Grading evaluation of non-API OCTG quality level based on working conditions

Abstract

The non-API standard series of oil country tubular goods (OCTG) have been developed rapidly to meet the increasing demand of the oil and gas fields, while the frequent accidents of non-API OCTG still occur due to the lack of a perfect quality management system. In this paper, the main types, service conditions, and the current status of quality evaluation technology of non-API OCTG at home and abroad were introduced. For the quality problems of non-API OCTG during the domestic application, the needs of the industry development needs and continuous improvement of quality management system were taken into consideration. Based on the working conditions, the quantitative evaluation method of quality grading was built by the grading idea represented by capability maturity model integration (CMMI) based on the field working conditions. And an evaluation method, including process maturity level, items, indexes and procedures, was proposed and verified. The results showed that the average value and level of quantitative evaluation results of quality grading were 81.5 and C, respectively, which was in good accordance with the current status of non-API product management. The evaluation method is more quantitative and targeted, which would provide for the completeness of the non-API product quality management system with methodological support and theoretical reference.