Dr. Jon Schwalbach, will be presenting:
The Ventura Field has produced over 1 billion barrels of oil during its more than 100 years of production from Pliocene turbidites of the Pico and Repetto Formations. In addition to being an important economic resource, these turbidites played an historic role in the understanding of clastic deposition in deep-water settings. In the 1930’s and 40’s, most geologists considered coarse sand indicative of proximal deposition in non-marine to shallow marine settings. Shedding this paradigm was facilitated by the collaboration of an experiment-oriented process sedimentologist (Kuenen) and a micropaleontologist (Natland) who demonstrated convincingly the deep-water origin of sandstone deposits in Ventura Field. Subsequent studies of Ventura turbidites (Hsu) added important details about sand body geometry and lithofacies relationships.
Many of the recent advances understanding deep-water depositional settings rely on seismic, but Ventura’s onshore location with steep bed dips and significant topography precludes this approach. Our work instead focused on linking cores and a dense grid of well logs (over 2500) to characterize these rocks on a very detailed scale. This analysis revealed the variety, stacking, lateral continuity and transitions on the bedset scale, and delineation of key stratigraphic surfaces and architectural elements in this compensational lobe setting. The sedimentologic and stratigraphic framework are the primary focus of this talk, and form the basis for geologic and reservoir simulation models. The results can be applied to optimizing primary production from turbidite reservoirs, but the enhanced understanding of reservoir properties likely has the most utility when evaluating secondary processes such as injection of water or carbon dioxide.
Jon Schwalbach is a consulting geologist with over 35 years of experience. He began his career with Exxon and had assignments in exploration, development, and research organizations. Much of that time was spent evaluating various aspects of the Monterey Formation, specifically depositional systems, fracture distribution, and general reservoir characterization. More broadly, he worked on the sequence stratigraphic expression of mudstones in a variety of settings, and their roles in petroleum systems as source, seal and reservoir rocks. Jon moved on to Occidental in 2000 to help develop the Monterey reservoirs at Elk Hills, and finished up his industry career with 10 years at Aera Energy where he spent much of his time studying turbidites in Ventura.
Jon’s geology degrees include a B.S. from Duke University and an M.S. and Ph.D. from the University of Southern California. He has held a numerous volunteer positions with Coast Geological Society, Pacific Section AAPG, and national AAPG; helped coordinate a number of technical meetings for geoscience societies, organized short courses and core workshops, and led many field trips along the coast for industry and academic groups. His recent work has focused on utilizing borehole images to better understand subsurface geology, and he has dabbled in the application of sequence stratigraphy to environmental remediation projects.
