内腐蚀是陇东地区套管腐蚀穿孔的主要因素

INTERNAL CORROSION—A MAIN FACTOR CAUSING CORROSION AND PERFORATION OF CASING IN EAST GANSU REGION

长庆油田陇东油区套管腐蚀的严重程度在国内是知名的，曾作过不少的研究工作，其主要结论是洛河水引起的外腐蚀穿孔，为此提出的措施是封固洛河水层，采用阳极保护等。近两年来，通过对１９９０ 年以来完井的套管腐蚀穿孔井的穿孔段、腐蚀段的层位、固井质量、穿孔段与动液面的关系，以及现场井下挂片试验等八个方面的分析与研究表明，在水泥已全封固以及油井进入中后开发期的情况下，套管内腐蚀已成为陇东油区套管腐蚀穿孔的主要因素。这一结论是该区套管腐蚀研究工作的一次认识上的突破，并为这一区域采取防腐新措施提供了理论依据。

The severity of casing corrosion in Longdong (East Gansu) oil area of Changqing oil field is widely known at home.More research works have been done and the main conclusion is the perforation by external corrosion caused by the water of Luohe river.The measures proposed are to seal up the water layer of Luohe river and to adopt anodic protection.Through the analysis and study of the casing perforated interval,horizons of casing corroded interval,cementing quality,relation between casing perforated interval and producing fluid level as well as downhole coupon test,etc.,for the wells in which casings have been corroded and perforated and which have been completed in the past two years,it is shown that,on condition that the cement has fully set and the oil wells have entered the middle late development period,the internal corrosion of casing is the main factor causing casing to be corroded and perforated in Longdong oil area.This conclusion is a breakthrough in the research on casing corrosion in this area and furnishes a theoretical basis for adopting new anti corrosion measures in this area.