Shale gas exploitation bottleneck

shale gas and tight gas, coalbed methane, gas hydrates, like, are considered unconventional reservoirs. Although its main components with the same gas are methane (CH4), but the difference in the specific mining process considerably. Shale shale gas exists in the gap to adsorb gas, or water-soluble form of gas. Its penetration is very low, you must find a way to open the gap to be sealed are extracted. This resource has been discovered about 200 years, the reason to have only recently started to develop, precisely because of the technical difficulty of shale gas is quite big. Therefore, it has been described as the development of shale gas, "virgin bleeding from a stone." U.S. shale gas success, largely due to hydraulic fracturing technology matures.  Hydraulic fracturing  technology development of shale gas, of course, need water, but plenty of water. Add drugs in the water due to the need to avoid drugs with other substances in water loss from the chemical reaction effect on the water quality requirements are quite high. It is said that it was even higher than that of pure drinking water. In the current technical conditions, water scarcity, no matter how many areas of shale gas resources, and its significance is also equivalent tasteless but wasteful to discard the chicken. And we all know, China is the relative scarcity of water resources in the country. Also, add in hydraulic fracturing fluid medication, many of which are harmful to the environment. For example, to increase the viscosity of the fracturing fluid added guar gum, to prevent swelling of clay in the reservoir and added to the potassium salt. These drugs into the underground, the short term may have little effect, but after long-term penetration, diffusion, is likely to contaminate groundwater. This contamination so far basically ungovernable. Meanwhile, the main component of shale gas methane easily spread, volatile, has been able to survive, simply because the shale seal. To exploit shale gas shale must first destroy the seal, seal after the destruction of methane will rapidly dissipated. The current mining methods can only be used before destruction, and then try to recover. Even with low damage fracturing fluid and other advanced technologies, most can only be restored to the original level of 10% to 20%. This characteristic causes shale oil recovery is quite low. Conventional gas recovery can reach about 60%, while the recovery of shale gas is only about 5% to 6%. If you follow the recovery calculation, tens of trillions of cubic meters of recoverable shale gas resources developed, perhaps the only hand could get only a few one trillion cubic meters only.