AIR INJECTION STUDIES FOR ENHANCED OIL RECOVERY

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Department of Engineering

ABSTRACT
Conventionally, air injection has been used for recovery of heavy crude oil in the production field, but studies have shown that depletion of light crude oil in the reservoir leads to abandonment of such wells. Hence, this work studied the kinetics and combustion of light crude oil in-situ the reservoir to understand their potentials for high-pressure air injection (HPAI) enhanced oil recovery (EOR). Advanced thermo-kinetic simulation and Pressure-Volume-Temperature tools (AKTS and PVTsim) were coupled with non-isothermal Differential Scanning Calorimetry (DSC) measurements and Accelerating Rate Calorimeter (ARC) for the studies. The combustion and kinetics of three (3) light crude oils obtained from Offshore of Newfoundland, Canada were precisely described by the methods. It was observed that the crude with the lowest API of 30.214 had the lowest enthalpy change of 10.9 J/g and the highest onset oxidation temperature of 220 oC, while the crude with the highest API gravity of 46.963 had the highest enthalpy of 24.6 J/g and the lowest onset oxidation temperature of 140 oC. Effect of 10% water saturation of one of the crude samples (Sample A) was studied and it was observed that there was increase in the onset oxidation temperature by 40 oC and lowering of the enthalpy change by 9 J/g. These findings provided evidence that the versatile Differential Scanning Calorimetry thermograms when coupled with kinetic simulation technique can yield reliable results with respect to oil recovery with high correlation coefficient (r > 0.9). This reliable information such as onset, peak and endset temperatures with their respective heat flow patterns, could then be used to provide precise thermo-kinetic parameters. Kinetic triplets such as activation energy, pre-exponential and the reaction model necessary for reservoir screening in an air injection EOR process can also be accurately determined. Mine tailings containing high pyrrhotite content were.