چكيده به لاتين
Gas injection is one of the main EOR methods. Injection is of miscibile type if a minimum required pressure is provided, which is called Minimum Miscibility Pressure (MMP).Slim Tube Test is the most reliable method for determining MMP. However, this method os very expensive and tedious. Beside from Laboratory methods are MMP correlations, Analytical methods and Numerical methods. Analytical and Numerical methods are EOS-based and their accuracy depends on EOS potency in predicting fluid behavior.
Multiple Mixing Cells and Slim Tube sample in compositional simulator are the best numerical methods. In this study an Automatic method for MMP calculation is developed then the two methods are compared for some real fluids. Regarding effectrive parameters, sensitivity analysis is performed. Thermodynamic parameters were the most effective, meanwhile effect of porous media parameters, shows that MMP can not be purely a thermodynamic value.
If providing minimum required pressure is imposasible, MMP value can be lowered to reservoir pressure by enriching the injection stream at a minimum level (Minimum Miscibility Enrichment-MME). MME calculation is modelled using both compositional simulator and multiple mixing cell method.
Regarding great effect of thermodynamic parameters on MMP value and ununique nature of matching procedure, matching convetional tests can even increase MMP error. It is impossible to match conventional tests and MMP simultaneously. For this reason so little real fluids are studied in MMP calculation litrature. In order to solve this problem, an optimization algorithm is used along with the automatic MMP algorithm to match saturation pressure, its liquid density and MMP simultaneously.
At the end, MME calculation was done for a real reservoir fluid and different enrichment levels were simulated and Economical aspects were calculated for each scenario. Although miscibility was achieved at the MME, due to high expenses of condesate and equipments and active gravity drainage mechanism, miscible injection is not the best scenario for gas injection. For this sector, supplying drained pressure is the best scenario and dry gas injection provides maximum level of income for the sector.
