塔里木盆地蓬莱坝组原型盆地特征及地质意义

发布时间：2018-05-05 08:07

本文选题：原型盆地 + 油气勘探　；参考：《特种油气藏》2017年02期

【摘要】：构造-岩相古地理对塔里木盆地下奥陶统蓬莱坝组白云岩储层的分布具有重要的控制作用。当前研究认为其具有"西台东盆"的古地理格局,但对该时期塔西台地内是否存在分异、该时期末期塔西台地是否发生暴露等问题依然存在争议。利用最新的露头、钻井及地震资料,结合盆地与造山带(下文简称盆山)的演化,由点—线—面对沉积充填实体进行分析,重建了塔里木盆地蓬莱坝组的构造-岩相古地理,并探讨其油气勘探意义。研究表明:蓬莱坝组沉积时期,塔里木盆地西部和东缘为浅水台地相,东部为深水盆地相,台地与盆地之间以斜坡相过渡。塔西台地内沉积出现分异:顺南地区发育潮下高能颗粒灰岩,间歇性地受到风暴浪的改造;而其他大部分地区为潮间—潮上带白云岩沉积。该时期塔里木盆地处于稳定伸展构造环境,台地建造作用显著,其构造-岩相古地理具有"两台夹一盆"的格局,并在塔西台地内分异出顺南开放式台内洼地。该台内洼地与广海连通性好,沉积水体比局限台地深,水体能量较高。由于相对海平面的下降,该组在沉积末期遭受了短暂的暴露溶蚀改造,具备成为优质储层的潜力,其中,塔中和古城地区为蓬莱坝组白云岩储层勘探优选区,顺南地区为蓬莱坝组颗粒滩储层勘探优选区。该研究有利于深化对蓬莱坝组沉积时期盆地构造-岩相古地理和盆山耦合关系的认识,推动蓬莱坝组碳酸盐岩的油气勘探。
[Abstract]:Tectonic-lithofacies paleogeography plays an important role in controlling the distribution of dolomite reservoirs in Penglai formation of Lower Ordovician in Tarim Basin. At present, it has the paleogeographic pattern of "West Taitung Basin", but there are still disputes about whether there are any differences in the Taxi platform during this period and whether the Taxi platform is exposed at the end of this period. Based on the latest outcrop, drilling and seismic data and the evolution of basin and orogenic belt (hereafter referred to as basin and orogenic belt), the tectonic-lithofacies paleogeography of Penglai dam formation in Tarim Basin was reconstructed by point-line-face sedimentary filling entity. The significance of oil and gas exploration is also discussed. The results show that the western and eastern margin of the Tarim basin are shallow platform facies and the eastern part is deep water basin facies, and the transition between platform and basin is slope facies during the sedimentary period of Penglai Ba formation. In the Taxi platform, there is a differentiation between the subtidal high-energy granular limestone and the storm waves in Shunnan area, while the dolomite deposits in the other areas are intertidal and supratidal. In this period, the Tarim basin was in a stable extensional tectonic environment, and the platform formation was significant. Its tectonic-lithofacies paleogeography had a pattern of "two platforms with one basin", and the depression in Shunnan open platform was differentiated from the Taxi platform. The depressions are well connected to the wide sea, the sedimentary water is deeper than the limited platform, and the water energy is higher. As a result of the relative sea level drop, the group suffered a short period of exposure and corrosion modification at the end of the sedimentary period, which has the potential to become a high-quality reservoir. Among them, the Tazhong and Gucheng areas are the preferred exploration areas for the dolomite reservoirs of the Penglai formation. The Shunnan area is the preferred area for exploration of Penglai formation granular-beach reservoir. This study is helpful to deepen the understanding of the basin tectonic-lithofacies paleogeography and basin-mountain coupling relationship during the Penglai formation sedimentary period, and to promote the exploration of carbonate rocks in the Penglai formation.
【作者单位】：中国石油勘探开发研究院;中国地质大学(北京);海相储层演化与油气富集机理教育部重点实验室;中国石油天然气勘探开发公司;
【基金】：国家重点基础研究发展规划项目“中国西部叠合盆地多期构造过程叠加与深部古温压场重建”(2011CB201101) 国家科技重大专项“全球油气资源评价与选区选带研究”(2016ZX05029)
【分类号】：P618.13

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