Salt Lake Oil Field
[2] The field is also notable as being the source, by long-term seepage of crude oil to the ground surface along the 6th Street Fault, of the famous La Brea Tar Pits.
While the entire former field area is dotted with abandoned wells, now entirely overbuilt with dense residential and commercial development, all active drilling takes place from a shielded, soundproofed drilling island adjacent to the Beverly Center, east of San Vicente Boulevard between Beverly Blvd.
[3] The field is near the northern edge of the Los Angeles Basin, about two miles (3 km) south of the Hollywood Hills, the nearest portion of the Santa Monica Mountains.
[4] A layer of sediments of Quaternary age, both alluvial and shallow marine, forms a cap of approximately 200-foot (61 m) thickness on the underlying formations, several of which are oil-bearing.
The Repetto Formation is a sandstone and conglomerate unit probably deposited in a submarine fan environment, and is a prolific petroleum reservoir throughout the Los Angeles Basin.
Land values rose, corresponding to the fast growth of the adjacent city of Los Angeles, and the field was mostly idled in favor of housing and commercial development.
[11] With the shutting down of the Gilmore drilling island, royalty payments to many of the property owners of the land directly over the field ended.
This hazard was realized spectacularly on the night of March 24, 1985, when a Ross clothing store filled with gas overnight and exploded, injuring 23 people.
[1] Seepage of methane upwards along conduits, such as faults and old well boreholes, caused an explosion at a Ross Dress for Less store in 1985 on 3rd Street in the Fairfax District which injured 23 people.
Overnight on March 24, 1985, methane gas filled an auxiliary room at the store and ignited, causing a spectacular explosion which blew out the windows and tore the roof off of the building, injuring 23 people, and reducing the inside to rubble.
In addition to blowing up the building, the methane explosion burst out portions of the adjacent parking lot and sidewalks, venting burning gas over a wide area, creating an eerie scene with pillars of flame lighting the night.
[18] A later theory, and the one now accepted, was that the gas originated in the oil field itself, and had migrated to the surface along a combination of the 3rd Street Fault and any number of improperly abandoned boreholes from the hundreds of now-lost wells drilled in the early years of the twentieth century.
[19] This finding had enormous implications for all of the urban development over old oil fields, and resulted in the construction of gas monitoring and venting wells in several locations in Los Angeles.
[17] In 1989, a similar methane gas buildup occurred underneath 3rd Street and adjacent buildings, probably because of the accidental plugging of a gas-venting well built after the Ross incident.
[21] Since the venting well had become clogged with a buildup of debris, methane slowly collected under the street and adjacent impermeable surfaces, bursting out on the morning of Tuesday, February 7, 1989, in a fountain of mud, water, and methane gas; no explosion occurred, since there was no source of ignition, and city emergency crews quickly cordoned off the area.
