This article illustrates the impacts of slim-tube experimental conditions on test results of minimum miscibility pressure(MMP).The numerical simulation results show that the MMP is smaller when the slim-tube's length is longer

diameter is smaller

displacement speed is greater

and the porosity is smaller.In addition

it discusses the influences of reservoir temperature

injected gas compositions and crude oil compositions and properties on the miscible pressure.Through comparing the condition of CO

2

miscible flooding reservoirs and fluid flow in foreign and domestic fields

it explains the reasons behind the difficult application of CO

2

miscible flooding in China's fields are high formation temperature and high oil viscosity.It is suggested that a research on technologies of reducing minimum miscibility pressure and preventing gas breakthrough be carried out to address the issue of low sweep efficiency of injected gas and to enhance oil recovery.