Research status and exploration enlightenment on over-pressure and enrichment shale gas in North America

ln order to acutely seek a rich and high production target of the shale gas in China.the analysis on the exploration and developmentfeatures of the shale gas in North America would have high benefts. Based on the discussion on the distribution and features of the overpressureshale gas in North America,the paper had a study on the overpressure formation mechanism of the shale gas and the evaluation techmnology of the favorable enrichment zone.The results showed that the overpressure features of the emerging North America shale gas zone were obvious andthe gas reservoirs of the Marcellus shale and Haynesville shale were typical. The organic matter content of the overpressure shale was high generally and would have a high thermal evolution degree,a relative high porosity and a good preservation condition.The fre-gas volume had a highpercentage in the overpressure shale gas zone and the gas reservoir productivity would be relatively high generation and the pressure increased to make the micro fractures and could highly enhance the seepage performances of the reservoir. Meanw hile,the pressure increased could improve the shale gas content and could be favorable to improve the sealing of the shale oil and gas.As for each exploration block in China,the core zone determined would be important to the pressure relationshio of the strata. The certain enrichment evauation should enhance the pressure analysis on the fuid of the strata and should emphasize to seek the over-pressure sweet zones in the shalegas reservoir.