Analysis Of Characteristics And Favorable Facies In F1 And F2 Of Fuyu Oil Reservoirs In Daqing Placanticline

Daqing Placanticline which spans the Central Depression of the basin is one of the Oil pre-exploration targets of mid-shallow strata in Daqing Oilfield.The productive layers are the formation ??? and ? of Fuyu oil layer,and the reservoirs are mainly channel sand of rivers(meandering river and braided river)and crevasse splays,and distributary channel sand of delta plains and delta fronts.By calculating and analogizing the reservoir properties,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,sedimentary facies,sand thickness and oil-bearing thickness,the favorable phase belts are predicted in this area.The reservoir properties of the Fuyu oil layer in Daqing Placanticline are bad,and the porosity and permeability varied widely.The porosity ranges form 4%to 20%,with a min 1.00%,and a max 27.4%,averaging 10.3%.The permeability is mostly below 10mD,with a min 0.01mD,and a max 93.4mD,averaging 1.22mD.According to the China's eastern clastic reservoirs criteria for the classification,Fuyu oil layer is divided into low-porosity and ultra low permeability reservoir.Sedimentary microfacies and their plane distribution,mechanical compaction,dissolution,and calcareous cementation are the main factors which affect the reservoir properties.Sedimentary microfacies and their plane distribution play a control action.As a result of the low permeability,porosity feature,sand thickness and oil bearing thickness are take into consideration to predict the favorable phase belts.Studies have shown:in formation F1.1,the ? class favorable phase belts are braided river channel and distributary channel,the ? class are sheet sand and crevasse channel,the ? class favorable phase belt is crevasse splay;in formation F1.2,the ?class favorable phase belts are braided river channel and meandering river,the ?class are crevasse channel and distributary channel,the ? class is crevasse splay;in formation F1.3,the ? class favorable phase belts are braided river channel and meandering river,the ? class is crevasse splay,the ? class is crevasse channel;in formation F2.1 and F2.2,the ? class is meandering river,the ? class are crevasse splay and crevasse channel.