Much has been written recently on the topic of shale gas. The following represents an attempt to explain the topic to the uninitiated. Space limitations dictate that this description is very brief and far from complete.
Shale gas is considered to be unconventional gas, along with coalbed methane and tight gas. The presence of shale gas has been known for a long time but its economics of production were always questionable because of the low permeability of the rock in which the gas is located. In other words, a given well would produce a relatively small amount of gas which was not as economic as other wells. Advances in hydraulic fracturing and horizontal drilling have improved the picture for shale gas. Wells are now routinely drilled down and then horizontally, thus exposing the well bore to a greater area. Combined with techniques to fracture the rock and thereby free the gas, greater production is possible from a given well.
Advances in shale gas technology have resulted in large natural reserve additions, particularly in the United States where the trend is more advanced. Indeed, the US has seen net additions to its gas reserves in the last couple of years, following years of decline.
The prospect in Canada is similar although the industry is not as far along. Shale reserves exist in many areas of Canada, particularly in the Montney and Horn River areas of B.C. but also over large areas of Alberta and in the St. Lawrence River basin. Areas in B.C. are producing already. The Alberta Department of Energy estimates that the Western Canada Sedimentary Basin, the chief producing area of Canada, contains up to 100 trillion cubic feet of gas, although by no means all of that gas would be recoverable in an economic fashion based on today’s technology.
It is also true that shale gas production is seen as a potential health hazard by many people. The fracturing process referred to requires large volumes of water, sand and several toxic chemicals. Home owners in areas of shale gas production have complained about fouled drinking water and illness. Recently, New York City requested a ban on shale gas production in the catchment area for its drinking water supply.
In brief, shale gas represents a significant additional source of natural gas although techniques for its production may need refinement to improve its acceptability to all stakeholders.