Exploration potential of the Yanxi formation in Middle Ordovician of Hunan province

摘要

A organic rich black shale was widely developed in the central Hunan province, because of the low degree of exloration and lack of petrolum geologic data, there was not a compelete evaluation on this shale. Through comprehensively investigation and analysis of the geological characteristics of Yanxi formation (O_2) and sedimentary evolution of the Ordovivian in this area, it is found that the black shales of O_2 are characterized by widely distribution, great thickness (ranging from 40 to 135m) and high level of organic carbon (ranging from 0.87% to 6.20%). Compared to the discovery area, the thermal maturity and the illite crystallinity (IC) analysis of O_2 is at the mature to over mature stage (1.83%