辽河盆地过渡带有机地球化学（Ⅰ）──不同赋存状态的有机质与过渡带气的形成  

Organic Geochehemistry of Bio-Thermocatalytic Transition Zone Gases in the Liaohe Basin (I)-Correlation Between Bio-Thermocatalytic Transition Zone Gases and Organic Matter in Different Existing Conditions

作　　者：张柏生[1] 刘文汇[1] 徐永昌[1] 王兆云[1] 吴铁生[1] 

机构地区：[1]中国科学院兰州地质研究所,辽河油田勘探开发研究院

出　　处：《沉积学报》1994年第4期58-65,共8页Acta Sedimentologica Sinica

摘　　要：辽河盆地东部凹陷中部沙一段和沙二段烃源岩主要处于成岩演化阶段，本文通过对其可溶有机质和干酪根的研究探讨了它们与过渡带气之间的关系，发现可溶有机质与同一样品的干酪根之间往往表现出不同的生源组成，前者以Ⅱσ—Ⅲ型有机质为特征，而后者主要属Ⅰ—Ⅱ．型母质。在埋深１８５０～３０６０ｍ的范围内，沥青Ａ、非烃和沥青质的红外特征吸收及其有关参数呈一致的变化规律。由此划分出三个明显不同的演化阶段．并指出２２００～２７７０ｍ左右为沥青Ａ、非烃和沥青质急剧降解的阶段，２５００ｍ左右达到高峰，其结果与过渡带气的形成密切相关。干酪根在该阶段虽然也表现出脱氧、脱脂基因特征，但以生成解聚沥青为主，与过渡带气不存在直接的联系。因此认为可溶有机质，尤其是其中的非烃和沥青质是东部凹陷过渡带气最主要的母源物质。Ebstract System in East Depression of the Liaohe basin is at the diagenesis stage. The correlation between the Extractable Organic hater (EOM), kerogen the the Bio-thermocatalytic Transition Zone Oases (BTZG) in the source rocal has ben discussed in this paper. It is discovered that there exist different organic source materials in the EOM and kerogen of the same sample. A higher carbon -number preference of the saturated hydrocarbons, and a sghicant distribution of land plantderived biomarkers, i. e., C29 sterane, pimarane, abieboe, r-lupane and oleanane in the EOM show that the EOM is characterized by orpoic matter of type, Ⅱ-Ⅲ. However, the carbon i8OtOPic competion of the keroggn indicate that it mainly consists of organic matter of type Ⅰ -Ⅱa. The difference in organic compositions between the EOM and kerogen at the diagenesis stage can be explained by the selective accumulation of sedhoenlary orpoic matter. Specific IR absorption spectra and corresponding parameters of bitumen A, non-hydrocarbons and asphaltene show the same pattern of variation in the depth Of 1850￣ 3060m. Three evolution stages have been determined in this study. The EOM are rapidly degradated in about 2200-2770m, i. e., the stage. and highest at about 2500m, which results in fotming BTZO. Although kerogens are characteristic of deoxygen and delipidic groupo at the sarge, they have no direct relationS to the formation Of BTZG beCause they mainly Produce depolyineric betumen at the stage. Therefore the EOM, especially non-hycrocarbons and asphaltene, could be considered as the most important source materials of BTZG in East Depression of the Liaohe basin.

关 键 词：过渡带 有机地球化学 天然气 成因 

分 类 号：P618.130.1[天文地球—矿床学]