Delineating a Diatomite Reservoir Extension of the Casmalia Field, Santa Barbara County, California

Wilson, Mark L.¹, E. L. Berger², R. Elias² (1) Consulting Geologist, Bakersfield, CA (2) Consulting Geologist,

Santa Maria Pacific, LLC is currently delineating and testing an oil-saturated diatomite reservoir in the Sisquoc Formation on the NW end of the Casmalia Field, Santa Barbara County, CA. Outcrops of oil-saturated diatomite occur along a trend several miles long that includes the Casmalia and Orcutt oil fields. These deposits have been exploited as prehistoric sources of tar, a source of siliceous sinter for use as a concrete additive and have drawn interest as a source for contentional and non-conventional oil recovery.

The Neavada Texas Utah (NTU) Mining Company attempted to mine and recover oil from the resource beginning in 1923 usisng oil shale retort methods. The Standard Oil Company (Chevron) tested productivity of the resource using conventional wells in the 1950s. Union Oil revisited the mining idea in the late 1970s with some delineation drillling. Similarly, gulf Oil core-drilled the Airox mine in the northern Casmalia Field in 1981-1982 to define mineable oil ressource. Neither of these have developed into viable projects.

Exploitation of a similar resource by Chevron et al. at the Cymric Field in Kern County, CA, started in 1996, with a similar project initiated in W. Midway-Sunset Field. Both clearly showed that oil can be commercially produced from oil-saturated diatomite using cyclic steam injection.

Pilot steaming of oil saturated diatomite by Breitburn Energy in the Orcutt Field has been performed. A drilling program conducted by Santa Maria Pacific (SMP) in 2005-2006 has started to delineate a large resource of oil-saturated diatomite in the Sisquoc Formation near the old NTU mine. A site specific, pilot cyclic steam injection project was initiated on the SMP Casmalia leaseholds in the fourth quarter of 2006.