Straddle Packer Stress Anisotropy Alteration
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Solution Overview
Problem
Conventional hydraulic fracturing methods often fail to create complex fracture networks due to stress conditions in subterranean formations, limiting hydrocarbon recovery by restricting the extension of fractures and dilation of natural fractures.
Innovation Solution
A method involving a straddle-packer assembly is used to alter stress anisotropy in fracturing intervals by isolating and fracturing specific intervals, thereby inducing complex fracture networks by altering the stress conditions and promoting branched fractures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydraulic fracturing methods are used, then fractures can be created in subterranean formations, but the stress conditions prevent fracture extension and natural fracture dilation, limiting complex fracture network formation
Solution Approach 1:
The method applies preliminary actions by first creating initial fractures in specific intervals, then using those fractures to alter stress conditions in adjacent intervals before creating additional fractures. This sequential approach prepares the formation stress state to enable subsequent complex fracture network development that would not be possible under original stress conditions.
Solution Approach 2:
The wellbore is divided into multiple discrete fracturing intervals separated by packers, allowing independent fracture creation in each interval. This segmentation enables controlled stress modification in specific zones, which can then influence fracture behavior in adjacent zones to create complex networks rather than simple single-plane fractures.
2Adaptability or versatility
If stress anisotropy is not altered, then conventional single-plane fractures are formed, but complex fracture networks and branched fractures cannot develop
Solution Approach 1:
The fracturing operation is conducted in periodic stages, with each stage creating fractures in specific intervals and allowing stress conditions to evolve. This periodic fracturing approach enables stress anisotropy to be progressively altered, creating conditions favorable for complex fracture network development while maintaining manageable operational complexity through structured pacing.
Solution Approach 2:
Previously created fractures act as intermediaries that transfer and modify stress conditions to adjacent formation intervals. These fracture-induced stress changes serve as a mediator between the fracturing operation and the natural formation stress field, enabling complex fracture network development without requiring direct complex intervention in each zone.
3Quantity of substance
If multiple fractures are propagated simultaneously, then fracture interaction may occur, but stress conditions discourage sufficient dilation of natural fractures and branched fracture development
Solution Approach 1:
The method creates fractures in a predetermined sequence rather than simultaneously, allowing each fracture to establish itself and modify local stress conditions before the next fracture is created. This preliminary fracture creation serves as preparation for subsequent fractures, enabling natural fracture dilation and branched fracture development that would be inhibited by simultaneous fracturing operations.
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 method effectively creates complex fracture networks, enhancing hydrocarbon recovery by increasing the connectivity of the reservoir and allowing more pathways for hydrocarbon production.
Implementation Method 1
providing a straddle-packer assembly to alter the stress anisotropy of a fracturing interval of the subterranean formation
Implementation Method 2
The straddle-packer assembly comprises a first packer at a lower end of the straddle-packer assembly, an injection port sub-assembly above the first packer, and a second packer above the injection port sub-assembly
Implementation Method 3
a fracturing fluid may be introduced into a portion of a subterranean formation penetrated by a wellbore at a hydraulic pressure sufficient to create or enhance at least one fracture therein
Data Source
AI summary
A method of inducing fracture complexity within a fracturing interval of a subterranean formation is provided. The method comprises defining a stress anisotropy-altering dimension, providing a straddle-packer assembly to alter a stress anisotropy of a fracturing interval, based on defining the stress anisotropy-altering dimension, isolating a first fracturing interval of the subterranean formation with the straddle-packer assembly, inducing a fracture in the first fracturing interval, isolating a second fracturing interval of the subterranean formation with the straddle-packer assembly, inducing a fracture in the second fracturing interval, wherein fracturing the first and second fracturing intervals alters the stress anisotropy within a third fracturing interval, isolating the third fracturing interval with the straddle-packer assembly, and inducing a fracture in the third fracturing interval. The straddle-packer assembly comprises a first packer, an injection port sub-assembly above the first packer, and a second packer above the injection port sub-assembly.