An Integrated Approach to Predicting Lithology Using Statistical Analysis, Acoustic Inversion, and Well Logs

Andrew A. Peloso, Lorinda E. Driskill, Sheldon B. Gorell

An integrated approach to reservoir characterization provides robust validation for exploration and development concepts in an area. This paper presents a Gulf Coast example of integrating techniques using a geophysical and geostatistical software suite to predict lithology. After identifying an interval of potential interest from well logs, acoustic impedances at the wellbore are calculated. Bivariate analysis of impedance and other log data confirm lithologies at the wellbore, and the identified impedance ranges are compared with acoustic impedance sections to determine lateral extent of the reservoir. The analysis of these crossplots, combined with acoustic inversion of the seismic data, produces additional constraints to help characterize the reservoir. Porosity calcu ations from log data provide a cross-check of the lithology prediction. A group of these lithology predictions can be mapped in conjunction with other seismic attributes and porosity values to determine optimum locations for additional drilling over the area. This study illustrates how this integrated approach, drawing from geophysical, geological, and petrophysical data, can reduce uncertainty in hydrocarbon recovery.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995