TURNING WIGGLES INTO OIL: 3D SEISMIC INCREASES PRODUCTION IN THE EASTERN SHALLOW OIL ZONE, ELK HILLS FIELD, CALIFORNIA
The ESOZ is an extremely large and prolific set of oil reservoirs with a long history of production. Discovered in the early 1900s and later rolled into a government strategic petroleum reserve, the 13,000 acre area was developed in fits and starts directly correlated with the historical war and peace eras of the United States. To date about 1,500 wells have been completed, at depths from 1,800 to 4,500. Gravity drainage, enhanced by gas injection, is the primary drive mechanism. Complex faulting and multi-stacked sand/shale sequences sub-divide the five main reservoirs creating a significant challenge to optimizing performance.
The insights from the 3D seismic data have been employed on over 20 prospects through December 2000. The 3D data has accurately pin pointed fault locations, identified gasliquid contacts, and ultimately reduced risk. As the interpretation progresses, the team continues to integrate the information, locating wells that will produce previously by-passed perched oil in areas once thought to be completely exploited. The team has already gained more valuable insights about the geology from wavelet character mapping and inversion. Seismic data is being integrated into a 3D reservoir model in order to better extrapolate reservoir properties between discrete petrophysical measurements in existing wells.