Hydraulic fracturing is to use the ground high pressure pump

Hydraulic fracturing is to use the ground high pressure pump, through the wellbore to squeeze oil layer with high viscosity of frac sand fluid. When the injection rate of fracturing fluid exceeds the absorptive capacity of the reservoir, the reservoir is formed on a high pressure on bottom, when the pressure is more than near the bottom of a well fracture pressure of reservoir rocks, reservoir pressure will be open and cracks. Then, on and on to reservoir squeeze fracturing fluid, cracks will continue to expand inside the reservoir. To keep the pressure on cracks in the open state, then to the reservoir into with proppant carrying fluid (usually quartz sand), after carrying fluid into the cracks, cracks on the one hand, can make its way, on the other hand can have open cracks, so that it is not closed. Then into the displacement fluid, the carrying fluid of wellbore entirely replace into the cracks, prop up the cracks with quartz sand. Finally, the injection of high viscosity fluid will fracturing proppant degrade the discharge shaft, left one or more of the oil length, width and height of crack and reservoir and established a new fluid passage between the wellbore. After fracturing, the output of oil and gas Wells are generally increase substantially. It can be generated in various stages of organic origin on the subject of natural gas in free phase (about 50%), very little stored in dissolved state in kerogen, asphalt and oil. Natural gas are also present in the interlayer of siltstone, silty mudstone, argillaceous siltstone, sandstone formation even. After gas generated in the source rock in the nearby gathered themselves together, and show the typical shale gas on the patterns of in situ, with a greater difference between shale, tar sands, asphalt, etc. Different from conventional gas reservoir, shale is gas generation of source rocks, and gather and save gas reservoir and cap rock. As a result, high organic matter content of black shale, such as high carbon mudstone is often the best conditions for shale gas development