System and method for simulating fluid flow in a fractured reservoir

A system for simulating fluid flow in a fractured subterranean reservoir, the system comprising:

• a database configured to store data comprising a reservoir model representative of a fractured subterranean reservoir, the reservoir model including porous matrix control volumes and a plurality of networks of fractures overlying the porous matrix control volumes, wherein each network of fractures comprises fracture control volumes, and wherein each fracture control volume of a particular network of fractures is highly connected to at least one other fracture control volume of the particular network of fractures;
• a computer processor;
• and
• a computer program configured to be executed by the computer processor and cause the computer processor to perform a method, the method comprising:
• (a) providing the reservoir model representative of the fractured subterranean reservoir;
• (b) for each network of fractures, splitting a pressure vector corresponding to the network of fractures into an average pressure value and remainder pressure values;
• (c) constructing a system of equations based on scale separation for pressure values in the porous matrix control volumes and the average pressure value of each network of fractures;
• and
• (d) for each network of fractures, solving sequentially the system of equations based on scale separation by:
• (i) approximating a pressure field on a coarse-scale grid responsive to a matrix pressure vector and the average pressure value for the corresponding network of fractures;
• (ii) obtaining a fine-scale pressure solution responsive to the pressure field on the coarse-scale grid;
• (iii) computing the remainder pressure values for the corresponding network of fractures;
• (iv) smoothing the fine-scale pressure solution;
• and
• (v) repeating steps (i) through (iv) until the remainder pressure values have converged to a convergence criterion.

A computer program product, comprising a non-transitory computer usable medium having a computer readable program code embodied therein, the computer readable program code configured to be executed by a computer processor and cause the computer processor to perform a method for simulating fluid flow in a fractured subterranean reservoir, the method comprising:

• (a) providing a reservoir model representative of a fractured subterranean reservoir, the reservoir model including porous matrix control volumes and a plurality of networks of fractures overlying the porous matrix control volumes, wherein each network of fractures comprises fracture control volumes, and wherein each fracture control volume of a particular network of fractures is highly connected to at least one other fracture control volume of the particular network of fractures;
• (b) for each network of fractures, splitting a pressure vector corresponding to the network of fractures into an average pressure value and remainder pressure values;
• (c) constructing a system of equations based on scale separation for pressure values in the porous matrix control volumes and the average pressure value of each network of features;
• and
• (d) for each network of fractures, solving sequentially the system of equations based on scale separation by:
• (i) approximating a pressure field on a coarse-scale grid responsive to a matrix pressure vector and the average pressure value for the corresponding network of fractures;
• (ii) obtaining a fine-scale pressure solution responsive to the pressure field on the coarse-scale grid;
• (iii) computing the remainder pressure values for the corresponding network of fractures;
• (iv) smoothing the fine-scale pressure solution;
• and
• (v) repeating steps (i) through (iv) until the remainder pressure values have converged to a convergence criterion.