In the Santa Clara Avenue oil field, the nonmarine
Sespe Formation of Oligocene age has produced 4 million
barrels of oil trapped by a Miocene mafic igneous
intrusion that cuts across bedding. Throughout most of
the oil field, the Miocene and older beds dip about 15°
northwest. The intrusion may be related to the outpouring
of Conejo Volcanics throughout much of the southern
Ventura basin. The Pacific Farms #1 well penetrated 1000
feet of igneous rocks below 5100 feet, whereas wells less
than 500 feet to the northwest penetrated Sespe Formation
over this interval. The western wall of the intrusion is
located by 10 wells which pass repeatedly through the
Sespe-intrusive contact. Structure contours on the
intrusive contact with the Sespe on the northwest show
Redacted for Privacy
that the contact varies from N20°E,80°SE in the southern
portion of the field, to N90°E,85°S in the northern end of
the field. The southeast wall of the intrusion is not cut
by wells, but its location is controlled by a well about
1200 feet southeast of the northwest wall. If the
intrusive contact is rotated to its position when it was
intruded prior to tilting of the middle and late Miocene
Modelo Formation, the Sespe overhangs the igneous body
along a contact with a paleo-dip of 80°NW. Lateral
closure in the field may be due to early Miocene normal
faulting of the Sespe Formation.
In the Las Posas area, two faults are documented.
Both faults cut the entire Miocene section but do not cut
the Pliocene-Pleistocene Pico Formation. The Miocene
Vaqueros is found only on the south side of the Las Posas
fault. Intra-Sespe correlations show that the upthrown
block of the Las Posas fault lost to erosion 1000 feet of
Sespe in addition to the Vaqueros Formation. The Epworth
syncline and Beryiwood anticline were folded prior to the
deposition of the Pico Formation. / Graduation date: 1986
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/26496 |
| Date | 14 June 1985 |
| Creators | Richards, Matthew E. |
| Contributors | Yeats, Robert S. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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