考虑夹层绕流的底水油藏水平井产能预测模型

Productivity prediction model of horizontal well in bottom-water reservoir considering flow around interlayer

目前关于底水油藏水平井产能的研究较多,但大多均未考虑流体沿夹层绕流对水平井产能的影响且结果与现场实际差别较大,因此有必要进行更深入的研究。利用保角变换、势函数理论及圆周定理建立了考虑夹层平板绕流的底水驱油藏水平井流动模型,求解了水平井产能的解析解,并分析了夹层范围及夹层空间位置对水平井产能的影响。研究结果表明:无因次夹层范围越大,夹层的遮挡限流作用越强,水平井产能越小;当夹层空间位置距水平井越近,水平井产能越小,且水平井长度越长,产能下降的幅度就越大;当夹层尾部横向位置开始远离水平井时,水平井产能显著上升,当夹层完全远离水平井时,水平井产能基本保持不变。该模型较为实用且符合含夹层底水油藏中流体的实际流动情况,对含夹层底水油藏水平井的开发评价、编制科学的开发方案具有重要的理论指导意义。

There are many findings on horizontal well productivity of bottom-water reservoir nowadays, while the influence of interlayer on the productivity of horizontal well is ignored. Besides, most of the researches appears to be quite different from the actual situation on the field, so it is necessary to make an intensive study on it. In this paper, a flow model for a horizontal well in bottom-water reservoir with interlayer is established based on the conformal transformation, the potential function method and the circle theorem. The analytical solution to the productivity of horizontal well is solved. The influence of the size and the position of interlayer on the productivity of horizontal well is analyzed. The results show that the larger the dimensionless size of interlayer is, the stronger the barrier effect of the interlayer is, and the smaller the horizontal well productivity is;when the position of interlayer is closer to the horizontal well, the smaller the horizontal well productivity is, and the longer the length of horizontal well is, the sharply the productivity drop is;when the lateral position of the tail of interlayer starts to be far away from the horizontal well, the productivity of horizontal well increases significantly, and when the interlayer is completely far away from the horizontal well, the productivity of horizontal well is almost unchanged. The model is very practical and in line with the actual flow of fluid in bottom-water reservoir with interlayer. It has important theoretical guidance significance for the development evaluation of horizontal well in bottom-water reservoir with interlayer and the formulation of a scientific development plan.