Patent Document ID: 20120173220
Application ID: 13040270
Patent Flag: 0

Claim One:
1. A numerical simulation method for characterizing fluid channeling along large fractures of reservoirs, comprising the steps of: (1) determining a region of interest for numerical reservoir simulation research and creating a boundary trace file of the simulation region boundary, wherein the boundary trace file comprises the number of trace points, a serial number and X, Y coordinates of each trace point, the region of interest is an enclosed area formed by connecting each trace point in turn; (2) forming a trace file of large-aperture fractures which influence the fluid flow, based on the geologic research, wherein the trace file of large-aperture fractures consists of the total number of large-aperture fractures, a serial number and aperture of each fracture, corresponding trace point coordinates and vertical ranges of simulation layers crossed by each large-aperture fracture; (3) based on the trace data of the simulation region boundary obtained in step (1) and the trace information of each fracture trace segment obtained in step (2), making an unstructured grid division using a pre-processing software of numerical simulation, wherein the divided grids are classified into two types: non-fracture grids and discrete fracture grids, here two sides of the horizontal projection for a discrete fracture grid have to be parallel to the corresponding fracture trace segment; (4) based on the grids obtained in step (3) and the geologic research, build a static model for the numerical reservoir simulation by an interpolation method, wherein the static model consists of the specification of geometry of computational grid (location of grid block corners), and of rock properties (effective thickness, porosity, absolute permeability) in each grid block; (5) making a hydraulic similarity treatment of the large-aperture fractures, namely, adjusting the static model obtained in step (4), and modifying the permeability of the grid face crossed by a fracture for each discrete fracture grid, with a formula of: 
 permeability=(fracture aperture) 2 /12, here an unit of the fracture aperture is μm, and an unit of the permeability is Darcy(μm 2 ); (6) based on the adjusted static model in step (5), creating a reservoir simulation model by the conventional modeling method, wherein the reservoir simulation model comprises grid geometry data (location of grid block corners), reservoir rock properties, fluid physical parameters, relative permeability and capillary pressure data, positions of injection and production wells, dynamic data, process parameters and convergence control parameters needed by solving iteratively; (7) improving a traditional dual porosity numerical simulation software to be capable of accepting the unstructured grids formed in step (3); and (8) running the reservoir simulation model obtained in step (6) with the unstructured grid simulator obtained in step (7), as a result, the rapid fluid channeling along large-aperture fractures can be characterized effectively.