水平气井全井筒携液模拟试验研究

目前有关水平井临界携液的诸多预测模型均需要满足环雾流条件,这些模型所得到的携液流速却未达到环雾流条件,或与正常生产的气井井筒流态相矛盾,同时未考虑水平井的全井筒井深结构变化对井筒流态及携液的影响。为此,开展了水平井全井筒可视化携液模拟试验,并基于试验测试数据,结合Kelvin-Helmholtz(K-H)不稳定气液两相流理论,建立了K-H波动理论修正携液模型。研究结果表明:水平井携液困难主要在倾斜管段,倾斜管段是水平井积液的起始位置,但不应单纯地看某一段有、无液体回落,应按全井筒液量有、无增加与各段液体回落程度来综合判断积液起始;K-H波动理论修正模型预测结果与测试结果很接近,平均绝对误差小于9%;利用K-H波动理论修正模型对海上11口(13井次)气井进行了全井筒携液预测诊断,诊断结论与实际生产情况吻合。所得结果有助于水平井临界携液流速的判断。

Simulation Experiment of Liquid Carrying in Whole Wellbore of Horizontal Gas Well

At present,many prediction models for critical liquid carrying in horizontal wells need to meet the annular fog flow condition,but the liquid carrying velocity obtained by these models does not meet the annular fog flow condition,or is inconsistent with the wellbore flow pattern of normal production gas wells;meanwhile,these models do not consider the influence of the change of whole wellbore structure of horizontal wells on the wellbore flow pattern and the liquid carrying.Therefore,the whole wellbore visualization liquid carrying simulation test of horizontal well was carried out,based on the test data and the Kelvin-Helmholtz(K-H)transient gas-liquid two-phase flow theory,the K-H wave theoretical corrected liquid carrying model was built.The study results show that the difficulty of carrying liquid in horizontal wells is mainly in the inclined pipe section,which is the initial position of liquid accumulation in horizontal wells;however,the liquid accumulation initiation should be judged by the increase of liquid volume in the whole wellbore and the liquid fallback degree of the sections,and not simply by the liquid fallback of a section;the prediction results of the K-H wave theoretical corrected model are very close to the test results,and the average absolute error is less than 9%;the K-H wave theoretical corrected model is used to conduct prediction diagnose on the whole wellbore liquid carrying of 11 offshore gas wells(13 times),and the diagnosis results are consistent with the actual production status.The study results are helpful to judge the critical liquid carrying velocity of horizontal wells.