Techniques of Predicting Remaining Oil in a Mature Oil Field With High Water Cut—Case Study

Abstract

Abstract The remaining oil in mature oilfields at high water cut stage is highly scattered in the whole field and relatively abundant in some localities. In view of this feature, a new approach is proposed to predict the distribution of the remaining oil in mature oilfields by integrating multidisciplinary means such as geology, seismic, geophysical well logging and reservoir simulation. At the high water cut stage, oilfields are always thin sand-shale interbedded layers and with numerous of wells, sophisticated target processing method of seismic data, sophisticated structure interpretation, combining of logging and seismic data in thin interbedded layers prediction and seismic constrained geology modeling technique are researched to construct the logging and seismic unit sophisticated reservoir characterization in mature oilfields. This technique has been applied in reprocessing old seismic data of Gangdong area in Dagang oilfield and improved the main frequency of seismic data by 10-15 Hz, and in X4-5 block in Xingshugang oilfield in Daqing with an average well distance of 200m, some new cognitions have been obtained in the faults, microtectonics and the distribution of the river channel sands in the block. With the result of combining logging and seismic prediction, high precision determinable reservoir model is established. Also the distribution of the remaining oil is predicted through large-scale sophisticated reservoir numerical simulation on the basis of this model. The case application shows that integrating multiple disciplines technique of predicting remaining oil in a mature oilfield with high water cut has a profound meaning for finding remaining oil effectively.