Integration of Discrete Feature Network Methods with Conventional Simulator Approaches

Dershowitz, Bill; LaPointe, Paul; Eiben, Thorsten; Wei, Lingli

doi:10.2523/49069-ms

Cited by 39 publications

(46 citation statements)

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“…A more accurate but also more expensive procedure is to combine a discrete fracture network model with the dual-porosity concept. This idea has been explored by Dershowitz et al [2000] and Sarda et al [2002] for the case of single-phase flow.…”

Section: Introductionmentioning

confidence: 99%

Generation of coarse‐scale continuum flow models from detailed fracture characterizations

Karimi-Fard

Gong

Durlofsky

2006

Water Resources Research

133

101

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[1] A procedure for developing coarse-scale continuum models from detailed fracture descriptions is developed and applied. The coarse models are in the form of a generalized dual-porosity representation, in which matrix rock and fractures exchange fluid locally while large-scale flow occurs through the fracture network. The methodology developed here introduces local subgrids to resolve dynamics within the matrix and provides appropriate coarse-scale parameters describing fracture-fracture, matrix-fracture, and matrix-matrix flow. The geometry of the local subgrids, as well as the required parameters for the coarse-scale model, are determined from local flow solutions using the underlying discrete fracture model. The method is applied to two-and three-dimensional singlephase and two-phase flow problems, and the accuracy of the coarse models is assessed relative to fully resolved discrete fracture simulations. For the cases considered, it is shown that the technique is capable of generating highly accurate coarse models with many fewer unknowns than the detailed characterizations, and speedups of about a factor of 100 are achieved.

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Section: Introductionmentioning

confidence: 99%

Generation of coarse‐scale continuum flow models from detailed fracture characterizations

Karimi-Fard

Gong

Durlofsky

2006

Water Resources Research

133

101

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“…We focus on dual permeability modeling rather than dual porosity because allowing flow to occur between matrix gridblocks can provide a more accurate simulation of NFRs than dual porosity. Moreover, to improve dual continuum simulations, we extend the approach proposed by Dershowitz et al (2000) to dual permeability modeling as described below.…”

Section: Dual Permeability Modelingmentioning

confidence: 99%

Development of an Efficient Embedded Discrete Fracture Model for 3D Compositional Reservoir Simulation in Fractured Reservoirs

et al. 2013

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Summary Many naturally fractured reservoirs around the world have depleted significantly, and improved-oil-recovery (IOR) processes are necessary for further development. Hence, the modeling of fractured reservoirs has received increased attention recently. Accurate modeling and simulation of naturally fractured reservoirs (NFRs) is still challenging because of permeability anisotropies and contrasts. Nonphysical abstractions inherent in conventional dual-porosity and dual-permeability models make them inadequate for solving different fluid-flow problems in fractured reservoirs. Also, recent technologies for discrete fracture modeling may suffer from large simulation run times, and the industry has not used such approaches widely, even though they give more-accurate representations of fractured reservoirs than dual-continuum models. We developed an embedded discrete fracture model (DFM) for an in-house compositional reservoir simulator that borrows the dual-medium concept from conventional dual-continuum models and also incorporates the effect of each fracture explicitly. The model is compatible with existing finite-difference reservoir simulators. In contrast to dual-continuum models, fractures have arbitrary orientations and can be oblique or vertical, honoring the complexity of a typical NFR. The accuracy of the embedded DFM is confirmed by comparing the results with the fine-grid, explicit-fracture simulations for a case study including orthogonal fractures and a case with a nonaligned fracture. We also perform a grid-sensitivity study to show the convergence of the method as the grid is refined. Our simulations indicate that to achieve accurate results, the embedded discrete fracture model may only require moderate mesh refinement around the fractures and hence offers a computationally efficient approach. Furthermore, examples of waterflooding, gas injection, and primary depletion are presented to demonstrate the performance and applicability of the developed method for simulating fluid flow in NFRs.

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“…Various authors 4,5 have developed techniques for upscaling of permeabilities given a generalized discrete fracture distribution. Dershowitz et al 5 used finite element 16 simulation to construct permeability tensors for each individual simulator block.…”

Section: Fig 23 -mentioning

confidence: 99%

“…However, none of these yet provide as robust a solution to the generalized multi-phase problem as the finite difference dual porosity formulation. Finite element methods implemented by Dershowitz et al 5 allow use of Discrete Feature Network (DFN) models of fracture distributions for more 'realistic'…”

mentioning

confidence: 99%

Integration of Seismic Anisotropy and Reservoir Performance Data for Characterization of Naturally Fractured Reservoirs Using Discrete Feature Network Models

Will¹,

Archer

Dershowitz

2003

All Days

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This dissertation presents the development of a method for quantitative integration of seismic (elastic) anisotropy attributes with reservoir performance data as an aid in characterization of systems of natural fractures in hydrocarbon reservoirs. This new method incorporates stochastic Discrete Feature Network (DFN) fracture modeling techniques, DFN model based fracture system hydraulic property and elastic anisotropy modeling, and non-linear inversion techniques, to achieve numerical integration of production data and seismic attributes for iterative refinement of initial trend and fracture intensity estimates. Although DFN modeling, flow simulation, and elastic anisotropy modeling are in themselves not new technologies, this dissertation represents the first known attempt to integrate advanced models for production performance and elastic anisotropy in fractured reservoirs using a rigorous mathematical inversion. The following new developments are presented:• Forward modeling and sensitivity analysis of the upscaled hydraulic properties of realistic DFN fracture models through use of effective permeability modeling techniques. iv• Forward modeling and sensitivity analysis of azimuthally variant seismic attributes based on the same DFN models.• Development of a combined production and seismic data objective function and computation of sensitivity coefficients.• Iterative model-based non-linear inversion of DFN fracture model trend and intensity through minimization of the combined objective function.This new technique is demonstrated on synthetic models with single and multiple fracture sets as well as differing background (host) reservoir hydraulic and elastic properties. Results on these synthetic control models show that, given a well conditioned initial DFN model and good quality field production and seismic observations, the integration procedure results in convergence of both fracture trend and intensity in models with both single and multiple fracture sets. Tests show that for a single fracture set convergence is accelerated when the combined objective function is used as compared to a similar technique using only production data in the objective function.Tests performed on multiple fracture sets show that, without the addition of seismic anisotropy, the model fails to converge. These tests validate the importance of the new process for use in more realistic reservoir models.

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Integration of Discrete Feature Network Methods with Conventional Simulator Approaches

Cited by 39 publications

References 0 publications

Generation of coarse‐scale continuum flow models from detailed fracture characterizations

Generation of coarse‐scale continuum flow models from detailed fracture characterizations

Development of an Efficient Embedded Discrete Fracture Model for 3D Compositional Reservoir Simulation in Fractured Reservoirs

Integration of Seismic Anisotropy and Reservoir Performance Data for Characterization of Naturally Fractured Reservoirs Using Discrete Feature Network Models

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