Integration of Faults in Dynamic Reservoir Models Application to a Streamline Simulator.

Marie Callies and Guillaume Caumon and Christophe Antoine. ( 2009 )
in: Proc. 29th Gocad Meeting, Nancy

Abstract

Whereas many techniques have been developed to model small reservoir fractures, real characteristics of faults are often overly simplified in flow simulation. Faults are complex geological objects whose properties widely affect subsurface fluid flow, and it is thus very important to understand and qualify their influence on transmissibilities within a reservoir. StreamLab is a gOcad research plugin for streamline-based flow simulation which includes a finite volume pressure solver, a streamline particle tracker, and several transport equation solvers for fluid flow. The aim of streamline simulation is to decouple a complex 3D problem into a set of 1D problems. Its recognized efficiency remains mainly on its speed, which allows for instance considering large reservoirs. This paper focuses on the geometric aspect of fault representation in reservoir grids and presents how faults and their transmissibilities are incorporated into the plugin. Many flow simulators cannot handle some fault displacements which introduce small gaps and overlaps between fault blocks when discretizing models. The proposed method corrects for these issues. The first step consists in determining all cells connections induced by faulting. The matrix of transmissibilities used in the pressure solver is then modified according to these connections to reflect the geometrical changes. Transmissibilities between cells at a fault contact are computed using the contact areas of a cell with all its neighbors at a splitted face. The Pollock particle tracker has also been adapted in order to handle fault contacts. These two modifications contribute thus to the first steps towards a better modeling of fault transmissibility within a reservoir. One major future prospect is to incorporate fault rock properties through transmissibility multipliers. The method could then be applied to a well known field and the results compared to those obtained using the commercial flow simulator Eclipse.

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BibTeX Reference

@INPROCEEDINGS{CalliesGM2009,
    author = { Callies, Marie and Caumon, Guillaume and Antoine, Christophe },
     title = { Integration of Faults in Dynamic Reservoir Models Application to a Streamline Simulator. },
 booktitle = { Proc. 29th Gocad Meeting, Nancy },
      year = { 2009 },
  abstract = { Whereas many techniques have been developed to model small reservoir fractures, real characteristics of faults are often overly simplified in flow simulation. Faults are complex geological objects whose properties widely affect subsurface fluid flow, and it is thus very important to understand and qualify their influence on transmissibilities within a reservoir. StreamLab is a gOcad research plugin for streamline-based flow simulation which includes a finite volume pressure solver, a streamline particle tracker, and several transport equation solvers for fluid flow. The aim of streamline simulation is to decouple a complex 3D problem into a set of 1D problems. Its recognized efficiency remains mainly on its speed, which allows for instance considering large reservoirs. This paper focuses on the geometric aspect of fault representation in reservoir grids and presents how faults and their transmissibilities are incorporated into the plugin. Many flow simulators cannot handle some fault displacements which introduce small gaps and overlaps between fault blocks when discretizing models. The proposed method corrects for these issues. The first step consists in determining all cells connections induced by faulting. The matrix of transmissibilities used in the pressure solver is then modified according to these connections to reflect the geometrical changes. Transmissibilities between cells at a fault contact are computed using the contact areas of a cell with all its neighbors at a splitted face. The Pollock particle tracker has also been adapted in order to handle fault contacts. These two modifications contribute thus to the first steps towards a better modeling of fault transmissibility within a reservoir. One major future prospect is to incorporate fault rock properties through transmissibility multipliers. The method could then be applied to a well known field and the results compared to those obtained using the commercial flow simulator Eclipse. }
}