准噶尔盆地东部克拉美丽地区石炭系烃源岩研究

Study on the Carboniferous source rocks in Kelameili Area, eastern Junggar Basin.

准噶尔盆地东部克拉美丽地区的勘探一直没有突破,是否存在有效烃源岩成为制约勘探决策的主要因素。文章在分析地表样品地球化学特征的基础上,运用有机相的方法研究和预测了石炭系烃源岩性质与分布,滴水泉组现今处于成熟到高成熟演化阶段,主要分布在克拉美丽山前五彩湾凹陷至陆梁隆起一带,推测乌伦古坳陷可能也存在对应分布,最大厚度可达700m以上;巴塔玛依内山组是一套以腐殖型干酪根为主的湖相好烃源岩,主要分布在北三台、吉木萨尔凹陷、五彩湾凹陷及乌伦古坳陷一带,厚度在100m以上;石钱滩组为成熟到高成熟较差海相烃源岩,主要分布在石钱滩凹陷,生油能力较差,以生气为主。石炭系烃源岩在侏罗纪-白垩纪末进入二次生烃高峰期和排烃期,较晚的生烃期对油气的保存较为有利,对石炭系烃源岩的油气勘探具有重要意义。

Exploration of Kelameili area in eastern Junggar Basin has not broken. Whether effective source rocks exist or not has become the main factors of controlling exploration decision. Based on the analysis of geochemical characteristics of surface samples,organic facier method was applied in study and forecast on the property and distribution of Carboniferous source rocks. The source rocks of Dishuiquan Formation is at the evolutional stage of maturity to high maturity, which are mainly distributed in Wucaiwan sag to Luliang uplift in the front of Kelameili Mountain with a thickness of more than 700m, corresponding distribution may exist in Wulungu Depresion by forecast. The source rocks in Batamayineishan Formation are also lacustrine,which are mainly distributed in the north of Santai,Jimusaer sag, Wucaiwan sag and Wulungu Depression with a thickness of more than 100m. The source rocks are dominated by humic kerogen and have good hydrocarbon generation potential. Shiqiantan Formation is a set of marine sediments,which are mainly distributed in Shiqiantan sag with poor oil generation capability and mainly gas generation. Source rocks in this formation have low to fair potential and have been reached mature to high mature level. The Carboniferous source rocks reached secondary hydrocarbons generation peak stage and expulsion stage at the end of Jarrassic-Cretaceous period. The relatively late hydrocarbons generation is favorable for oil and gas preservation. The study will have great significance in the exploration on Carboniferous source rocks.