Advanced techniques for oil reservoir simulation: Discrete fracture model and parallel implementation.

详细信息   

• 作者：Kim ; Jong Gyun.
• 学历：Doctor
• 年：1999
• 导师：Deo,Milind D.,eadvisor
• 毕业院校：The University of Utah
• ISBN：9780599484870
• CBH：9946493
• Country：USA
• 语种：English
• FileSize：4046086
• Pages：149

文摘

Major reservoir development decisions are often based on results of numerical simulation of oil reservoirs. Partial differential equations PDEs) derived from material balance coupled with Darcys law are solved in the simulator. The speed and efficiency of the simulator are determined to a large extend by the efficiency of the linear solver,which is usually ultimate step in the solution of the system PDEs. In this work,the efficiency of the following linear solvers was examined on shared and distributed memory parallel machines: the line successive over relaxation,Bi-conjugate gradient stabilized Bi-CGSTAB),the restarted generalized minimum residual and the transpose free quasi minimal residual TFQMR) methods. All the methods except the Bi-CGSTAB were stable and exhibited fast convergence behavior. Of the conjugate gradient like methods,TFQMR appeared to be the best. Considerable speedup factor of about 4 with eight processors) was observed on shared and distributed memory machines. Naturally fractured oil reservoirs have been simulated using the conventional dual porosity dual permeability) and single porosity models. Even though these techniques have served the practical purpose of simulating real reservoirs,it is recognized that it is impossible to represent fractures,spatially accurately through these approaches. A discrete fracture model was developed as an alternative to these conventional simulation methods. In a two-dimensional test problem,lines represented fractures while the matrix space was discretized into triangular elements. Results from this model were compared to simulation results using a variety of homogenization methods. At high permeability contrast between the matrix and the fracture) and high flow rates injection),the discrete fracture model captured the explicit features of the fractures,which the homogenization method failed to reproduce. Fully implicit formulation of the discrete fracture model resulted in a system of nonlinear equations,which were solved using the inexact Newtons scheme. The inexact scheme,which utilized the agreement between the function and its local linear model,was found to be significantly better than the methods that arbitrarily fixed the level of inexactness. A successful parallel implementation of the discrete fracture model using domain decomposition was achieved on both SGI Power Challenge and SGI Origin 2000.