05.07.2009
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The substance produced from the treatment of kerogen, that hydrocarbon found in some shales, which is difficult and costly to extract. Shale is a dense rock formation common in many parts around the world which has long been known to contain natural gas. Production, however was impractical when the price of oil was low because the rock is not porous enough for the gas to flow. In the 1990s, however, companies figured out how to crack the shale using pressurized water, thus releasing the gas, with the technique being perfected in the Barnett Shale, a massive shale-gas field around Fort Worth, Texas which produces in 2008 about 4 bcf of natural gas per day. US shale plays could hold as much as 840 trillion cubic feet of gas, the equivalent of more than 140 billion barrels of oil, more than half the proven reserves of Saudi Arabia, but the amounts produced could eventually definitely be lower and production will require billions of dollars of drilling. Limited availability of drilling rigs, oil-field workers and pipelines as well as environmental and regulatory constraints will restrict how fast production will advance. The discovery however of this new source of natural gas has increased production and could change the supply and demand equilibrium
Shale gas is natural gas produced from the fractures, pore spaces and physical matrix of shales. Shale gas plays are considered area plays since shale gas, similar to coal bed methane is often found over large contiguous areas. Most shales have low matrix permeabilities and require the presence of extensive natural fracture systems to sustain commercial gas production rates. In North America, the drilling boom for shale gas got under way after advanced techniques — horizontal drilling combined with hydraulic fracturing — allowed companies to tap gas trapped in huge shale beds that had been out of reach just a decade earlier. Shale fracs however require significant greater quantities of water than sand fracs
Problems with shale gas drilling include: over usage of water which is problematic (very true of China where water is needed for rice growing and using it for shale gas could lead to hunger); fugitive emissions could mean that shale gas is less environmentally friendly than coal; fracking or fracturing has been said to cause problems such as the possibility of small earthquakes (stills needs further study). The geological conditions in China are very different to those in the US in that the reservoirs are believed to be very deep so conditions are very difficult
A type of rock composed of common clay or mud
Opposite of jointly liable. Namely, each party is only liable for its respective obligations
The five US firms: Exxon (Esso), Gulf, Texaco, Mobil, Chevron (Socal); two UK firms: Shell and BP and one French firm CFP-Total
Tank filled with drilling mud that is not circulated. By having mud slowly pass through such a container, most large drilling solids sink to the bottom, cleaning the mud somewhat.