Characteristics and control factors on favorable reservoirs of carbonate sedimentary microfacies:a case study of Middle-Upper Ordovician in well X,southeastern margin of Tahe Oilfield
In order to clarify the relationship between carbonate sedimentary microfacies and reservoir physical properties,based on the core,thin section and logging data of Middle-Upper Ordovith in well X in the southeastern margin of Tahe Oilfield,the reservoir lithology types and sedimentary microfacies characteristics are analyzed,and the controlling factors of reservoir physical properties are studied.The results show that there are eleven rock types in Middle-Upper Ordovician in well X of Tahe Oilfield:bioclastic packstone,bioclastic grainstone,algal oolitic grainstone containing spherulite,microsparry grainstone with pane structure,bioclastic wackestone containing calcareous green alga,bioclastic wacke-stone,aggregate grainstone,oolitic grainstone containing aggregate grain,bioclastic and clastic pack-stone,clastic grainstone,mudstone.There are six types of sedimentary microfacies:sandy bank,bio-clastic bank,oolitic bank,inter-bank sea,algal oolitic bank and gray flat microfacies.Reservoirs can be divided into three types:karst caves,fractures-cave and fractures.Quantitative analysis of reservoir physical properties,it is considered that the difference of porosity and permeability is mainly affected by sedimentary microfacies and later dissolution transformation.The sedimentary microfacies of sandy bank,bioclastic bank,oolitic bank and algal oolitic bank have relatively good physical properties,be-longing to fracture-cave type reservoir,which is a favorable facies zone for the development of high-qual-ity reservoir.The results provide a reference for further exploration and research of Ordovician carbon-ate reservoirs in the southeastern margin of Tahe Oilfield.
万方数据
