塔里木盆地东部古城—肖塘地区寒武纪—奥陶纪台地类型、演化过程及有利储集相带

基于岩心、岩石薄片和地震资料分析，对塔里木盆地东部（塔东）古城—肖塘台地—盆地过渡区寒武纪—奥陶纪碳酸盐岩台地类型、演化过程及其油气勘探潜力进行了系统研究。从盆地构造演化、岩性特征、地震相特征等方面详细分析了不同时期碳酸盐台地边缘的类型及特征，建立了4种碳酸盐岩台地边缘类型及沉积模式。寒武系纽芬兰统—黔东统肖尔布拉克组—吾松格尔组沉积期为匀斜碳酸盐岩缓坡，有利储集相带为古隆起围斜部位的浅缓坡微生物丘滩；寒武系苗岭统为镶边碳酸盐岩台地，发育加积型丘滩体，有利储集相带为古地貌高点的丘滩体核部及丘坪滩体；寒武系芙蓉统发育弱镶边碳酸盐岩台地，丘滩脊和前积滩体为有利储集相带；下奥陶统蓬莱坝组—鹰山组三段沉积期为远端变陡的碳酸盐岩缓坡，浅缓坡上部的白云石化滩为有利储集相带；中奥陶统鹰山组二段—一间房组沉积期为弱镶边开阔台地，有利储集相带为古地貌高点的泥粒灰岩滩及礁滩相；晚奥陶世演化为淹没台地。受构造运动和海平面变化影响，塔东古城—肖塘台地—盆地过渡区寒武纪—奥陶纪碳酸盐岩台地经历了"缓坡—镶边台地—缓坡—弱镶边开阔台地"的演化过程。苗岭统—芙蓉统镶边台缘带丘滩、蓬莱坝组—鹰山组三段远端变陡缓坡白云石化滩、鹰山组二段—一间房组弱镶边开阔台地颗粒灰岩滩是近期增储上产的3类现实勘探领域，纽芬兰统—黔东统肖尔布拉克组—吾松格尔组匀斜缓坡微生物丘滩、苗岭统—芙蓉统斜坡重力流是2类潜在的风险勘探领域。

Types,evolution and favorable reservoir facies belts in the Cambrian-Ordovician platform in Gucheng-Xiaotang area,eastern Tarim Basin

Based on the analysis of cores, thin sections and seismic data, this paper systematically studies the types, evolution and oil-gas exploration potential of the Cambrian-Ordovician carbonate platform in the transition zone from platform to basin in Gucheng-Xiaotang area, eastern Tarim Basin. From the aspects of tectonic evolution of basin, lithofacies characteristics, and seismic facies characteristics, this paper analyzes the types and characteristics of carbonate platform margins in different periods, and establishes four types of deposition models of carbonate platform margins. During the deposition of the Xiaoerbulake Formation and Wusonggeer Formation, it was shown as a homoclinal carbonate ramp, and the microbial mound beach on a shallow gentle slope at the periclinal position of paleo-uplift is the favorable reservoir facies belt. The Cambrian Miaoling series develops a rimmed carbonate platform with the development of accretion-type mound-beach complex, and the favorable reservoir facies belt is the core of the mound-beach complex at high positions of ancient landscape and mound-flat-beach complex. Weakly rimmed carbonate platform is developed in the Cambrian Furongian Series, and mound-beach ridges and foreset beach bodies are favorable reservoir facies belts. During the deposition of the Lower Ordovician Penglaiba Formation and Member 3 of Yingshan Formation, it was presented as a distally steepened carbonate slope, and the dolomitized beach on the upper part of the shallow gentle slope was a favorable reservoir facies belt. During the deposition of Member 2 of the Yingshan Formation and the Yijianfang Formation, weakly rimmed open platform is developed, where the favorable reservoir facies belt was packstone beach and mound beach facies at high positions of the ancient landscape, which evolved into a drowned platform in the Late Ordovician. Affected by tectonic movement and sea level changes, the Cambrian-Ordovician carbonate platform in the transition zone in Gucheng-Xiaotang area underwent an evolutionary process of gentle slope-rimmed platform-gentle slope-weakly rimmed open platform. The rimmed platform marginal mound beach during Miaolingian-Furongian, the distally steepened dolomitized beach in the Penglaiba Formation and Member 3 of Yingshan Formation, the weakly rimmed open platform grainstone beach in Member 2 of the Yingshan Formation and the Yijianfang Formation are three exploration fields for increasing reserve and production. The microbial mound beach in the Xiaoerbulake Formation and Wusonggeer Formation, as well as the slope gravity flow in Miaolingian Series-Furongian Series are two potential risk exploration fields.