Giant Gas Gusher in Louisiana

Tuscaloosa Sand, "geopressured" zones could raise nation's supply

The night of Aug. 13 was one that Lucy Parlange, wife of a plantation owner near New Roads, La., will never forget. She recalls: "We were sitting up here on the gallery, when we heard this terrific sound, like a sonic boom. I thought the air conditioner in the kitchen had blown up." What had really blown was a giant natural-gas well that probably will make Lucy and her husband, Walter Parlange, royalty rich.

The well's importance goes far beyond that. Its discovery indicates that a major new gas-exploration effort in the Tuscaloosa Sand geological formation of southern Louisiana is hitting pay zones. That promises new production not only for Louisiana but for an energy-hungry nation that counts natural gas as both its cleanest-burning and most critically scarce fuel. Last week the Louisiana Office of Conservation estimated that gas reserves in the Tuscaloosa Sand may reach 3 trillion cu. ft. That would be equal to 86% of last year's production in Louisiana, which leads the nation in gas output, and 18% of annual consumption in the whole country. To its discoverers that much gas would be worth $5.5 billion at existing wellhead prices on Louisiana's intrastate free market.

Moreover, as TIME Correspondent Robert Parker reported after a tour of the area, an even bigger potential bonanza lies near by, in the "geopressured" zones full of hot, salty water and dissolved gas that underlie thousands of square miles along the Gulf Coast. David Lombard, a physicist for the Department of Energy, asserts: "If everything works, we will have as a goal to produce 2 trillion cu. ft. of gas a year from geopressured zones by the year 2000." That would equal 10% of the present U.S. gas consumption.

The Parlange well extended the known limits of the Tuscaloosa Sand, which is named for the Alabama county where it crops to the surface. In Louisiana, the "trend" (main potential gas-producing formation) lies four miles beneath the green bayous and sugar-cane fields and stretches 200 miles from Lake Pontchartrain to the Texas border. Because of its depth, high temperature and geological history, the Tuscaloosa Sand has produced mostly gas, very little oil.

Exploration crews have been probing the Tuscaloosa Sand since the early 1960s, but the gas proved elusive. Formed 65 million years ago in northern Louisiana and swept southward by ancient rivers, it lay hidden under a layer of limestone that distorted the echoes of shock waves by which geologists map underground formations. But a Chevron geologist's hunch, confirmed by tests using computer techniques, led prospectors to a swampy field on the Parlange plantation. When the drill bit spun into a zone of extreme pressure 21,345 ft. down, the gas and steam crushed the well casing, ripped out a blowout preventer at the top of the well and blew out of control.

For six weeks, a crew of red-suited blowout experts battled to cap the wild well. A crane removing a ten-ton piece of wellhead plumbing was smashed like a Tinkertoy, when the gas jet tossed the load into the air. The crew succeeded in diverting the gas to an open pit, where they set it ablaze to prevent an accidental explosion. By the end of September, workers managed to pipe the gas through a purifying plant and into a pipeline, through which it flowed at an uncontrolled rate of 140 million cu. ft. per day. Says Chevron's Exploration Manager David Johnson: "If we had tried to shut it off, the gas would have blown the control equipment out of the hole."

Eventually, the workers pumped enough drillers' mud into the well to stop the flow of gas and permit the installation of proper wellhead equipment. Next year the well will go on stream at a manageable 20 million cu. ft. per day, six times the volume of a typical south Louisiana well and enough to meet the daily needs of 61,000 American homes.

The Parlange strike and an earlier successful Chevron well called the No. 1 Alma Plantation have touched off fresh waves of leasing and prospecting activity. Altogether, major oil companies and independents have leased more than 1.8 million acres. Some landowners got as much as $350 an acre and a one-third share in future production. The state of Louisiana, controlling 5 million acres, leased land on the bottom of Lake Pontchartrain for $324 an acre and a choice site elsewhere at $1,500 an acre in competitive bidding. So far, the Tuscaloosa Sand has yielded 14 producing or potentially producing wells.

The new discoveries have significant implications for gas consumers nationwide as well as for Louisiana, where one worker in twelve draws his paycheck from an energy company. A recent report to the Governor of Louisiana estimated that 85% of the state's potential oil-and gas-producing deposits have not yet been drilled, but most of the unexplored reserves are very deep and difficult to find, as in the Tuscaloosa Sand. There the wells are four times as deep as the average U.S. well. Drilling one costs about $5 million if it is a producer, almost as much if it is a dry hole--and dry holes outnumber the producers 3 or 4 to 1. Louisiana officials argue that the heavy costs will require higher prices for interstate gas, which is now federally price controlled at $1.47 per 1,000 cu. ft., v. an average $1.85 on Louisiana's intrastate free market. Even at that price, Louisiana last year piped 75% of its gas to other states; higher prices could attract still more of the gas into interstate pipelines.

While the search for gas in the Tuscaloosa Sand is being conducted mostly by private business, the U.S. Department of Energy is providing funds to assemble information on the Gulf Coast's geopressured zones. In theory, the water from these zones, emerging at a wellhead pressure of 6,000 lbs. per sq. in. and a temperature much above boiling, could spin turbines and yield heat for such purposes as oil refining, food processing and rice drying. The gas that is dissolved underground in the hot water fizzes out of solution at atmospheric pressure to be captured for fuel. The billion-dollar question is whether all this can be done at an economic cost.

At a conference on geopressure at the University of Southwest Louisiana in November, a research team that had converted an abandoned gas well into a geopressured test hole reported recovering 10,300 bbl. a day of superheated gas-saturated brine, which yielded up 1.5 million cu. ft. of gas. The Department of Energy's David Lombard estimates that a geopressured well would have to yield 40,000 bbl. of water a day for five to ten years to turn a profit. Whether the reservoirs can produce at that volume is one of the questions to be answered by drilling a series of test wells in Louisiana and Texas during the next two years.

Other sticky problems will challenge the engineers and designers. Sand will probably have to be screened out by costly stainless-steel filters at the bottom of each well. The corrosive quality and high temperature and pressure of the brine will demand specially designed piping, valves and moving machinery. The exhaust water will have to be pumped back into the earth to avoid turning the area into a swamp. The economics will look more encouraging, however, if Congress adopts a provision now in a pending tax bill that will allow a tax credit of 50-c- per 1,000 cu. ft. of geopressured gas recovered.

Should geopressure prove to be a viable resource, the implications would be global. Similar zones are believed to exist in at least 45 countries, including those in Western Europe and in the deltas of the Nile, Ganges and Niger rivers. Wells drilled into geopressured zones could supply fresh water as well as energy. At atmospheric pressure the hot water flashes into steam and concentrated brine. The steam can be condensed into pure drinking water, which in desert regions is almost as precious as oil.

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