| 摘要 |
<p>A method of controlling water influx and improving oil recovery by injecting a high density miscible fluid, such as carbon dioxide, at the water-oil contact is described. The fluid must be miscible with the oil and must have a density intermediate between that of water and the reservoir oil. A sufficient amount of fluid is injected to form a bank between the oil and encroaching water. As oil is produced from the reservoir, water influx from the aquifer displaces this bank of fluid, which in turn displaces the oil. Due to the miscibility of the fluid with the reservoir oil, a low residual oil saturation remains behind the displacement front. The density of the fluid is intermediate to that of the water and the reservoir oil restricting the bank of fluid therebetween and allowing little tendency for the fluid to bypass or override the oil and migrate to the structurally higher portions of the reservoir.</p> |
