Friday, May 20, 2005

Methane In Geopressurized Brine

Winds of Change has a monster energy roundup post with links-a-plenty for you ravenous readers, but the one that really caught my eye was the one about geopressurized brine. Unfortunately, the WoC story link was busted, but I found it again at Searching For The Truth. This paragraph explains what they are and how they can be useful:
Geopressured reservoirs or aquifers exist deep underground, usually as a salty solution or brine, in locations throughout the world. The brine is typically saturated with methane, with between 30 to 80 cubic feet of methane gas contained in each barrel of fluid. Fluid pressures in such aquifers can be as much as twice the normal hydrostatic gradient, meaning that significant pressure will exist at the wellhead when the reservoir is tapped. The water is also often quite hot, with temperatures typically within the range of 90 °C - 200 °C. Three types of energy could potentially be derived from geopressurized brine: (1) Thermal energy from the temperature of the fluid; (2) mechanical energy from the fluid pressure; and (3) chemical energy from the methane that is suspended within the fluid.
Researcher Vaclav Smil claims that as much as 110 times the amount of conventional natural gas could exist in geopressurized brine. With higher energy prices (natural gas and oil), market conditions that made extraction of these resources uneconomical in the 1990's now no longer exist, and extraction becomes feasible. A paper by Unocal's Jeremy Griggs (PDF) suggests that with further research, these resources could be successfully harvested.