Failure Control of Drill String Components: Nondestructive Inspection

Abstract

Nondestructive inspections of dnll string components play a fundamental role in reducing failures. For this reason, ENEL dedicated special attention to the inspection of material in both the manufacturing and acceptance phases. During the dnlling phase, adequate and control is the starting point for correct management. Since the inspection standards normally adopted are the ones prescribed by the API oil dnlling standards, ENEL thought it necessary, because of the particular of the material, to prepare own specifications for inspection standards and acceptance criteria. Although still satisfying the API standards, these specifications are specially tailored to geothermal drilling. This, together with other for the handling and control of drilling fluids, helped to greatly reduce the number of failures. Just in the period failures were reduced to a third. This paper the procedures adopted by ENEL to guarantee high quality and to minimize failures even in a field like where the material is constantly subjected to severe stresses.