Analysis Of Reservoir Characteristics Of Dongying Formation In Liaoxi South Depression

Based on the theory of reservoir geology,the thesis aimds at Dongying Formation in Liaoxi south depression and LD10-1 south area.By calculating and analogizing the reservoir properties,combined with core observation,drilling and well logging,seismic data,this article analyzes the change law of reservoir properties both on the plane and on the profile.Integrating with the distribution features of reservoir properties and sedimentary facies,makes the high quality reservoir evaluate.The reservoir Petrology types of Dongying Formation,Paleogene in Liaoxi south depression include lithic arkose and feldspathic litharenite,followed feldspathic lithic quartz sandstone and arkose,and some litharenite occasionally;the component maturity of sandstone is poor.The sorting of sandstone is better,prismatic roundness which is hypo-angularity to hypo-roundness is middling.Interstitial fillings include clay minerals matrix and carbonate cement.The matrix formed mainly by crystalline kaolinite and hydromica.The carbonate cement mainly include dolomite,and a little calcite,and some siderite occasionally.Diagenesis of reservoir include compaction,pressure solution,cementation and dissolution.Reservoir sandstones mainly belongs to the B period of early diagenetic period,and some in the A period of early diagenetic period and A period of middle diagenetic period.The porosity of reservoir basicly ranges from 15.5%to 37.8%,with a minimum 5.3%,and a maximun 42.2%and average of 28.71%,The permeability is mostly greater than 1 mD,with a minimum lmD,and a maximun 2220mD and average of 204mD.According to the China's clastic reservoirs criteria for the classification,Dongying Formation is divided into high-porosity and middle permeability reservoir.Sedimentary microfacies and their plane distribution,mechanical compaction,dissolution,and carbonate cementation are the main factors which affect the reservoir properties.Sedimentary microfacies and their plane distribution play a control action.On the base of studying sedimentary system and sedimentary faeies,identifying three kinds of sand types.Integrate with the lithologic characters and properties of this area,it coule be considered that braided delta is the mainly type of resevoir,and the located in the lower section of the second menber of Dongying Formation.