| Soaring hydrocarbon-based energy prices have been playing a major role in the country's energy strategies. Although attempts have been made to replace fossil fuels with a renewable source of energy, it is unlikely that this goal will be achieved in the near future. On the other hand, limited proven oil reservoirs are not giving a positive prospect about increasing the supply of oil in the future. The gap between supply and demand is becoming wider and wider with increasing energy needs of countries like the USA, China and India.; To overcome this gap between the supply and demand, increasing the oil recovery factor will play a major role. In situ combustion, as a well known process for secondary and tertiary oil recovery, it is an important alternative approach for higher production efficiency in light and heavy oil reservoirs.; In this study, an attempt has been made to better understand the spontaneous ignition process in light oil reservoirs. Through a novel approach, a three dimensional spherical ignition cell has been designed and manufactured. To gain the greatest advantage from this setup, the vessel was modified to a thermal conductivity cell to pursue two main purposes: (1) study the effect of pressure on effective thermal conductivity and determine the magnitude of natural convection and gravity effect on the effective thermal conductivity of three different gases in porous media, and (2) learn about the thermal behaviour of the spherical cell and to confirm the mechanical integrity of the design from a safety perspective. Air, N2, and helium were the three gases involved in this experiment. Four different sets of tests were performed at ambient pressure, 3.44 MPa (500 psig), 6.89 MPa (1000 psig), and 10.34 MPa (1500 psig), when air was the gas in the spherical cell. An additional set of tests under evacuated (vacuum) conditions was performed using air to further investigate the effect of the natural convection on the effective thermal conductivity. Three sets of experiment were performed, on both nitrogen and helium, at 3.44 MPa (500 psig), 6.89 MPa (1000 psig), and 10.34 MPa (1500 psig).; After becoming familiar with the set up and operation, and gaining confidence regarding the mechanical integrity of the design, the high pressure cell was changed to study spontaneous ignition. Three oils, labelled oil A, oil B, and oil C were tested. Effect of pressure, initial temperature, and air flux were studied to evaluate their role in spontaneous ignition in crude oil reservoirs. It was found that the reservoir pressure and temperature play a significant role in the spontaneous ignition process. |
