达尔其油田油井摩蚀与防治措施

Analysis of Friction and Corrosion Mechanisms of Oil Well in Dahl Oil Field and Control Measures

达尔其油田达14和达33区块油井发现偏摩和腐蚀现象,腐蚀因素包括pH值、氯离子、硫酸盐还原菌和总铁含量等.实验表明,油井的平均腐蚀速率为0.1 mm/a,腐蚀产物包括钙铁氧化物Ca_4Fe_9O_(17)和碳酸盐Mg_3Ca(CO_3)_4等,对偏摩和腐蚀的相互作用机理进行了分析,发现在油井中管杆腐蚀和磨损之间相互促进,针对以上情况提出加注杀菌剂和缓蚀剂、井斜段抽油杆使用双向保护接箍等针对摩蚀的防治措施,SRB由104个/mL降至10个/mL,平均腐蚀速率也下降到0.045 mm/a,达14区块的平均检泵周期从原来的平均216 d延长到478 d,延长一倍以上。

The oil wells in the Da 14 block and Da 33 block of Daerqi Oil Field are hmnd to suffer from offset and corrosion. The corrosion factors include pH, chloride ion, sulfate reducing bacteria （SRB） and total iron content, etc. Experimental results show that the average corrosion rate of oil wells is 0.1 mm/a, and the corrosion products are calcium iron oxide Ca4FegO17 and carbonate Mg3Ca （CO3 ）4, etc. The analysis of partial friction and corrosion mechanisms of the interaction has been performed, and it is found that there is a mutual promotion between the conditions, fungicide and corrosion inhibitor have been injected oil pipe rod corrosion and wearing. In consideration of above The deviation sucker rod using a two - way proteetion connecting hoop for friction corrosion prevention has been applied. As the result, SRB has been reduced from 10^4/mL to 10 /mL, the average corrosion rate has dropped to 0. 045 mm/a, the average pump examination period of Da 14 block is extended from the original average of 216 days to 478 days, which is more than two times of the original.