不同阶段页岩气井返排液对脱水装置影响分析

Analysis on the influence of shale gas well flowback fluid on dehydrationunit at different production stages

川南地区中深层页岩气进入较大规模开发阶段,已建立起一套完整成熟的由山地丛式井组平台管输至脱水站处理生产集输系统。应用实验室化验方式对紫金坝区块在不同时期脱水站三甘醇溶液、TEG再生系统内不溶性杂质进行化验分析,将化验结果与三甘醇脱水系统在运行过程中的故障诊断进行对应研究。研究发现:气井返排液进入TEG再生系统是引发脱水单元产生结垢物的主要因素;不同生产阶段,三甘醇溶液含杂质成分及引发故障后果不同;气井开发采用不同的工艺,将对脱水系统产生不同的影响。研究认为:在天然气脱水系统中保持循环系统内较为纯净的三甘醇是保障天然气脱水装置正常生产的关键因素,提前采用优化处理工艺、改进生产装置、完善维护制度等方式,预防不同阶段页岩气返排液对天然气脱水装置不利影响,保障天然气脱水站正常生产。

At present,the middle-deep shale gas in south Sichuan province has entered a large-scale development stage,and a complete and mature production gathering and transportation system has been established from the mountain cluster wellhead platform to the dehydration station for processing.Laboratory analysis has been conducted for the insoluble impurities in triethylene glycol solution and TEG regeneration system of dehydration station in Zijinba block,at different production stages.The test results were compared with the fault diagnosis of Triethylene Glycol Dehydration System in operation.It is found that the back-flow fluid from gas well into TEG regeneration system is the main factor causing scaling in dehydration unit;the impurity in triethylene glycol solution is different at different production stages,and the consequences of failure is different;different processes used in gas well development will pose different effect on the dehydration system.The study considered that keeping the triethylene glycol in the circulation system in a relatively pure state in the natural gas dehydration system is the key factor to ensure the normal operation of natural gas dehydration unit.The adoption of process optimization,improvement of production equipment and enhancing maintenance system can well prevent the adverse effects of shale gas backflow on natural gas dehydration unit at different production stages and ensure the normal production of natural gas dehydration stations.