Plug Assembly with Expandable Ring and Untethered Object
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Solution Overview
Problem
There is a need for methods and apparatus to provide a plug inside a tubing string containing well fluid, particularly using a two-step expansion mechanism involving deformable and rigid plug components for effective isolation and stimulation in wellbore operations.
Innovation Solution
The solution involves a plug assembly with an expandable continuous ring and a locking ring, where the expandable ring is radially deformed using a retrievable setting tool, and an untethered object is used to further expand the ring, creating a secure seal within the tubing string by anchoring devices penetrating the inner surface, enhancing the sealing and anchoring action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-step expansion mechanism is used, then the device complexity is reduced, but the reliability of fluid isolation is insufficient
Solution Approach 1:
The expansion mechanism is divided into two distinct steps: a first expansion step that expands the plug body to engage with the tubing wall, and a second expansion step that further expands the plug body to enhance sealing. This segmentation allows each expansion phase to perform a specific function, improving overall isolation reliability while keeping each individual expansion mechanism relatively simple.
Solution Approach 2:
The first expansion mechanism performs a preliminary expansion action to establish initial engagement and sealing before the second expansion mechanism acts. This preliminary action ensures the plug is properly positioned and initially sealed, creating a foundation for the subsequent expansion that enhances rather than replaces the initial sealing function.
2Manufacturing precision
If the plug components are made rigid, then the manufacturing precision is improved, but the adaptability to tubing surface variations is reduced
Solution Approach 1:
The plug body incorporates regions with different mechanical properties: some portions are designed to be more compliant to conform to tubing surface irregularities, while other portions maintain higher rigidity to provide structural support and precise dimensional control. This local differentiation allows the plug to simultaneously achieve manufacturing precision and surface adaptability.
Solution Approach 2:
The plug transitions from a static, rigid structure to a dynamic system that changes its mechanical properties during operation. The expandable components can adjust their degree of expansion and local compliance based on the tubing surface conditions, allowing the plug to adapt its shape and sealing characteristics while maintaining overall structural integrity.
3Force
If the untethered object is made larger, then the anchoring force is improved, but the ease of conveyance to the target location is reduced
Solution Approach 1:
The untethered object is designed with a nested structure where internal components are housed within external compartments. This nesting allows the object to maintain a compact overall size for easy conveyance through the tubing, while internal expansion mechanisms can generate substantial anchoring forces when deployed at the target location.
Solution Approach 2:
The untethered object transitions from a compact one-dimensional form during conveyance to a three-dimensional expanded structure when activated. The object remains small and easily transportable until it reaches the target location, at which point expansion in multiple dimensions generates the required anchoring force without requiring the object to be large throughout the entire conveyance process.
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 approach enables reliable fluid isolation and stimulation by ensuring a substantial flow isolation and anchoring within the tubing string, allowing for effective downhole operations with the plug assembly maintaining its position under pressure.
Implementation Method 1
the expandable ring is radially deformed using a retrievable setting tool
Implementation Method 2
expandable continuous ring... maintaining its position under pressure
Implementation Method 3
anchoring devices penetrating the inner surface, enhancing the sealing and anchoring action
Implementation Method 4
an untethered object is used to further expand the ring, creating a secure seal
Data Source
AI summary
A plug assembly includes an expandable assembly, a locking ring and a cup. The expandable assembly is adapted to be deformed radially over the locking ring and the cup. The locking ring has a stopping inner surface. The plug assembly is used with one or more untethered objects, the untethered objects having an outer surface adapted to couple with the cup, and the cup having an outer surface adapted to couple with the stopping inner surface of the locking ring. The combination of cup and untethered objects is also adapted to contact an inner surface of the plug assembly and, using well fluid pressure, to apply forces to the plug assembly. The forces cause the longitudinal movement of the cup and untethered objects while contacting the inner surface of the plug assembly until the cup contacts the stopping inner surface of the locking ring.