Patent Document ID: 8156812
Application ID: 12379944
Patent Status: 1

Claim One:
1. A method for non-destructive inspection of defects in a surface of a pipeline or storage tank for hydrocarbon transport or storage, including the steps of: a) carrying out a first way of non-destructive inspection of a first part of the surface by moving a first inspection tool along the first part of the surface for determining a first defect pattern that includes dimensions and positions of defects in the first part of the surface; b) carrying out a second way of non-destructive inspection of a second part of the surface by moving a second inspection tool along the second part of the surface for determining a second defect pattern that includes dimensions and positions of defects in the second part of the surface, wherein a total area of the second part of the surface is smaller than a total area of the first part of the surface and the second part of the surface overlaps with the first part of the surface, and wherein a systematic error of the second way of non-destructive inspection is smaller than a systematic error of the first way of non-destructive inspection; c) identifying at least one defect of the first defect pattern and at least one defect of the second defect pattern which represent one and the same defect; d) comparing the dimensions and optionally also the positions of the identified defects in step c) which represent one and the same defect so as to obtain a difference in dimensions and optionally also in the positions measured with the first way of non-destructive inspection and the second way of non-destructive inspection respectively; e) repeating steps c) and d) so as to obtain a plurality of differences and obtaining at least one parameter representing said differences; and f) correcting the dimensions and optionally also the positions of defects of the first defect pattern by using the at least one parameter obtained in step e).