Segmented Ball Seat and Rotational Locking Collet for Frac Ball Counter
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Solution Overview
Problem
Existing downhole tools face challenges in targeting multiple stages of a wellbore for stimulation and production due to the incremental size difference of frac balls, which limits the number of stages and reduces the flowbore cross-sectional area, compromising the effectiveness of stimulation operations.
Innovation Solution
A plug seat assembly with radially expanding seating elements and circumferentially oriented locking components allows multiple instances of the same size plug to be used, eliminating the need for incremental plug size reduction and maintaining a larger flowbore for stimulation fluids, while shortening the tool size through incremental radial disengagement of the collet and plug seat racks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If incremental size difference of frac balls is used to operate multiple frac sleeves, then the number of stages is limited, but the flowbore cross-sectional area is significantly reduced
Solution Approach 1:
The plug seat is divided into multiple arcuate seat segments that can independently move radially. Each segment can be actuated by a plug of the same size to seal off a specific frac sleeve, allowing multiple stages to be targeted without reducing plug size and maintaining flowbore cross-sectional area.
Solution Approach 2:
The invention transitions from axial movement (incremental plug size reduction) to radial movement (seat segments moving outward). This dimensional change allows the same sized plug to interact with multiple frac sleeves at different radial positions, eliminating the need for progressively smaller plugs and preserving the flowbore area.
2Adaptability or versatility
If radially expanding plug seat segments are used, then multiple same-size plugs can be used, but the device complexity increases
Solution Approach 1:
Multiple seat segments are merged into a single integrated plug seat assembly that operates as one unit. The segments are collectively actuated by plugs traveling through a single flowbore, combining the functionality of multiple independent mechanisms into a unified structure that reduces overall complexity.
Solution Approach 2:
The plug seat assembly is designed with multi-functionality, where the same structural components (seat segments, racks, collets) serve multiple purposes: radial expansion for sealing, rotational locking for stage isolation, and incremental disengagement for sequential operation. This universality reduces the need for additional specialized components.
3Length of stationary object
If collet and plug seat racks disengage radially, then tool size is shortened, but the locking mechanism complexity increases
Solution Approach 1:
The locking mechanism employs dynamic interaction between the collet rack and plug seat rack, where incremental radial disengagement during rotation creates a self-locking effect. The ratchet and pawl mechanism provides automatic one-way locking without requiring complex external actuation systems, achieving compact tool length through dynamic mechanical interaction.
Solution Approach 2:
The locking mechanism is self-service in nature, where the relative rotation between the collet and plug seat automatically engages the ratchet and pawl locking components. The mechanical interaction between racks and teeth provides inherent locking without requiring additional energy input or complex control systems, simplifying the overall mechanism while achieving the desired tool size reduction.
Data Source
AI summary
An apparatus for performing a wellbore operation with a plug includes a plug seat assembly that has a plug seat having a plurality of seat segments, at least one seat segment having a plug seat rack, and each plug seat segment having an inner surface contacting the plug. The plug seat assembly also has a collet having a collet rack and a locking ratchet, the collet rack incrementally radially disengaging from the plug seat rack during relative rotation between the collet and the plug seat, and a mandrel having a mandrel rack complementary to the locking ratchet. The plug seat assembly is positioned in a wellbore and a plug radially displaces the at least one plug seat segment of the plug seat assembly.