应用常规的油藏工程方法进行低渗透油藏动态预测普遍存在较大的误差。对此,在考虑启动压力梯度、应力敏感性及牛顿流体微压缩性的基础上,运用复变函数理论,建立了低渗油藏垂直裂缝井的产能模型,应用解析方法对模型进行求解。结合低渗透某井区的开发参数,对影响油井的产能因素进行参数敏感性分析,绘制了不同参数下油井的产能曲线。提出该模型可用来评价低渗油藏油井产能以及进行产能预测。分析认为低渗油藏渗透率低,压力传播速度较慢,宜采用小距离井网系统;在开采过程中地层压力下降较快时,应采用超前注水来保持地层压力。

Currently, conventional reservoir engineering methods for dynamic analysis and low permeable reservoir performance forecast are often inaccurate, especially they are not suitable for oil well productivity forecast. Aiming at this problem, taking threshold pressure gradient, reservoir stress-sensitivity, micro-compressibility of Newton fluid, and pressure dependent viscosity into consideration, a nonlinear radial stable flow model for low permeable reservoir has been built by using the complex function theory; an analytical solution method is adopted for the solution. Combining with the concrete parameters collected from the certain well area in Changqing low permeable oilfield, all parameters' sensitivity on production performance in the productivity equation have been analyzed and the deliverability curves with different parameters have also been drawn. At last, the superiority, adaptability, and feasibility for evaluating productivity and forecasting oil productivity of the model are also discussed in comparison with a linear flow model. As a result, low permeable reservoir should be developed with a short pattern system due to its low permeability and low pressure transmitting speed. When formation pressure drops rapidly, advanced water injection should be adopted to remain formation pressure.