井下节流技术在X井区的应用研究

Application of Downhole Throttling Technology to X Well Block

气井生产过程中如果产生水合物,将严重影响气井的正常生产,井下节流技术应用能有效防止水合物的形成。针对X井区气井在开采过程中产生水合物的问题,根据井下节流机理,选择适用的井筒压力和流动温度预测数学模型,分析计算了X井区各类气井井下节流前后温度和压力的分布,采用统计热力学模型对这些井中水合物的生成情况进行了预测分析,并进一步计算了水合物生成的井深范围和节流器的下入深度范围。研究结果表明:距离井口越近,越容易生成水合物,生成位置一般在井深200 m内;X9-37、X3-41、X6-8井的节流器下入深度分别在1 500 m、1 800 m、2 000 m处,就能有效防止水合物生成,而X7-37井则需要采取两级节流才能防止水合物的生成。

For a gas well, hydrate generated severely affects a normal production. But, a technology of downhole throttling may avoid forming hydrate very effectively. Hydrate can be found in X well block and this technology has been applied to the study area.Based on mechanism of downhole throttling, some suitable wellbore pressure and flowing temperature are selected to predict a mathematics model at first; then the temperature- pressure distribution before and after downhole throttling is analyzed for different gas wells; thirdly, a statistical thermodynamic model is used to analyze hydrate forming in these wells; at last, both one scope of well depth occurring hydrate and another scope of running depth for a choke are further calculated. Results show that(1) hydrate easily generates closer to wellhead, and its forming well depth is within the limits of 200 m;(2) for X9-37, X3-41, and X6-8 wells, their running depth of chokes should be respectively at 1 500 m, 1 800 m, and 2000 m in order to prevent hydrate forming; and(3) for X7-37 well, a two- stage throttling technology should be adopted to prevent hydrate forming.