Abstract: Reservoir spaces of fractured-vuggy carbonates mainly,include large caverns,dissolved pores and fractures,which are varied in scale,irregular in shapes and discontinuous in distribution.There still have no effective geological modeling method for quantitative descriptions of 3D reservoir space distributions in fractured-vuggy carbonate reservoirs.In this paper,taking Tahe fractured-vuggy carbonate reservoir as an example,we put forward a 3D geological modeling method of fractured-vuggy reservoir under the constraint of multiple geological factors,i.e.two-step modeling under the control of ancient karst development pattern.In the first step,4 single-type reservoir models were established.After large cavens and large-scale fractures were identified by using seismic data,a discrete large cavern model and a discrete large-scale fracture model were established first with deterministic modeling method.Then,under the constraint of karst facies and based on development probability volumes of dissolved pores and interwell fractures,a dissolved pore model and a discrete small-scale fracture model were established by using the stochastic multi-attribute coordinated modeling method.In the second step,the 4 single-type reservoir models were merged into a 3D multiscale discrete geological model of fractured-vuggy carbonate reservoirs by using the diadochic assignment algorithm.The final model can quantitatively describe the 3D distribution of the fractured-vuggy carbonate reservoirs,and provide geological foundation for oilfield development.

Key words: discrete fracture modeling, dissolved pore modeling, discrete large cavern modeling, geological modeling, fractured-vuggy carbonate reservoir