四川盆地川西坳陷中段上三叠统烃源岩评价

EVALUATION ON UPPER TRIASSIC HYDROCARBON SOURCE ROCKS OF WESTERN SICHUAN DEPRESSION,SICHUAN BASIN

地球化学分析结果表明,川西坳陷中段上三叠统以泥质烃源岩为主,有机质丰度较高,多处于成熟—过成熟演化阶段,具备较好的生烃能力。研究表明排烃强度可以最终体现烃源岩的质量,文中以排烃强度为基础将研究区分为3类：一类烃源区位于什邡、彭州、温江、大邑和都江堰地区,面积约为5 412 km^2,烃源岩厚度约为1 000-1 650 m,排烃强度约为（100-270）×10^8m^3/km^2;二类烃源区位于绵阳、绵竹、中江和成都地区,面积约为6 281 km2,烃源岩厚度约为700-1 500 m,排烃强度约为（50-100）×10^8m^3/km^2;三类烃源区位于安县、丰谷和龙泉驿地区,面积约为4 895 km^2,烃源岩厚度约为400-700 m,排烃强度约为（10-50）×10^8m^3/km^2。

Based on detailed pre-treatment works of hydrocarbon rocks in the Upper Triassic of Western Sichuan Depression of Sichuan Basin,organic geochemistry features are analyzed.Hydrocarbon source rocks have high organic matter abundance in total.Organic matter is mainly humosapropelic,and is during the mature and post mature evolutionary phase.Studies have shown that expulsion intension can ultimately materialize the quality of source rocks.In this paper,based on expulsion intension,the study area has been divided into 3 categories.Type Ⅰ locates in Shifang,Pengzhou,Wenjiang,Dayi and Dujiangyan,covering about 5 412 km^2.The hydrocarbon source rock thickness is about 1 000-1 650 m,and the expulsion intension is about（100-270）×10^8 m^3/km^2.Type Ⅱ locates in Mianyang,Mianzhu,Zhongjiang and Chengdu,covering about 6 281 km^2.The hydrocarbon source rock thickness is about 700-1 500 m,and the expulsion intension is about（50-100）×10^8 m^3/km^2.Type Ⅲ locates in Anxian,Fenggu and Longquanyi,covering about 4 895 km^2.The hydrocarbon source rock thickness is about 400-700 m,and the expulsion intension is about（10-50）×10^8 m^3/km^2.