塔里木盆地南华纪古裂谷对寒武系沉积的控制及勘探意义  

Control of the Nanhua paleo-rift on Cambrian sedimentation and its exploration significance in Tarim Basin

作　　者：易士威[1] 李明鹏[1] 郭绪杰 范土芝 杨帆 方辉 缪卫东[1] 林世国[1] 高阳[1] 李德江[1] Yi Shiwei;Li Mingpeng;Guo Xujie;Fan Tuzhi;Yang Fan;Fang Hui;Miao Weidong;Lin Shiguo;Gao Yang;Li Dejiang(PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China;PetroChina Exploration&Production Company,Beijing 100083,China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中国石油勘探与生产分公司,北京100007

出　　处：《石油学报》2020年第11期1293-1308,共16页Acta Petrolei Sinica

基　　金：国家科技重大专项(2016ZX05007-002,2016ZX05007-003)资助。

摘　　要：塔里木盆地前寒武系经历了南华纪断陷构造沉降和震旦纪坳陷热沉降2个阶段,发育众多不同走向、不同规模的古裂谷。根据古裂谷的走向、规模、性质及其对上覆沉积的控制作用可将其分为台间古裂谷和台内古裂谷2种类型。众多古裂谷形成的垒-堑相间的古构造对寒武纪岩相古地理具有明显的控制作用,即古裂谷控制了寒武系的生烃中心、优质储层和优质盖层的发育。在古裂谷之上继承性发育的古地貌低洼区是寒武系玉尔吐斯组优质烃源灶的发育区。在裂谷肩部形成的古地貌高隆区则往往沉积丘滩建造,为优质储层发育区。满加尔台间古裂谷的两侧肩部由于长期处于稳定发育的古地貌高部位,可形成沿该古地貌高呈SN向展布的镶边台地边缘丘滩建造,由此导致塔西地区、罗西地区在寒武纪吾松格尔组—阿瓦塔格组沉积期形成封闭的台地环境,并在轮台—古城一线以西沉积大面积的膏盐岩优质盖层。在台内古裂谷之上,玉尔吐斯组烃源岩相对较厚,成为有利生烃中心;在古裂谷间的相对古地貌高部位,肖尔布拉克组白云岩滩相储层更加发育。二者与上覆的中寒武统膏盐岩盖层构成优越的生-储-盖组合,是寒武系盐下油气最有利的成藏区,也是形成大气藏和实现勘探突破最有利的地区。Tarim Basin has experienced two stages of the tectonic subsidence in the Precambrian,i.e.,the Nanhua fault depression and the thermal subsidence of the Sinian depression,and also developed many paleo-rifts with different strikes and scales.According to the strike,scale,property and control of overlying sediments,the paleo-rift can be divided into two types:inter-platform rift and intra-platform rift.The horst-graben paleo-structure formed by many paleo-rifts has obvious control on the Cambrian lithofacies and palaeogeography,i.e.,the paleo-rifts control the development of the Cambrian hydrocarbon generation centers,high-quality reservoirs and caps.The high-quality hydrocarbon kitchen of Cambrian Yuertusi Formation is developed in the low-lying parts of paleo-landforms inherited and developed above the paleo-rifts.Reefs and shoals are often deposited in the paleo-uplift areas at the shoulders of the rift,where high-quality reservoirs are developed.Since the shoulders on both sides of the inter-platform rift in Manjiaer are located in the high part of the paleo-landform developed steadily for a long time,they can form the rimmed marginal reefs and shoals distributed in a south-north direction along the high part of the paleo-landform,resulting in a closed platform environment formed during the deposition period of the Cambrian Wusonggeer-Awatage formations in Taxi and Luoxi areas and a large area of high-quality gypsum caprock deposited in the west of Luntai-Gucheng.Above the intra-platform,the source rocks of Yuertusi Formation are relatively thick and become a favorable hydrocarbon generation center.In addition,the dolomite shoal facies reservoirs of Xiaoerbulake Formation are more developed in the relatively high parts between the paleo-rifts.The superior combination of the two and the upper Middle Cambrian gypsum salt caprock is the most favorable area for Cambrian presalt hydrocarbon accumulation,and also the most favorable area for forming giant gas reservoir and achieving exploration breakthrough.

关 键 词：塔里木盆地 古裂谷 沉积响应 生烃中心 边缘丘滩 成藏模式 

分 类 号：TE121.2[石油与天然气工程—油气勘探]