Development of a Correlation Between Performance of CO2 Flooding and the PastPerformance of Waterflooding in Weyburn Oil Field

摘要

Weyburn oil field, located in southeast Saskatchewan, is thelocation of one of the largest CO2 flooding projects in theworld since September 2000.In this paper, data of the past performance of waterflooding inthe Weyburn field was used to develop empirical correlationsto predict the performance of CO2 flooding. Two differentcorrelations were developed based on CO2 injection schemesin Weyburn. The first correlation is based on a WAG processthrough vertical wells, and the second correlation is based onthe cases in which CO2 is injected through horizontal wellsand water is injected separately through vertical wells. As thefirst step, production data from 1958 to 2004 were collectedand analyzed. Oil production rates for both waterflooding andCO2 flooding periods, water injection rates, and CO2 injectionrates were used in developing the correlations. The empiricalmodel for injecting CO2 and water through vertical wells wasverified using the Kinder Morgan CO2 Scoping Model andactual field production data. The comparative analysis showed12% error between our simple correlation and the KinderMorgan model. For injecting CO2 in horizontal wells, thecorrelation could not be verified against the Kinder Morganmodel, but the correlation followed the actual oil production inthe field very closely.This new model can be used effectively as a screening tool forpredicting the performance of CO2 flooding in variouslocations in the Weyburn reservoir based on the data obtainedfrom past waterflooding performance and the rate of CO2injection. Hence, it can contribute significant savings in timeand expense to the operating oil company. Also, this approachcan be utilized for other potential CO2 flooding processes in reservoirs with histories and properties similar to those of theWeyburn field.