P110SS抗硫套管在高含硫气井环空保护液中的整体性能研究

Overall performance study on P110SS sulfur-resistant casing in the high sulfide gas well annulus protection fluid

关键词:  P110SS钢  环空保护液  高含H₂S/CO₂  抗挤强度  管体屈服强度  抗内压强度

Key words:  P110SS sulfur-resistant casing  annulus protection fluid  hyperbaric H₂S/CO₂ environment  collapse strength  pipe body yield strength  internal pressure strength

摘要:

利用高温高压反应釜模拟普光气田的气井油套环空工况环境,研究了抗硫套管钢P110SS在环空保护液中的腐蚀规律和与镍基合金电偶腐蚀规律,并对P110SS抗硫套管的整体性能(抗挤强度、管体屈服强度和抗内压强度)进行了计算分析研究。结果 表明,在无H₂S/CO₂条件下,环空保护液对P110SS保护效果非常好,电偶加速P110SS腐蚀的效果不显著；P110SS抗硫套管的抗挤毁强度、管体屈服强度、抗内压强度下降很小。在p(H₂S)为 5.0 MPa、p(CO₂ )为3.0 MPa的条件下,环空保护液保护效果不好,P110SS腐蚀严重,腐蚀速率呈百倍增长,电偶加速P110SS腐蚀的效果显著；P110SS抗硫套管的抗挤毁强度、管体屈服强度、抗内压强度下降严重。

Abstract:

The behaviors of corrosion and galvanic nickel based alloy couple of sulfur-resistant casing P110SS in the high sulfide gas well annulus protection fluid were studied. This study was conducted in a high temperature/pressure reactor which simulated the operating environment of oil ring annulus in Puguang Gas Field well. In addition, P110SS sulfur-resistant casing overall performance such as collapse strength, pipe body yield strength and internal pressure strength was also analyzed. Without the presence of hyperbaric H₂S/CO₂, the annulus protection fluid protected the casing excellently and the galvanic accelerated couple corrosion on P110SS casing was not significant. Thus, the collapse strength, pipe body yield strength and internal pressure strength of P110SS casing were reduced slightly. However, in the hyperbaric environment of H₂S 5.0MPa , CO₂ 3.0MPa, the annulus protection fluid did not protect the casing properly and the corrosion rate was increased by around 100 times. Additionally, the galvanic accelerated couple corrosion on P110SS casing was significant. As a consequence, the performance of P110SS casing including the collapse strength, pipe body yield strength and internal pressure strength was decreased considerably.