准东博格达山山前带二叠系芦草沟组重油的发育特征及其指示意义

二叠系芦草沟组是准噶尔盆地东部地区最重要的烃源岩层系和勘探目的层系之一。2013年中国地质调查局油气资源调查中心在准噶尔盆地南缘博格达山山前带实施的油页岩调查井JZK1井钻探过程中,发现二叠系芦草沟组重油。通过对JZK1重油和岩心样品有机地球化学的测试数据研究表明:二叠系重油原油演化程度适中,主要赋存于岩石裂缝中,且经历过后期生物降解作用;油源对比指示,原油来自于芦草沟组本身,属自生自储型油藏。据此推测西起乌鲁木齐市雅玛里克山,东至奇台的白杨沟,断续延长136 km,宽2~10 km,分布面积约2×10⁴ km²的芦草沟组均为下步油气勘探的有利区。基于钻井和过井地震测线的解释结果,指出存在推覆体上盘和推覆体下盘两个勘探领域,且推覆体下盘的原生油藏领域埋藏深、规模大,是下步勘探重点领域。

Characteristics of Heavy Oil Hosted in Permian Lucaogou Formation Discovered in Bogeda Mountain of Zhunggar Basin and Its Importance for Further Exploration

Permian Lucaogou Formation is one kind of the most important hydrocarbon source rocks and exploration targets in East Junggar basin .Heavy oil is discovered in Permian Lucaogou Formation in well JZK1 ,which was drilled in 2013 at the northern foot of Bogeda Mountain in Xinjiang by Oil & Gas Survey ,China Geological Survey .According to the organic geochemical data of the heavy oil and core samples from JZK1 well ,the heavy crude oil ,which mainly exists in rock fissure ,is in moderate evolution stage and experienced later biological degradation .Based on the correlation between oil and source rocks ,the crude oil is from Lucaogou Formation itself .The result indicates that this is a kind of self‐generated reservoir .Lucaogou Formation extends from Yamalike Mountain in Urumqi in the west to Baiyanggou in Qitai in the east ,which covers an area about 20 000 km2 with 136 km in length and 2 10 km in width .It is favorable exploration target in the near future in the region .According to the drilling and seismic interpretation results from seismic lines across wells ,the strata above and below a nappe is predicted to be the two key exploration regions .The primary reservoir located in the lower wall of thrust anappe is buried deeply in a large scale ,w hich is a significant target for future exploration .