A new geological three-dimensional computer modeling system has been developed that should greatly aid any task that depends upon accurate geological reservoir description. The new system, call STRATAMODEL, is a Geo-Cellular™ type of geological modeling that portrays the stratigraphic patterns and structural complexities of sedimentary rocks so that a resulting model closely approximates the "state of nature". Geologic volumes of any scale are divided into stratigraphic sequences and structural blocks. Into these are placed layers of cells which are positioned to be approximately parallel to the depositional surfaces or time-lines of strata being modeled. This results in the cell layers usually being at attitudes other than horizontal. Values and attributes are distributed from wells and assigned to individual cells within each unique cell layer. The resulting variation along cell layers is closely analagous to the variation of rock properties along strata in nature.

There are many potential benefits from using three-dimensional computer modeling. For example, in many reservoirs, the benefit of costly and detailed data is lost because of excessive vertical averaging. The use of accurate Geo-Cellular™ modeling will properly distribute parameters such as porosity and saturation. Pore volume can then be calculated at the individual cell level. This will lead to volumetrics more accurate than those determined by present conventional methods. Having a computer reservoir model will also allow the engineer and geologist the luxury of using alternate interpretations and multiple hypotheses.

The proper use of geological three-dimensional computer modeling system should greatly improve geological reservoir description and therefore lead to: 1) more productive infill drilling and recompletion programs, 2) more accurate deliverability and reserve determinations, 3) more efficient reservoir maintenance and surveillance, 4) more accurate reservoir simulation modeling, and 5) better enhanced recovery planning.

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