| A principal goal of reservoir characterization is to derive a spatial understanding of interwell heterogeneity. Traditionally, geologic attempts to characterize interwell heterogeneity have been made using hand-drawn or computer generated 2-D maps and cross sections. Results can be improved dramatically using 3-D interpretation and analysis techniques. The goal of three-dimensional geologic modeling is to construct an accurate, digital depiction of a three-dimensional body of rock. The hypothesis of this dissertation is that the stratigraphic framework exerts a primary control on the accuracy of a 3-D reservoir model, and that a sequence-stratigraphic interpretation results in the most accurate stratigraphic framework. In order to test the hypothesis, an experiment had to be designed that would result in a "known" geologic interpretation, which could then be used to test the effect of contrasting stratigraphic framework interpretations on 3-D reservoir model results.;The continuous, well-exposed shelf-to-basin outcrops of the carbonate-dominated Permian Seven Rivers, Yates and Capitan Formations along the north wall of North Mckittrick Canyon, New Mexico and Texas, provide the ideal laboratory in which a sequence-stratigraphic interpretation can be made with a high degree of confidence. The data collected from McKittrick Canyon were used to create two 3-D reservoir models, one with a sequence-stratigraphic framework and one with a lithostratigraphic framework. Model results were compared against the "known" interpretation in order to test the hypothesis. In contrast to the outcrop, subsurface data are always limited, and interpreting the sequence-stratigraphic framework is the most difficult and creative part of the 3-D modeling process.;This dissertation is presented in three sections. The first section focuses on the detailed sequence-stratigraphic interpretation of the carbonate-dominated outcrop exposures in McKittrick Canyon, and addresses important issues regarding lithofacies distributions and proportions, timing and amount of aggradation versus progradation, sediment production rates, and a dynamic model for Capitan deposition during late Guadalupian time. The second section discusses the mechanics of 3-D reservoir modeling, and illustrates the conceptual importance of a correct stratigraphic framework using two outcrop and three subsurface examples. In the third section, data from the continuous outcrops in McKittrick Canyon were used to construct six 3-D reservoir models. Lithofacies distributions, volumetric calculations, and synthetic seismic are compared and confirm the hypothesis that the stratigraphic framework exerts a primary control on the accuracy of a 3-D reservoir model, and that a sequence-stratigraphic interpretation provides the best stratigraphic framework for 3-D reservoir modeling. |
