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沉火山尘凝灰岩:一种赋存油气资源的重要岩类——以新疆北部中二叠统芦草沟组为例

作    者:朱国华1,张杰1,2,姚根顺1,李玉文1,王鑫1,余朝丰1
单    位:1 中国石油杭州地质研究院;2 中国石油天然气集团公司碳酸盐岩储层重点实验室
基金项目:受国家科技重大专项《海相碳酸盐岩沉积与有效储层大型化发育机理与分布研究》资助
摘    要:
新疆北部中二叠统芦草沟组的一套重要致密含油岩类一直被误认为是泥岩、泥晶白云岩、粉砂岩或油页岩。经过详细而系统的X衍射研究发现,在这套所谓"泥岩"的岩石中,以泥晶级别(约30μm)的火山灰为主要组分,主要矿物成分为长石、石英和自生硅质成分,还有少量方沸石和黄铁矿,黏土的含量极低(约5%)或无,属于火山凝灰岩中最细的一级,可定性为沉火山尘凝灰岩。全岩X衍射分析还表明,随着芦草沟组中白云石含量的递变,沉火山尘凝灰岩呈现向白云岩的渐变序列。沉火山尘凝灰岩在镜下具有非常好的荧光显示,TOC 含量达2%~20%,有机质具有似层状和分散状两种赋存状态。岩石中有几种重要的储集空间院泄水通道、泄气孔、构造缝、硅质岩的碎裂缝、火山灰方沸石化溶孔及藻类(?)溶孔等。与非火山成因类泥岩和页岩的岩石学特征对比表明,芦草沟组沉火山尘凝灰岩可成为重要的烃源岩,而沉火山尘凝灰岩生烃过程中,大量的黏土矿物并非是必需的。沉火山尘凝灰岩可以是一种很好的自生自储岩类。
关键词:沉火山尘凝灰岩;烃源岩;油气成因;油气储集;中二叠统;芦草沟组;新疆北部

Sedimentary Volcanic Dust Tuff, An Important Kind of Rock StoringHydrocarbon Resources: Disscusion on the Lithology of Middle PermianLucaogou Oil-bearing Rocks in the North of Xinjiang

Author's Name: Zhu Guohua, Zhang Jie, Yao Genshun, Li Yuwen, Wang Xin, Yu Chaofeng
Institution: : male, Research Professor. Add:
Abstract:
There is a set of dense oil -bearing rock in Middle Permian Lucaogou Formation in the north of XinjiangProvince and the rock has been ever regarded as mudstone, dolomicrite, siltstone or oil shale. Attributing to the systematicanalysis of X-ray, it is known that the rock called “mudstone” can be defined as the sedimentary volcanic dust tuff (SVD tuff), in which volcanic dust (约30μm in grain diameter) is dominant in composition and the minerals commonly are feldspar,quatz and authigenic silicon and a small mount of analcime and pyrite with a littl (约5%) or no clay. The X-ray analysis also shows that the SVD tuff presents a change gradually to dolostone with changing content of dolomite in Lucaogou Formation.The SVD tuff displays good fluorescent reflection in microscope. The is ranged from 2% to 20% in and the organic materials are present in laminaroid and scattered occurrences. This tuff is of many types of significant reservoir spaces, such as water-drainage channels, gas-drainage pores, structural fractures, silicalite fissures, volcanic ash-analcitized solution pores, algae (?) solution pores, and other pores. Through petrologic correlation of the Lucaogou tuff with nonvolcanic mudstone and shale, it is shows that this tuff can be an important source rock. Not a great abundance of clay minerals are necessary during hydrocarbon generation in the SVD dust tuff, which does not accord with the clay-catalyzing theory. This SVD tuff may be a good owner-source and owner-reservoir rock.
Keywords: Middle Permian; Lucaogou Fm; Sedimentary volcanic dust tuff; Source rock; Hydrocarbon origin; Hydrocarbon reservoir
投稿时间:2013-02-23  
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