Laboratory Investigation of Air Injection Process for Depleted Light Oil Reservoirs

Because of injectant low access cost and unlimited availability, light oil reservoir air injection is now a proven field technique. To understand the process of air injection, asses the consumption of oxygen, and sustain the combustion front for, from depleted light oil reservoirs, improved oil recovery, a laboratory experimental set up was developed. Non-isothermal experiments were conducted from a 300 and 500 psig and 40-500°C temperature. In these experiments, unconsolidated formation with a light crude oil impregnation was used, with impregnated formation oxidation for combustion front sustenance through the combustion cell done by synthetic air injection (21% oxygen and 79% nitrogen). Analysis of nitrogen, oxygen, carbon monoxide, carbon dioxide, and other combustion gases produced was done using a gas chromatograph with a thermal conductivity detector. There was observation of higher oxygen consumption at a temperature immediately after oil ignition, resulting in high temperature oxidation zone generation, as well as creation of an oil bank ahead of the thermal front and more efficient carbon oxides.