Study On The Heterogeneity Of Clastic Reservoir Of Paleogene Formation Of KL6-C Block

The study of reservoir heterogeneity is the basis for the establishment of exploration and development program of reservoir,which provides the geological basis for the evaluation of reservoir and prediction of ultimate recovery,and it is one of the core contents in the study of oil and gas reservoirs.The previous drilling evaluation results reveal that KL6-C structure has good economic benefits.However,according to the previous logging data,KL6-C structure has the characteristics of strong heterogeneity.So it is necessary to study the heterogeneity of KL6-C structure,which is of great significance for the later exploration and development.This paper's study is based on sedimentology,sedimentary petrology,geology of oil and gas development,and combined with the experimental methods such as the rock slice identification,whole rock analysis,core routine analysis,etc.Firstly,this paper studied the petrologic feature of the reservoir,the types of diagenesis of the reservoir,the division of diagenetic stages and diagenetic evolution of the reservoir.Secondly,by using the Lorenz curve,this paper studied the heterogeneity of the reservoir from three aspects: pore heterogeneity,particle heterogeneity and interstitial heterogeneity.In addition,by using the parameters of permeability heterogeneity,the paper studied the macroscopic heterogeneity of reservoir,too.Finally,the influence factors of reservoir heterogeneity are studied from the aspects of diagenesis and sedimentation,and also analyzed the influence of reservoir heterogeneity on reservoir developmentThis study shows that:(1)there exist compaction,cementation,dissolution and metasomatism in the clastic reservoir of KL6-C.The reservoir has experienced four diagenetic stages,which various form the early diagenetic stage A and B to the middle diagenetic stage A and B.(2)The study of heterogeneity shows that the grain heterogeneity and filler content heterogeneity of Ed3 and Es3 is strong and medium respectively,and the pore heterogeneity of Es3 and Ed3 is weak and medium respectively,there is a strong layer heterogeneity in part of the sandbodies of the reservoir,and interlayer heterogeneity of Ed3 and Es3 are strong.(3)The lapidofacies types of KL6-C clastic reservoir are divided into 11 types,mainly contains weak compaction,weak cementation,weak dissolved phase,weak cementation,strong dissolved phase,strong ferruginous calcite cementation,weak dissolved phase,sec.(4)Cementation is the precondition that affecting the reservoir property,dissolution is the main factor that cause the reservoir property becoming better,and the impact of compaction is relatively stronger in the early diagenetic stage.(5)The reservoir property of glutenite is the best,and the siltstone is the worst.Median grain size is positively correlated with porosity and permeability.The sandbody of underwater distributary channel microfacies have the best reservoir property,followed by the mouth bar microfacies and the underwater distributary channel microfacies have the worst reservoir property.