Deep-water oil: ocean explorers probe the potential

The relentless search for new sources of petroleum and natural gas is forcing US oil companies into deeper water. Nearly a dozen US oil companies may team up with the National Science Foundation to fund the first year of 10-year, $700 million "ocean margin drilling program."

Oil companies are hopeful the drilling project will help them learn some of the potential for petroleum under thousands of feet of water.

Ostensibly, the project's only objectives are to try to learn more about the formation of the oceans and the movement of the continental plates, based on studies of the ocean margins. These margins extend from the coastline to where the continental shelf slopes down to the deep-ocean basins.

But these regions also are believed to be potentially rich in hydrocarbons. Thus, much of the information could be valuable to finding new energy supplies.

Oil company interest in the proposed venture dates back to a similar program in the Gulf of Mexico 12 years ago, when scientists aboard the ship Glomar Challenger found more than they bargained for while drilling for sediment samples in the Gulf of Mexico.

The deep-water core samples, in what was a purely scientific venture, showed traces of oil and natural gas. The surprised crew quickly plugged the hole to prevent the possibility of a blowout or a contamination of sea water. But news of the find could not be plugged. The discovery flew in the face of conventional wisdom, which said that hydrocarbons tended to be close to shore and in relatively shallow water.

But this scientific expedition had found oil and gas beneath 12,000 feet of water, in the middle of the Gulf halfway between Louisiana and Mexico's Yucatan Peninsula.

Word of the find spread quickly through the scientific community and the oil industry.

"It was one of the first pieces of real evidence that there was oil in deep waters," said Dr. Yves Lancelot, chief scientist for the "deep sea drilling project," which was resonsible for the oil find in 1968. The project, funded by the National Science Foundation, is still under way exploring the ocean bottoms to gain clues about the origins and the history of the Earth. Dr. Lancelot works at the Scripps Institution of Oceanography in San Diego, Calif., which manages the project.

"That little bit of evidence showed you could not condemn an area of [of energy potential] just because it was in deep water," explains Owen D. Thomas, vice-president of energy resources activities for Phillips Petroleum Company.

The drill hole, located at a site in the gulf called the Sigsbee Knolls, is still plugged. But interest in the energy potential of the deep oceans has grown dramatically in the years following the discovery.

The true geologic significance of the 1968 oil find was the discovery of salt domes at Sigsbee Knolls. It was a surprise to find these large salt formations in such deep water because salt domes are formed through evaporation and usually associated with shallower waters. The discovery set off new theories about the origin of the Gulf of Mexico.

It was good news for oil companies and energy consumers because hydrocarbons are often found near salt formations. "Very often salt domes entrap oil. They force up a 'cap rock' that may contain oil trapped between the salts and sediment," Dr. Lancelot explained.

The oil industry has major technological hurdles to clear before it can produce much oil in water at depths of more than 1,000 feet. Fixed platforms that extend all the way to the ocean floor are so costly in steel and other materials that many consider them uneconomical much beyond 1,000 feet.

Exxon company USA and Conoco Inc. have unveiled new types of platforms that are designed to work at greater ocean depths. The Conoco platform floats on the water surface, and the Exxon structure uses guy wires to minimize the size of the derrick structure.

Still, some energy firms take the view that deep-water production techology is so sensitive to the particulars of each site -- the weather, ocean currents, etc. -- that developing a full production system does not make sense until they have a specific discovery to warrant the expense.

"We have all the elements to package the production system once we are faced with a site specific problem," claimed Charles L. Blackburn, executive vice-president of Shell Oil Company.

Oil companies are still eager to know more about the oceans and how much energy resource they might conceal.

The "deep sea drilling project," which has been exploring the oceans since 1968 as a purely scientific venture, will cease at the end of fiscal year 1981 when federal funding runs out. However, the National Science Foundation will consider this month a request from Scripps to extend the program for two more years.

At the same time, the National Science Foundation has asked Congress for $5 million in federal funds for fiscal year 1981 for the new program, to be matched with equal oil company contributions. The full projected cost for the 10-year program is $700 million.