Shales’ production also boosted domestic chemicals, says Kevin Swift, chief economist for Washington, D.C.-basedAmerican Chemistry Council (ACC,www.americanchemistry.com): “The [current] surge in oil prices has helped competiveness in the U.S. because overseas competitors use crude for naptha, whereas here in the U.S. feedstock is natural gas.” He cites Central Appalachia’s Marcellus Shale Play formation as contributing to the current favorable situation. “After Hurricane Katrina, natural gas cost $10 per million BTU (British thermal unit). Now, natural gas is about $4 per million BTU.”
近年来，三个因素创造了页岩气的经济可行性，据化石能源和国家能源技术实验室办公室。这些包括横向钻井的进步，液压压裂的进步（也称为水力发电或压裂），并且天然气价格的快速增加。
Reliability also makes natural gas an attractive energy source. “Eighty-four percent of the natural gas consumed in the U.S. is produced in the U.S., and 97 percent of the gas used in this country is produced in North America,” explains the Department of Energy. “Thus, the supply of natural gas is not dependent on unstable foreign countries and the delivery system is less subject to interruption.”
目前，11个主要的页岩气游戏 - 含有大量天然气和在大陆美国的地质和地理特性存在类似的地质和地理特性。“多种来源的估计表明了技术上可收回的页岩气的巨大资源，”Rayola Dougher，a高级经济学家与华盛顿，D.C.为基础American Petroleum Institute (API,www.api.org). For example, in March 2011, EIA estimated 827 trillion cubic feet (Tcf) of potentially recoverable natural gas.
Forecasts change, though. “Over the past decade, as more shale formations have gone into commercial production, the estimate of technically and economically recoverable shale gas resources has skyrocketed,” notes EIA in its recently published Annual Energy Outlook 2011. Further, “many shale formations (particularly, the Marcellus Shale) are so large that only a portion of the formation has been extensively production tested,” EIA states, adding technical advances could lead to more productive and less-costly well drilling and completion.
Gigantic promise
The Marcellus holds gigantic promise. Extending over approximately 95,000 square miles and six states, the formation contains 1,500 Tcf of natural gas and potentially could produce 3,000 cf per day per well, according to EIA. “Fully developed, the Marcellus Shale has the potential to be the second largest natural gas field in the world . . . Converted to British thermal units, the natural gas found in the Marcellus could be equivalent to the energy content of 87 billion barrels of oil, enough to meet the demand of the entire world for nearly three years,” said Timothy J. Considine, Robert Watson and Seth Blumsack, professors at The Pennsylvania State University, in a 2010 assessment.
Predictably, though, problems accompany promise. “The use of hydraulic fracturing in conjunction with horizontal drilling has opened up resources in low permeability formations that would not be commercially viable without the technology,” the ACC explains. “Public concern, however, has been raised regarding the extensive use of hydraulic fracturing because of the large volumes of water required, the chemicals added to fracturing fluids, and the disposal of these fluids after a well has been completed.” This concern manifests itself as bromide in western Pennsylvania rivers. That’s led the Commonwealth to ask drillers to voluntarily cease disposal, beginning in late May, of drilling waters at more than a dozen municipal wastewater treatment plants.
Two other states overlying the Marcellus also buzz with shale-gas activity. In West Virginia, the Marcellus found its way into May’s special-gubernatorial-election primaries. There’s also news of chemical companies committing to produce and/or purchase liquid ethane, a byproduct of natural-gas processing. In New York, where the State Comptroller’s Office has invested approximately $1 billion in natural-gas and hydro-fracking companies, the state ban on horizontal hydro-fracking ends July 1, 2011.
其他一些整体问题存在。一个提出的是地下饮用水含水层的潜在污染。另一项关于收集，运输和处理，因为例如Marcellus'和其他一些Shales的存款不属于传统的天然气供应基础设施。
Through all this, however, Dougher sees good news. “It’s the potential that new technologies [such as horizontal drilling] have enabled us to go places that we could never before. And there’s shale gas all over the nation. It’s changing the way we look at our country.”
C. Kenna Amos，ckamosjr@earthlink.net., is anAutomation World贡献编辑器。
Energy Information Administration (EIA,www.eia.doe.gov.)
American Chemistry Council (ACC,www.americanchemistry.com)
American Petroleum Institute (API,www.api.org)
