南方海相层系不同类型烃源(岩)生烃模拟实验及其产物同位素演化规律  

Thermal Pyrolysis of Hydrocarbon Generation for Marine Hydrocarbon Sources in Marine Sequence of South China and Stable Carbon Isotopes of Gas Products

作　　者：王杰[1,2] 刘文汇[1,2] 腾格尔[1,2] 秦建中[1,2] 郑伦举[1,2] 

机构地区：[1]中国石油化工集团公司油气成藏重点实验室,江苏无锡214151 [2]中国石化石油勘探开发研究院无锡石油地质研究所,江苏无锡214151

出　　处：《天然气地球科学》2011年第4期684-691,共8页Natural Gas Geoscience

基　　金：中国石油化工联合基金(编号:40739902);国家"973"项目(编号:2005CB422102)资助

摘　　要：利用常规高压釜热压模拟仪和仿真地层热压生排烃模拟仪对南方海相不同类型烃源进行生烃模拟实验,研究发现不同类型原油烃气产率最高,分散可溶有机质烃气产率次之,产率最低的为不同类型干酪根。不同类型烃源烃气产率与烃源的有机碳含量、可溶有机质含量高低、有机质类型有密切关系,与烃源原始成熟度具有较好负相关性。烃源碳同位素组成决定产物甲烷碳同位素组成的演化规律,碳同位素组成较轻的烃源其产物甲烷碳同位素组成总体上要轻于碳同位素组成较重烃源的甲烷碳同位素组成。不同类型烃源产物甲烷碳同位素组成随热模拟温度增高具有先变轻再变重的演化特征,但不会重于其烃源的碳同位素组成。乙烷等碳同位素组成也随着热模拟温度增高逐渐变重,演化至生烃高峰时,碳同位素组成接近于其烃源碳同位素组成,可以示踪烃源。当演化至高过成熟阶段,乙烷等δ13C值大于其烃源碳同位素值,故不能仅用重烃碳同位素组成判断天然气母质类型。不同类型干酪根与可溶有机质CO2组分和同位素组成演化规律具有明显区别,可溶有机质生成的CO2和甲烷之间同位素分馏程度要比不同类型干酪根的大。在不同类型烃源生烃过程中,干酪根和液态烃碳同位素组成主要受母质类型控制,继承效应强,同位素分馏程度较小,具有很好的示踪意义,可以用于油源对比和烃源示踪研究。The hydrous pyrolysis experiments for potential hydrocarbon sources in the marine sequence of south China were subjected in the high pressure and geological condition simulation vessels. The results indicate that the productivity of hydrocarbon gas generation for hydrocarbon sources is various, the highest productivity for crude oil （light oil and condensate） , the secondary productivity for the dispersed soluble organic matter （solid bitumen and heavy oil） ,and the poor productivity for kerogen. The yield of hydrocarbon gas products for hydrocarbon sources is positively related with total organic carbon, soluble organic matter and organic matter type,but negatively with thermal maturity. The carbon isotopes of hydrocarbon sources inhibit the tendency of methane carbon isotopes. The carbon isotopic composition of methane derived from the hydrocarbon source with the lighter carbon isotope is lighter than that of methane from the hydrocarbon sources having the heavier carbon isotope. With thermal maturity increase,δ^13C value of methane increases but is less than that of its hydrocarbon sources. The δ^13C values of ethane and propane in the pyrolysate products also increase with pyrolysis temperature increase, gradually approaching of the carbon isotope of their sources at the peak stage of hydrocarbon generation. At high-over mature stages, the δ^13C values of ethane and propane are often more than that of their sources. Thus the carbon isotope of heavy hydrocarbon gases would be ineffective as gas genetic indicators. The contents and isotope compositions of carbon dioxide are different between kerogens and dispersed soluble organic matter. The carbon isotope fractionation between carbon dioxide and methane derived from soluble organic matter is greater than that from kerogen. During the process of hydrocarbon generating for hydrocarbon sources, the carbon isotope compositions of kerogen and liquid hydrocarbons are mainly controlled by precursor type, tracing their sources. Therefore,the carbon isotope

关 键 词：南方海相 不同类型烃源 热模拟实验 产率变化特征 碳同位素组成 烃源示踪 

分 类 号：TE122.113[石油与天然气工程—油气勘探]