Chico-Martinez oil field (California, USA)
In 2009 electromagnetic survey using the CSEM technology of vertical currents sounding (VECS) was performed by EMTEK at the Chico-Martinez oil field (California, USA). Measurements were car-ried out on the 200×100 m spaced network within 1.8 x 2.4 km area leased by CRUDECORP with two differently sized circular electric dipoles (CED) used as two sources. CED with a diameter of 1.5 km was located to the north-east of the investigated area, and CED with a diameter of 0.6 km – to the east.
At the Chico-Martinez field oil was found in the formation named Etchegoin Sands which is divided into seven stratigraphic units, from shallow to deep. Effective thickness of Etchegoin Sands reservoir beds at the Chico-Martinez field reaches 300 feet (91 meters). Base oil, found here, is “heavy” oil, mak-ing it difficult to produce by traditional methods. It should be noted that productive ranges at the Chico-Martinez field are not well defined in the eastern part of the field.
A diatomite zone of Antelope Hills (underlying formation for Etchegoin Sands) can turn out to be a separate productive horizon of the Chico-Martinez field in addition to Etchegoin Sands themselves. This interval is productive two miles to the southeast from the site of interest, at the Cymric Field and two miles east at the South Belridge field.
Accomplished exploration was focused on the localization of sites that may be promising for finding oil in the diatomite formation, as well as on research of Etchegoin Sands collectors for potential oil pro-duction in the eastern part of the license area leased by CRUDECORP.
According to the results of dozens of works carried out by EMTEK, measured areal signal
(dBz / dt) behaves in the following way: it has positive sign above the oil deposit, change of signal sign is registered above the deposit border and signal sign is negative outside the deposit. Central and south-western part of the site, where the most productive wells are drilled, is characterized by high levels of positive signal. The work performed helped to contour the oil field and showed low probability for oil production in the eastern part of the area.
At present 2 wells that have been drilled at the site recommended by EMTEK as promising flow commercial oil.
Articles
V.S. Mogilatov, A.V. Zlobinskiy. The complex prospecting of a variety of electromagnetic parameters of the medium above seismic uplifting for the detection of oil deposits. // Geophysics, 2013, No. 2, p.51-57 1 Mb, pdf-file
About VECS
Electrical prospecting by the method of vertical electric current sounding (VECS) as applied to oil targets. 2 Mb, pdf-file