水驱油藏开发后期经济井网密度计算的改进方法

井网加密调整是水驱油藏开发后期提高采收率的一项重要手段。通过计算确定合理的井网密度,既能提高油藏最终采收率,又能提升经济效益,对水驱油藏后期开发具有重要的现实意义。对水驱油藏开发后期经济的计算方法做出了改进。首先,采用加密调整后油藏最终采收率与加密调整前采出程度之差计算新增可采储量;然后,利用产量递减规律预测油藏井网加密后未来生产年限中的产油量;最后,在充分考虑储层物性、原油物性、注采井数比以及经济因素的基础上,根据净现值原理计算经济合理井网密度与经济极限井网密度。实例计算与对比分析表明,改进方法计算结果可靠,更符合水驱油藏开发后期的客观实际,对油藏开发后期合理井网密度的确定及井网调整具有重要的指导意义。

Modified Method to Calculate Economic Well Spacing Density in Development Late Stage of Water-Flooding Reservoir

Well pattern infilling is an important method to enhance oil recovery in the late stage of water-drive reservoir. By calculating the appropriate well spacing density, it can not only enhance ultimate recovery, but also promote economic efficiency. Therefore, it has practical significance for water-flooding reservoir in late development phase. In this paper, the calculation method of economy well spacing density in the late stage of water-flooding reservoir has been improved. Firstly, the recoverable reserves are calculated by the difference between ultimate recovery and recovery percent. Then, the oil production in the future life after well pattern infilling is predicted by the law of production decline. Finally, based on the full consideration of reservoir physical property, fluid physical property, injector producer ratio and economic factors, the economy rational well spacing density and the ultimate well spacing density is calculated by the NPV principle. The calculation and comparative analysis shows that this method is reliable and more suitable for the well pattern infilling in development late stage of water-flooding reservoir. And it has strong guiding significance for the determination of reasonable well pattern density and well pattern infilling in the late stage of oilfield development.