Buoyancy Assist Sleeve With Rupture Disk for Casing Drag
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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, especially in long lengths where friction is significant.
Innovation Solution
A buoyant chamber within the casing is created using a gas or fluid lighter than the well bore fluid, such as nitrogen, carbon dioxide, air, water, or diesel fuel, to reduce drag and facilitate easier placement by increasing buoyancy, and a buoyancy assist tool with a rupture disk mechanism that opens the casing once the desired depth is reached to allow passage of other tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If long lengths of casing are used to reach desired depth in deviated or horizontal well bores, then the casing can reach the target depth, but friction and casing drag increase significantly making it difficult to run the casing
Solution Approach 1:
The patent applies buoyancy as a counteracting force to reduce the effective weight of the casing string. A buoyancy chamber is created within the casing by introducing a buoyant fluid (such as nitrogen, carbon dioxide, air, water, or diesel fuel) that is lighter than the well bore fluid. This buoyant force opposes the gravitational force acting on the casing, significantly reducing the casing drag and friction during installation in deviated or horizontal well bores.
2Force
If a buoyant chamber is created in the casing to reduce drag, then casing drag is reduced making it easier to run casing to desired depth, but the casing becomes obstructed preventing passage of other tools
Solution Approach 1:
The patent employs a dynamic system where the buoyancy chamber can be selectively activated or deactivated. A rupture disk mechanism is installed within the casing that can be triggered at specific depths or conditions. When activated, the rupture disk allows the buoyant fluid to escape or be compressed, collapsing the buoyancy chamber and opening the casing bore for tool passage. This dynamic transformation enables the casing to switch between two functional states: buoyant for installation, and open for subsequent operations.
Solution Approach 2:
The patent divides the casing into functional segments: an upper section with the rupture disk mechanism and a lower section that can form the buoyancy chamber. The rupture disk acts as a separable element that, when activated, allows the buoyant fluid to be contained in a specific lower portion of the casing while leaving the upper portion open for tool passage. This segmentation enables simultaneous achievement of buoyancy reduction and tool accessibility.
3Reliability
If the casing is obstructed by the buoyancy mechanism, then buoyancy is maintained to reduce friction, but other tools cannot pass through the casing
Solution Approach 1:
The patent utilizes parameter changes in the buoyant fluid's state to resolve the contradiction. The buoyant fluid can be in different states (contained vs. released) depending on operational requirements. The rupture disk mechanism controls the transition between these states by allowing the fluid to escape or be compressed at predetermined points. This parameter change enables the system to maintain buoyancy when needed while allowing tool passage when required, without compromising the reliability of the buoyancy 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 buoyant chamber significantly reduces friction, enabling the casing to reach the desired depth without becoming stuck and allows for the passage of other tools through the casing without obstruction, maintaining an open bore that matches the casing's inner diameter.
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
a rupture disk mechanism that opens the casing once the desired depth is reached to allow passage of other tools
Data Source
AI summary
A buoyancy assist tool has an outer case and a rupture disk connected in the outer case. A sleeve is disposed in the outer case and movable from first to second position in the outer case. A rupture disk membrane of a rupture disk prevents the sleeve from moving to the second position prior to the rupture disk membrane rupturing. The outer case is configured to be connected in a well casing. A lock ring holds the sleeve in the first position.