中东地区X油田Mishrif组生物碎屑灰岩成岩作用特征及其对储层品质的差异控制  

Diagenesis of bioclastic limestone in Mishrif Formation and its control on reservoir quality of X Oilfield in Middle East

作　　者：毛先宇 宋本彪[1] 田昌炳[1] MAO Xianyu;SONG Benbiao;TIAN Changbing(Research Institute of Petroleum Exploration&Development,PetroChina,Beijing City,100083,China)

机构地区：[1]中国石油勘探开发研究院,北京100083

出　　处：《油气地质与采收率》2021年第1期17-32,共16页Petroleum Geology and Recovery Efficiency

基　　金：国家科技重大专项“伊拉克大型生物碎屑灰岩油藏注水开发关键技术研究与应用”(2017ZX05030-001);中国石油集团有限公司科技专项“海外油气田开发关键技术研究与应用”(2017D-4406)。

摘　　要：基于岩心、测井、薄片、阴极发光等资料,系统梳理了中东地区X油田Mishrif组生物碎屑灰岩的主要岩石特征、岩相类型以及各岩相差异成岩作用特征与序列、多期白云岩化作用特征与其成因模式,并分析了各成岩作用对储层品质的差异控制。研究结果表明:根据生屑类型与结构特征将X油田Mishrif组生物碎屑灰岩分为12种岩石类型以及5大类岩相类型,其经历溶蚀、胶结、白云岩化、压实以及压溶等多种成岩作用。对比区分各岩相差异成岩作用类型与强度,并着重分析多期次大气淡水胶结、海水胶结作用、地层水胶结作用以及白云岩化作用发育特征与相互次序。研究区生物碎屑灰岩发育早、中、晚3期4种白云岩化作用,通过对不同岩相白云岩化产物特征分析认为,早期第1种白云岩化作用为回流渗透白云岩化作用,早期第2种为混合水白云岩化作用,中期、晚期为埋藏白云岩化作用,并对混合水白云岩化作用成因模式进行探讨。在对储层品质差异控制方面,部分岩相早期生屑颗粒间的胶结作用有助于孔隙的保存,有利于储层品质提高;早期白云岩化作用一般有利于局部渗流能力的增强,晚期白云岩化作用形成的白云石占据储层残余空隙,降低储层品质。Based on the core,logging,thin section and cathodoluminescence data,etc.,the main rock characteristics,litho⁃facies types,differential diagenesis characteristics and sequences of each lithofacies,multi-stage dolomitization character⁃istics and their genetic models in Mishrif Formation of X Oilfield are systematically sorted out,and then the control of each diagenesis on reservoir quality is analyzed.The results show that the bioclastic limestone in Mishrif Formation can be divid⁃ed into 12 rock types and 5 lithofacies types according to bioclastic types and structural characteristics.It has undergone many diagenetic events such as the dissolution,cementation,dolomitization,compaction and pressure solution.The types and intensity of diagenesis of different lithofacies are compared and distinguished,and the mutual sequence and develop⁃ment characteristics of multi-stage atmospheric fresh water cementation,seawater cementation,formation water cementa⁃tion and dolomitization are analyzed emphatically.Four kinds of dolomitization at the early,middle and late stages of bio⁃clastic limestone are developed in the study area.Based on the analysis of the characteristics of dolomites in different litho⁃facies,it is concluded that the first type at the early stage is percolation-reflux dolomitization,the second is dorag dolomiti⁃zation at the early stage,and burial dolomitization is at the middle and late stages.The genetic model of dorag dolomitiza⁃tion is discussed.In terms of controlling the difference in reservoir quality,the early cementation between bioclastic parti⁃cles in some lithofacies is beneficial to the preservation of pores and the improvement of reservoir quality.The early dolomitization is generally beneficial to the improvement of local percolation,while the late dolomitization occupies the residual pores of the reservoir and reduces the quality of the reservoir.

关 键 词：Mishrif组 生物碎屑灰岩 成岩作用 储层品质 白云岩化作用 中东地区 

分 类 号：TE122.2[石油与天然气工程—油气勘探]