川南页岩气地面流程测试管线刺漏原因及机理分析  

Cause and Mechanism Analysis of Spillage of Shale Gas Ground Flow Testing Pipelines in Southern Sichuan

作　　者：徐军 李世勇[1,2] 陈世波 XU Jun;LI Shiyong;CHEN Shibo(CCDC Drilling&Production Technology Research Institute,Xi’an,Shaanxi 710018,China;National Engineering Laboratory of Low Permeability Oil and Gas Field Exploration and Development,Xi`an,Shaanxi 710018,China;CCDC Chongqing Downhole Technology Co.,Xi’an,Shaanxi 710018,China)

机构地区：[1]中国石油川庆钻探工程有限公司钻采工程技术研究院 [2]低渗透油气田勘探开发国家工程实验室 [3]中国石油川庆钻探工程有限公司长庆井下技术作业公司

出　　处：《钻采工艺》2021年第6期83-87,共5页Drilling & Production Technology

基　　金：川庆钻探工程有限公司项目“川庆风险合作区油气集输管道缺陷检测与修复技术研究”(编号:CQ2020B-47-6-Z2)。

摘　　要：川南页岩气自营区块地面流程测试管线近3年发生22起刺漏事件。刺漏主要发生在分离器配管,刺漏部位集中在弯头和焊缝处。频繁的刺漏事故,严重影响了页岩气的正常生产。文章通过室内失效分析,利用金相显微镜、扫描电镜等设备,从宏观形貌、微观形貌、化学成分、显微组织、腐蚀产物以及流体流态等方面对不同部位刺漏原因及机理进行分析。结果表明,分离器配管弯头发生流体冲刷腐蚀失效是由于弯头处结构的特殊性,多相流介质经过后流速、液相分布、压力都发生改变,腐蚀程度加剧;而焊缝发生沟槽腐蚀失效,是由于焊缝化学成分与母材差异大,组织不均匀,导致其具有较低的腐蚀电位,耐蚀性降低,优先发生腐蚀。同时管内输送介质中含有硫酸盐还原菌和二氧化碳,则加速了弯头和焊缝的失效。In recent 3 years,there have been many leaking incidents(22cases)in the ground flow testing pipelines of a shale gas self-run block in southern Sichuan.The leakage were mainly concentrated on the pipe elbows and welds of the separator piping.Frequent leakage accidents have seriously affected the normal production of shale gas.In this paper,through failure analysis,using metallographic microscope,scanning electron microscope and other equipment,the reason and mechanism of leak were analyzed from the macro morphology,micro morphology,chemical composition,microstructure,corrosion products and fluid flow pattern.The results showed that the separator piping elbow failure was erosion failure.Due to the particularity of the structure at the elbow,the velocity,liquid distribution and pressure of the multiphase flow medium changed after the elbow,so the corrosion degree was intensified.Groove corrosion failure occurred in weld.The chemical composition of the weld was quite different from the base metal,and the structure was uneven,which caused lower corrosion potential,corrosion resistance reduced and preferential corrosion.The conveying medium in the pipeline contains SRB and CO_(2),which also accelerated the failure of elbows and welds.

关 键 词：页岩气 测试管线 刺漏 弯头 焊缝 

分 类 号：TE983[石油与天然气工程—石油机械设备]