Displacement and development characteristics of fire flooding of vertical wells in old heavy oil areas

Abstract

As the vertical-well fire flooding technology is industrially applied in the steam-injection old heavy oil areas of Xinjiang and Liaohe oilfields, its enhanced oil recovery potential is gradually clear. According to laboratory experiment, field test and reservoir engineering, the displacement characteristics of vertical-well fire flooding in the steam-injection old heavy oil areas are systematically investigated. Laboratory experiments and core data show that the vertical-well fire flooding has significantly high flooding efficiency, no residual oil are remained in the firing front sweeping zone, and the lateral sweep efficiency and ultimate recovery can be achieved. The vertical-well fire flooding is a strategic replacement technology to enhance the recovery greatly. Development characteristics and advantages of areal and linear fire flooding are well investigated, and research results are applied in the design of industrial test plan of fire flooding in the Hongqian block, Xinjiang. The research shows that the linear well pattern has advantages of easy construction of ground facilities and management, less well of stage management, simple matching technology and easy achievement of purposeful control for fire front; the areal well pattern has advantages in reducing the air/oil ratio during the fire flooding period, increasing the total recovery rate of reservoirs and reducing the geological and reservoir management risks. To select well patterns of fire flooding, some factors such as geology, reservoir, fluid properties, oil price, and reservoir development degree should be mainly considered. In the Hongqian block, an improved linear well pattern with a combination of new wells and old wells is applied, this not only absorb experiences of linear well pattern pilot test, but also use advantages of areal well pattern. Keywords: Old heavy oil area, Fire flooding, Residual oil, Oil displacement efficiency, Sweep efficiency, Linear and areal well patterns