Abandoned Oil and Gas Wells Become Pollution Portals

From the Louisiana bayous to the arid plains of Texas and Oklahoma, thousands of oil and gas wells, abandoned at the end of their productive life, have become conduits for noxious liquids that bubble up from deep below the earth's surface to kill crops and taint drinking water.

For state governments in America's oil patch, these abandoned wells have become an expensive legacy left by a fading industry.

The Federal Environmental Protection Agency estimates that there are about 1.2 million abandoned oil and gas wells nationwide and that some 200,000 of them may not be properly plugged. In Texas alone, officials calculate there are 40,000 to 50,000 abandoned wells that could pose pollution problems.

Often drilled to depths of a mile or more, oil wells typically tap into sandy formations permeated with a brine that is up to four times saltier than sea water and that is laced with radioactivity, heavy metals and other toxins. Without extensive and costly plugging, that brine can flow up the well shaft and seep into fresh water aquifers or sometimes reach the surface.

Occasionally the brine from abandoned wells hits the surface with explosive force. In the last few years it has erupted through a parking lot in San Angelo, Tex. Mixed with natural gas, it spewed into the backyard of a home in Bartlesville, Okla., and oozed onto a freeway construction site in Tulsa. Slow, Insidious Process

But the damage is usually slower and more insidious. A single unplugged exploration hole in West Texas leaked brine for 22 years before being discovered, polluting the ground water beneath 400 to 600 acres of land, a 1990 study by the Bureau of Economic Geology at University of Texas found.

Many of the problem wells date to a freewheeling time before the oil business kept records or was regulated. In Texas, state records indicate that the sites of some 386,000 wells were never registered.

And it was not until the mid-1960's that the oil-producing states enacted regulations to protect fresh water supplies by requiring that hundreds of feet of cement be poured into the wells at different levels in the process of closing them properly. A majority of the wells listed as plugged in Texas records were plugged before the rules were in place. Plugging Style of Past

"We've found leaking wells from the old days that were rock-plugged, bucket-plugged, tree-stump-plugged and even one plugged with nothing more than a glass jug because back then they didn't give a darn and they just stuck whatever they had down the hole," said Wayne Farrell, director of the San Angelo-Tom Green County Health Department in West Texas.

Oilfields are primarily the province of state, rather than Federal, regulators. They have usually been overseen by agencies like the Texas Railroad Commission or the Oklahoma Corporation Commission whose primary purpose is to promote the oil industry rather than protect the environment.

The dangers posed by abandoned and improperly plugged wells began to attract attention from state officials only in the mid-1980's. The oil industry was a cherished source of revenue, and there was little research to distinguish contamination in oil fields from the naturally occurring salinity common in places like West Texas.

Since 1990, both Texas and Oklahoma have created funds specifically dedicated to plugging abandoned wells by imposing new taxes or fees on companies drilling or operating oil wells. Louisiana, which has 1,493 abandoned, unplugged wells listed as awaiting action, eliminated money in its budget for plugging wells this year because of a state budget shortage.

With exhausted fields and low prices driving down production, the number of wells abandoned by bankrupt operators has increased rapidly since the mid-1980's. Last year, Oklahoma began plugging 260 wells that were orphaned when a single company went bankrupt. The average cost is $4,000 a well.

Lena Guerrero, chairwoman of the three-member Texas Railroad Commission, said: "In a very short time Texas has gone from denial, to saying maybe there's a problem but there's no money to fix it, to now where we're saying there's a real problem and we can find the resources."

Declining production has brought other problems as well. In depleted fields, wells commonly pump more than five barrels of brine for every barrel of oil, and those vast quantities of brine are often forcefully injected back into the ground. The goal is to dispose of the brine and increase pressure in the oil-bearing formation so that more crude can be extracted from a nearby active well. But if an improperly plugged well has penetrated the formation, the added pressure helps push the brine up that shaft. Threat to Wildlife, Too

Ken Kramer, director of the Texas Sierra Club, said that abandoned wells "pose the most extensive and most critical environmental problems caused by oilfield activities, but they are not the only ones." The storage of brine and other wastes in open pits is another source of water pollution as well as a hazard to wildlife, he said.