Experimental study on determining relative permeability of heavy oil reservoir with nonsteady state method

In order to better find out the development characteristics of heavy oil reservoir,aiming at the geologic features and the fluid property characteristics of reservoir,the oil-water relative permeability curve of heavy oil reservoir is determined by the use of waterflooding nonsteady state method through laboratory experiment.JBN empirical formula is adopted in the process of data processing,using the logarithm for fitting and regression calculation to gain oil-water relative permeability curves,which obtains the experimental result.The study result shows that the two-phase fluid flow area is larger,residual oil saturation is relatively high,water permeability is relatively low and the isotope point saturation is larger than 50%.The oil-water relative permeability curve can be used to judge the reservoir wettability.The heavy oil reservoir is a weak water-wet reservoir.During the waterflooding,the water breakthrough time is early and the pressure difference of water breakthrough is 0.72,with less recovery ratio than 30% in water breakthrough.Ultimate recovery ratio is low.The study can provide a theoretical basis for EOR decision-making.Meanwhile,the reservoir wettability can be judged through the analysis of relative permeability curve.