Visualizing Heterogeneous Clastic Reservoirs: Price Formation (Early Mississippian) Oil Fields in West Virginia
Michael E. Hohn, Ronald R. McDowell, and David L. Matchen
A procedure has been developed using public-domain and published software for creating 3-D models of facies in structurally-deformed clastic reservoirs. The procedure was tested successfully on two oil fields in Early Mississippian sandstone reservoirs in central West Virginia. The procedure has four stages: removal of structural deformation; definition of electrofacies from digitized electric logs and cores; classification of additional logs; and 3-D kriging.
Reconstruction of original bedding was needed before variography and kriging, but no datum was available: the reservoir sandstone lies just below an angular unconformity, and many wells were not drilled far enough below the reservoir to penetrate a potential datum. In a novel application of automated stratigraphic correlation, a published algorithm was used on digitized gamma-ray logs to find the relative vertical shift between pairs of wells giving the highest cross-correlation. Multidimensional scaling of a matrix of shifts yielded a vector of values necessary for restoring the relative elevation of each well. Cluster analysis of gamma-ray and density log responses from cored wells defined four groups matched through core descriptions with environments of deposition. Discriminant fu ctions calculated for these groups were used to classify log responses from uncored wells. Kriging of electrofacies followed conventional variography. Results are displayed as cross-sections and maps.
AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California