Float Collar Buoyancy Chamber for Horizontal Casing Drag
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Solution Overview
Problem
In hydrocarbon well drilling, significant friction or drag between the casing and the wellbore, especially in horizontal or deviated wells, limits the depth to which the casing can be run due to insufficient weight in the vertical section, making it difficult or impossible to complete the well.
Innovation Solution
A float collar tool with a cylindrical housing and an isolation barrier that creates a buoyancy chamber by trapping a light fluid, reducing drag by isolating it from heavier fluids, and a mechanism to transition the barrier from a closed to an open state to restore the passageway diameter after landing the casing, allowing for fluid communication and minimizing debris.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the casing weight is increased to overcome friction and drag in the wellbore, then the ability to progress casing to depth improves, but the device complexity and risk of casing damage increase
Solution Approach 1:
The patent introduces a buoyancy chamber filled with a light fluid (such as air or foam) within the casing string. This buoyant force counteracts the gravitational force acting on the casing, effectively reducing the downward weight. By reducing the effective weight of the casing string, the system can overcome friction and drag forces in deviated and horizontal wellbores without requiring excessive casing weight, thereby simplifying the casing configuration and reducing the risk of damage while maintaining the ability to progress to depth.
2Ease of operation
If a buoyancy chamber is created within the casing string, then drag forces are reduced and ease of running casing improves, but the device complexity increases due to additional components
Solution Approach 1:
The float collar tool is designed as a segmented structure with distinct functional zones: an isolation barrier section, a buoyancy chamber section, and a protective region section. This segmentation allows each component to perform its specific function independently while maintaining overall system simplicity. The isolation barrier can be a simple disc or valve that divides the chamber, the buoyancy chamber is a defined volume within the tool housing, and the protective region is a designated space for debris containment. This modular segmentation reduces the complexity of integrating these functions into a single compact tool.
Solution Approach 2:
The float collar tool employs a nested structure where the isolation barrier, buoyancy chamber, and protective region are arranged concentrically within the tool housing. The isolation barrier is positioned within the tool to define the buoyancy chamber volume, and the protective region surrounds or contains the other components. This nested arrangement maximizes space utilization and minimizes the overall tool diameter, allowing the complex multi-functional tool to be integrated without excessive size or complexity.
3Ease of operation
If the isolation barrier is used to create buoyancy chamber, then drag reduction is achieved, but debris may damage the barrier and restrict passageway diameter
Solution Approach 1:
The protective region is pre-configured within the float collar tool structure before the tool is deployed into the wellbore. This protective region acts as a sacrificial containment zone positioned between potential debris sources and the isolation barrier. By establishing this protective structure in advance, the system proactively prevents debris from reaching and damaging the isolation barrier, thereby maintaining barrier integrity and passageway diameter throughout the casing running operation and subsequent well operations.
4Length of moving object
If the casing string is run to greater depths in horizontal wells, then well completion capability improves, but friction and drag forces increase making running difficult
Solution Approach 1:
The buoyancy chamber filled with light fluid creates an upward buoyant force that counteracts the downward gravitational force on the casing string. In horizontal and deviated wellbores, this buoyant force directly opposes the friction and drag forces that resist casing movement. By reducing the effective weight through buoyancy, the net force required to overcome friction and drag is significantly reduced, enabling the casing string to be successfully run to greater depths in horizontal wells where drag forces would otherwise be insurmountable.
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
Enables the casing string to be run to greater depths and horizontal distances without damaging debris or restricting the casing diameter, overcoming drag forces that prevent completion of non-vertical wells by utilizing buoyancy and minimizing friction.
Implementation Method 1
a buoyancy chamber in which a light fluid is trapped... reducing drag by isolating it from heavier fluids
Data Source
AI summary
A float collar tool for running a casing string assembly into a wellbore includes a non-fragmenting rupture disc that temporarily isolates light fluid trapped in a lower portion of the casing string from heavier fluid in the upper portion of the casing string, thereby reducing the horizontal weight of the casing string by an amount sufficient to overcome a drag force. After the casing string is landed at a final location in the wellbore, the rupture disc is burst by increasing fluid pressure in the upper portion of the casing string. The increased pressure activates a piston that then moves the burst rupture disc into a protective region of the tool so that the inside diameter of the casing string is substantially restored.