准噶尔盆地东道海子凹陷平地泉组烃源岩地球化学特征

对准噶尔盆地腹部东道海子凹陷二叠系平地泉组烃源岩地球化学特征进行评价,通过对烃源岩有机质丰度、类型与成熟度及烃源岩厚度特征分析表明,平地泉组发育湖相泥岩,在凹陷内分布广泛、厚度大,为东道海子凹陷的主力烃源岩;凹陷东北部滴南地区平地泉组烃源岩为中等-好的烃源岩,有机质类型为Ⅱ2型-Ⅲ型,热演化达到成熟-生油高峰阶段;平地泉组门限深度为2 350m,生油高峰深度为2 900m左右。结合邻区资料,认为东道海子凹陷主体平地泉组烃源岩有机质丰度高、类型较好,达到生油高峰-高成熟阶段,具有较高的资源潜力。

Geochemical characteristics of Permian Pingdiquan Formation hydrocarbon source rocks in Dongdaohaizi sag,Junggar Basin,China

This paper studies the geochemical characteristics of the Permian Pingdiquan Formation hydrocarbon source rocks in the Dongdaohaizi sag of Junggar Basin in China through analysing the characteristics of the organic matter abundance,type,maturity and thickness of the hydrocarbon source rocks. There develops and widely distributes over lacustrine mudstone in Pingdiquan Formation.These mudstone constitutes the principal hydrocarbon rocks in the Dongdaohaizi sag. According to this study,the hydrocarbon rocks have huge thickness and are distributed widely and their total organic carbon content (TOC)is abundant but the organic matter type is of poor quality. The organic matter is of mature degree at present.An integrated evaluation of the Pingdiquan Formation hydrocarbon source rocks in the Dinan area shows as below,the source rocks are of medium to superior quality,the organic matter type is mainly Ⅱ2-Ⅲ,and the thermal evolution degree is up to mature or the oil-generating peak phase.The threshold depth is 2 530 m and the oil-generating peak depth is 2 900 m or up and down.Coupled with the analysis of the data about the adjacent regions,the paper thinks that the Pingdiquan Formation hydrocarbon source rocks in the sag have high TOC,superior organic matter type,and high mature or oil-generating peak thermal evolution degree.They have favourable resources potential.