Natural Gas
Conventional natural gas can be sour (containing hydrogen sulphide, or H2S) or sweet, be trapped under high or low pressure, and be located in deep or shallow reservoirs. It can be very expensive to find and produce, as with deep gas wells in the foothills that routinely cost several millions of dollars, or relatively inexpensive to tap, such as shallow wells in eastern Alberta, which can average a few hundreds of thousands of dollars to drill and complete.
Unconventional gas is generally found in formations that are difficult to produce from and that require special completion, stimulation, and production techniques to recover the resource. Coalbed methane (CBM), also known as natural gas from coal, is the best known unconventional gas found in Alberta, but others are gas from tight sands, shale gas (natural gas found in reservoirs predominantly composed of shale), and gas hydrates (crystalline solids comprising gas molecules contained within a lattice of water molecules).
