What is crude oil? Oil that has not yet been refined. Refining separates gasoline from kerosene, lube oil, asphalt and other petroleum products.

What is a wildcat well? A well drilled in a basin that has not yet had oil produced from it. Chris Fling, Tecton Energy's vice president of land and business development, said the name comes because drillers were "way out in the middle of nowhere," where the wildcats lived.

How deep is a well? The 33 wells in the Española Basin are generally between 1,000 and 3,000 feet deep. One, drilled in 1978, reached 8,100 feet.

Ron Broadhead, petroleum geologist at the New Mexico Bureau of Mines and Mineral Resources, said one well in the Albuquerque Basin reached 19,000 feet. His colleague Patrick Walsh said wells in the Permian Basin, in the southeast corner of the state, are 12,000 to 14,000 feet. He said some North American wells reach 32,000 feet.

State regulations allow one oil well per 10 acres, but Broadhead said modern wells are commonly drilled with 40-acre spacing. Better technology and higher cost discourage closely packed wells in modern fields. Since gas flows more easily than oil, gas wells are drilled farther apart, generally one well per 160 acres.

What is hydrofracturing? Drillers pump water into oil- and gas-producing layers to crack them and allow more hydrocarbons to reach the well. Walsh said engineers carefully monitor the fracture process. They calculate the stress needed to fracture the rock to a certain distance. He said they are careful and accurate, because drillers don't want fractures to extend past where they can extract oil or into areas where hydrocarbons would penetrate fresh water.

What is coal-bed methane? Consulting geologist John Hawley said gas pockets form around decaying swamp vegetation in environments such as what currently exists along the Gulf of Mexico. The resulting methane can be extracted through gas wells, as at Vermejo Park in northeastern New Mexico. This gas is the cause of mine explosions, including two disastrous ones at Dawson, near Raton.

Fling said to extract methane gas from the beds, they have to be "dewatered" by pumping fresh water off, reducing the pressure and causing gas to "desorb" from the coal. The Menefee formation contains coal, but Fling said in the Galisteo Basin, Tecton isn't concentrating on those beds as sources of gas.

How much does a new well cost? According to Fling, it costs about $1.5 million to drill each 8,000-foot well.

What is casing a well? After a well is drilled, a steel casing is inserted to the bottom and cemented in. The steel pipe is then perforated, but only at the exact depths where gas and oil can be extracted. This seals off other levels and prevents contamination between separate geological formations.

What is "plugging" a well? This is filling a well with concrete to put it out of commission. Government regulatory agencies prescribe the steps to follow to do this. Fling said many of the wildcat wells in the Española Basin are plugged. He likened the process to spackling a nail hole in a wall.