The June 2008 issue of Ontario Oil & Gas, a publication of the Ontario Petroleum Institute, says the first known shale gas production in North America occurred in 1821 when local townsfolk in Fredonia, NY drilled an 8.3 meter deep well into Upper Devonian Dunkirk shale, after accidental ignition of a natural gas seep, and piped the gas through hollowed logs to light the nearby houses.
The black shale called the Marcellus formation, laid down in the Devonian period, some 400 million years ago, underlies much of Virginia, Ohio, Pennsylvania and New York, and even Lake Erie, with surface outliers in southern Ontario. From its surface expression the beds slope downward to a depth of 9000 feet to the southeast. The United States Geological Survey in 2002 estimated it as potentially bearing 1.9 trillion cubic feet (tcf) of gas, but held in impermeable rock, which for a time seemed unpromising. Exploratory drilling began shortly after, however, with Range Resources Appalachia in 2003, which appears to have been the first to drill a well, or at least a reasonably productive one, in Pennsylvania.
In any case, a 2008 estimate revised the total upwards to perhaps 500 tcf, of which ten percent might be extractable using horizontal drilling and hydro fracturing techniques.
According to an introductory article on geology.com, from which most of this summary is extracted, the thickest and most productive beds are in northeastern Pennsylvania.
Production rates from a new well can exceed one million cubic feet per day. As the existing fissures in the rock, natural and artificially created, become drained, further rounds of fracturing become necessary to maintain the output. Hydrofracking (a form of fracturing) is accomplished by sealing off a portion of the well and injecting water or gel under very high pressure into the isolated portion of the hole. The high pressure fractures the rock and pushes the fractures open. Then, tonnes of sand or other “proppant” are pumped down to the fractured zone to to prevent the fractures from closing again and maintain gas flow.
There are several shale gas formations that reach into Ontario besides Marcellus, notably Kettle Point. A story in the Toronto Star, March 20, describes how Calgary-based Mooncor Oil & Gas Corp. has obtained rights on nearly 23,000 acres (9.30776 hectares) of land in Lambton and Kent counties to explore for both conventional and shale gas.
So far, only two or three unproductive exploratory wells have been drilled in Ontario, says Rudy Rydansky, in the Petroleum Resource Centre in London, Ontario, an office of the provincial Ministry of Natural Resources (MNR). At present, Ontario has no special regulations covering shale gas exploration and extraction, he explained in a telephone interview. Regulation is under the Oil, Gas and Salt Resources Act and administered by the MNR. Any wells need to be licensed, but the requirements basically only cover the effect of operations on the surface (noise, and other typical industrial operations), not any effects that might be associated with shale gas in particular, such as the water withdrawals and disposal issues involved (see companion sidebar on environmental effects, page 27). However, Rydansky says, permitting requirements can be bumped up to EA status, and if the office starts receiving hundreds of permit requests, it would take notice and decide if anything else is needed.
Please see the following related articles, including a special feature by John Wolnik on the Marcellus Shale deposit, in this issue of IPPSO FACTO:
* How shale gas is redrawing the map for Canadian power generators
* Marcellus gas — a game changer, feature article by John Wolnik
* Environmental considerations impact shale gas options
* Editorial: Will Ontario miss another great gas opportunity?