Abstract: Effects of Heterogeneity in the Red River Formation Bainville North Field, Roosevelt County, Montana

SAFLEY, L. EUGENE, BDM

Various scales of heterogeneity control dolomite distribution and fluid flow in the Ordovician Red River Formation. The scale of the heterogeneity, and the resolution required to measure it, dictate the appropriate tools to be used. Analysis of reservoir heterogeneity plays an important role in developing reservoir models used to determine optimum recovery processes.

Basin-scale heterogeneities define reservoir boundaries and control petroleum reserves. Tools used for characterizing basin-scale heterogeneities in the Bainville North field include 3-D seismic and analog field studies. Field-scale heterogeneities form internal barriers affecting interwell fluid communication and production behavior. Lateral discontinuities at this scale were estimated by drill stem tests, pressure build-up tests, fracture interpretations, fluid analyses, and geological correlations.

Reservoir-scale heterogeneities occur within a genetic body and include bed boundaries and stratification type. Tools used at this scale include well log measurements and petrophysical analyses. Pore-scale heterogeneities promote the trapping of fluids in the pore spaces. Specialized core and log analyses were used to interpret heterogeneities at the pore-scale.

The amount and type of data needed to characterize the reservoir is determined by the recovery processes being considered and economic sensitivity analyses. Selection of the optimum improved recovery process depends upon reservoir setting, recoverable reserves, and the type and scale of heterogeneities found in the reservoir.

AAPG Search and Discovery Article #90944©1997 AAPG Mid-Continent Section Meeting, Oklahoma City, Oklahoma