基于瞬态模拟的柱塞排采工艺参数优化方法

目前气井柱塞排水采气参数设计主要采用经验计算法,对气液在井筒及地层流动状态的简化处理会导致柱塞运行周期制度不合理,限制气井产量发挥。考虑井筒气液流动状态对柱塞运动特征的动态影响,采用瞬态多相流计算方法建立柱塞动态模拟模型。针对常规柱塞优化方法采用静态IPR描述地层产能,在模型中引入近井地层动态描述功能,实现对柱塞运动特征的准确模拟;基于不同柱塞运行周期制度下累计产气量模拟结果,采用基于最小二乘法的最优化方法实现柱塞运行制度的最优化。经大庆油田现场气井试验,利用方法优化后提高日产量0.94×104 m3/d,累计产气量实际值与预测计算值的误差为9.5%。研究结果表明,通过瞬态计算模型与最优化方法相结合,能够确定合理的柱塞运行周期制度,对于提高柱塞排采工艺的应用效果具有指导意义。

Optimization method of plunger water-drainage process parameters based on transient simulation

Currently, design of parameters in the plunger water drainage and gas production in the gas well is operated by the empirical calculation method. Simplifying the flow state of gas and liquid in the well and reservoir leads to unreasonable plunger operation cycle system and restrains the production of gas wells. Considering the dynamic influence of the borehole gas-liquid flow state on movement of the plunger, the transient multiphase flow calculation method was used to establish the model of plunger dynamics. For the conventional plunger optimization method, the static IPR method was used to describe the productivity, and the near-well formation was introduced into the model. The dynamic description function was introduced to realize simulation of the characteristics of plunger movement. Based on the simulation results of cumulative gas production under different plunger operating cycle system, the least squares optimization method was used to optimize the operation system of the plunger. After verification in one gas well in Daqing Oilfield, the optimized method increases the daily production by 0.94×104 m3/d, and the calculation error of cumulative gas production is 9.5%. The research shows that a reasonable plunger operating cycle system is optimized by integrating the transient calculation model with the optimization method and provides guidance for improving the effect of plunger plunger water drainage and gas production.