倾斜油藏水气交替驱提高采收率机理研究

以冀东油田柳北大倾角油藏为原型建立了剖面地质模型，在流体相态拟合基础上．应用数值模拟技术讨论了地层倾角、油层厚度、地层压力、注入速度、气水比等参数对倾斜油藏水气交替驱开发效果的影响。结果表明，倾角的存在可显著提高水气交替驱开发效果，模型中倾角15°时提高采收率比无倾角时大6．18％；对于倾斜油藏。油层厚度越大对水气交替驱越有利．而无倾角时，规律相反；通过控制注入速度，倾斜油藏水气交替驱在较低的适宜压力下也可获得较好的开发效果；此外注入速度、气水比等对倾斜油藏水气交替驱的影响与无倾角时规律不同且均存在最佳取值。

Study on Enhanced Oil Recovery Mechanism of Inclined Reservoirs by Water Alternating Gas Flooding

Based on the prototype of Liubei Reservoir with large dip angle in Jidong Oilfield, a geologic profile model was developed. On the basis of matching of phase state, the influence of main factors, including formation angle, reservoir thickness, reservoir pressure, injection rate and gas-water ratio on the development effect of inclined reservoirs by water alternating gas flooding (WAG) was discussed by numerical simulation. The result shows that the existence of angle can significantly improve the development effect of WAG flooding. For the study model, the enhanced oil recovery with angle of 15 degree is 6. 18 percent more than that of non-declined one. For the inclined reservoirs, the more reservoir thickness is, the more favorable is for WAG flooding, its law turns to be opposite if the reservoir is non -declined. The declined reservoir by WAG flooding under the condition of lower reservoir pressure may also obtain better effect by controlling injection rate. Besides, injection rate and gas-water ratio on the declined and non-declined reservoirs obeys different laws and both existing optimal values.