塔里木盆地轮南—富满台缘带寒武系层序格架中生储盖组合特征及勘探意义

Characteristics and exploration significance of source-reservoir-cap assemblage in Cambrian sequence framework of Lunnan-Fuman platform margin in Tarim Basin

为明确塔里木盆地轮南—富满台缘带寒武系储盖组合类型,基于岩心、测井、地震及地球化学分析等资料,在层序地层格架控制下,通过岩相分析、地震同相轴变化以及C/O同位素识别层序界面,将寒武系划分出4个二级层序、11个三级层序。随着层序地层的不断演化,寒武系台缘带沉积结构继承性发育与变化,经历了从早期缓坡过渡为弱镶边台地到中后期强镶边台地的演化过程。根据层序地层发育特征,将塔里木盆地轮南—富满台缘带寒武系层序格架中生储盖组合划分为准同生岩溶控制型储盖组合和潜山岩溶控制型储盖组合2大类5小类。研究区油气勘探现实的储盖组合为高能滩→膏盐岩储盖组合;潜在的生储盖组合包括高能滩→致密碳酸盐岩、高能礁滩→致密碳酸盐岩、高能礁滩→膏盐岩、潜山岩溶控制型储盖组合;值得探索的生储盖组合为潜山岩溶控制型储盖组合。

In order to clarify the Cambrian reservoir cap assemblage types in Lunnan-Fuman platform margin belt of the Tarim Basin,based on core,well logging,seismic and geochemical analysis and other data,under the control of sequence stratigraphic framework,Cambrian can be divided into four second-order sequences and 11 third-order sequences through lithofacies analysis,seismic event changes and C/O isotope identification sequence boundaries;with the continuous evolution of sequence stratigraphy,the sedimentary structure of the Cambrian platform margin zone has undergone a continuous development and change,transitioning from an early gentle slope to a weakly bordered platform to a strong bordered platform in the middle to late stages of evolution.According to the development characteristics of sequence stratigraphy,the source-reservoir-seal assemblages in the Cambrian sequence framework of Lunnan-Fuman platform margin belt in the Tarim Basin can be divided into two categories:quasi syngenetic karst controlled reservoir-seal assemblages and buried hill karst controlled reservoir-seal assemblages.The actual reservoir-cap combination for oil and gas exploration in the research area is high-energy beach→gypsum salt rock reservoir-cap combination;potential source-reservoir-cap rock combinations include high-energy shoals→dense carbonate rocks,high-energy reef shoals→dense carbonate rocks,high-energy reef shoals→gypsum salt rocks,and buried hill karst controlled reservoir-cap rock combinations.The source-reservoir-cap combination that is worth exploring is the buried hill karst controlled reservoir cap combination.