Fluid-Activated Ball Seat Support for High Pressure
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Solution Overview
Problem
Ball seats in oil and gas wells face limitations due to the high contact stresses on plastic balls, which can lead to failure, restricting the number of balls and actuations that can be performed through a conduit, as the seat inner diameter is reduced to manage pressure, limiting the size and number of balls that can be used.
Innovation Solution
Incorporating actuatable plug element support members within the ball seat housing that extend to provide additional mechanical support to the ball during pressurization, distributing the contact force across a larger area and reducing stress on the ball, allowing for higher pressure ratings and increased seat inner diameters, enabling more balls to be used without compromising sealability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the seat inner diameter is reduced to increase the contact area, then the contact stress on the ball is decreased, but the number of balls that can be used through the conduit is reduced
Solution Approach 1:
The invention introduces a new spatial dimension by adding support members that extend radially inward from the seat wall into the flow path. These support members create additional contact surfaces with the ball in the radial dimension, effectively increasing the total contact area without reducing the seat inner diameter, thus resolving the contradiction between contact stress reduction and maintaining conduit capacity for multiple ball passages.
Solution Approach 2:
The contact area between the seat and ball is segmented into multiple regions: the primary annular contact area between the ball equator and seat, plus additional contact areas between the ball poles and the support members. This segmentation distributes the contact stress across multiple discrete locations, reducing peak stresses while preserving the seat inner diameter for ball passage.
2Reliability
If the outer diameter of the ball is increased, then the sealability is improved, but the contact stress on the ball becomes higher
Solution Approach 1:
By extending support members radially into the flow path, the invention creates additional contact surfaces that distribute the load from larger balls. This allows balls with larger outer diameters (and thus better sealability) to be used without exceeding contact stress limits, as the support members share the burden of supporting the increased ball cross-sectional area exposed to pressure.
Solution Approach 2:
The support members are positioned at specific locations (radially inward from the seat wall) to provide localized support where needed. This local reinforcement allows the use of larger balls with improved sealability while concentrating the stress distribution benefit exactly where the ball contacts the support members, preventing excessive contact stress.
3Area of stationary object
If the contact area between ball and seat is minimized, then the seat inner diameter is maximized for tool passage, but the contact stress increases
Solution Approach 1:
The invention adds contact area in the radial dimension by extending support members into the flow path, rather than increasing contact area in the axial dimension by reducing seat inner diameter. This allows the seat inner diameter to remain maximized for tool passage while still providing increased contact area through the support members, thereby reducing contact stress without compromising conduit capacity.
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 solution effectively reduces contact stresses on the ball, allowing for higher pressure ratings and increased seat inner diameters, enabling more balls to be used in various applications, such as frac systems, without compromising sealability, thus enhancing the functionality and capacity of ball seats in oil and gas wells.
Implementation Method 1
The plug element support members are in fluid communication with the bore of the housing such that fluid, e.g., hydraulic fluid, being pumped into the ball seat can actuate the plug element support members causing the plug element support members to move from their retracted positions to their extended positions
Data Source
AI summary
Apparatuses for closing a well conduit comprise a housing having a longitudinal bore and a seat disposed within the bore. A chamber is disposed within the housing and includes a plug element support member, such as ram or piston, operatively associated within the chamber. The plug element support member has a retracted position and an extended position. A passageway is in fluid communication with the bore and the chamber. A plug element such as a ball or drop plug, is adapted to be disposed into the bore and landed on the seat to restrict fluid flow through the bore and the well conduit. Landing the plug element causes and allowing fluid pressure to build causes the plug element support member to move from the retracted position to the extended position to provide support to the plug element landed on the seat.