Three-phase method for injecting carbon dioxide into oil reservoirs

A method for stimulating a low permeability subterranean formation comprising:

• a first injection phase that comprises injecting a first gas-based fluid into a low permeability subterranean formation at a first pressure that exceeds a fracture pressure of the low permeability subterranean formation, wherein a permeability of the low permeability subterranean formation is less than 100 millidarcies, and wherein the first gas-based fluid comprises at least 65% carbon dioxide (CO2) by weight;
• a second injection phase that comprises two or more cyclical injections of a second gas-based fluid into the low permeability subterranean formation at a second pressure that exceeds a minimum miscibility pressure of the second gas-based fluid followed by a shut in period, wherein the second gas-based fluid comprises at least 65% carbon dioxide (CO2) by weight;
• and
• a third injection phase, after a final repetition of the second injection phase, that comprises injecting the first gas-based fluid or a third gas-based fluid into the low permeability subterranean formation at the first pressure exceeding the fracture pressure of the low permeability subterranean formation or at a third pressure that exceeds the fracture pressure of the low permeability subterranean formation, wherein the third gas-based fluid comprises at least 65% carbon dioxide (CO2) by weight.