To further enhance production potential of water-drive reservoirs, core gas-drive (C0₂) laboratory displacement test is carried out in G 94416 Wellblock. Since long-core gas injection (C0₂) displacement test can reflect seepage parameters more accurately than short-core gas injection, this test contrasts oil displacement efficiency in long-core water injection displacement and long-core gas and water alternate displacement mode and the test also proves that C0₂ injection can reduce crude oil inteifacial tension, enhance oil mobility and replenish formation energy effectively. The main purpose of numerical simulation study on long core displacement experiment is to correct such data as permeability saturation curves and capillary pressure curves according to experimental data and provide basic seepage characteristic parameters matching the actual ones for numerical reservoir simulation study. After phase matching of oil reservoir fluids in G 94416 wellblock is completed, multi-component model software is used to conduct numerical simulation study on long-core gas and water alternate displacement test data and good effect has been obtained.