Study on Flow Mechanism of Gas Injection in Porous Carbonate Core

There are wide scale of porous carbonate reservoirs in around the world, that have low permeability with undeveloped fracture. With study target of Savark formation in Middle East, core gas flooding experiments are conducted and microscope seepage mechanism is researched further. The study results indicate, with formation condition, miscible associated gas flooding is not achieved easily because of high minimum miscible pressure; flooding efficiency of hydrocarbon gas injection is high, especially for miscible flooding, because gas flooding makes oil volume expanse and viscosity decrease, and then oil mobility will be improved. In the experiments, gas injection mainly displace mobile oil in macropore, so changing displacement manner should be considered to improve flooding efficiency further.