Pressurized Flotation Apparatus for Tubular Collapse Prevention
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Solution Overview
Problem
In directional drilling, especially extended reach drilling, tubulars face collapse due to equivalent circulating density (ECD) created by the running speed, which existing technologies fail to effectively prevent.
Innovation Solution
The use of a flotation apparatus with a tubular, base, and float shoe, where the inner volume is filled with a flotation fluid of lower density than the surrounding fluid, and sealing members that rupture at specific pressure differential values to allow pressurization and prevent collapse, combined with flow control devices to manage fluid flow and maintain buoyancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If tubulars are run at high speed in directional drilling, then productivity is improved, but tubular collapse occurs due to equivalent circulating density (ECD)
Solution Approach 1:
The patent applies buoyancy as a counteracting force to prevent tubular collapse. A flotation device filled with low-density fluid (such as nitrogen or air) is attached to the tubular, creating an upward buoyant force that counterbalances the external hydrostatic pressure and ECD-induced collapse forces, allowing high-speed running without structural failure
Solution Approach 2:
The flotation device utilizes pneumatic principles by filling an enclosed volume with compressible gas (nitrogen or air) at controlled pressure. This pneumatic cushion absorbs pressure differentials and maintains structural integrity under varying downhole conditions, preventing collapse while enabling high-speed installation
2Strength
If flotation fluid is used to provide buoyancy, then tubular collapse is prevented, but device complexity increases
Solution Approach 1:
The flotation device is merged with the tubular assembly as an integrated unit rather than a separate attachment. The base connects to the tubular, and the float shoe with sealing members is combined into a single coordinated system, reducing overall complexity while maintaining collapse prevention functionality
Solution Approach 2:
The patent employs rupture members with specific pressure differential thresholds that change the system state from sealed to open. These parameter-based triggers automatically activate buoyancy when needed, simplifying control while ensuring collapse protection activates at critical pressure differentials
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
Prevents tubular collapse by providing buoyancy and maintaining internal pressure, allowing safe installation of tubulars in wellbores even at challenging depths and speeds, thereby enhancing the execution of directional drilling operations.
Implementation Method 1
The inner volume is filled with a flotation fluid of lower density than the surrounding fluid
Implementation Method 2
The first sealing member is configured to rupture when exposed to a pressure differential that is at least equal to the first threshold pressure differential value
Data Source
AI summary
An apparatus includes a tubular, a base, and a float shoe. The base includes a first sealing member and a flow control device. The first sealing member is configured to prevent fluid flow into and out of the inner volume of the tubular up to a first pressure differential value. The first sealing member is configured to rupture when exposed to a pressure differential that is at least equal to the first pressure differential value. The flow control device is configured to allow fluid to enter the inner volume and prevent fluid from exiting the inner volume through the flow control device. The float shoe includes a second sealing member configured to prevent fluid flow into and out of the inner volume up to a second pressure differential value and configured to rupture when exposed to a pressure differential that is at least equal to the second pressure differential value.