介质流态对凝析气集输管道的腐蚀影响分析

Analysis on Corrosion Effect of Medium Flow Pattern on Condensate Gas Gathering and Transportation Pipeline

凝析气田集输管道内介质为气液两相流,气液比较大,流体流型复杂,不同流态对管道弯管和水平管道产生不同的腐蚀机制,其中冲击流对腐蚀的影响最大,雅克拉、大涝坝凝析气田集输管道内介质流态主要为冲击流和分层流,对于冲击流,由于冲刷腐蚀、空泡腐蚀、流体促进腐蚀作用,弯管、管道底部等腐蚀严重,主要呈整体均匀减薄、蜂窝状、沟槽状腐蚀形貌,对于分层流,由于地层水分离沉积,在管道底部、油水分离界面腐蚀严重,呈溃疡状、台地状及烧杯口状腐蚀形貌。针对雅克拉、大涝坝凝析气田流态特征、腐蚀特征,对介质流态对集输管道的腐蚀影响进行了初步分析。

Medium in condensate gas field gathering and transportation pipeline is gas/liquid two-phase fluid,with relatively large gas/liquid ratio,complex fluid flow patterns,and different flow patterns have different mechanism of corrosion on elbows and horizontal pipelines,in which impact fluid has the greatest corrosion on the elbows and pipelines. Flow patterns of medium in gathering and transportation pipelines of Yakla and Dalaoba condensate gas field are impact fluid and stratified fluid mainly. Due to erosion corrosion,cavitation corrosion and fluid acceleration corrosion,impact fluid has serious corrosion effect on bottoms of elbows and pipelines,with overall uniform thinning,honeycomb-like,groove-like corrosion features. Due to stratum water separation and sediment,stratified flow has serious corrosion effect on pipeline bottoms and oil/water separation interface,with ulcer-like,mesa-like and the beaker mouth shape corrosion features. In connection with flow pattern and corrosion features of Yakla and Dalaoba condensate gas field,analyzed briefly is the corrosion effect of medium flow pattern on condensate gas gathering and transportation pipelines.