New methods to determine minimum miscibility pressure

Two new, fast, and reliable experimental methods can determine minimum miscibility pressure (MMP) for miscible CO2 injection. In the first method, interfacial tension (IFT) between injected gas and oil at reservoir temperature and varying pressures is measured by use of vapor-/liquid-equilibrium IFT (VLE IFT) equipment. The second method uses a gas-extraction and -miscibility analyzer (GEMA) that uses a capillary-sized unpacked column instead of the conventional packed slimtube. MMP-analysis time can be reduced to one-tenth of that required for conventional slimtube or sandpack-flood methods.