EDFM-Based Transient Thermal Simulation in Complex Fracture Networks
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Solution Overview
Problem
Existing models struggle to accurately simulate the thermal behavior and fluid flow in subterranean regions with complex fracture geometries, particularly in unconventional reservoirs and Enhanced Geothermal Systems (EGS), due to the challenges of modeling realistic three-dimensional fracture networks and thermal-induced stress.
Innovation Solution
A system and method that uses non-intrusive embedded discrete fracture modeling (EDFM) to create new fracture cells, identify geometric relationships, and calculate thermal variances between these cells and matrix cells, incorporating multi-phase fluid flow, to generate a digital data set for simulating subterranean regions with complex fracture geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional reservoir simulators are used to model subterranean regions, then computational efficiency is maintained, but the ability to accurately represent complex fracture geometries and thermal behavior is insufficient
Solution Approach 1:
The fracture network is segmented into discrete fracture elements that are embedded within the matrix grid. Each fracture is represented as separate entities with defined geometries, allowing complex fracture patterns to be modeled by combining multiple simpler fracture segments. This segmentation enables accurate representation of three-dimensional fracture networks while maintaining compatibility with traditional reservoir simulator grid structures.
Solution Approach 2:
A preprocessor is introduced as an intermediary component that generates fracture geometry data and thermal property calculations from diagnostic tools. This preprocessor creates the necessary input data for the reservoir simulator, bridging the gap between complex fracture geometry representation and traditional simulator capabilities. The preprocessor handles the complex calculations and generates simplified input parameters that the reservoir simulator can process efficiently.
2Reliability
If isothermal assumptions are used in reservoir modeling, then computational simplicity is maintained, but thermal-induced stress and thermal fractures are not captured
Solution Approach 1:
The model transitions from isothermal to non-isothermal conditions by introducing temperature as a dynamic parameter. Thermal properties such as heat conductivity, heat capacity, and thermal expansion coefficients are incorporated into the fracture and matrix elements. This allows the simulation to capture thermal-induced stress and thermal fracture formation by dynamically adjusting parameters based on temperature variations throughout the reservoir system.
3Measurement precision
If detailed thermal field modeling is implemented, then accuracy of thermal behavior is improved, but computational efficiency and ease of operation are reduced
Solution Approach 1:
The preprocessor automatically performs complex thermal property calculations and generates all necessary input data for the reservoir simulator without requiring manual intervention. The system self-generates fracture geometry representations, thermal property assignments, and simulation input files based on diagnostic tool outputs. This automation maintains high computational precision while significantly simplifying the ease of operation, as users only need to provide basic diagnostic data and the system handles the complex thermal modeling automatically.
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
Enables accurate simulation of fluid flow and thermal behavior in complex fracture networks, providing valuable data on fluid flow rates, pressure and temperature distributions, and well performance, suitable for both conventional and unconventional reservoirs, including EGS systems.
Implementation Method 1
calculate thermal variances between the new created fracture cells and the matrix cells
Implementation Method 2
calculating thermal variances between the new created fracture cells and the matrix cells, wherein the calculation comprises a determination of multi-phase fluid flow
Implementation Method 3
the calculation comprises a determination of multi-phase fluid flow associated with the identified non-neighboring connections of (i)-(iii)
Data Source
AI summary
Systems and methods for simulating subterranean regions with fracture geometries. Using a microprocessor to receive simulator data including matrix grid data and fracture data; produce a matrix grid using the simulator data; identify geometric interactions between fractures and matrix cells; create new fracture cells; assign physical properties to new created fracture cells; identify geometric relationships between new created fracture cells and between new created fracture cells and matrix cells, including i) non-neighboring connections between new created fracture cells and matrix cells; ii) non-neighboring connections between new created fracture cells corresponding to individual fractures; and iii) non-neighboring connections between intersecting new created fracture cells; calculate thermal variances between created fracture cells and matrix cells, including determination of multi-phase fluid flow; create a data set associated with the thermal variances for simulator input, including digital keywords to generate a second digital output for visual display of a simulation accounting for thermal variances.