Compared with the regular oil and gas resources, there is a large difference in the exploiting methods of shale gas. With difficult in exploitation, it requires for high-pressure fracturing technology. With high risk, such a technology also requires for large amount of water consumption. According to the data, if high-pressure fracturing technology is applied, the water consumption for each gas well reaches 1 to 4 million gallon (3800 to 15,100 m3), 50 to 100 times of the one for a regular fracturing well. Moreover, 50 to 70 percent of water is purely wasted during such a process. The water consumption per well is equal to that of 5000 to 10,000 normal families in a month in China. Such huge water consumption is undoubtedly a deadly restriction for the dry shale gas area lack of water.
The fracturing fluid used during the shale gas exploitation cannot be ignored, either. Besides a large amount of sand and stone, the fracturing fluid used in each shale gas well also contains 200,000-litre acid liquor and chemical additive like bactericide, scale inhibitor, lubricant and surfactant. In addition, the flow back liquid contains formation water with highly dissolved solids. Improper treatment of the fracturing fluid when it flows back to the surface will seriously affect the surface source of drinking water. Furthermore, the fracturing fluid may contaminate the underground source of drinking water through channels like the induced geological fault and poorly-sealed bushing wall.
Weekly Photos of China: Nov 5-11