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Abstract: Geostatistical Analysis of Incised Paleovalley Reservoir Analogs, Wyoming

TILLMAN, RODERICK W., Consultant, Tulsa, Oklahoma, Ekrem Kasap, Western Atlas, Bayram Kara, University of Tulsa


Outcrop reservoir analogs allow scaling and geologic input into stochastic reservoir simulation programs and provide information on a between well scale which is commonly difficult to obtain using subsurface data only. Three outcrops of incised paleovalleys, filled with tidally deposited sediments, were selected for study from the Muddy Sandstone (Newcastle Formation) in eastern Wyoming. Seven sections were measured, interpreted sedimentologically and lithofacies were designated. Both vertically oriented and horizontally oriented surveys were obtained using a probe-permeameter and gamma-ray logs. Geostatistical analysis was based primarily on probe permeameter data. Appropriate uses for, and differences in, vertical and horizontal variograms are discussed and compared with results from calculations of Coefficients of Variation and Dyktra-Parsons coefficients of the same data sets. Reasons for strong correlation between deposition “bounding surfaces” and permeability correlation structure are discussed. Significant differences in geostatistics calculated from vertical and horizontal permeability data are shown to be facies dependent and allow recognition of geological structure in a geostatistical.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah