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Thrust Faulting in Temblor Range, Kern County, California

SIMONSON, RUSSELL R., Independent, Glendale, CA

Surface and subsurface studies confirm the presence of overthrusting in the Temblor Range between Gonyer Canyon and

Recruit Pass. The Cree fault is the easternmost of one or more of the westerly dipping thrusts mapped in the Central Temblor Range. Detailed stratigraphic measurements, age determinations, and structural relationships confirm the presence of the Cree fault in outcrop.

In the subsurface, three wells have penetrated the Cree fault, the Hudbay "Cree" No. 1 (7300 ft), the Frantzen Oil Company "Cree" No. 1 (5865 ft) and the Arco "Cree Fee" 1A well (5915 ft). In these wells there are duplicated McDonald shale sections with 1000 ft or more of steep dips above the sole of the Cree fault. Below the fault, 25 to 35 degree of westerly dips on the west flank of the sub-thrust Phelps anticline are encountered. The McDonald section below the fault is comprised of siliceous fractured shale which contains live oil and gas showings.

A drill-stem test of the interval from 8247 to 8510 ft in the Frantzen well resulted in a recovery of 1200 ft clean 34 degree oil and 40 MCF per day gas. The shut in pressure was 3430 lb, which is a normal hydrostatic pressure common to the producing structures in the southern San Joaquin Valley. The equivalent of this interval has produced over 7000 bbl of oil in the Arco "Cree" 1A well. The Arco "Cree Fee" No. 1A well crossed the axis of the Phelps Anticline as indicated by good dipmeter and bottomed in Lower Zemorrian at 14,512 ft total depth. This well was not drilled deep enough to reach the Point of Rocks Sand and did not test the gas showings in the lower Miocene section.

In the Gonyer Canyon area, subsurface evidence indicates conditions are similar to those in the Cree area because a large structure is present below a thrust fault. The exact structural relation between these two areas cannot be determined without reliable deep seismic, subsurface, or other definitive information. The structural similarity, however, is evident.

It is believed that significant accumulations will be found beneath thrust faults in the eastern part of the Temblor Range where conditions are similar to those that were instrumental in forming fields such as the Elk Hills, B. V. Hills, Belgian Anticline and others.


AAPG Search and Discovery Article #91009©1991 AAPG-SEPM-SEG-SPWLA Pacific Section Annual Meeting, Bakersfield, California, March 6-8, 1991 (2009)