Oil-water mutual driving microscopic simulation research on low permeability reservoir

Abstract

Oil-water mutual driving microscopic characteristics of the low permeability reservoirs are analyzed for the example of the H area in Qaidam Basin. The reservoir lithology and pore characteristics are studied by thin section observation, scanning electron microscopy (sem), physical property analysis and mercury injection experiment, etc. Then oil-water mutual driving microscopic simulation is studied by the experiment system device. It indicate that it is poor reservoir property, strong heterogeneity, rock types are mainly lithic arkose and arkose, reservoir space is mainly primary intergranular pore, pore throat characteristics are wide distribution, poor sorted, there are many distribution types and dispersed. Flow of crude oil in the reservoir rocks is non-darcy seepage, start-up pressure gradient is reduced along with the increase of permeability, but the correlation is poor, increase pressure gradient can make the single phase oil seepage achieve linear flow. It is the non-uniform displacement process, the microscopic heterogeneity is strong and the original oil saturation is low; Water flooding breakthrough rapidly along one or two channels, water-free oil production period is short, the efficiency is low, it can increase the water displacement efficiency by increase the pressure, but the effect is not obvious. The residual oil are flow around oil, oil film and the residual oil at the edge of the corner, the formation mechanism is different.