酸性天然气注入参数对管柱腐蚀的影响

Influence of injection parameters of sour natural gas on corrosion of string

王金忠 黄晓蒙 彭政德 曾德智 戚亚东2

中国石油冀东油田分公司钻采工艺研究院，河北 唐山 063004 西南石油大学油气藏地质及开发工程国家重点实验室，四川 成都 610500

Drilling and Production Technology Research Institute, Jidong Oilfield Company, PetroChina, Tangshan 063004, China State Key Laboratory of Oil ＆ Gas Reservoir Geology and Exploration, Southwest Petroleum University, Chengdu 610500, China

为研究酸性天然气注入参数对管柱腐蚀的影响规律，采用高温高压釜模拟气体注入工况，对P110，N80，3Cr三种钢材进行失重实验，测试钢材在不同注入工况下的腐蚀情况，并结合扫描电镜与能谱仪对钢材的腐蚀产物进行表征，最后对管柱的安全服役期限进行评估。研究结果表明：P110，N80，3Cr钢材的腐蚀速率大小依次递减，随着注入压力升高，钢材的腐蚀速率会显著上升；随着CO2质量分数的增加，钢材腐蚀速率先增大后减小，在 CO2质量分数为8%时达到最大值；在注气过程中，流体的流动会加剧钢材的腐蚀；计算得出苛刻工况下管柱的安全服役期限在7～8 a。研究结果明确了注入参数对管柱的腐蚀及安全服役期限的影响程度，为优化注气工艺参数和制定针对性的腐蚀防护对策提供了依据。

To study the influence of injection parameters of acid natural gas on the corrosion of pipe string and calculate the safe service life of the pipe string, this article uses high temperature and pressure autoclave to simulate acid gas injection well condition. The weight loss and uniform corrosion rates of P110, N80 and 3Cr steel were tested. Then the corrosion products of steel were characterized by SEM and EDS, Finally the safe service life of the tubing string is predicted. The results show that under the experimental conditions, the corrosion rates of P110, N80 and 3Cr steel are P110>N80>3Cr. With the increase of injection pressure, the corrosion rate of steel increases significantly. With the increase of CO2 mass content, the corrosion rate of steel increases first and then decreases, reaching the maximum at 8% CO2 mass content. Under dynamic conditions, the flow of fluid will aggravate the corrosion of steel. The safe service life of the pipe string under harsh working conditions was calculated to be between seven and eight years. The results of the study clarify the impact of injection parameters on the corrosion of the pipe column and the safety service life, which provide the basis for optimizing the gas injection process parameters and developing targeted corrosion protection countermeasures.

10.6056/dkyqt201903027