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    三种防腐蚀抽油杆在CO2驱采条件下的腐蚀评价与优选

    Material Selection and Corrosion Evaluation of Three Corrosion-resistant Sucker Rods under CO2 Flooding Condition

    • 摘要: 利用高温高压动态循环腐蚀试验,研究了KH型、聚乙烯包覆型和镀钨型3种防腐蚀抽油杆材料在60℃,含20%~80% CO2,19 MPa CO2驱采出井环境中的腐蚀行为。利用电子万能试验机进行了三种抽油杆的力学性能评价。结果表明:在试验环境中,KH型抽油杆腐蚀严重,其最小腐蚀速率也高于行业标准;镀钨型抽油杆受到轻微CO2腐蚀;聚乙烯包覆型抽油杆腐蚀后的质量无减小,可视为没有腐蚀发生。三种抽油杆材料在CO2腐蚀环境中的腐蚀速率由小到大为:聚乙烯包覆型 < 镀钨型 < KH型。三种抽油杆在含CO2原油中浸泡后,KH型抽油杆的力学性能较未浸泡的大幅下降,聚乙烯包覆型抽油杆的力学强度降低较小,镀钨型抽油杆试样的力学性能最佳,建议采用镀钨型抽油杆作为CO2驱采出井井下防腐蚀抽油杆。

       

      Abstract: High-temperature and high-pressure dynamic cyclic corrosion test was used to study the corrosion behavior of three types (KH-type, polyethylene-coated type and tungsten-plated type) of anti-corrosion sucker rod materials in flooding well environment at 60℃, containing 20%~80% CO2, and 19 MPa. Mechanical properties of the three sucker rods were evaluated using an electronic universal testing machine. The results show that in the test environment, KH sucker rod was corroded severely and its minimum corrosion rate was also higher than that of the industry standard, tungsten-plated sucker rod was slightly corroded by CO2, and polyethylene-coated sucker rod had no mass loss after corrosion and it could be regarded as no corrosion. The corrosion rate of the three sucker rod materials in the CO2 corrosive environment from small to large was as follows:polyethylene-coated type < tungsten-plated type < KH type. After the three sucker rods were immersed in crude oil containing CO2, the mechanical properties of KH sucker rod dropped significantly compared with those without immersion. The decrease in mechanical strength of the polyethylene-coated sucker rod was small. The mechanical properties of tungsten-plated sucker rod samples were the best. It is recommended to use tungsten-plated sucker rod as an anti-corrosion sucker rod for CO2 flooding wells.

       

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