The Pumping of the Palisades : A Look at the Scientific Arguments Over Occidental Petroleum’s Plan to Drill for Oil

More than 20 years ago the Occidental Petroleum Corp. first proposed to drill for oil at the base of the Pacific Palisades cliffs. Since then many questions have emerged about the plan to drill 60 wells at the 1.5-acre site near Will Rogers State Beach, but the main issue remains: Will the drilling project encourage further landslides along the crumbling bluffs?

In 1958 a huge slide tore away a section of the cliffs and buried the Pacific Coast Highway so deeply that engineers were forced to reroute the coastal road. Critics of the project have claimed that vibration, ground subsidence and other impacts produced by the drilling process could lead to further slides. Occidental officials, backed by an environmental impact report, contend that modern techniques will allow them to extract the oil with negligible effects on the bluffs.

Last year, in a controversial decision that was approved by Los Angeles Mayor Tom Bradley, the city council gave the company permission to begin the project. But before it can proceed, Occidental must also obtain a permit from the California Coastal Commission, and a heated debate is expected before that body. Further, the company faces another hurdle in the state courts, where a Superior Court judge recently ruled that the environmental impact report was inadequate.

Occidental says it will continue to pursue its case with both the Coastal Commission and the courts. If it finally succeeds, the company will spend approximately $250 million to drill the 60 wells, hoping to produce up to 60 million barrels of oil and 120 billion cubic feet of natural gas.

The key technical issues being debated are:

Vibrations: According to city engineers, any vibration in the region of the drilling project could be “geologically significant” because of the instability of the bluffs. Occidental’s environmental impact report states that the operation will create vibrations during both the drilling and production phases. However, under the current plan these vibrations will be greatly reduced by shock-absorbing equipment, and the total vibration impact is now projected to be only one-tenth as great as that produced by the nearby Pacific Coast Highway.

Subsidence: Withdrawal of crude oil reserves from underground formations sometimes leads to compaction of surrounding sediments and a gradual decline in surface elevation. This could contribute to further instability of the cliffs, but city and Occidental officials maintain that the great depth of the wells--more than 10,000 feet--suggest that subsidence is highly unlikely. The city has required Occidental to conduct a monitoring program and initiate a repressurization program if necessary. Such a program would involve injecting salt water underground to replace the extracted oil.

Induced seismicity: Oil wells have also been known to induce small earthquakes in the region of oil production. This occurs as the oil is removed from its formation and higher rock strata slip downward along existing fault lines. As in the subsidence issue, Occidental maintains that its monitoring program would detect problems before they occur. Should the rock strata be in danger of slipping, repressurization would be initiated.

Bluff saturation: A series of studies by Occidental, Palisades residents, and the city have concluded that the greatest danger to future landslides comes from saturation of the bluffs with water during rainy periods. This water adds enormous weight to the cliffs and provides lubrication to potential failure zones. Occidental has offered to install a drainage system to carry water out of the sediments during wet periods. Costing an estimated $300,000, it will consist of a series of perforated pipes inserted horizontally into the cliffs. Water would be collected by the pipes and carried away from the cliffs by concrete sluices.