摘要
塔中Ⅰ号坡折带45个原油样品的地球化学分析表明,原油富含轻烃组分、贫重质组分,反映源岩较高的热成熟度。原油中发育异常高丰度的含硫芳烃-二苯并噻吩,反映了海相成因特征。伽马蜡烷/C30藿烷、规则甾烷与C30甾烷相对分布等多项指标与生物标志物指纹反映区内至少有两种油源。双金刚烷系列与链烷烃分布指示塔中Ⅰ号坡折带东端存在一强气侵注入点。观察到邻井原油、不同层系原油烃类化学成分显著的差异,指示油气成因与成藏条件的差异。塔中Ⅰ号坡折带油气的地球化学特征反映了叠合盆地海相成因油气的普遍特征,包括高过成熟性、多源与多期成藏、油气化学成分的非均一性及油气藏的相对分隔性。本研究为区内寻找多种成因类型油气与油源确认提供了依据,指示塔中低凸起油气勘探潜力巨大。
Considerable quantity of oils and gas with diverse characteristics and origins has been discovered in the Tazhong-I faulted slope break zone, Tarim basin. Totally 45 oil samples were gathered and analyzed with conventional geochemical approaches. The results show that the oils are characterized by significant predomi- nance of light fractions and lack of heavy fractions, suggesting high thermal maturity of source rocks and/or thermal cracking of the oils. High absolute abundance of dibenzothiophene was detected in the oils, indicating a ma- rine source. Several indexes （ including relative distribution of gammacerane/C30 hopane, C27- to C29-steranes, and C30-steranes） and biomarker fingerprints indicate that the oils in the area were generated from at least two kinds of primary source rocks. It was suggested that there is a strong gas invasion point at the eastern end of Tazhong-I faulted slope break zone according to the abnormal distributions of diamondoid hydrocarbons and nalkanes. There are evident differences among those oils even from closely adjacent wells, inferring different hy- drocarbon generation and accumulation processes. All the features for the oil samples analyzed indicate the common characteristics of the oils in the superimposed basins in western China, i. e. , high thermal maturity, multiple sources and muhiphase pooling, heterogeneity of chemical composition, and relative compartmentalization. This study is helpful for investigating the origin and accumulation mechanisms of the oils. It was suggested that great petroleum potential could be expected in the Tazhong-I faulted slope break zone.
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
2008年第2期210-216,共7页
Oil & Gas Geology
基金
国家重点基础研究发展规划(973)项目(2006CB202308)
关键词
海相油气
成熟度
生物标志物
气侵
混源
塔中I号坡折带
塔里木盆地
marine oil and gas
maturity
biomarker
gas invasion
mixed source
Tazhong-I faulted slopebreak zone
Tarim Basin
