Self-Centralizing Slip and Cone System for Downhole Tools
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Solution Overview
Problem
Existing downhole tool anchoring assemblies often fail to center the packing element properly within the wellbore, leading to premature failure due to uneven expansion and increased force requirements, and removal of components is hindered by rotational interference with drilling or milling tools.
Innovation Solution
A non-rotational cone and integral slip assembly system that breaks into designated segments, utilizing a geometric structure with longitudinal fins and channels to ensure even spacing and rotational locking, preventing premature failure and facilitating easy removal by preventing rotation during drilling or milling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional slip assembly is used, then the anchoring function is achieved, but the packing element cannot be centered properly leading to uneven expansion and premature failure
Solution Approach 1:
The slip assembly is divided into multiple individual slips (typically 3-6) spaced around the circumference of the mandrel, rather than using a single continuous slip ring. Each slip is an independent component that can be positioned at specific angular locations. This segmentation allows the slips to be distributed evenly around the mandrel, providing uniform radial support and enabling proper centering of the packing element, thereby preventing uneven expansion and premature failure.
2Ease of repair
If the downhole tool components are allowed to rotate during drilling or milling operations, then the removal process becomes difficult or impossible
Solution Approach 1:
The mandrel is designed with a non-circular cross-section (such as hexagonal or octagonal) that includes flat surfaces or corners. The slip assemblies are positioned such that their outer surfaces contact these flat surfaces or corners of the mandrel. This asymmetric geometric configuration creates mechanical interference that prevents rotational movement of the mandrel and attached components during drilling or milling operations, ensuring the tool remains stationary for easy removal.
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 system effectively centers the packing element within the wellbore, preventing premature failure and enabling easier removal of downhole tools by ensuring the anchoring assembly remains stationary during drilling or milling operations.
Implementation Method 1
The improved cone and integral slip assembly are adapted to interact break the slip assembly into slip segments at predetermined locations as the integral slip assembly traverses the cone
Implementation Method 2
The slips include a tapered surface that is adapted to mate with a tapered surface of the cone. As an axial force is applied to the downhole tool, the slips ride up on the tapered surface of the cone, and are thus driven outwardly, away from the mandrel
Implementation Method 3
The axial compression of the packing element causes the packing element to expand radially against the wellbore creating a sealing barrier that isolates a portion of the well
Implementation Method 4
A non-rotational cone and integral slip assembly system that breaks into designated segments, utilizing a geometric structure with longitudinal fins and channels to ensure even spacing and rotational locking
Data Source
AI summary
An improved cone and integral slip assembly is described for use in the anchoring assembly of a downhole tool, such as a bridge plug, frac plug, or cement retainer. The cone may include external fins that are integral to and run axially along the cone. The integral slip assembly includes at least one axial slot, which facilitates subsequent breaking up of the integral slip assembly into individual slip segments. Each slip segment may include a channel that is adapted to mate with an external fin of the cone. As the integral slip assembly traverses the cone, the channels of the slip segments ride on the fins encouraging the integral slip assembly to break apart along the slots into the slip segments. The spacing of the fins and corresponding channels in the slip segments are positioned such to ensure that the slip segments are advantageously positioned around the cone thus, locating the packing element of the plug in the center of the wellbore. The channels in the slip segments mating with the fins also provide an anti-rotation mechanism to facilitate removal of the tool.