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.