Geologic Setting of Beverly Hills and Las Cienegas Fields: ABSTRACT

Abstract

Exploration and development during the last decade, primarily by slant drilling from only a few drill sites, have revealed several previously unknown or only partly suspected complexities of structure and stratigraphy beneath the Pleistocene or Recent cover along the northern flank of the Los Angeles basin between Western Avenue and the city limits of Santa Monica. Very little well information has been released for publication or even into restricted industry channels. Permission however has been granted to the author by the various operators in the area to present this general paper. Tight folds, which are in places overturned toward the south, and high angle thrust faults are characteristic. These features are aligned east-west and transect the Beverly-Newport lineament, suggesting that the latter feature is either over-ridden, swings sharply westward north of Inglewood field, or dies out before reaching Cheviot Hills. Pronounced unconformities are present at the base of Wissler's Zone 4 of the upper Repetto (Pliocene), within the upper Miocene at the top of the E (Nodular shale) and probably elsewhere, and between the E and F zones. There is also onlap of the beds of Delmontian age onto various older beds. Difficulties of paleontological correlation have been further confounded by salting of older forms into younger beds. The southeastern portion of the area has a thinned section of Pilocene and Miocene overlapping a granodiorite high. Defining pool as a continuous, pressure-connected body of oil and gas, there are at least five new pools in the Beverly Hills-Cheviot Hills field, one in the Salt Lake field, and four or more in the Las Cienegas field. Production figures for the separate pools are not given, but the new pools of Beverly Hills-Cheviot Hills have produced about 18 million barrels of oil and 76 million MCF of gas, and Las Cienegas about 4 million barrels and 3½ million MCF of gas. The production from the new pool in the Salt Lake field is about 3/4 million barrels. At the time of preparation of this paper, development was continuing with three rigs active in the Beverly Hills-Cheviot Hills area and one active at the third drill site in Las Cienegas. Exploratory core holes were being drilled from time to time in and near the area. The complexity of the area and the difficulty of exploration by slant drilling suggest that there may be several undiscovered oil accumulations of considerable magnitude in the area. The presence of saturated but tight oil sandstone in a wildcat at the extreme northwestern corner of this area is not to be discounted. End_of_Article - Last_Page 1765------------