Retaining Bands in Downhole Sealing Assemblies

Solution Overview

Problem

Conventional downhole tools, such as packers and bridge plugs, are prone to inadvertent deployment due to radial protrusions of bands, which can lead to damage and premature activation, especially when encountering wellbore or casing contact during drilling or milling operations.

Innovation Solution

A downhole apparatus featuring a radially expandable sealing assembly with a retaining assembly comprising segments and bands positioned in grooves, designed to resist extrusion and engage the wellbore, preventing premature activation and enhancing resistance to inadvertent deployment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If bands are used to hold segments tightly against the mandrel, then the segments are retained in place, but the bands protrude radially and offer limited resistance to inadvertent deployment

Engineering Contradiction:

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The retaining assembly is divided into multiple segments that can be held together by bands. This segmentation allows the structure to be retained tightly against the mandrel while the segmented design itself provides flexibility and controlled deployment characteristics, resolving the contradiction between tight retention and resistance to inadvertent activation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from a two-dimensional band structure to a three-dimensional retaining assembly with segments that can expand radially. This dimensional change allows the assembly to provide both tight retention when collapsed and significant resistance to inadvertent deployment when expanded, as the multi-layered structure engages with the wellbore in multiple directions.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the sealing assembly is made radially expandable, then it can engage the wellbore effectively, but it becomes more susceptible to extrusion and premature deployment

Engineering Contradiction:

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The retaining assembly is positioned and secured to the sealing assembly before deployment into the wellbore. This preliminary action of pre-securing the retaining structure prevents extrusion and premature deployment during handling and installation, while still allowing the sealing assembly to expand radially for effective wellbore engagement when intended.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The retaining assembly acts as an intermediary structure between the sealing assembly and the external environment. It mediates the conflicting requirements by providing a protective framework that prevents harmful extrusion while allowing the sealing assembly to perform its primary function of radial expansion for wellbore engagement.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If bands are positioned exposed to the wellbore, then they can be easily installed, but they protrude radially and may contact the wellbore causing premature activation

Engineering Contradiction:

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The bands are nested within grooves on the segments of the retaining assembly, rather than being exposed externally. This nesting arrangement maintains the simplicity of band installation while preventing radial protrusion that could cause premature deployment, as the bands are contained within the groove structures during both installation and operation.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 extrusion of the sealing assembly and reduces the risk of premature deployment, ensuring the downhole tool remains stable and functional during operations, even in high-pressure and high-temperature environments.

Implementation Method 1

The sealing assembly is radially expandable from an unset position to a set position in response to the application of axial force on the sealing assembly

Methodology Applied

Scientific EffectRadial expansion:

Implementation Method 2

The plurality of segments is adapted to resist extrusion of the sealing assembly

Methodology Applied

Scientific EffectMechanical constraint:

Implementation Method 3

The plurality of segments is adapted to expand radially to engage the wellbore when the sealing assembly is in the set position

Methodology Applied

Scientific EffectRadial expansion:

Data Source

PatentUS9133681B2Protected retaining bands

Publication Date: 2015.09.15

AI summary

An improved downhole tool apparatus for limiting the extrusion of a sealing elements in downhole tools that use segmented retaining assemblies, retaining shoes or retaining limiters. The apparatus provides for locating the retaining bands for the retaining assemblies in a groove on the inner surface of the retaining assembly so that the bands are protected from breaking prematurely by inadvertently contacting the wellbore, casing within a wellbore, or other object.