Markovian model for the growth of corrosion defects and its application for the control of pipeline integrity

Abstract

A Markovian model for the growth parameters of defects (length, depth, and width) based on the use of in-pipe and verification measurements has been developed. Its consistency and adequacy were verified by an independent method based on the combination of a differential equation describing the growth of defect parameters with the modeling of the initial sizes of defects by the Monte Carlo method. The developed model allows for the determination of the probability of the existence of defect parameters in a determined state at any time and the intensity of the transition from one state to another. The model provides the possibility to obtain an evaluation of the conditional probability for the breakdown of any section of the pipeline by the defect growth parameters obtained as a result of in-pipe crack detection. Based on the developed model, an algorithm for the time optimization of the subsequent inspection/repair of the pipeline was constructed. The methodology was approved on a virtual real pipeline with the use of results of in-pipe and verification measurements.