Maximizing the utility of centrifuge capillary pressure/relative permeability experiments

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One of the standard methods used to determine capillary pressure versus saturation curves in a sample ofpetroleum reservoir rock is the centrifuge technique. In addition to capillary pressure, modern centrifugesallow determination of relative permeability using the transient period observed in capillary pressureexperiments - by implementing an inverse data analysis technique, relative permeability curves can bedetermined using this production versus time data during this period. The main criticisms of determining bothtypes of curves simultaneously are related to the uniqueness of the curves that are obtained. Statoil has a verylarge data base of capillary pressure/relative permeability curves obtained by simultaneous centrifugeexperiments but do not know how much confidence they can place in these data. If it can be shownconclusively that both relative permeability and capillary pressure can be found simultaneously in a singleexperiment, the confidence in using the centrifuge to determine these properties would be greatly enhanced. Ofall the methods used to determine relative permeability, the centrifuge offers the best overall speed andprecision. Making use of Statoil's extensive data base, and in cooperation with Statoil personnel, a collectionof data sets that include a wide range of petrophysical properties will be selected. A comprehensive study ofthe performance of a numerical simulator to determine both capillary pressure and relative permeability curveswill be performed on these data. In this way the validity of the data will be verified. Furthermore, the datawill be studied to determine a protocol for optimizing the quality of the data. The study will be conductedusing commercial simulators, PORLAB© and Sendra©. The petroleum industry is a major source of wealth inCanada. Capillary pressure and relative permeability are fundamental properties essential to the prediction ofrecoverable oil reserves - any research that can improve the quality of these data will have a major impact onthe efficient and environmentally safe recovery of these reserves and will therefore bring major economicbenefits to Canada.