The Characteristics And Exploration Prospects Of The Carboniferous-Permian Mud Shale In Juyanhai Depression,Yin'e Basin

The exploration degree of Juyanhai depression in the Yin'e basin is low,lacking of understanding of core samples of Carboniferous-Permian mud shale.This study is focused on the Carboniferous-Permian mud shale in Juyanhai depression of Yin'e basin,and through the analyses of test data,logging data,stratigraphic data and core photographs,the geochemical characteristics,hydrocarbon generation and expulsion characteristics and reservoir characteristics of mud shale were studied.The comprehensive evaluation of shale gas is based on the above characteristics,providing the basis for the selection of optimum exploration level of shale gas.The Carboniferous-Permian mud shale in Juyanhai depression of Yin'e basin is rich in organic matter,and generally reaches high standard.The types of organic matter are mainly types II~III,being anastomosis with offshore lake facies kerogen.The thermal evolution is at the mature stage,which is conducive to the formation of shale oil and gas.At the end of the late Permian,the mud shale strata was rapidly subsiding,and the temperature rapidly increased and entered the threshold of hydrocarbon generation,and at the early Triassic,the strata reached the maximum depth,but no HC expulsion process occurred in this stage.During the Triassic period,the effect of the long-term uplift of the Indo-Chinese period made strata greatly uplifted and eroded.In the Jurassic to the Cretaceous,the strata were slowly subsiding,and begun to discharge hydrocarbon in Cretaceous.At the end of the Cretaceous period,the Yanshan movement made strata uplifted and eroded again.Since entering the Neogene,the stable deposition of strata has existed,and a large number of hydrocarbons expelled from source rock occurred.The main mineral composition of Carboniferous-Permian strata is quartz and clay minerals,the storage spaces are various,and the heterogeneity is strong,which is conducive to the occurrence and accumulation of shale gas.The strata of the area have geological conditions for the formation of shale gas,and can be used as the next exploration and development target of shale gas.