Integrated Reservoir Characterization And Remaining Oil Prediction In High Water-cut Stage, CR Oilfield

This paper is focused on the integrated reservoir characterization and remaining oil prediction in high water-cut Stage, CR Oilfield, SUNDA Basin. The challenges of are high water-cut, pressure decline and defeated infill wells. CR Oilfield is a lithologic– structural oil pool, with complicated faults and fluvial- delta facies. The complication of structure and reservoir requires integrated reservoir characterization. The exploitation history of 33 years and the abundance of performance data make the integration of static geological study and dynamical analysis possible. Thus, the study scheme is designed as following: based on study of subtle structure and reservoir description, combine static feature and analysis of production performance together with geological modeling and numerical simulation, and predict the distribution of remaining oil. The geological factors control the distribution of remaining oil is concluded.First, local structure explanation is applied. 9 local structures are discovered and selected out according to volume, reservoir quality, nearby well production history..Second, base on seismic, logging and geological data, deposition facies study and reservoir characterization is carried out. Three facies, including braided channel, meandering channel and delta, and 14 micro-facies are recognized. The distributary channel, point bar and mouth bar are the main reservoir type. The TAF formation is divided into 4 sequences: S1 and S2 were braided channel deposition; former S3 were meandering channel; later S3 and S4 were delta deposition. Seismic frequency division is applied to predict reservoir with the integration of depositional facies analysis.Third, a geological model is built up based on local structure explanation, micro-facies analysis and reservoir prediction. With numerical simulation and production performance analysis, remaining oil potentials is predicted. The corresponding production adjustment schemes are advanced and then approved effective by production.The main geological factors that control the distribution of remaining oil in CR Oilfield are local structures and micro-facies. Correspondingly, the remaining oil is distributed in local highs, near faults and in isolated sands.