Buoyancy Assist Tool for Casing Drag Reduction
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Solution Overview
Problem
Running well casing to the desired depth in deviated or horizontal well bores is challenging due to high casing drag, which can cause the casing to become stuck, leading to potential damage when excessive force is applied.
Innovation Solution
A buoyancy chamber is created within the casing using a fluid lighter than the well bore fluid, such as air or a liquid, to reduce friction, and a buoyancy assist tool with a rupture disk and permeable membrane mechanism that opens the casing path once the desired depth is reached, allowing tools to pass through without obstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a buoyancy chamber is created in the casing using air or fluid, then casing drag is reduced and it becomes easier to overcome friction, but the device complexity increases due to the additional buoyancy assist tool with rupture disk and membrane mechanism
Solution Approach 1:
The buoyancy assist tool is divided into distinct functional segments: a buoyancy chamber for reducing drag, a rupture disk for pressure-activated deployment, and a membrane mechanism for controlling casing movement. This segmentation allows each component to perform its specific function independently, resolving the contradiction by making the complex device more manageable and effective.
Solution Approach 2:
The buoyancy chamber is pre-filled with air or lighter fluid before deployment, and the rupture disk is pre-set to burst at a specific pressure threshold. This preliminary preparation ensures that when the tool is deployed, the buoyancy force is immediately available to reduce casing drag, and the rupture disk automatically activates the membrane mechanism without requiring additional control systems, thus reducing operational complexity.
2Adaptability or versatility
If the casing path is opened by moving the sleeve to allow tools to pass through, then the bore remains accessible for other tools, but the structural integrity and sealing of the buoyancy chamber may be compromised
Solution Approach 1:
The membrane mechanism is extracted as a separate, movable component that can be independently actuated. When tools need to pass through, the membrane is selectively moved or retracted, opening a passage without requiring removal of the entire buoyancy assist tool. This allows tool passage while maintaining the integrity of the buoyancy chamber structure.
Solution Approach 2:
The membrane is designed as a dynamic component that can change its position or configuration based on operational needs. It can seal the passage when buoyancy maintenance is critical, and open when tool passage is required. This dynamic adaptability resolves the contradiction by providing both sealing reliability and tool passage versatility through a single flexible mechanism.
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 buoyancy chamber significantly reduces friction, enabling the casing to reach the desired depth while maintaining an open bore for other tools to pass through, preventing damage and ensuring proper placement.
Implementation Method 1
Creating a buoyant chamber in the casing utilizing air or a fluid lighter than the well bore fluid can reduce the drag making it easier to overcome the friction and run the casing to the desired final depth
Implementation Method 2
Fluid flow through the permeable membrane detaches the sleeve from the outer case and moves the sleeve from the first to the second position
Data Source
AI summary
A buoyancy assist tool has an outer case and a sleeve disposed in the outer case. The sleeve is movable from first to second positions in the outer case. A permeable membrane is attached to the movable sleeve at a lower end thereof. A rupture disk is mounted in the outer case. Fluid flow through the permeable membrane detaches the sleeve from the outer case and moves the sleeve from the first to the second position. In the second position, the sleeve creates an open bore for the passage of downhole tools therethrough.