Fractured reservoir simulation

A system comprising:

• one or more processors;
• a memory;
• instructions stored in the memory and executable by at least one of the one or more processors to cause the system to:
• generate a hybrid grid model (HG model) by generating a grid for a fractured reservoir model comprising a fracture and a matrix to obtain a generated grid;
• modify the hybrid grid model to generate a hybrid grid cross flow equilibrium model (HG-CFE model), wherein modifying comprises:
• selecting a volume expansion parameter for a plurality of cross flow equilibrium elements, wherein the volume expansion parameter comprises an amount the fracture is expanded to include surrounding matrix elements of the matrix;
• generating the plurality of cross flow equilibrium elements based on the generated grid and the volume expansion parameter, the plurality of cross flow equilibrium elements comprising a plurality of physical properties,
• wherein generating the plurality of cross flow equilibrium elements further comprises combining a portion of the fracture with a fraction of neighboring matrix blocks on either side of the fracture, within a volume defined by the volume expansion parameter, into larger cross flow equilibrium elements, and
• wherein the plurality of cross flow equilibrium elements comprise the larger cross flow equilibrium elements;
• and
• executing a sensitivity analysis with respect to a volume of the plurality of cross flow equilibrium elements without re-gridding the fractured reservoir model by integrating flow equations in cross-flow equilibrium elements, of the plurality of cross flow equilibrium elements, related to fracture-fracture flow;
• correcting inaccuracies by calibrating fluid saturations in the fracture by scaling a relative permeability in the fracture according to an oil saturation scaling factor;
• and
• calculating, using the plurality of cross flow equilibrium elements, a plurality of pore volume and transmissibility multipliers;
• simulate, using the HG-CFE model, a fluid flow in the fractured reservoir model by using the plurality of pore volume and transmissibility multipliers and a fracture relative permeability curve to obtain a result, wherein the fluid flow is calculated for the plurality of cross flow equilibrium elements;
• and
• present the result.

A computer program product comprising computer readable program code for causing a computing system to perform operations, the operations comprising:

• generating a hybrid grid model (HG model) by generating a grid for a fractured reservoir model comprising a fracture and a matrix to obtain a generated grid;
• modifying the hybrid grid model to generate a hybrid grid cross flow equilibrium model (HG-CFE model), wherein modifying comprises:
• selecting a volume expansion parameter for a plurality of cross flow equilibrium elements, wherein the volume expansion parameter comprises an amount the fracture is expanded to include surrounding matrix elements of the matrix;
• generating the plurality of cross flow equilibrium elements based on the generated grid and the volume expansion parameter, the plurality of cross flow equilibrium elements comprising a plurality of physical properties,
• wherein generating the plurality of cross flow equilibrium elements further comprises combining a portion of the fracture with a fraction of neighboring matrix blocks on either side of the fracture, within a volume defined by the volume expansion parameter, into larger cross flow equilibrium elements, and
• wherein the plurality of cross flow equilibrium elements comprise the larger cross flow equilibrium elements;
• and
• executing a sensitivity analysis with respect to a volume of the plurality of cross flow equilibrium elements without re-gridding the fractured reservoir model by integrating flow equations in cross-flow equilibrium elements, of the plurality of cross flow equilibrium elements, related to fracture-fracture flow;
• correcting inaccuracies by calibrating fluid saturations in the fracture by scaling a relative permeability in the fracture according to an oil saturation scaling factor;
• and
• calculating, using the plurality of cross flow equilibrium elements, a plurality of pore volume and transmissibility multipliers;
• simulating, using the HG-CFE model, a fluid flow in the fractured reservoir model by using the plurality of pore volume and transmissibility multipliers and a fracture relative permeability curve to obtain a result, wherein the fluid flow is calculated for the plurality of cross flow equilibrium elements;
• and
• presenting the result.