Summary
Multi-scale (milli-micro-nano) X-ray CT imaging technology has been employed to build 3D model of core matrix of tight oil reservoir in Juggar basin in west China. Then the Micro pore network model is extracted from high resolution imaging results with maximal ball approach. The fluids distribution is simulated in this micro pore system. The porosity, permeability, elastic properties, tortuosity and pore size distribution have been directly calculated from Multi-scale models. Numerical simulation of Capillary pressure curve, NMR T2 distribution, m n of Archie equation and two-phase flow displacements (Primary drainage, Imbibition, Secondary drainage) with these models have been performed respectively. Combining with the single simulation, the upscaling techniques are employed to reduce the influence of inhomogeneities. With the integrated analysis, we found that two sets of favorable reservoir developed in "Upper sweet spots" and "lower sweet spots". The numerical simulation results agree with the experimental measurement results very well.
Introduction
The geophysical and petrophysical experiment are difficult to performance with the samples of tight oil reservoir because of the low porosity, low permeability and complex mineral components. It is always expensive and takes long time for the laboratory test, especially for special core analysis (SCAL) experiments. Conventional scanning electron microscope (SEM) and cast thin sections method can only provide 2D slice information. 3D X-ray microtomographic imaging and visualization of core samples at the pore scale, and subsequent analysis of petrophysical properties, can give important insight into understanding the properties of reservoir (Knackstedt et al. 2009). Combining with quantitative identification technique, 3D microtomographic and nanotomographic imaging is also very important for the study of components of hydrocarbon source rock and the calculation of brittle index for the determination of the effect of fracturing. In this study, we proposed a method to build a petrophysical model for the numerical study of electrical, elastic, NMR and nuclear properties of reservoir.
