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

Abstract

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.

Keywords

• Organic-rich shale
• Mineral composition
• Organic matters
• Tectonic deformation
• Production