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

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...

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

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.