塔河油田集输管线绝缘法兰附近内腐蚀穿孔因素分析

Study and Analyse of Insulated Flange Corrosion Holiday of Transportation Pipeline in Tahe Oilfield

塔河油田主力油区为奥陶系碳酸盐岩溶缝洞型块状油藏,原油物性特征复杂,部分区块伴生气含有大量的H2S、CO2,地层产出水平均矿化度在20×104mg/L左右,pH值5.5～6.0,呈弱酸性,呈现出较强的腐蚀性。油气集输系统自投产以来多次出现了腐蚀穿孔,以内腐蚀为主,且大部分集中在集输管线外加电流阴极保护绝缘法兰附近,较严重地影响了油田的正常生产。为系统地了解、分析腐蚀穿孔原因,开展了集输管线绝缘法兰附近内腐蚀穿孔因素分析与研究,明确了造成腐蚀穿孔的主要原因,提出了改进措施及建议。

The main oil area of the Tahe Oilfield is the carbonate rock type oil reservior of Ordovician.The crude oil's characteristic is complicated.The associated gas contains a great deal of H2S,CO2,some oil wells have formation water and the formation water rate rises quickly.The formation water has a high mineralization rate(average about 20×104 mg/L),the pH value is low(average at 5.5-6.0),the corrosion is heavy.The pipeline leaking was obtained many times by pitting corrosion since producing,and inner corrosion is the main reason,most of them near insulated flange.This article studies the reasons of corrosion in oilfield pipeline near insulated flange,and finds the ways to solve the problems.