Segmented Inflatable Packer for Wellbore Stress Testing
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Solution Overview
Problem
Conventional downhole tools are unable to withstand high-pressure stress test operations required for accurate measurement of downhole geological formation stresses, which is crucial for designing effective fracturing treatments in hydrocarbon production.
Innovation Solution
An inflatable packer assembly is used in the wellbore, comprising a mandrel with inflatable members that isolate a portion of the wellbore, allowing for high-pressure fluid injection to create microfractures and subsequent pressure monitoring to determine fracture closure and reopening pressures, thereby enabling the measurement of formation stresses without the need for proppants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional downhole tools are used for stress testing, then device simplicity is maintained, but the tools cannot withstand high-pressure stress test operations required for accurate measurement of formation stresses
Solution Approach 1:
The packer assembly is divided into multiple segments including inflatable members, sliding sleeves, and fixed sleeves that can independently move and seal. This segmentation allows each component to handle specific stress loads separately, enabling the overall assembly to withstand high pressures that would exceed the capacity of conventional single-structure tools.
Solution Approach 2:
The packer assembly incorporates movable sliding sleeves that can dynamically adjust their position along the mandrel in response to pressure changes. The sliding sleeves move to maintain sealing contact with the wellbore wall under varying high-pressure conditions, providing adaptive strength and reliability that static conventional tools cannot achieve.
2Measurement precision
If high-pressure fluid injection is used to create microfractures for accurate stress measurement, then measurement precision is improved, but the risk of tool failure increases
Solution Approach 1:
The inflatable members are constructed as flexible elastic shells that can expand and contract in response to pressure changes. These flexible membranes distribute high injection pressures uniformly across the wellbore wall, preventing stress concentration that could cause tool failure while enabling precise microfracture creation for accurate stress measurement.
Solution Approach 2:
The packer assembly is designed with redundant sealing mechanisms and pressure-distributing structures that cushion against potential pressure spikes during injection. The sliding sleeves and elastic inflatable members act as mechanical cushions that absorb and distribute extreme pressure loads before they can reach critical failure thresholds, protecting the tool while maintaining measurement precision.
3Measurement precision
If multiple inflatable members are used to isolate wellbore portions for stress testing, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The sliding sleeves serve multiple functions: they seal between the inflatable members and mandrel, provide pathways for inflation fluid, guide the movement of inflatable members, and maintain structural integrity under pressure. This multi-functionality reduces the need for separate components, allowing multiple inflatable members to be integrated without proportionally increasing overall device complexity.
Solution Approach 2:
The inflatable members are nested along the mandrel in a telescoping arrangement, with each inflatable member and its associated sliding sleeve contained within the structure of the previous one. This nested configuration allows multiple isolation zones to be created while minimizing the overall axial length and reducing the complexity of fluid distribution pathways compared to side-by-side arrangements.
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 allows for precise measurement of formation stresses, improving the design of fracturing treatments and enhancing hydrocarbon production by accurately determining key reservoir properties like fracture width, length, and closure pressure.
Implementation Method 1
An inflation flowline is disposed within the mandrel and in fluid communication with interiors of the first and second inflatable members for inflating the first and second inflatable members to isolate a portion of the wellbore
Implementation Method 2
An injection flowline is disposed within the mandrel for injecting a fluid into the isolated wellbore portion at a high enough pressure to create microfractures in the subterranean formation
Data Source
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AI summary
An inflatable packer assembly comprising a first fixed sleeve fixed to a mandrel, a first sliding sleeve moveable along the mandrel, and a first inflatable member connected to the first fixed sleeve and the first sliding sleeve. A second sliding sleeve is moveable along the mandrel, and a second inflatable member is connected to the first sliding sleeve and the second sliding sleeve. A second fixed sleeve is fixed to the mandrel and slidably engages the second sliding sleeve. An inflation flowline disposed within the mandrel is in fluid communication with interiors of the first and second inflatable members for inflating the first and second inflatable members to isolate a portion of a wellbore penetrating a subterranean formation. An injection flowline is disposed within the mandrel for injecting a fluid into the isolated wellbore portion at a high enough pressure to create microfractures in the subterranean formation.