大产液量水平气井不同气举方式气液两相流研究

连续气举是产水量大的水平气井重要排采措施，针对现场正举和反举的特点，为揭示气田开发过程中反举条件下油管和正举条件下油套环空内的气液两相流流动规律，分别用水和空气在套管内径为127.3mm、油管外径为73mm的油套环空和内径为60mm的油管内进行了井筒气液两相管流模拟实验，对低压积液气井气举时井筒流动规律进行了研究分析，分析了井筒中气相和液相的体积流量、注气方式等因素对井筒压降和持液率的影响。实验结果表明，在相同气、液流量条件下，反举时的持液率比正举持液率小；不同气举方式下的井筒压降随注气量的增加呈不同的变化趋势，反举时的井筒压降比同工况下正举的压降大，对于产液量较大且有一定地层能量的气井，推荐采用反举方式进行气井排水采气。

Study on gas-liquid two-phase flow in large liquid horizontal gas well with different gas lift modes

Continuous gas lift is an important drainage and production measure for horizontal gas wells with large water production. According to the characteristics of on-site normal and inverse circulation of air lift, in order to obtain the gas-liquid two-phase flow law in a circular pipe under reverse lift and the law in the annulus under forward lift, the experiments of gas-liquid two-phase pipe flow in wellbore were carried out with water and air in annular pipe with casing inner diameter of 127.3mm, tubing outer diameter of 73mm and test pipe with inner diameter of 60mm.The wellbore flow law of low-pressure effusion gas well during gas lift was studied and analyzed. The effects of gas and liquid phase volume flow and gas injection mode on wellbore pressure drop and liquid holdup were analyzed. Through comparison, it is found that under the same gas-liquid flow rate, the liquid holdup in inverse circulation of air lift is smaller than that in normal circulation of air lift; The pressure drop under different lifting modes shows an opposite trend with the increase of gas volume. The wellbore pressure drop during inverse circulation of air lift is greater than that under normal circulation of air lift under the same working condition. Therefore, for gas wells with large liquid production, the normal circulation of air lift method is recommended for drainage and gas production.