低渗气田井筒连续携液规律研究

目前,国内许多低渗透气田已进入低压、低产生产阶段,许多气井因积液而危害其正常生产,正确判断气井井底积液是有效开发此类气田的前提.针对低压、低产的特点,以李闽模型为基础,敏感性分析了井口压力、温度对气井井口临界携液流量的影响；同时,考虑到气井压力、温度是沿井深变化的,计算了不同井深对应的临界流量,最终通过实例井验证了该方法的正确性,得出如下认识:在预测气井临界携液流量时,对于低压气井,应先求出沿井深的压力和温度分布,再求解出沿井深的所有临界流量,最终以最大值为准.不考虑临界流量沿井深的变化会造成积液预测误差大.井口压力的降低或井口温度的增加均会降低气井临界携液流量,有利于气井携液；同时,高压气井临界携液流量易出现在井口,而低压气井临界携液流量易出现在井底.

Study on Law of Wellbore Continuous Liquid Carrying in Low Permeability Gas Field

At present,many domestic low-permeability gas fields have been at low pressure and low production stage.Wellbore liquid loading affects normal production in many gas wells.How to judge the wellbore liquid of the gas wells correctly is the premise that this kind of gas field can be developed effectively.Aiming at the characters of low pressure and low production,sensitivity analysis is made to confirm how the wellhead pressure and temperature impact on critical liquid carrying flow rate base on Lin Min model.Meanwhile,considering that the pressure and temperature of gas wells vary with well depth,the corresponding critical flow rate under different well depth are calculated.Finally,the case proved the validity of the proposed method.The following conclusions are drawn:when critical liquid carrying flow rate is predicted for low pressure gas wells,pressure and temperature distribution varies with well depth should be known first,and then all critical flow rate should be known,and the maximum value should be regarded as the accurate value.Wellbore liquid prediction error will be great without considering that the critical liquid carrying flow rate varies with wells depth.Drop of the wellhead pressure or rise of wellhead temperature will reduce the critical liquid carrying flow rate of the gas wells.It will conducive to carrying liquid of the gas wells.At the same time,the critical liquid carrying flow rate easily appears in the wellhead of the high-pressure gas wells,while it easily appears in the bottom of the low-pressure gas wells.