减氧空气驱套管寿命校核方法与实践应用

Design Method and Application of Casing Life under Corrosion Condition of Oxygen Reducing Air Flooding

减氧空气驱油工艺可有效提升油井产量,但也加剧了井内流体对套管的腐蚀,是后续生产重大风险源之一。从套管设计问题切入,考虑磨损、腐蚀引起壁厚损失,得出老井套管剩余壁厚;开展多种套管钢材挂片腐蚀实验,给出了适用于目标油田减氧空气驱的套管寿命校核图版,对套管使用寿命进行预测。结果显示,Cr钢对减氧空气驱腐蚀有一定的抑制作用;在减氧空气驱生产工况下原井套管无法长期生产。

Oxygen reducing air displacement technology can effectively increase the oil well production,but it intensifies the corrosion of the well casing.This will cause major dangers in the subsequent production process.This paper obtained the residual casing wall thickness of old wells,under the analyzing of the casing wall thickness loss caused by casing wear and corrosion.In view of the working conditions under the coexistence of oxygen and carbon dioxide,a variety of commonly used casing steel coupon corrosion tests were carried out.According to the results,the casing life check chart suitable for the target oilfield under the condition of oxygen reducing air flooding was given.With the casing life check chart,the service life of the well casing could be predicted.The results show that Cr steel can inhibit the corrosion of deoxidized air flooding to some extent.Under the production condition of oxygen reducing air drive,the original casing cannot be produced for a long time.