Abstract：Stochastic modeling and stochastic inversion are two commonly used reservoir prediction methods, and variogram is the core technology of stochastic simulation and stochastic inversion. With SⅢ Formation of North-North second block in the Lamadian Oilfield as the study object, the authors made a comparative analysis of the stochastic simulation and stochastic inversion on different variograms of 300 m×300 m, 600 m×600 m, 800 m×800 m and 1 200 m×1 200 m, so as to probe into the effects of ranges of different variables on prediction results. The results show that, with the increasing range, the stochastic simulation results vary from the sand body to a continuous sheet of discrete distribution, and stochastic inversion sand distribution are consistent with the overall trend, with only a thin layer of sand being affected in an insignificant degree. Blind shaft verification shows that stochastic inversion has higher consistency between predicted sand bodies and well points than stochastic simulation. An analysis reveals that relative to stochastic simulation, stochastic inversion is subjected to seismic constraints, thus reducing the uncertainty of sand distribution and multiple solutions and improving the prediction precision of inter-well sand bodies. Therefore, it deserves extension and application at the oilfield development stage.
