China organic-rich shale geologic features and special shale gas production issues

摘要

The depositional environment of organic-rich shale and the related tectonic evolution in China are rather different from those in North America.In China,organic-rich shale is not only deposited in marine environment,but also in non-marine environment:marine-continental transitional environment and lacustrine environment.Through analyzing large amount of outcrops and well cores,the geologic features of organic-rich shale,including mineral composition,organic matter richness and type,and lithology stratigraphy,were analyzed,indicating very special characteristics.Meanwhile,the more complex and active tectonic movements in China lead to strong deformation and erosion of organic-rich shale,well-development of fractures and faults,and higher thermal maturity and serious heterogeneity.Co-existence of shale gas,tight sand gas,and coal bed methane(CBM)proposes a new topic:whether it is possible to co-produce these gases to reduce cost.Based on the geologic features,the primary production issues of shale gas in China were discussed with suggestions.