces a buoyant chamber as an intermediary mechanism that fills the space between the liner and wellbore with a low-specific-gravity fluid. This intermediary fluid mediates the interaction between the liner and wellbore by providing upward buoyant forces that reduce friction and contact forces, eliminating the need for complex low-friction centralizers or chemical additives.
3Force
If floating a liner against the wellbore is used to increase buoyancy, then the contact forces are reduced, but the liner may not be able to maintain proper positioning and contact with the wellbore
Solution Approach 1:
The buoyant chamber is positioned at specific locations along the liner, creating localized buoyant forces at those positions. This local quality approach allows the liner to maintain proper positioning and contact with the wellbore at critical points while reducing overall contact forces, balancing buoyancy with positioning stability.
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 solution effectively reduces friction and contact forces, enabling the casing string to reach deeper locations without becoming stuck, thus improving the efficiency and success rate of tubular running operations in challenging wellbore configurations.
Implementation Method 1
a buoyant chamber formed between the sealing device and the valve assembly, the buoyant chamber including a fluid having a lower specific gravity than a fluid in the wellbore
Data Source
AI summary
In one embodiment, a sealing device includes a tubular body having a bore; a collet seat having a plurality of collets; a frangible sealing element disposed in the collet seat and blocking fluid communication through the bore; and a releasable sleeve releasably attached to the tubular body and retaining the collet seat against the tubular body.