克深气田“三超”气井采气树配件的研发及应用

Christmas-tree accessories and their application to"three-super"gas wells,Keshen gasfield

为了充分认识高压气井采气树阀门损坏机理、提高采气阀门使用寿命,以塔里木盆地克深气田(超高压、超深、超高温)“三超”气井采气树阀门存在的内漏和和外漏问题为研究对象,深入分析了在应对气田出砂、出水等极为复杂的生产工况下阀门失效模式;在此基础上,从阀板、阀座材质进行优化改进、硬质合金材料和喷涂工艺优选、非金属密封材料改进3个方面开展了研究。研究结果表明:(1)采用高速火焰喷涂方式,选择WC硬质合金A型作为喷涂材料,动摩擦系数最低,耐磨性更好、密封性更好;(2)选择Inconel718高温镍基合金作为阀板、阀座材质,能够进一步提高阀板、阀座强度及耐腐蚀性,可以满足极为复杂工况下气井开发需求;(3)选择在纯四氟材料里面添加石墨、玻纤等进行改性,改性后的四氟材料增加了强度,提高了密封等级,降低了摩擦系数,提升了耐磨性能。结论认为:通过上述3个方面的改进,生产制造的阀门使用寿命平均为424 d,使用寿命得到了显著提升。

In order to better understand the failure mechanism of Christmas-tree valves used in high-pressure gas wells and improve a service life of these valves,some failure modes of valves under extremely complex working conditions were analyzed,such as sand and water production,by taking the inner and outer leakage in the Christmas-tree valves in"three-super"gas wells in Keshen gasfield as an objective.Moreover,a series of researches were carried out from three aspects,i.e.,the optimization and modification of valve plate and valve seat material,the selection of hard alloy and coating process,and the modification of non-metal sealing material.Results show that(1)a high-velocity oxygen flame method is adopted and the WC hard alloy A is selected as coating material,which may minimize the dynamic friction coefficient and improve both abrasion resistance and sealing capacity;(2)the Inconel718 high-temperature nickel-base alloy is used for valve plate and valve seat,which may further improve the strength and corrosion resistance of valve plate and valve seat to satisfy the requirements of well development under extremely complex conditions;and(3)the pure tetrafluoro material is added with graphite and glass fiber for modification.The modified material has higher strength and sealing grade.The friction coefficient is reduced whereas the abrasion resistance is improved.In conclusion,the modification in these three aspects greatly prolongs the service life of valves,and the average service life is 424 d.