Fractured Reservoir Modeling via Equivalent Block Segmentation
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Solution Overview
Problem
Current petroleum reservoir modeling techniques struggle to accurately represent fractured reservoirs, leading to imprecise estimation of fluid flows and hydrocarbon recovery, as they cannot directly utilize three-dimensional images of fracture networks due to numerical limitations and the complexity of geological realities.
Innovation Solution
A method is introduced to optimize reservoir development by modeling the reservoir as a porous medium with irregularly shaped blocks, simplifying it into equivalent blocks of regular shapes and sizes, allowing for accurate fluid recovery simulation through a double-medium reservoir simulator, using derivative curves to determine block dimensions and surface proportions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a detailed three-dimensional representation of fracture networks is used, then the accuracy of geological modeling is improved, but the computational complexity and numerical difficulties increase
Solution Approach 1:
The fracture network is segmented into discrete fracture elements with defined geometric parameters (position, orientation, aperture, length). This segmentation allows the complex three-dimensional fracture system to be broken down into manageable components that can be processed numerically without overwhelming computational complexity.
Solution Approach 2:
The patent creates a simplified digital copy of the fracture network that preserves essential geometric and hydraulic characteristics while reducing computational complexity. The double-porosity model creates an equivalent representation where matrix blocks and fracture networks are modeled with simplified geometries that replicate the behavior of the detailed fracture network.
2Productivity
If simplified equivalent blocks are used, then the computational efficiency is improved, but the accuracy of fluid flow simulation deteriorates
Solution Approach 1:
The patent transforms the complex fracture network into equivalent blocks with modified parameters (size, shape, permeability) that preserve the essential fluid flow characteristics. By changing the parameters of simplified geometric representations to match the hydraulic behavior of the detailed fracture network, computational efficiency is improved while maintaining simulation accuracy.
Solution Approach 2:
The double-porosity model acts as an intermediary between the detailed fracture network and the flow simulator. It translates complex fracture geometries into an equivalent representation with simplified blocks and adjusted permeability parameters, enabling accurate fluid flow simulation without requiring direct input of detailed fracture network data into the simulator.
3Reliability
If the complex geometry of fractured reservoirs is accurately represented, then the reliability of production prediction is improved, but the difficulty of numerical modeling increases
Solution Approach 1:
The reservoir is segmented into matrix blocks and fracture networks within each double-porosity cell. This segmentation allows the complex geometry to be handled by dividing it into manageable components with distinct properties, reducing the difficulty of numerical modeling while preserving the essential geometric features needed for reliable production prediction.
Solution Approach 2:
A simplified digital copy of the fracture network geometry is created that captures the essential spatial distribution and connectivity patterns. This copied representation is then used in the double-porosity model to achieve reliable production predictions without the computational burden of directly modeling the complete complex geometry.
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 method enables precise simulation of fluid flows and hydrocarbon production scenarios, improving the accuracy of oil recovery estimation and optimizing reservoir development by effectively representing the complex geometry of fractured reservoirs.
Implementation Method 1
a simplified representation substantially leading to the same fluid recovery during a capillary imbibition process of the porous medium
Data Source
AI summary
A method of modelling a fractured reservoir having application for petroleum reservoir development is disclosed utilizing a set of several families of equivalent blocks of regular shapes and sizes. The fractured reservoir is modelled by a complex porous medium made up of irregular blocks. A function defining the progress of an imbibition front within these blocks, whose derivative A′(X) is calculated, is determined. A function defining the progress of an imbibition front within regular equivalent blocks, whose derivative A′eq(X) is calculated, is then determined. This derivative, which constitutes at least two line segments with distinct slopes, depends on the dimensions of the equivalent blocks. Finally, the dimensions of the equivalent blocks are obtained by adjusting the two derivatives A′eq(X) and A′(X).