BENEFITS OF SATURATION PROFILES FOR ESTIMATING GAS AND LIQUID RELATIVE PERMEABILITIES FROM CENTRIFUGE TESTS

摘要

In conventional centrifuge tests,the relative permeability of just one phase is obtained – the phase with the lowest mobility.As a result,centrifuge tests are most often used for obtaining relative permeabilities of a liquid in a gas-liquid pair.In order to obtain more relative permeability insight from a centrifuge test,data in addition to production data must be obtained.In this paper,we discuss measurements of evolving air-water saturation profiles for a spinning-disk geometry.The saturation profiles were obtained by processing video images of the spinning rock sample,which was held in a transparent rotor assembly.Relative permeabilities of the water and the air were obtained by historymatching the saturation profiles and the production data.Critical gas saturation can be approximately estimated from the saturation profiles.In addition to the relative permeability results,we show a comparison of capillary pressures measured with the centrifuge(standard geometry and the spinning disk geometry),with a porous plate,and with mercury injection.For one of the samples,all four methods agreed well.For most samples,the centrifuge and the porous-plate methods agreed well.