产水气井冲缝套动态冲蚀机理研究

Dynamic Erosion Mechanism of Punched Sleeve in Water-Producing Gas Wells

在产水气井中,冲缝筛管同时受到腐蚀和冲蚀磨损,服役寿命远远低于预期。为了解冲缝筛管在产水气井中快速失效的原因,模拟含水气井的腐蚀环境,进行了室内腐蚀试验,并建立了冲缝套的2种缺陷分布模型,模拟计算不同缺陷分布模型,以腐蚀速率为动网格速率,探究了不同缺陷深度和含水体积分数下冲缝套的冲蚀机理。研究结果表明:含水体积分数从0增加到100%,腐蚀速率从0.0115 mm/a增加到0.0399 mm/a,腐蚀坑的截面为圆形;缺陷在边缘中间区域时,最大冲蚀磨损量分布在缺陷处;缺陷在其他区域时,最大冲蚀磨损量分布在边缘四角区域的非缺陷区域;最大冲蚀磨损速率与缺陷深度、含水体积分数成正比,这种腐蚀与冲蚀的共同作用是冲缝筛管在产水气井中服役寿命大幅缩减的原因。所得结论可为延长冲缝筛管服役寿命研究提供理论参考。

In water-producing gas wells,the punched screen is subjected to both corrosion and erosion wears,making its service life much shorter than expected.In order to analyze the reasons for the rapid failure of punched screen in water-producing gas wells,a laboratory corrosion test was conducted under simulated corrosion environment of water-containing gas wells,and the distribution model of 2 flaws of punched sleeve was built and solved.Then,taking the corrosion rate as the dynamic grid rate,the erosion mechanism of punched sleeve under different flaw depths and volume fractions of water was explored.The results show that when the water cut increases from 0 to 100%,the corrosion rate increases from 0.0115 mm/a to 0.0399 mm/a,and the section of the corrosion pit is circular.When the flaw is located in the middle area of the edge,the maximum erosion wear amount is distributed at the flaw location.When the flaw is in other areas,the maximum erosion wear amount is distributed in the non-flaw areas at the four corners of the edge.The maximum erosion wear rate is directly proportional to the flaw depth and the volume fraction of water,and the combined action of corrosion and erosion is the reason for the significant reduction in service life of the punched screen in water-producing gas wells.The conclusions provide theoretical reference for improving the service life of punched screen.