四川盆地海相层系天然气成因类型与TSR改造沥青证据  

Genesis of Natural Gas in Marine Carbonate of Sichuan Basin and Bitumen Evidence of TSR Alteration

作　　者：刘全有[1,2] 金之钧[1] 王毅[1] 杨春[3] 高波[1] 张殿伟[1] 

机构地区：[1]中国石化石油勘探开发研究院,北京100083 [2]中国石油大学(北京),北京102249 [3]浙江大学地球科学系,浙江杭州310027

出　　处：《天然气地球科学》2009年第5期759-762,共4页Natural Gas Geoscience

基　　金：国家自然科学基金项目(编号:40802028);国家重点基础研究发展规划项目(编号:2005CB422108);国家重大专项(编号:2008ZX05005-004-004)联合资助

摘　　要：通过对四川盆地海相层系天然气组分和碳同位素以及储层固体沥青元素分析,四川盆地海相层系天然气地球化学特征不同于我国典型煤成气,而与油型气相似,热演化程度普遍很高,已处于油气裂解阶段。烷烃气碳同位素组成普遍存在局部倒转现象,即δ13C1>δ13C2<δ13C3。造成烷烃气碳同位素倒转的原因可能是后期热化学硫酸盐还原反应(TSR)改造;四川盆地海相层系储层沥青元素与陆相碎屑岩明显不同;在川东北地区非海相砂岩中储层固体沥青贫S并具有较低反射率;而海相层系固体沥青中富S。海相层系固体沥青主要为原油热裂解和TSR共同作用产生的,而陆相则仅为原油裂解产生。Measured the element composition of reservoir bitumen in marine strata of Sichuan basin, and chemical compositions and carbon isotopes of its natural gas, the origin of natural gas could be determined and result in the conclusion that the geochemical origin of natural gas is different from the typical coal-type gasin China, but similar with the oil-type gas. The thermal maturity of natural gas is generally high, reaching at the stages of that between oil and gas cracking. The partial reverse of the carbon isotopic trend of C1-C3 alkanes is observed, i. e δ^13C1〉δ^13C2〈 δ^13 C3. The abnormal phenomena are related to the later thermal sulfate reduction （TSR） to hydrocarbons, for the characteristics of the element composition （i. e. C, H, O, N, S） are different betweenmarine and non-marine reservoir bitumen. The bitumen in non-ma- rine sand reservoirs in the NE Sichuan basin has low sulfur concentration and low bitumen reflectance; whereas the marine carbonate accumulated bitumen contains high sulfur. The bitumen in marine carbonate was formed by both oil cracking and TSR; in contrast, that in non-marine sandstone was generated from oil cracking.

关 键 词：四川盆地 海相层系 天然气成因 固体沥青 TSR改造 

分 类 号：TE122.11[石油与天然气工程—油气勘探]