Transient Shape Function for Fractured Reservoir Simulation
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Solution Overview
Problem
Current methods for simulating fluid flows in fractured reservoirs are inadequate due to their simplified representation of matrix-fracture exchanges, which fail to accurately account for transient nature and geometric complexity, leading to inaccurate production forecasts.
Innovation Solution
A method that determines transient exchanges between matrix blocks and fractures using a geological and transient shape function, allowing for more realistic simulation of fluid flows by considering the detailed information available about the fracture network, including dimensions and distribution of matrix blocks, to optimize hydrocarbon production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simplified dual-medium model is used to simulate fluid flows in fractured reservoirs, then the computational complexity is reduced and the simulation can be performed with available data, but the accuracy of production forecasts deteriorates due to inadequate representation of transient matrix-fracture exchanges and geometric complexity
Solution Approach 1:
The patent applies the dynamics principle by transitioning from static shape factors to transient shape functions that evolve over time. The shape function S(ξ,t) is defined as a dynamic parameter that changes with time, allowing the model to capture the transient nature of matrix-fracture fluid exchanges. This is implemented through the transient exchange term in the mass balance equation, where the shape function evolves from initial to final values based on the dimensionless time parameter ξ, thereby improving forecast accuracy while maintaining computational feasibility.
Solution Approach 2:
The patent applies parameter changes by modifying the shape factor from a constant geometric parameter to a time-dependent shape function. The transformation involves changing the parameter definition from a fixed value to a function that varies with the dimensionless time ξ, where S(ξ,t) transitions from an initial shape factor S_i to a final shape factor S_f. This parameter evolution allows the model to adapt to changing flow conditions and capture transient exchange behavior, resolving the contradiction between model simplicity and forecast accuracy.
2Measurement precision
If detailed information about fracture network geometry is incorporated into the simulation model, then the accuracy of hydrodynamic behavior prediction is improved, but the device complexity and data requirements increase
Solution Approach 1:
The patent applies local quality by introducing shape functions that are specific to each matrix block's geometric characteristics. Instead of using a uniform model for all blocks, the shape function S(ξ,t) is tailored to reflect the local geometry of individual matrix blocks through parameters like initial and final shape factors (S_i and S_f). This allows the model to capture local variations in fluid exchange behavior while maintaining a manageable overall model structure, thereby improving predictive accuracy without excessive complexity.
Solution Approach 2:
The patent uses shape functions as intermediary parameters that bridge the gap between detailed fracture network geometry and the dual-medium simulation model. The shape function S(ξ,t) acts as a mediator that encapsulates the effects of complex geometric details (such as matrix block shape and fracture configuration) into a simplified functional form that can be incorporated into the mass balance equations without requiring explicit representation of every geometric detail, thus improving accuracy while controlling model complexity.
3Reliability
If the transient nature of matrix-fracture exchanges is accounted for in the simulation, then the reliability of production forecasts is improved, but the computational requirements and model complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-defining the functional form of the shape function S(ξ,t) and its governing parameters (initial shape factor S_i, final shape factor S_f, and dimensionless time ξ) before running the full simulation. The transient behavior is built into the model structure in advance through the mass balance equation that incorporates the time-evolving shape function, allowing the simulation to capture transient exchange effects without requiring complex real-time calculations during the production forecast, thus improving reliability while managing computational complexity.
Data Source
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AI summary
The object of the invention relates to a method for optimizing the exploitation (EXP) of a fluid reservoir traversed by a network of fractures, in which the transient exchange terms between matrix blocks and fractures (FFA, FFN) are determined, for any type of information available (INFO) concerning the fracture network, i.e. regardless of the level of knowledge of the fractured medium.