摘要
通过岩心、薄片观察和地震资料,重点对四川盆地元坝地区长兴组生物礁碳酸盐岩层序、沉积相、储层类型和成岩作用进行了研究,分析了生物礁储层结构和发育控制因素,总结了储层发育模式。研究结果显示,长兴组生物礁主要发育在SQ2中的台地边缘相带,纵向上由两个明显的成礁旋回构成,横向上呈"东早西晚"不对称分布,是储层发育的有利相带。生物礁(滩)型优质储层以低孔、中低渗溶孔云岩为主,主要发育于四级层序上部生物礁礁盖部位,具典型"双层储层结构"。成岩早期大气水溶蚀和白云岩化是储层发育最重要的建设性成岩作用。综合分析认为,受高频层序控制生物礁沉积相是储层发育的基础,也是控制长兴组生物礁准同生期的大气水溶蚀和白云岩化作用的关键因素。埋藏溶蚀、埋藏白云岩化以及破裂作用进一步改善储集岩物性。元坝气藏长兴组生物礁储层具有"岩相控储、早期形成、后期改造"的发育模式。
Based on detailed observation of cores,thin sections and analysis of seismic data,this paper studied the high frequency sequence,sedimentary facies,reservoir types and diagenesis of the biohermal reservoiors in the Changxing Formation in Yuanba area,the Sichuan Basin,analyzed the architecture of the biohermal reservoir and the factors controlling its development,and formulated its development models.The results show that the bioherms in the Changxing Formation were favorable facies and were developed mainly on platform margin of the SQ2.Vertically,the bioherms consist of two distinct reef cycles.Laterally they are in asymmetrical distribution featuring in ＂early in the east and later in the west＂.The quality biohermal reservoirs are dominated by dissolved dolomite with low porosity and moderate-low permeability and mainly occur in reef caps of the upper fourth-order sequences,and feature in typical ＂double layer reservoirs architecture＂.Meteoric dissolution and dolomitization in the early diagentic stage were the most important constructive diagenesis in the Changing Formation.A comprehensive analysis indicates that the biohermal facies controlled by high-frequency sequence is the foundation of reservoir development,and also is the key factor controlling penecontemporaneous meteoric dissolution and dolomitization of the bioherms in Changxing Fm.Burial dissolution,burial dolomitization and fracturing further improve the physical properties of reservoir rocks.The development model of the biohermal reservoirs in the Changxing Fm of Yuanba area is ‘lithofacies-controlling reservoir,early formation and late reformation’.
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
2016年第5期744-755,共12页
Oil & Gas Geology
基金
国家科技重大专项(2011ZX05005-002)
中国石化科技部项目(P15050)
关键词
成岩作用
储层结构
生物礁
层序
长兴组
元坝地区
四川盆地
diagenesis, reservoir architecture, bioherm, sequence, Changxing Formation, Yuanba area, Sichuan Basin
