The Formation Mechanisms Of Abnormal Pressure And Factor In Control Of The Coal Bed Gas In Qinshui Basin

Pressure is one of the main control factors for coal-bed gas existing. The geologic strata pressure not only is the oil move of first time mainly drive, at the same time Pressure prediction provides the base to study the reservoir-forming dynamics of coal-bed gas. text based On origin of interior and external of abnormal formation pressure in coal bed gas, according to the coal bed reservoir characteristic of oneself. firstly on the basis of analysis on the data form the coal layer gas reservoirs in China, this paper thoroughly described the genesis , the environment condition and the characteristics and tapes of the abnormal pressure in the coal layer-related gas reservoirs , and analyzed the reasons for the low pressure in the coal layers in China The study showed that process-forming mechanism was resulted from the high abnormal pressure during the burial process and the gas formation in the geological history , and the ioints and outbursts of the cap rocks played an important role in the process of large-scale outward migration of fluid In addition , the water heating , tectonic stress and hydrodynamics are of dual effects at different periods and different locations The up lift in the late stage , the erosion , the decrease of overlying loading pressure , the destruction of capping condition ,especially the change of hydrogeoiogical condition near the surface of the earth ,were the main factors controlling the current pressure, finally in the light of much more collection Qinshui basin formation pressure data from exploitation stage, and the hydrocarbon history, bury the history and constructed of...