合兴场须二段气藏油管腐蚀断裂原因及对策研究

合兴场须二段气藏经开发证实为裂缝-孔隙双重介质、低孔、低渗、非均质、异常高压、高束缚水饱和度、具统一压力系统的干气型底水气藏。开发过程中，由于忽视了缓蚀措施而导致投产气井管串均发生严重腐蚀穿孔及断裂。通过腐蚀调查与分析，确定了须二段气藏气井油管腐蚀原因主要是CO₂腐蚀。同时受到介质温度、CO₂分压、水介质组成等众多因素的影响。通过模拟实验，提出了适合合兴场须二段气藏油管防腐对策首选为全井或仅在腐蚀严重管段（600～1500 m）使用耐蚀合金，其次选用QHS-1、UT-15作为缓蚀剂，或者二者联合使用。

STUDY ON REASONS OF TUBING CORROSION AND BREAKDOWN AND COUNTERMEASURES FOR GAS RESERVOIR AT SECTION XU 2 IN HEXINGCHANG AREA

It is proved by production that the gas reservoir at Section Xu 2 in Hexingchang area is a bottom-water dry gas reservoir with fracture-pore dual medium, low porosity, low permeability, heterogeneity, abnormal high pressure, high irreducible water saturation, and united pressure system. In the process of production, severe corrosion and breakdown of the tubing strings happen for the production wells since omitting the anti-corrosion measures. By investigation and analysis of corrosion, it is found that CO_2 is the main cause leading to the tubing corrosion in the gas reservoir at Section Xu 2. Meanwhile, many factors, such as the medium temperature, the CO_2 fractional pressure, water medium composition etc., influence the corrosion. With simulation tests, the countermeasures are proposed suitable for tubing corrosion in the gas reservoir at Section Xu 2. First of all it is to use corrosion-proof alloy in the whole hole or the interval (600~1500 m) where corrosion is severe. The secondary proposal is to use QHS-1 or UT-15 as corrosion inhibitor. Otherwise the first and the second proposals can be combined to use.