Geological characteristics and shale gas potential of Lower Cambrian Hetang Formation in Lower Yangtze region: a case study of Jiangshan-Tonglu area, western Zhejiang province

Abstract

The high degree of thermal evolution is a main factor restricting the development of the Lower Paleozoic shale gas in the Yangtze region. The latest field study shows that there is a region with relatively lower thermal evolution in the Jiangshan-Tonglu area in western Zhejiang province. Centering on the lower thermal evolution area, this paper analyzes the geological and geochemical characteristics of the Lower Cambrian Hetang Formation, based on the regional geological survey of the western Zhejiang province and the latest borehole data analysis. The study area is located in a good sedimentary facies belt (basin-shelf facies), with a large deposition thickness, and a high organic matter abundance. While the thermal evolution degree is relatively low, with high brittle mineral content and moderate clay mineral content. And micro-pores and micro-fractures are well developed. The study area has a good material basis for accumulation. The Changshan-Kaihua area has been identified as the most favorable area for shale gas exploration on the basis of considering a thick shale deposit with high organic matter abundance, relatively low thermal evolution, stable tectonic background and deeply buried area, while avoiding the areas with relatively strong igneous activity.

Keywords

• geochemical characteristics
• reservoir property
• favorable exploration area
• hetang formation
• lower yangtze region
• shale gas