Straddle Packer Equalizing Valves Pressure Unsetting

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Solution Overview

Problem

The existing straddle packer systems face difficulties in unsetting the upper and lower packers from a wellbore after a treatment operation due to pressure differentials, which require excessive force that can lead to equipment failure or swabbing, damaging the packers.

Innovation Solution

Incorporating upper and lower equalizing valves that equalize pressure across the seal members, allowing the packers to remain engaged without moving when the valves are actuated, and then de-energizing them for easy movement and repositioning within the wellbore.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If excessive force is applied to unset the packers from engagement with the wellbore, then the packers can be removed, but the work string may break or collapse

Engineering Contradiction:

Improveunpacker operationVSAvoidwork string strength

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The patent replaces the purely mechanical force-based unsetting system with a pressure-based system. Equalizing valves allow pressurized fluid to equalize the pressure differential across the packer elements, eliminating the need for excessive mechanical force on the work string. This substitutes hydraulic pressure control for mechanical force application, resolving the contradiction between ease of operation and work string strength.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If excessive force is applied to unset the packers, then the packers can be removed, but the packers may swab and become damaged

Engineering Contradiction:

Improveunpacker operationVSAvoidpacker integrity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent replaces mechanical force-based unsetting with a pressure-based unsetting mechanism. By using equalizing valves to balance pressure across the packer elements, the system eliminates swabbing motions that would damage the packers. This allows easy operation while maintaining packer integrity through controlled pressure equalization rather than mechanical forcing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If the pressure differential is maintained across the packers, then the packers remain sealed, but the packers cannot be unset without excessive force

Engineering Contradiction:

Improveseal engagementVSAvoidunpacker operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent makes the pressure differential dynamic rather than static. The equalizing valves can be opened to equalize pressure when unsetting is needed, and closed to maintain the pressure differential for sealing during operation. This dynamic control allows the system to switch between sealed engagement and easy unsetting by simply changing the valve state, resolving the contradiction between maintaining seal engagement and enabling unpacker operation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The equalizing valves act as intermediaries between the pressurized fluid and the packer elements. By controlling the flow of pressurized fluid through these valves, the system can mediate the pressure differential across the packers, allowing controlled equalization for unsetting while maintaining the pressure differential for sealing when needed.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Ease of operation

If the straddle packer system is designed for easy movement, then it can be repositioned, but it cannot maintain sealed engagement under pressure differential

Engineering Contradiction:

Improvesystem repositioningVSAvoidseal engagement

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent makes the pressure control dynamic through the equalizing valves. During operation, the valves remain closed to maintain the pressure differential that ensures reliable seal engagement. When repositioning is needed, the valves are opened to equalize pressure, allowing easy movement without compromising seal integrity during the operational phase. This dynamic pressure control resolves the contradiction between easy repositioning and reliable seal engagement.

Inventive Principle:

Principle #15Dynamics

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 solution enables the straddle packer system to be easily moved and repositioned without swabbing or equipment damage, facilitating multiple uses by maintaining seal engagement while equalizing pressure across the packers.

Implementation Method 1

equalizing pressure across the upper seal member by applying a tension force to actuate an upper equalizing valve of the system

Methodology Applied

Scientific EffectPressure equalization: Pressure Gradient

Data Source

PatentUS10138704B2Straddle packer system

Publication Date: 2018.11.27 WEATHERFORD TECHNOLOGY HOLDINGS LLC

AI summary

A straddle packer system includes an upper seal member, a lower seal member, an upper equalizing valve configured to equalize pressure across the upper seal member, a lower equalizing valve configured to equalize pressure across the lower seal member, and an anchor. The upper and lower seal members do not move when actuating the upper and lower equalizing valves, respectively, into an unloading position to equalize the pressure across the upper and lower seal members.