四川盆地西北地区热流史及烃源岩演化  

Thermal history and hydrocarbon source rock evolution in the northwestern Sichuan basin

作　　者：龚浩[1] 朱传庆[2,3] 徐明[2,3] 单竞男[2,3] 胡圣标[2] 袁玉松[4] 

机构地区：[1]天津市地质工程勘察院,天津300191 [2]中国科学院地质与地球物理研究所,北京100029 [3]中国科学院研究生院,北京100049 [4]中国石油化工股份有限公司石油勘探开发研究院,北京100083

出　　处：《地球物理学进展》2010年第3期1031-1036,共6页Progress in Geophysics

基　　金：国家自然科学基金项目(40672197);国家自然科学基金项目(40974048)联合资助

摘　　要：根据四川盆地西北地区镜质体反射率数据(R_o)进行的埋藏史和热史恢复结果表明:该地区中生界与新生界之间不整合面的剥蚀量在1000～2500 m之间.该区在晚二叠世初期达到最高古热流,研究区南部最高古热流达～100 mW/m^2,研究区北部为～70 mW/m^2.从晚二叠世初到现今古热流持续降低,在～220 Ma时古热流平均为～54mW/m^2.下二叠统烃源岩在二叠纪末达到生油门限.研究区南部,下二叠统及下伏古生代烃源岩短时间内经历了超高古地温,因此具有一次性生烃且生烃时代久远(中二叠世之前)的特点,研究区北部的中、下二叠统和下伏古生代烃源岩存在二次或多次生烃.上二叠统烃源岩在三叠纪达到生油门限并进入生油高峰(成熟早期),之后在侏罗纪和白垩纪又有两次生烃过程.三叠系烃源岩的演化特征与上二叠统相似.Buried and thermal history reconstruction by using vitrinite reflectance data of the northwestern Sichuan basin indicats that the erosion thickness on the Mesozoic and Cenozoic unconformity varied from 1000m to 2500m. The maximum paleo-heat flow reached in the early stage of late Permian, which was 100mW/m2 in the south area and -70mW/m2 in the north, and then decreased to present, and the paleo-heat flow at 220Ma was 54mW/m2 on average. The Lower Permian source rocks came into the oil-generating window in late Permian. In the south, the Lower Permian source rocks experienced high temperature in a short time, so there was only one time of hydrocarbon generation. However, there were more times of hydrocarbon generation in the north. The upper Permian source rocks came into the oil-generating window in Triassic and then reached the oil-generating peak. And there were also two times of hydrocarbon generation in Jurassic and Cretaceous. The evolution of the upper Triassic source rocks is similar to that of the upper Permian.

关 键 词：热历史 剥蚀量 热流史 生烃史 川西北 

分 类 号：P631[天文地球—地质矿产勘探]