塔里木盆地下寒武统肖尔布拉克组北部台缘带展布及其油气勘探意义

礁滩型白云岩是世界范围内油气勘探开发效果最好的领域之一。塔里木盆地震旦-寒武系具备规模礁滩型白云岩发育基础,但其特征与分布研究基础十分薄弱。本文采用野外剖面观察、单井资料分析、地震资料刻画等手段,落实了柯坪-塔北西部存在下寒武统台缘带,命名为北部台缘带,该台缘带呈北东走向,长约330 km,宽约7 km。野外露头资料显示,下寒武统北部台缘带发育两期微生物礁,岩性以针孔状白云岩为主,溶蚀孔洞发育;地震剖面上,可见丘状前积反射特征。北部台缘带具有得天独厚的生储盖配置优势,位于长期继承性发育的古隆起之上,具备形成大油气田的有利条件。北部台缘带的展布特征为该区下古生界白云岩的区带评价及目标优选指明了方向。

Distribution of Northern Platform Margin and Implications to Favorable Exploration Regions on Lower Cambrian Xiaoerbulake Formation,Tarim Basin

Reef-bank dolomite is one of the most promising oil and gas reservoir types. Although the foundation of developing reef-bank dolomite type reservoir existed, the research of its characterization and distribution is fairly poor. In this paper, by using the methods of outcrop observation, single well data analysis, seismic data characterization, we identified the Lower Cambrian platform margin in Keping-western Tabei area, which was named as the northern platform margin. With the scale of 330 km length and 7km width, it extends as NE-trending. Outcrop data shows that the Lower Cambrian northern platform margin developed two periods of microbial reef, with the main lithology of pinhole dolomite developing dissolution pores. A group of seismic reflection units with mounded geometry can be seen in the seismic section clearly. The Northern platform margin located in the long-term developed ancient inherited uplift has a unique reservoir-cap configuration advantage, which makes it have the favorable conditions to form a large oil and gas field. The distribution of the northern platform margin has made clear the direction of play evaluation and target optimization in the Lower Paleozoic dolomite area.