Grid Modification During Simulated Fracture Propagation

A geologic modeling system that comprises:

• a memory having geologic modeling software;
• and
• one or more processors coupled to the memory to execute the geologic modeling software, the software causing the one or more processors to perform operations including:
• obtaining a geologic model representing a subsurface region as a mesh of cells, at least some of the cells in the mesh having one or more interfaces representing boundaries of subsurface structures including at least one natural or induced fracture;
• determining a fracture extension to the at least one natural or induced fracture;
• evaluating whether the fracture extension is collocated with, or is proximate to, an existing cell interface, and:
• if collocated, using the existing cell interface to represent part of the at least one natural or induced fracture in an updated version of the geologic model;
• if proximate, displacing the existing cell interface to represent part of the at least one natural or induced fracture in the updated version of the geologic model;
• and
• if neither collocated nor proximate, splitting a cell to create a new cell interface that represents part of the at least one natural or induced fracture in the updated version of the geologic model;
• said existing or new cell interface being defined by mesh nodes, and said representing being performed by providing said mesh nodes with additional degrees of freedom enabling fracture separation without requiring extra geometric entities;
• and
• outputting the updated version of the geologic model.

A non-transitory information storage product having computer readable program code embodied therein, which when executed configures a computer to implement a geologic modeling method that comprises:

• obtaining a geologic model representing a subsurface region as a mesh of cells, at least some of the cells in the mesh having one or more interfaces representing boundaries of subsurface structures including at least one natural or induced fracture;
• determining a fracture extension to the at least one natural or induced fracture;
• evaluating whether the fracture extension is collocated with, or is proximate to, an existing cell interface, and:
• if collocated, using the existing cell interface to represent part of the at least one natural or induced fracture in an updated version of the geologic model;
• if proximate, displacing the existing cell interface to represent part of the at least one natural or induced fracture in the updated version of the geologic model;
• and
• if neither collocated nor proximate, splitting a cell to create a new cell interface that represents part of the at least one natural or induced fracture in the updated version of the geologic model;
• said existing or new cell interface being defined by mesh nodes, and said representing being performed by providing said mesh nodes with additional degrees of freedom enabling fracture separation without requiring extra geometric entities;
• and
• outputting the updated version of the geologic model.