Next Generation Reservoir Simulation Using Russian Linear Solvers

Abstract

TX 75083-3836 U.S.A., fax 01-972-952-9435. AbstractDuring the late 1990's, Exxon and Mobil had each independently developed next-generation reservoir simulation systems.Both next-generation systems embodied a substantial number of step-out simulation technologies, which were extremely complementary. ExxonMobil moved aggressively to combine the best of both companies' technologies into one industry-leading simulation system called EM power TM . This new simulation system is currently being used to actively manage ExxonMobil's global resource base. Key features of this industry-leading simulator are described in this paper.The new simulator employs unstructured grids to more accurately model complex geologic features, near-wellbore flow, and aquifer support. The computations are performed within the unstructured grid fabric. Interactive simulation ties together the geologic and reservoir simulation models with production data yielding high-confidence forecasts of future performance.The linear systems that are created by an unstructured grid cannot be efficiently solved by conventional solution methods normally applied to simulators using rectilinear gridding. As a result, ExxonMobil looked to collaborate on research and development activities in the area of linear solvers for unstructured grids area and found capable research and development peers in Russia. The technical capabilities of the Russian scientific community were a natural fit to help develop a new library of linear solution methods geared towards the matrices created by the EM power unstructured simulator. This collaborative effort yielded an unstructured linear solution library called SparSol and is the result of over 20 work years of effort at four Russian research organizations and contains numerous methods for efficiently solving the TM EM power is a trademark owned by ExxonMobil Upstream Research Company. unstructured matrices produced by the EM power unstructured reservoir simulator.

Solver Preconditioning Using the Combinatorial Multilevel Method

“…The second example is extracted from a matrix of a reservoir simulation application (Beckner 2006). The original matrix is highly unsymmetric and describes a coupled system with more than one unknown per gridblock.…”

“…also provide tests on a series of matrices from unstructured gridding (Beckner et al 2006;Diyankov et al 2007). Finally, we test the performance of these methods on a finite element displacement sub-block matrix using a test instance from the University of Florida sparse matrix collection (Davis 1994).…”

“…To assess the applicability of the solvers in unstructured reservoir simulation, we perform further experiments using a series of matrices from unstructured reservoir models (Beckner et al 2006;Diyankov et al 2007). Unfortunately, there is no publicly available information of these models except the system matrices alone.…”