复杂环境下CO_2驱低成本防腐技术研究

Research on the Low Cost Anticorrosion Technology of CO_2 Flooding under Complex Environment

吉林大情字油田CO_2驱受CO_2含量、压力、温度、含水以及细菌含量等因素的影响,矿场工况变化复杂,各系统不同腐蚀区间严重影响了CO_2驱的安全生产。为了实现对CO_2驱高效防腐,开展了室内实验研究和评价工作。结果表明:在单一存在SRB时系统腐蚀速率较低;当CO_2、SRB共存时,二者的协同作用加剧了各系统腐蚀程度。根据腐蚀主控因素研发了CO_2缓蚀体系,它具有较好的防腐性能与扩散性能;通过临界防腐浓度与原油吸附性能评价,确定矿场加药质量浓度应在80~150 mg/L之间。结合矿场工况,优选了连续加药工艺,确定了不同工况下的加药时机和加药浓度,形成了合理的加药制度,提高了药剂的利用率。矿场整体腐蚀速率低于0.076 mm/a,实现了低成本防腐和安全生产。

The CO2 flooding in Jilin Daqingzi Oilfield is affected by many factors such as CO2 content,pressure,temperature,water cut and bacterial content,and the change of the field working condition is complicated.The problem that each system is in the different corrosion interval seriously affects the safety production of CO2 flooding.In order to achieve the efficient anticorrosion of CO2 flooding,laboratory experiment study and evaluation are carried out.Results show that the system corrosion rate is lower when the SRB exists solely,and when CO2 and SRB coexist,the synergistic effect of the two increases the corrosion degree of each system.According to the main control factors of corrosion,the corrosion inhibition system of CO2 has been developed,which has good corrosion resistance and diffusion properties.By evaluating the critical anticorrosion concentration and the adsorption performance of crude oil,the dosing concentration of the field should be between 80 to 150 mg/L.Combining the working condition of the field,the continuous dosing process is selected,the dosing timing and concentration under different working conditions are determined,a reasonable dosing system is formed,and the utilization rate of the medicament is improved.The overall corrosion rate of the field is lower than 0.076 mm/a,thus achieving low cost anticorrosion and safe production.