Reducing Pipeline Maintenance Costs, Time, and Resources Through Nonintrusive Diagnostics

Abstract

Maintaining pipelines in optimum condition is a costly and time-consuming process for operators, which requires many resources. To help ensure an asset remains in a good operational state, it is necessary to understand its condition to allow it to be maintained in an efficient and cost-effective manner. Current methods for deposit assessment are limited to intrusive methods, theoretical modeling, or external measurement. This paper details a compressive solution to these challenges using pressure wave analysis. The method is based on analyzing the signal response generated by a pressure wave transiting the system as it is affected by geometrical changes in the system. By capturing high resolution pressure measurement on an ultrahigh speed logger, the generated pressure wave can be recorded for analysis. Applying acoustic velocity gradient modeling in conjunction with the effect of the of the system and the fluid parameters, the profile of the internal bore of the system can be accurately determined without the use of intrusive or localized external tools. Detailed is how the theory behind the method is confirmed by results observed when used during a controlled full-scale field-trial environment in addition to subsequent activities to survey system profiles. A case study is presented, demonstrating that the method allows operators to make decisive asset performance decisions and review deposit buildup in a safe and cost-effective manner without having to stop production. The theoretical method for calculation of acoustic velocity for known system and fluid parameters is shown to be accurate within tolerances compared to the acoustic velocity gained in the field by recording the time of flight between two known points. It is demonstrated that restrictions can be detected to a level of accuracy of plus or minus three millimeters of thickness, verified by comparison with other inspection methods. The described is a unique method for determining the internal profile of systems, which can offer significant advantages from traditional bore determination methods. It can provide information in a repeatable and verified level of accuracy without the requirement for expensive and time consuming intrusive intervention, this allows operators the opportunity to target remediation work in the most efficient and cost effective manner, therefore maximizing production uptime and throughput.