气井油管堵塞原因分析

ANALYSIS ON REASONS OF TUBING PLUGGING FOR GAS WELLS

油管作为天然气生产的必经通道,若气井生产或者修井作业时出现油管堵塞,不仅影响气井的正常生产,给修井作业也会带来一定程度的影响。文中针对川东气井近年来出现的油管堵塞现状和现场实际解堵情况,结合井下垢物分析及解堵过程中对堵塞物的推断认为,造成气井油管堵塞的主要原因是:缓蚀剂选型缺乏针对性,与现场井况适应性差,导致缓蚀剂在井下发生降解或沉淀,产生井下堵塞;钻井、完井过程中未排尽的井下脏物堵塞;井下腐蚀产物粘附在油管内壁,使油管通道变小引起堵塞以及井筒上部因气流温度下降形成水合物堵塞等。气井完井方式和管串结构的选择是否合理也是影响因素之一。

Tubing is the inevitable pass when gas exploiting. If tubing plugging happens during gas exploiting or well work-over, it will influence not only the normal production of the gas well but also the job of the well work-over. According to the cases of tubing plugging and broken down for East Sichuan gas wells in the recent years, with analysis of down-hole scales and inference from plugging objects in the process of broken down, it is suggested the main reasons to cause tubing plugging are as follows: The selected inhibitor is not suitable to real situation of the well, which leads degradation and deposition of the inhibitor and causes plugging in down-hole; The dirt objects that are not moved out completely in the process of well drilling and completion cause plugging; The objects produced by corrosion in down-hole adhere to the tubing wall to make the tubing lessening and cause plugging; And the hydrates form since the temperature of the gas flow downs in the up section of the well, which causes plugging, etc. It also is one of the effecting factors whether or not the selected style of well completion and the selected structure of tubing string are suitable.