Miscible CO2 injection is a method to increase oil production. Combinations of Carbon dioxide with other gases as miscible solvents are emphasized in this paper to improve CO2 miscible injection process. Emphasis is on identifying CO2 solvent mixtures with reduced MMP to achieve miscibility at reasonable injection pressures in Abu Dhabi fields. Two targeted crude oils (Oil 1 and Oil 2) from Abu Dhabi carbonate reservoirs are utilized. The minimum miscibility pressure (MMP) of targeted oils with mixtures of N2, CH4, C2H6, and HC rich gas of varying composition with CO2 injection gas are evaluated through simulation. Cell to Cell and Semi-analytical (key tie lines) methods are applied using CMG simulator. Results show that miscibility is predicted to occur with multiple contact miscibility (MCM): vaporization and/or condensation mechanisms. The increase of C2H6 concentration in the CO2 injected gas reduced MMPs for targeted Oil 1 by 100 psi/10 mol%. However, N2, CH4 and HC rich gas increments in CO2 injected gas increased the MMPs for targeted Oil 1. MMP was observed to be 2300 psi for pure ethane with Oil 1. In addition, MMPs for targeted oils with N2/ C2H6 and N2/ CH4 injected gas mixtures are assessed. This study can open possibilities for future enriching of CO2 and N2 miscible injection to improve miscibility and recovery of oil.

This content is only available via PDF.
You do not currently have access to this content.