Chapter 2: Geologically Based, Geostatistical Reservoir Modeling

Reservoir characterization encompasses all techniques and methods that improve our understanding of the geologic, geochemical, and petrophysical controls of fluid flow. It is a continuous process that begins with the field discovery and all the way through to the last phases of production and abandonment.

Reservoir modeling is the final step in the reservoir-characterization process, and consists of building an upscaled geologic model for input to the fluid-flow numerical simulator. Dynamic reservoir simulation is used to forecast ultimate hydrocarbon recovery on the basis of a given production scheme, or to compare the economics of different recovery methods. Conducting a dynamic flow simulation requires several input data types. The high-resolution geologic model (HRGM), for example, uses a grid-size specification; a geometric description of bounding surfaces, faults, and internal bedding geometries; a 3D distribution of permeability and porosity; and relative permeability and capillary pressure/saturation functions or tables. Other necessary information could include fluid pressure/volume/temperature (PVT) properties, well locations, perforation intervals, production indices, production or injection rates, and/or limiting production or injection pressures.