A NEW METHOD TO MEASURE WATER,OIL AND GAS SATURATION PROFILES IN THREE-PHASE GAS INJECTION

摘要

In the present paper an original method is presented to acquire simultaneously water,oil and gas saturation profiles as a function of time in tertiary gravity assisted gas injection.The method consists in combining local electrical resistivity and y-ray attenuation measurements.Resistivity measurements give the local water saturation whereas the oil and gas saturations are calculated based on the yray attenuation profiles.The method has been applied to measure three-phase local saturations during gravity assisted gas injection experiments in water-wet sandpacks;in these experiments the ability of oil to form films on water in presence of gas,that is characterised by the spreading coefficient,was investigated.The results are in very good agreement with local saturation CT-scanner measurements and with bulk saturations obtained by continuous weighing of the recovered fluids.As a validation of the method the oil relative permeability is calculated,based on the evolution of the saturation profiles and it is used to simulate the experiments.A good numerical description of the experimental behavior is obtained.Throughout the same experiments it is proved that the spreading coefficient plays a major role on the fluid distribution and recovery efficiency in tertiary gravity assisted gas injection e.g.when water is mobile.