普光气田集输系统的腐蚀控制技术

摘要

The gathering and transferring system in Puguang gas-field includes a central gas gathering station and 16 substations covering 38 gas wells and 37.78 km pipelines. The content of hydrogen sulfide in the natural gas is nearly 15%and carbon dioxide from 8% to 10%, so the wet high-sour gas makes great corrosion risk to transferring system. Based on tests of electrochemical corrosion, hydrogen-induced cracking （HIC）, sulphide stress cracking （SSC）, the materials of anti-sulphide~eorrosion were studied and selected for pipelines and equipment. And injection technique of corrosion inhibitors is used to prevent the pipes from internal corrosion ＂pre-coating ＆continuous injecting＂. Also, cathodic protection and intelligent pigging detection are applied as well. Furthermore, corrosion monitoring techniques including corrosion coupon （CC）, electro-resistance （ER）, linear polarization resistance （LPR） and field signature method （FSM） are introduced to monitor the corrosion development roundly. The monitoring results show that the average corrosion rate of Puguang gathering and transferring system is limited below 0. 044 ram/a.%普光气田集输系统共建有16座集气站、1座集气总站、38口开发井，站外管线37．78km。由于天然气中硫化氢含量15％左右，二氧化碳含量8％～10％，且采用湿气集输工艺，因此集输系统存在较大腐蚀风险。通过电化学腐蚀试验、抗氢致开裂（HIC）和抗硫化物应力腐蚀（SSC）试验，确定了集输系统抗硫材质，采用“预涂膜＋连续注入”的缓蚀剂加注工艺、阴极保护技术和智能清管技术等对设备实施保护。采用腐蚀挂片、电阻探针、线性极化探针和电指纹等多种腐蚀陈测手段。普光气田集输系统腐蚀速率控制在0．044mm／a以下。