A New Approach to History Matching of Water Driven Oil Reservoirs
Research output: Thesis › Doctoral Thesis
This dissertation presents a new technique for history matching. In the conventional approach the model wells are fixed and one seeks for a reservoir model in which they provide the historical rates, well pressures, WC and GOR over the entire time. The presented method does the opposite, the reservoir model is given and the computer places automatically wells which can do what they should do. These pseudo wells are perhaps at different location and open also other layers as the real wells but the overall material transfer will be correct for all the time. If such wells can not be placed, then the static model is fundamentally wrong and must be replaced. Stochastic realisations can be screened at this level already. Supplementary pseudo wells inject water to the model boundaries, assuring that the average pressure in any chosen region closely follows the historical pressure. After the global match succeeded, the pseudo wells are shifted toward the real ones and the reservoir and perforation properties will be tuned step by step, partly automatically partly manually. For the second one the procedure writes suggestions for the user. The HM is completed after all pseudo wells are replaced by the real wells. PRS is a fully developed not commercial user friendly tool which can be used stand alone but also as a certain kind of pre-processor to ECLIPSE. The tool needs some command lines added to ECLIPSE input only. PRS write out a modified SCHEDULE file containing the actual settings of the pseudo wells and the parameters for the Fetkovich and Carter-Tracy analytical aquifer models (replacing the boundary injections) for the next ECLIPSE run. Beside the methods and algorithm used in PRS the work present a full field application. The reservoir contains 700 MMstb OOIP and it was operated by 60 wells over 45 years.