I was recently exposed to the “Resource Triangle” during a talk about the future of fossil fuels and thought this visual had educational value in that it conveys the point that unconventional fossil fuels we are hearing more about these days have always been there, but now, thanks to advances in technology and rising energy costs some, like shale gas, are becoming economically viable to extract.
Masters and Gray published the concept of the resource triangle in the late 1970s to show that “oil and gas resources are distributed log normally in nature” just like any other natural resource. Stephen Holditch, Professor of Petroleum Engineering at Texas A & M University, is credited with keeping this concept alive in today’s publications about oil and gas reserves. For those of you wanting to read more about these resources and get a sense of their abundance and distribution, you may be interested in the a 2009 article titled How technology transfer will expand the development of unconventional gas, worldwide by Holditch and Ayers. A corresponding presentation (pdf) on this topic is also available and contains a slide of the resource triangle as well as other figures that can be useful in addressing this topic with your students.
The International Association for Drilling Contractors represents the worldwide oil and gas industry. A 2004 article in their magazine, Drilling Contractor, cites the resource triangle and generally summarizes the various unconventional energy sources, making this a reading suitable for most students.