INTEGRATING GEOLOGIC MODELS AND SEISMIC DATA TO CHARACTERIZE INTERWELL HETEROGENEITY OF THE MIOCENE TEMBLOR FORMATION, COALINGA, CALIFORNIA

A collaborative study between Clemson University and Virginia Tech is being done to evaluate methods of predicting interwell heterogeneity within the Miocene Temblor Formation near Coalinga, California. Using well-log data from a 5 sq-km area of the Coalinga well field, geologic computer models have been created at Clemson to provide realistic three-dimensional representations of lateral and vertical stratigraphic variation. The results are being integrated with models of subsurface heterogeneity produced from three-dimensional seismic data by researchers at Virginia Tech.

Four stratigraphic bounding surfaces, which are based on detailed stratigraphic study of the Temblor Formation, were identified and used in correlating geophysical logs and as constraints for the geologic models. Deterministic and stochastic modeling techniques using density and gamma-ray logs have been used to represent the stratigraphy of three 0.5 sq-km study areas within the Coalinga well field. Similar modeling techniques are now being applied to the entire 5 sq-km study area to characterize heterogeneity between data points and to provide detailed realizations of the stratigraphy and facies distributions within the Temblor Formation. Normalized density and sonic logs were used to generate synthetic seismograms, which allows for integration between the stratigraphic interpretations and seismic data. The stratigraphic bounding surfaces and the reservoir heterogeneity from the geological modeling compare favorably with amplitude variations on the seismic profiles.