Influence of early diagenesis on reservoir properties of Rumaila Formation in A Oilfield

Diagenetic features of Rumaila formation in A oilfield and its effect on the reservoir space development were studied by means of a large number of cores,casting thin-sections and scanning electron microscope( SEM).And then the impact of diagenesis on the reservoir property was discussed.Results indicate that there were some diagenesises occurred in the research area including compaction-presolution,neomorphism,micritization,cementation,dissolution,recrystallization and dolomization,etc.The occurred diagenetic environments were,in order,the bottom of the sea,atmospheric fresh water and shallow burial diagenetic environment.The cementation and dissolution,which went through the entire diagenetic stages,determined the final form of the reservoir space.The effects of other diagenesis on the reservoir space were relatively small due to their limited degrees.Among these diagenesises,the effects of the cementation and dissolution on the reservoir property were the largest.The strength of early cementation determined reservoir properties of different sections of Rumaila Formation.