准噶尔盆地凝析气藏成因与分布规律

Origin and distribution law of condensate gas reservoirs in Junggar Basin

准噶尔盆地凝析气资源丰富,但探明程度不高,为了拓展勘探领域,对盆地凝析油气的地质地球化学特征和成因进行了系统分析,在此基础上阐述了油气藏的分布规律,提出了勘探方向。研究结果表明,准噶尔盆地凝析油气主要来源于石炭系、二叠系、侏罗系气源岩,具有多层组含油气的特点。气藏类型主要为构造-岩性气藏,储层物性以低孔、低渗储层为主。凝析气藏类型按成因划分为油气同源热成因型和油气不同源气侵型。高—过成熟烃源灶对凝析油气分布起着决定性作用,断裂对油气运移和聚集起到良好的纵向调节作用,优势沉积相带对油气成藏的规模与分布具有局部控制作用。盆1井西凹陷及其周缘、沙湾凹陷西斜坡、南缘冲断带中段、滴水泉—五彩湾烃源槽及周缘、东道海子—吉木萨尔烃源槽及周缘是准噶尔盆地凝析气藏勘探的有利区。

Condensate gas resources are abundant in Junggar Basin,of which the exploration degree is low.To expand the exploration area,this paper systematically analyzes geological and geochemical characteristics and geneses of condensate oil and gas in the basin,elaborates the distribution law of oil and gas reservoirs,and further points out the exploration direction.Research has shown that the condensate oil and gas are mainly from Carboniferous,Permian and Jurassic gas source rocks,characterized by the multilayered formations containing oil and gas.Structural-lithologic gas reservoir plays a dominant role;the reservoir property is mainly characterized by low porosity and low permeability.Based the origins,condensate gas reservoirs can be divided into the thermogenic oil and gas type of the same source and the gas invasion type of different sources.High-mature and post-mature hydrocarbon kitchens play a decisive role in the distribution of condensate oil and gas;faults play a good role in the vertical adjustment for oil gas migration and accumulation;the dominant sedimentary facies belt plays a role in local control for the scale and distribution of oil/gas accumulation.The western Well Pen-1 sag and its surroundings,west slope of Shawan sag,middle section of southern thrust belt,Dishuiquan-Wucaiwan hydrocarbon source trough and its surroundings,as well as Dongdaohaizi-Jimusaer hydrocarbon source trough and its surroundings are favorable areas for the exploration of condensate gas reservoirs in Junggar Basin.