煤层气排采过程油管腐蚀机理浅谈

赵金 张遂安 涂乙

(中国石油大学(北京)煤层气研究中心，北京 102249)

煤层气排采过程油管腐蚀机理浅谈

赵金 张遂安 涂乙

(中国石油大学(北京)煤层气研究中心，北京 102249)

本文主要对煤层气前期排水阶段，中期气水同产阶段，后期的单相产气阶段，油管的腐蚀机理进行研究，并结合实际开采过程对SX107井组的油管腐蚀进行分析。研究结果表明:在煤层气的开采初期的排水过程中，油管的腐蚀主要是由吸氧腐蚀，析氢腐蚀，以及地层水所含的各种离子引起的;中期的排水产气阶段，油管的腐蚀主要是由产出的各种酸性气体以及地层水共同作用所造成的;后期的单相产气阶段，油管的腐蚀主要是由酸性气体所造成的;SX107井组的油管腐蚀主要是吸氧腐蚀造成的，腐蚀产物主要是红褐色Fe2O3。

煤层气 油管腐蚀 析氢腐蚀 吸氧腐蚀

Abstract:The paper mainly deals with corrosion mechanism of oil pipe in the early stage of dewatering，in the middle stage of co-production of water and gas，and in the later stage of single phase gas production．The paper analyzes and investigates the oil pipe corrosion of SX107 pilot well in practical extraction process．The results of the research indicate that corrosion of oil pipe is mainly due to absorption of oxygen，segregation of hydrogen and caused by all kinds of ions borne by ground water in the dewatering process in initial CBM extraction stage;that oil pipe corrosion is mainly due to common effect of various sour gases produced and the ground water in the middle stage of dewatering and production process;that oil pipe corrosion is mainly due to sour gases in the later stage of single phase gas production．Corrosion of oil pipe for SX107 pilot well is mainly resulted from adsorption of oxygen．The product of corrosion is mainly reddish brown Fe2O3．

Keywords:CBM;tubing corrosion;hydrogen evolution corrosion;oxygen corrosion

煤层气的开采过程中，随着煤层水和气体的产出，油管会产生腐蚀。油管腐蚀对煤层气井后期的作业以及排采会带来诸多不便，甚至导致油管直接报废，给煤层气生产带来巨大的经济损失。目前常规油气井油管腐蚀的报道已有不少，关于煤层气井的油管腐蚀研究还不多。由于煤层气井独特的开采方式，所以各个开采阶段油管的腐蚀机理也不尽相同。本文分析了煤层气的排水阶段，气水同产阶段，单相气体阶段油管腐蚀的机理，并结合实际情况对SX107井组油管的腐蚀进行分析。

1 煤层气井油管腐蚀机理

由于排采阶段，地层的产出物不同，油管的腐蚀原因也不同。……