超深高压含硫气井油管H_(2)S/CO_(2)腐蚀规律研究

Research on H_(2)S/CO_(2) Corrosion Law of Tubing in Ultra-Deep High Pressure Sour Gas Well

ST8井是一口超深高压含硫气井,该井的油管在高温、高压及H_(2)S/CO_(2)并存的恶劣环境下,极易发生腐蚀,严重威胁生产安全。因此有必要对油管在井下高温高压环境中的CO_(2)/H_(2)S腐蚀速率进行评价。本文根据ST8井的生产工况,利用fluent对ST8井全井段油管流场开展了数值仿真,以仿真结果为依据,设计并开展了BG110SS材质动态腐蚀挂片实验。基于动态腐蚀挂片实验的结果,评价了ST8井的油管腐蚀情况。结果表明,使用BG110SS油管的ST8井全井筒的腐蚀速率在0.4mm/a~2mm/a之间,远高于油田标准的0.076mm/a,腐蚀极为严重,难以保障长期安全生产。该研究成果对保障ST8井的安全稳定生产具有积极意义。

Well ST8 is an ultra-deep and high-pressure sour gas well.The tubing of this well is prone to corrosion under the harsh environment of high temperature,high pressure and H_(2)S/CO_(2) coexistence,which seriously threatens production safety.Therefore,it is necessary to evaluate the CO_(2)/H_(2)S corrosion rate of tubing in a downhole high temperature and high pressure environment.According to the production conditions of Well ST8,this paper uses fluent to carry out a numerical simulation of the tubing flow field of the entire section of Well Shuangtan 8.Based on the simulation results,a dynamic corrosion coupon experiment of BG110SS material is designed and carried out.Based on the results of the dynamic corrosion coupon experiment,the corrosion of the tubing in Well ST8 was evaluated.The results show that the corrosion rate of the ST8 wellbore using BG110SS tubing is between 0.4mm/a~2mm/a,which is much higher than the oilfield standard of 0.076mm/a.The corrosion is extremely serious and it is difficult to ensure long-term safe production.The research results have positive significance for ensuring the safe and stable production of ST8 well.