Characterization of Reservoir Heterogeneity by Using Locally Varying Variogram

In the application of geostatistics,a single stationary variogram was often set for the whole research area. The geologic complexities could not well described,especially for channel reservoirs,because the local direction of a channel was often changed,the continuity of reservoir petrophysical parameters was also changed along the flow direction of channels. In this situation,the anisotropy was varied locally. Locally varying variogram parameters based on their location should be established before simulation. According to the differences of positions in the research area,the variogram had different azimuths,ranges,nuggets and sill. When the local conditional distribution function was calculated,the local variogram was considered instead of global one. An example of Es3 reservoir in Pucheng Oilfield was presented. The result shows the ability of this method results in complex features that would be difficult to characterize a single global variogram.