Flotation Device with Breakable Glass Barrier for Horizontal Casing
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Solution Overview
Problem
Conventional flotation devices face challenges in installing tubular casing members in wellbores with increased horizontal lengths due to increased drag and friction, which can exceed the load capacity of casing hooks, especially in shale wells, where issues like static mud gelation, washout, ledges, hole collapse, or sloughing shale can hinder the process.
Innovation Solution
The use of a self-contained flotation device with a stack of tempered glass discs and a retention system, which creates a gas-filled buoyancy chamber and can be decommissioned by applied pressure without requiring a drill bit, providing a controlled burst mechanism to ensure unobstructed access for further well-completion activities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional flotation devices are used to install casing strings in wellbores with increased horizontal length, then buoyancy is provided to reduce drag, but the drag and friction force exceed the load capacity of the casing hook
Solution Approach 1:
The flotation device creates a gas-filled buoyancy chamber that generates an upward buoyant force to counteract the downward gravitational force and frictional drag on the casing string. This counterweight mechanism reduces the net force that the casing hook must bear, enabling installation in horizontal well sections where conventional gravity-dependent methods fail.
Solution Approach 2:
The flotation device uses gas (pneumatics) to create the buoyancy chamber, utilizing gas pressure to maintain the chamber's integrity and provide continuous buoyant force. This pneumatic approach allows the system to overcome friction and drag forces without requiring additional mechanical force from the casing hook.
2Ease of operation
If seal members in conventional flotation devices are machined away by drill bits, then access is provided for further well-completion activities, but debris management and mechanical intervention are required
Solution Approach 1:
The breakable barrier replaces the conventional machinable seal member that requires drill bit intervention. The barrier is designed to fail at a predetermined burst pressure, transitioning from a mechanical removal process (drilling) to a pressure-based failure mechanism. This substitution eliminates the need for mechanical intervention and debris management while providing the same access function.
Solution Approach 2:
The breakable barrier's structural integrity is designed to change at a specific pressure threshold. By controlling the barrier's material properties and geometric parameters, it remains intact during installation and casing running, then fails predictably when exposed to predetermined burst pressure from completion fluids, providing unobstructed access without requiring mechanical removal.
3Reliability
If the length of the lateral well section is increased, then wellbore integrity is optimized, but the drag and friction force obstructs the process of pushing the casing to total depth
Solution Approach 1:
The buoyancy chamber generates an upward force that counteracts the increased downward drag and friction forces resulting from longer lateral well sections. This counterweight mechanism enables the casing string to be pushed to total depth even when the horizontal length is increased to optimize wellbore integrity and fracturing operations.
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
This solution reduces friction and drag, allowing for successful installation of tubular members to total depth by creating a buoyancy chamber and ensuring unobstructed access through controlled pressure application, avoiding the need for mechanical intervention and debris management.
Implementation Method 1
The floating casing bottom or lower portion is a widely-used option. Conventional casing flotation devices use air or light fluid that is trapped in the lower section of the casing string to create a buoyant chamber on the casing's lower end. This buoyant chamber can significantly reduce the weight of casing resting on the wellbore, and reduce drag, and friction
Implementation Method 2
The breakable barrier is configured to fail when exposed to a predetermined burst pressure. The controlled failure of the barrier provides unobstructed access through the flotation device
Data Source
AI summary
A downhole tool includes a housing configured to be connected between two tubular members. The housing includes a chamber and a plug assembly is disposed in the chamber and divides the chamber into an up-hole portion and a downhole portion. The plug assembly includes a glass member having a predetermined residual surface compression, at least a first face, and at least one strength-reducing surface feature on the first face. The strength-reducing surface feature is configured to cause the glass member to disintegrate when the glass member is exposed to a pressure in the up-hole portion of a magnitude that creates a tensile stress on the first face that exceeds the predetermined residual surface compression.