Hydrostatic Setting Mechanism for Subterranean Tools
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Solution Overview
Problem
Existing hydrostatically operated setting mechanisms for subterranean tools face issues such as piston bore warping due to large pressure differentials and unreliable rupture disc failure, leading to inconsistent tool actuation and increased costs and assembly time.
Innovation Solution
A valve assembly that allows pressure buildup on one side of a piston to equalize pressure on the other side, with a valve mechanism that opens at a predetermined pressure to mix high pressure with an atmospheric or low pressure chamber, eliminating the need for rupture discs and enabling predictable tool setting without bore warping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rupture discs are used to create pressure differential for piston actuation, then tool setting can be achieved, but the rupture disc failure pressure is unreliable and fragments can form that disturb tool operation
Solution Approach 1:
The invention removes the rupture disc component entirely from the system. Instead of using a rupture disc to create the pressure differential, the patent employs a valve assembly that opens at a predetermined pressure to achieve the same functional result without the harmful fragmentation issue
Solution Approach 2:
The rupture disc is a disposable component that fails at a predetermined pressure. The invention replaces this with a valve assembly that can be reset or is more durable, eliminating the need for a disposable fragmenting component
2Force
If large differential pressure is applied to rod pistons for tool actuation, then piston movement is achieved, but the piston bore warps from the pressure differential
Solution Approach 1:
The valve assembly dynamically controls the pressure differential applied to the piston. Rather than applying full hydrostatic pressure differential immediately, the valve opens at a predetermined pressure threshold, allowing controlled pressure equalization that reduces bore warping while still achieving sufficient actuation force
Solution Approach 2:
The invention changes the pressure parameter dynamically through the valve assembly. The valve transitions from closed to open state at a predetermined pressure, modifying the pressure differential parameter to prevent bore warping while maintaining adequate actuation force
3Ease of operation
If rupture discs are used for pressure differential creation, then tool actuation is possible, but assembly time and cost increase
Solution Approach 1:
The valve assembly serves multiple functions: it creates the pressure differential, prevents bore warping through controlled opening, and eliminates the need for separate rupture disc assembly. This multi-functionality reduces both assembly time and component count
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 provides predictable and consistent actuation of subterranean tools by eliminating rupture disc variability and associated costs, reducing assembly time, and minimizing piston bore warping through controlled pressure equalization.
Implementation Method 1
A valve assembly on the low pressure side of the piston allows pressure buildup on the high pressure side of the piston to the point where the valve opens and allows pressure equalization
Implementation Method 2
A spring is threaded onto the rod and bears against the piston to bias the piston in the direction of movement
Data Source
AI summary
A hydrostatically set tool operates by pressure buildup on one side of a piston that builds up pressure to the same degree on the opposite side of the piston. There is a valve assembly on the opposite side of the piston that at a predetermined pressure on a high pressure side of the valve assembly allows the assembly to open to mix high pressure on the opposite side of the piston with pressure in an atmospheric or low pressure chamber. This reduces the pressure on one side of the piston and makes the piston move to set the tool. Optionally the piston can be urged to move with low pressure differential such as with sizing of the port leading into the atmospheric chamber so that piston bore warping is reduced from the low differential pressures.