Characteristics of Effective Reservoir Space and Genetic Analysis of Mishrif Carbonate Reservoir in a Oilfield in Central Iraq

With the deepening study of carbonate oil and gas reservoir in the Middle East, it is recognized that marine carbonate reservoirs have strong heterogeneity from macro to micro, and some reservoirs even show high permeability layers or special "spotted" heterogeneity. "Patch" is named according to the shape and meaning of the morphological characteristics of rock structure, that is, "Patch" carbonate rock core is mainly represented by patches of light gray, dark brown, black and other colors. Taking the late Cretaceous Mishrif main reservoir of a oilfield in Iraq as an example, based on the core, thin section and other basic data, the study on the characteristics of effective reservoir space of carbonate reservoir is carried out, and it is clear that the causes of effective reservoir space of Mishrif carbonate reservoir include: sea level height, hydrodynamic strength and sedimentary discontinuity events in sedimentary period, including biological disturbance, hard bottom cementation The transformation of primary pores by atmospheric fresh water dissolution plays an important role in controlling the formation of effective reservoir space.