INSPECTION OF ANTI-CORROSION COATING AND EVALUATION OF CATHODIC PROTECTION EFFECTIVNESS FOR A SECTION OF SOUTH MAIN LINE OF GAS GATHERING SYSTEM IN JINGBIAN GAS FIELD
靖边气田集气南干线A段防腐层检测与阴极保护效果评价

For anti-corrosion of the main pipeline of gas gathering system,Jingbian a combined method of external insulation coating and cathode protection. Through gas field commonly used close-interval measuring the electrical potential for the south main pipeline, and drawing electrical potential curves, degree of the protectiveness of pipeline and the area of requested protection then were evaluated. At the same time, by mesearing the decay degree of protective current of pipeline by using the way of current attenuation,calculating the insulation resistance of anti-corrosion layer ,so that the insulation quality of the coating was evaluoted, as well as any leakage of the insulation layer was found out by leak-check apparatus which was finally restored. Moreover, though mesearing the soil resistance, the corrosivity of soil was also evaluated which would offer a reference to decision-making and production management of the gas field.