Piver, Jaime L.¹, James W. Castle¹, Rex A. Hodges¹, Matthias Imhof² 
(1) Clemson University, Clemson, SC 
(2) Virginia Tech, Blacksburg, VA

ABSTRACT: Incorporation of Stratigraphic Heterogeneity in Reservoir Models of the Temblor Formation, Coalinga Area, California: Integration of Geologic Models and 3D Seismic Data

Methods for predicting interwell heterogeneity within the Miocene Temblor Formation near Coalinga, California, were developed and assessed through detailed integration of geological and geophysical data from heavy oil sands of West Coalinga Field. Using lithofacies data from core and outcrop studies, geophysical log data, and three-dimensional seismic data from a 5 sq-km area of the oil field, various types of deterministic and stochastic models were created to provide three-dimensional representations of lateral and vertical stratigraphic variation. Four stratigraphic bounding surfaces and fourteen lithofacies groups, which are based on sedimentological study of the Temblor Formation, were identified and used in correlating geophysical logs and as constraints for the computer models. 
The integration of core, outcrop, log, and seismic data through three-dimensional computer modeling produced realizations that resolve small-scale heterogeneities not identifiable using a single type of data. To define the relationship between seismic attribute values and the probability of encountering a particular lithofacies at a specific location within the formation, stochastic lithofacies models conditioned to seismic attributes were created using probability density functions. 
The results of our investigation indicate that stochastic lithofacies models conditioned to instantaneous amplitude provide the best representation of stratigraphic heterogeneity in the heavy oil sands of West Coalinga Field. By displaying geologically realistic continuity of lithofacies between wells, stratigraphic variations can be identified that are absent from geologic models that do not incorporate seismic data or that are based on smooth parameter interpolation between wells.

AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.