塔里木盆地东南缘瓦石峡凹陷山前地区侏罗系烃源岩特征及油气地质意义

Characteristics and petroleum geological significance of the Jurassic hydrocarbon source rocks in the piedmont area of Washixia sag in the southeastern margin of Tarim Basin

瓦石峡凹陷主要发育侏罗系康苏组、杨叶组烃源岩。通过地表调查、样品分析测试对侏罗系烃源岩的分布、厚度变化规律及有机地球化学特征研究,结合前人成果资料,初步评价油气资源潜力。侏罗系烃源岩累计厚度最大563.8 m。康苏组烃源岩累计厚度88.1 m,TOC为0.66%~38.3%,干酪根主要为Ⅱ2和Ⅲ型,Ro为0.42%~0.95%,以低成熟-成熟为主;杨叶组为主力烃源岩,累计厚度最大328 m,TOC为0.21%~55.23%,干酪根主要为Ⅱ2和Ⅲ型,少量Ⅰ型,Ro为0.44%~1.96%,以成熟为主,部分达高成熟。研究区烃源岩分布广、厚度大、有机质丰度高、成熟度适中,主要为好-优质烃源岩,达生油气阶段,生烃潜力较大,具良好的油气勘探前景。

The Jurassic Kangsu Formation and Yangye Formation hydrocarbon source rocks are mainly developed in the washixia Sag.By studying the regularity of distribution,thickness variation of Jurassic source rocks and the characteristics of organic geochemical,by surface investigation and sample analysis.Combined with the previous achievements in the study area,the potential of oil and gas resources is preliminarily evaluated.The maximum cumulative thickness of Jurassic source rocks is 563.8 meters.The cumulative thickness of the source rock of the Kangsu Formation can reach 88.1 meters,the TOC is 0.66%~38.3%,the kerogen is mainly typeⅡ2 and typeⅢ,and the Ro is 0.42-0.95%,which is mainly low Maturity-mature.The Yangye Formation is the main source rock,with a cumulative thickness of up to 328 meters,TOC of 0.21%~55.23%,kerogen mainly typeⅡ2 andⅢ,a small amount of type I kerogen,Ro of 0.44-1.96%,mainly mature,and some reach high maturity.This research illustrates that the of region of interest source rocks are featured by wide distribution,large thickness,high organic abundance and moderate maturity.They are mainly good-quality source rocks,have reached the stage of oil and gas generation,have great potential for hydrocarbon generation,and have good prospects for oil and gas exploration.