永梅坳陷二叠纪煤系的热演化特征与热历史分析  

Thermal Evolution and History of the Permian Coal Measures in Yongmei Depression

作　　者：房洪峰[1] 姚素平[1] 焦堃[1] 胡文瑄[1] 曹剑[1] 高玉巧[1] 

机构地区：[1]南京大学地球科学与工程学院,南京210093

出　　处：《高校地质学报》2010年第2期255-264,共10页Geological Journal of China Universities

基　　金：中国石化"中国东南部海相盆地差异演化及油气远景"(YPH08115)资助

摘　　要：中国东南部海相和近海相地层普遍遭受多次后期复杂岩浆作用的改造,因而,尽管不乏富有机质地层,但热演化特征、生烃史及其主控因素并不十分清楚,从而制约了基础石油地质研究的开展。以研究条件相对较好的永梅坳陷二叠纪煤系为代表,通过镜质组反射率和煤挥发份产率实测数据,研究了烃源岩的热演化程度及差异分布特征,并通过热史模拟和地质背景分析重建了永梅坳陷该套烃源岩的生烃演化史。结果表明,二叠纪煤系的热演化程度普遍已达过成熟—死气阶段,平面上总体呈现出由西向东逐渐增大的趋势,垂向上有机质的热演化程度与埋深的相关性并不明显。盆地热演化史与生烃史分析表明,燕山期是有机质热演化的重要变革时期;永梅坳陷二叠系烃源岩的热演化特征是多热源叠加变质作用的结果,其中燕山期岩浆活动是造成坳陷海相和近海相烃源岩异常高变质的主要因素。The marine sedimentary sequence in southeastern China was widely altered by the complicated multi-stage magmatic activities.In spite of high organic abundance in some strata,the characteristics and controlling factors of thermal evolution and hydrocarbon generation are still not clear,which restricts further understanding in basic petroleum geologic problems.Taking Permian coal measures in Yongmei depression as an example,based on the determination of vitrinite reflectance and volatile index and combined with the study of geological background and thermal modelling,the thermal maturation of hydrocarbon source rocks and their distribution was analyzed,and the evolution history of hydrocarbon generation was constructed.The results show that,generally speaking,the coal hydrocarbon source rocks have attained the phase of post-mature-dry gas.Horizontally,thermal maturation is increasing from west to east;and vertically,thermal evolution is not related to depth of burial.According to the history of thermal evolution and hydrocarbon generation,the Yanshanian stage is an important period for drastic change in thermal history of the Yongmei depression.Thermal evolution of the Permian source rocks was affected and metamorphosed by several thermal sources,among which the magmatic activities resulted in anomalously high metamorphism of marine source rocks in this region.

关 键 词：中国东南部 永梅坳陷 二叠纪 煤系 烃源岩 热演化 岩浆作用 

分 类 号：P618[天文地球—矿床学] P534.46[天文地球—地质学]