Sequenced Well Stimulation for Injector-Producer Connectivity
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Solution Overview
Problem
Current practices are inadequate for enhancing connectivity and permeability between injector and producer wells, particularly in Enhanced Geothermal Systems (EGS), which hinders efficient heat extraction from Dry Hot Rock (DHR) resources.
Innovation Solution
A system and process involving a perforated injector well that uses high-rate tensile fracturing, pulsating fracturing, and hydro-shearing stages to create a thermal lattice in the subterranean geologic formation, enhancing connectivity and permeability by intersecting and expanding natural fractures, with measurement systems to assess improvements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If horizontal wells are drilled within the resource to extract heat from Dry Hot Rock, then the area of contact with basement rock is increased, but the connectivity and permeability between injector and producer wells remain insufficient
Solution Approach 1:
The stimulation process is divided into three sequential stages: (1) high-rate tensile fracturing to create initial fractures, (2) pulsating fracturing to extend and branch fractures, and (3) hydro-shearing to create shear fractures. This segmentation of the stimulation process creates a more comprehensive fracture network that improves connectivity while maintaining contact area.
Solution Approach 2:
The pulsating fracturing stage uses periodic pressure pulses applied through the injector well to extend and branch fractures. The pulsating action creates a more extensive fracture network compared to continuous injection, thereby improving connectivity between injector and producer wells while maintaining the contact area.
2Reliability
If high-rate tensile fracturing is applied to create fractures in the formation, then permeability is enhanced, but the complexity of the stimulation process increases
Solution Approach 1:
The stimulation process is divided into three sequential stages: (1) high-rate tensile fracturing to create initial fractures, (2) pulsating fracturing to extend and branch fractures, and (3) hydro-shearing to create shear fractures. This segmentation allows each stage to build upon the previous one, achieving enhanced permeability through a systematic approach rather than a single complex operation.
Solution Approach 2:
The high-rate tensile fracturing stage creates initial fractures before the subsequent pulsating and hydro-shearing stages. This preliminary action prepares the formation structure, making it more responsive to subsequent stimulation and reducing the overall complexity by establishing a foundation for enhanced permeability.
3Reliability
If multiple stimulation stages are applied sequentially, then connectivity between wells is enhanced, but the time required for the process increases
Solution Approach 1:
The stimulation process is divided into three sequential stages that can be executed in a systematic manner: tensile fracturing, pulsating fracturing, and hydro-shearing. While sequential, this segmentation allows for optimized execution of each stage, building upon previous results to achieve enhanced connectivity efficiently.
Solution Approach 2:
Each stimulation stage performs preliminary action that prepares the formation for the next stage. The tensile fracturing creates initial pathways, pulsating fracturing extends them, and hydro-shearing creates additional connectivity. This preliminary action at each stage reduces the time needed for subsequent stages to achieve the same effect.
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 system effectively increases the connectivity and permeability between injector and producer wells, optimizing heat extraction efficiency and energy output on the surface by creating a robust thermal lattice.
Implementation Method 1
pumping one or more fluids at a high rate and volume and capable of tensile fracturing the subterranean geologic formation, generating a downhole pressure that produces a stress on the subterranean geologic formation exceeding Shmin
Implementation Method 2
pumping the one or more fluids in a pulsating mode (for example, but not limited to, sinusoidal) to cause fatigue to any existing natural fractures ('references') intersecting the tensile fracture
Implementation Method 3
creating a thermal lattice in the subterranean geologic formation by: (i) pumping one or more fluids at a high rate and volume... (ii) pumping the one or more fluids in a pulsating mode... (iii) pumping the one or more fluids in a long injection period as a hydro-shearing stage
Implementation Method 4
harness heat by convection and conduction and efficiently maximize energy output on the surface
Data Source
AI summary
Systems and processes for enhancing connectivity and/or permeability between injector and producer wells using sequenced stimulation. Methods of modeling same.