Study On Well Pattern Adjustment Technology Of Fluvial Sandstone Reservoir For Extremely High Water-cut Stage

Fluvial sandstone reservoir distribute widely in our country,it is the main support of oil resources and account about 42.6% of the total developed reserves.The main maturing field is in production tail now.Owing to the complicated geologic characteristics such as heterogeneity,the distribution of remaining oil in the sand reservoir is very complicate at extremely high water-cut stage.So the study which improve the development effect of remaining oil with the well pattern adjustment technology is significant.Combing with the Zhongyi block of Gudao field which is fluvial sand reservoir,reservoir characteristics and the remaining oil potential are summarized in this paper.Study the feasible well pattern transformation before extremely high water-cut stage and feasible well pattern adjustment at extremely high water-cut stage through the numerical simulation.The former one is mainly about the study on feasible well pattern transformation and the feasible time of the transformation.The latter one studies the remaining oil development effect with the vertical well pattern adjustment and horizontal well pattern adjustment.The rational well spacing density and limiting well spacing density are studied with the reservoir engineering method ,it indicates that we should infill 10 vertical wells or 8 horizontal wells to get rational well spacing density at high water-cut stage.During the study of horizontal well pattern adjustment, many parameters of the horizontal are considered,which affect the development efficiency of the remaining oil.It indicates that the distance between horizontal well and oil well array is zero which can make development efficiency good.And the distance of the horizontal section to the top of the layer should be 0.5m,the horizontal section should be oblique crossing with the well array,the length of the horizontal section should be 180m.