ABSTRACT
Two of the most important properties governing reservoir fluid flow are relative permeability and capillary pressure. Unfortunately, conventional techniques for measuring one are not without complications from the other. Worse yet, these complications become particularly inextricable for flow experiments on the short core samples typically available for analysis. The advantage of the present method is that it simultaneously measures both properties in an experiment where their effects have been largely decoupled.
The present method entails using an automated centrifuge to measure fluid productions at several speeds and history-matching the production data with the aid of a numerical simulator. Although history-matching problems are, in general, not well posed, the present case is exceptional. In each speed step the asymptotic production is determined only by capillary pressure and the transient behavior is determined mainly by relative permeability. Consequently, the effects can be distinguished.
A numerical simulator, tailor-made for centrifuge experiments, is presented along with typical results of history-matching. The error in a conventional capillary pressure is also estimated.