附加流速法压井的模拟计算

Simulated calculation of well killing by additional flow rate method

附加流速法是一种新的有效的深水压井方法。针对深水井控的特点,建立了附加流速法压井过程中的多相流控制方程,并给出了方程的求解方法。模拟计算结果表明:在一定的循环流量范围内使用附加流速法压井,能减小节流管线的摩阻,使节流压力升高,井口回压和井底的钻井液当量循环密度降低,使压井过程更安全;但是随着循环流量和附加流量比的提高,附加流速法会逐渐失去其优越性;在使用该方法压井前,应该通过模拟计算,选择合适的循环流量和附加流量比,以保证压井工作的顺利完成。

Additional flow rate method is a new effective well killing method in deep water. Based on the characteristics of deep water well control, multi-phase flowing control equations of well killing progress for additional flow rate method were established, and the solution method was given. The simulation results show that when the additional flow rate method is used in certain circulation rate, the choke line friction, well head back pressure and drilling fluid equivalent circulating density of well bottom pressure decrease and choke line pressure increases. But the method is not suitable with the circulation rate and additional flow rate ratio increasing. Therefore, the suitable circulation rate and additional flow rate ratio should be chosen by simulated calculation before using the method in order to accomplish well killing successfully.