Wedge-Shaped Extrusion Ring Assembly with Anchoring Feature

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Solution Overview

Problem

Current sealing systems in subterranean tools face challenges in maintaining effective seals across varying gap sizes and pressure differentials, particularly in unconventional drilling and completion operations, where elastomeric seals tend to extrude and overstress the wellbore, leading to leakage and loss of production.

Innovation Solution

A wedge-shaped extrusion ring assembly with a backup ring system that adjusts its position based on the gap size, using ramps and a pedestal ring to maintain contact with the borehole wall, directing reaction forces to prevent extrusion and anchoring the sealing element, thereby stabilizing the seal across extended reach applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a frack packer seal is used to prevent fluid and proppant travel in the borehole, then sealing effectiveness is improved, but the elastomeric seal tends to extrude through gaps in the anti-extrusion backup system

Engineering Contradiction:

Improvesealing effectivenessVSAvoidelastomer extrusion

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The anti-extrusion backup system is divided into multiple segments: a first anti-extrusion backup portion and a second anti-extrusion backup portion positioned at opposite ends of the elastomeric seal. This segmentation creates multiple barriers that the elastomer must pass through, significantly reducing extrusion risk while maintaining sealing effectiveness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The anti-extrusion backup portions are pre-positioned against the elastomeric seal before the packer is set. This preliminary positioning ensures that when the seal expands under pressure, the backup portions are already in place to prevent extrusion, eliminating the need for reactive measures after extrusion begins.

Inventive Principle:

Principle #10Preliminary action

2Stability of the object's composition

If anchoring mechanisms with anchor teeth are used to prevent packer movement, then packer stability is improved, but the anchor teeth create point load locations that can overstress the formation

Engineering Contradiction:

Improvepacker stabilityVSAvoidformation overstress

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

Instead of using discrete anchor teeth that create concentrated point loads, the invention employs a continuous anti-extrusion backup ring that distributes forces uniformly along the circumference of the packer. This local quality change transforms concentrated stresses into distributed stresses, preventing formation overstress while maintaining packer stability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The anti-extrusion backup ring serves as an intermediary between the elastomeric seal and the formation wall. It mediates the interaction by providing a continuous contact surface that distributes the anchoring forces, rather than allowing direct point-contact between anchor teeth and formation, thus preventing localized overstress.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the elastomeric seal is energized to maintain seal integrity, then sealing capability is improved, but movement from tube movement further energizes the seal causing additional overstress of the wellbore

Engineering Contradiction:

Improveseal integrityVSAvoidwellbore overstress

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The anti-extrusion backup portions are positioned beforehand to cushion and absorb the energizing forces generated by elastomeric seal expansion. This preliminary cushioning prevents these forces from being transmitted to the wellbore formation, protecting against overstress while allowing the seal to maintain its integrity through controlled energization.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 prevents elastomer extrusion and maintains a stable seal across varying gap sizes and pressure differentials, reducing the risk of leakage and overstressing the wellbore, while allowing for uniform load distribution and controlled packer movement.

Implementation Method 1

A sealing element is flanked by wedge-shaped extrusion ring assemblies. The rings climb a ramp on an adjacent pedestal ring on the way out to the borehole wall.

Methodology Applied

Scientific EffectWedge: Wedge

Data Source

PatentUS9995103B2Extended reach anti-extrusion ring assembly with anchoring feature

Publication Date: 2018.06.12 BAKER HUGHES CO

AI summary

A sealing element is flanked by wedge-shaped extrusion ring assemblies. The rings climb a ramp on an adjacent pedestal ring on the way out to the borehole wall. Depending on the dimension of the gap to be spanned the extrusion rings slide part way up the pedestal ring ramp or to the top of the pedestal ring. An anchor ring is initially forced up an opposite ramp of the pedestal ring. If the sealing gap is short the anchor ring touches the borehole wall to act as an anchor for the plug while remaining spaced apart from the extrusion ring assembly. For larger gaps the anchor ring moves out far enough to the borehole wall and in contact with the extrusion ring located on top of the pedestal so that reaction forces are directed to keep the anchor ring wedged in position for support of the extrusion ring assembly.