Hybrid Dissolvable Frac Plug With Anti-Rotation Drill-Out
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Solution Overview
Problem
Existing frac plugs in hydrocarbon wellbores face issues with components catching in drill bit teeth, leading to ineffective drilling due to free spinning, and sealing elements bouncing around, causing debris to bind up coiled tubing and disrupt drilling operations, which are costly and time-consuming to resolve.
Innovation Solution
A hybrid dissolvable plug with an annular sealing element and slip assembly that locks onto the wellbore wall, featuring anti-rotation connectors to prevent rotation and ensure effective cutting by the drill bit, and includes dissolvable materials to minimize drilling time and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional frac plugs are used, then zonal isolation is achieved, but components catch in drill bit teeth causing free spinning and ineffective drilling
Solution Approach 1:
The plug incorporates asymmetric features including a non-circular cross-section and angled extrusion rings that break symmetry to prevent rotation during drilling. The slip members are positioned at specific angular locations with asymmetric spacing, creating a configuration that resists rotational movement while maintaining drilling effectiveness.
Solution Approach 2:
The plug is pre-configured with extrusion rings and slip members in a compressed state during manufacturing, so that upon deployment and application of compression force, the slip members immediately engage with the wellbore wall to prevent rotation before drilling commences. This preliminary setup ensures rotational constraint is established prior to any drilling operations.
2Reliability
If sealing elements are made flexible for effective sealing, then sealing performance improves, but sealing elements bounce around causing debris to bind up coiled tubing
Solution Approach 1:
The extrusion rings serve as intermediary elements between the compression mechanism and the sealing elements. These rings distribute the compression force uniformly across multiple slip members and sealing surfaces, preventing localized stress concentrations that cause bouncing. The rings act as a mediating structure that stabilizes the flexible sealing elements during compression and drilling operations.
Solution Approach 2:
The sealing system is divided into multiple discrete slip members distributed around the plug circumference, with each slip member independently engaged by its own extrusion ring. This segmentation allows each sealing element to be controlled independently, preventing the bouncing and entanglement that occurs with single-piece flexible seals, while maintaining effective sealing through the collective action of multiple stable sealing points.
3Loss of time
If dissolvable materials are used to minimize drilling time, then drilling cost decreases, but material strength may be reduced
Solution Approach 1:
The plug employs a composite construction combining dissolvable materials (such as magnesium or aluminum alloys) for the main body to enable rapid dissolution, with reinforcement elements and structural components made from non-dissolvable or more durable materials. This composite approach allows the plug to maintain sufficient strength during the drilling and sealing operations while enabling timely dissolution after the wellbore is no longer in use.
Solution Approach 2:
Different portions of the plug are made from materials with different properties: the main body uses dissolvable materials for rapid removal, while critical structural elements like extrusion rings, slip members, and sealing components use stronger, more durable materials. This local differentiation ensures that each component has the appropriate material properties for its specific function during both the operational and post-operational phases.
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 plug effectively isolates wellbore sections, facilitates rapid drilling out by preventing rotation and debris entanglement, reducing downtime and costs associated with stuck tools and debris removal.
Implementation Method 1
a sealing element or 'packer' of the frac plug is squeezed end-to-end by one or more extrusion rings of the frac plug to thereby bulge and expand the sealing element outwardly toward the inside of the casing string to provide a hydraulic seal
Implementation Method 2
one or more slips of the frac plug extend outwards and bite into the inside of the casing string to secure the frac plug to the casing string at the desired location
Data Source
AI summary
A frac plug is disclosed that is used for isolating a lower portion of a wellbore from an upper portion to enable a fracking process on newly created perforations in casing or liner pipe where the frac plug is particularly designed rapid drill out after all the fracking operations have been completed. The frac plug includes arrangements for holding the polymer or rubber element from rotation as the plug is being drilled. One arrangement includes pins that lock the polymer element to the bottom cone. In another, the polymer element is simply bonded by adhesive to the faceted cone. The facets on the cone prevent the cone from rotating in the wellbore by being pressed against the flat bottom slip segments that remain locked to the casing or liner pipe.