Research On Prediction Method Of Recovery Factor In Low Permeability Oilifeld

The prediction of the oil recovery factor takes very important part during thedevelopment of the reservoir. The whole process and the ultimate effectiveness of the oilfielddevelopment depends on the accuracy of the oil recovery factor prediction. The recoveryfactor prediction for conventional reservoir has been a supeiror and mature technology. Whilethe study on recovery factor prediction for the low-permeability reservoir is not sufficientbecause of its special nonlinear lfow characteristics.Based on the literature research, this paper introduced the prediction method of the oilrecovery factor of early, middle and late period of oilifeld development, according to actualproduction data of recovery eiffciency of water flooding development of low permeabilityblocks in Changqing oilfield, analyzes the adaptability of four types of water lfoodingcharacteirstic curve about the prediction of the oil recovery factor in different water cut stagesand then make a choice, they provide evidence for the calculation of the oil recovery factor.At the same time, combined the waterlfood curve with the production decline method, theaverage dynamic recovery was calculated in multiple low permeability oilifeld.By analyzing the influential factors theory of recovery ratio, combined with the actualproduction data of Changqing Low permeability oil field, determined the mathematicalrelationship between oil recovery factor by waterlfooding and the single factor like wellspacing density，(well pattern reserves) production arte and cumulative injection-productionratio. Finally, consideirng the synthetical relationship between well spacing density andrecovery rate, oil production rate and recovery rate, cumulative injection-production ratio andrecovery ratio, using nonlinear regression pirnciple, established the prediction model of waterflooding recovery in Changqing low permeability oilfield.We predicted the recovery factor ofsome block of water flooding recovery in Changqing low permeability oilfield by using themodel, and the result shows that, the model has good applicability in Changqing oilifeld.