S48区块区域性井筒腐蚀评价

Corrosion evaluation of regional wellbore in block S48

S48区块气井随着产水量增大,气量下降,油管、套管长期浸泡在地层水中,油套管腐蚀严重,出现穿孔,甚至管串断脱等情况。为掌握S48区块井筒腐蚀主要因素,在开展S48区块水质分析的基础上,利用腐蚀挂片,MIT、MTT分析及灰色关联分析法研究气井井筒腐蚀的主控影响因素。结果表明:(1)S48区块水质为氯化钙(CaCl_(2))型,pH小于6,呈弱酸性;(2)气井腐蚀的影响因素由强到弱依次为日配产、CO_(2)、结垢性、缓蚀剂;(3)油管在井筒中段腐蚀严重;(4)油管中的轻烃和结垢,对腐蚀有一定的阻碍作用。

With the increasing water production and decreasing output gas trend of block S48 gas wells,problems like immersed tubing and casing under water constantly,serious corrosion,perforated condition,and even the broken string emerged out.In order to master the main factors of wellbore corrosion in S48 block,on the basis of water quality analysis of S48 block,the main mattered factors of gas well wellbore corrosion are researched by adopting corrosion coupons,MIT,MTT analysis and grey correlation analysis.And the results indicated that firstly,the water quality in block S48 is calcium chloride(CaCl_(2))type,with a pH of less than 6 which showed weakly acidic.Secondly,influencing factors of gas well corrosion are daily production,CO_(2),and scaling,corrosion inhibitor in order.Then,tubing that corroded severely was in the middle of the wellbore.Finally,the light hydrocarbons and scaling in the tubing displayed inhibitory effect on corrosion.