Shales have moved to the forefront of exploration in the onshore U.S. The rousing success of the Mississippian Barnett Shale play in North Texas has inspired a sweeping search for other producing shales throughout the country. For most working petroleum geologists, shales are a scientific frontier. Efforts are now centered on classifying shales by their productive potentials and characteristics. At the recent Rocky Mountain Natural Gas energy summit in Denver, co-hosted by the Colorado Oil & Gas Association, the Rocky Mountain Association of Geologists and the Denver Geophysical Society, lectures on shale plays brimmed with participants. John Curtis, a professor at Colorado School of Mines in Golden, Colorado, spoke about shale-gas exploration and current U.S. plays. According to Curtis, 7.4 trillion cubic feet (Tcf) of gas have been produced from shales in the U.S. since the first gas well was drilled in 1821 into Devonian strata in Fredonia, New York. "We're still trying to figure out black shales," he said. Geologists are now looking at every source rock/reservoir in the country that might have enough organic carbon and thermal maturity to generate gas, and enough permeability to be produced economically. Potential targets include the Floyd Shale in Alabama, the Woodford and Barnett in West Texas, the Cane Creek in Utah, and the Monterey in California. "It's a very busy time, and shale gas is being investigated around the country," he said. "It's a combination of price, demand and technology." For more on this, see the September issue of Oil and Gas Investor. For a subscription, call 713-260-6441.

Comments