Flow Unit Modeling in Complex Reservoirs

David K. Davies, Richard K. Vessell, and Maria Cristina Bernal G.

It is well known that hydrocarbon displacement is controlled at the pore level by the pore system geometry, yet reservoir descriptions are not normally based on pore geometry. This study illustrates how quantitative measurements of pore geometry can be used to provide a fundamental basis for reservoir description and flow unit modeling. Most of the research is funded by the US Department of Energy, as part of Class II and III Mid-Term reservoir studies.

Three distinctly different types of oil reservoirs are described, each in a different stage of development and each requiring significant future capital expenditure to maximize hydrocarbon recovery: 1) fluvial sandstones (Lisama Area, Oligocene, Colombia), currently on primary recovery - future plans involve infill drilling plus localized waterfloods or CO₂, 2) shallow shelf carbonates (North Robertson Unit, Permian, West Texas), currently on waterflood - future CO₂ is planned, and 3) deep water clastics (Pliocene, Tar Zone Wilmington Field, California) on active steamflood - improved productivity is required. Detailed flow unit modeling is being used to improve the accuracy of reserve determinations and to identify areas of the fields that are suitable for future development.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California