Baker & O'Brien, Inc.

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High Pipeline Pressure Forces Outage – Who’s to Blame?

North America

April 1, 2018

The capacity of a pipeline is ultimately limited by its maximum allowable operating pressure (MAOP).  The operator of an NGL transmission pipeline, which was fed by a number of different gas plants (NGL producers) with different injection points along the pipeline, experienced flow limitations due to indications that the pipeline was operating close to its MAOP.  In addition, it was observed that some of the filters on the pipeline were being clogged by a residue comprised of rust and an organic material.  Therefore, the pipeline was shut down for cleaning.  

The initial laboratory reports of the material deposited in the filters identified a certain amine, commonly used in gas plants to remove carbon dioxide and hydrogen sulfide from NGLs.  The pipeline operator identified one of the NGL producers as the source of the amine and initiated a process of assigning liability for the clogged filters, unrecovered costs, and lost profits.  The NGL producer contested the liability because the filter residue results did not point to a single contaminant, and the pipeline was operating at maximum flowrate in some segments that were upstream of its entry point.  The NGL producer asserted that the very high 

pressure drops in certain segments of the pipeline could have caused the removal of deposits from the pipe wall which, over time, accumulated in the downstream filters.

Baker & O’Brien was engaged to review and analyze the available pipeline pressure profiles, laboratory analyses and operation records, and opine on whether the pipeline contamination was caused solely by the NGL producer, or whether there were other possible sources of contamination.  We reviewed all relevant documentation concerning:  1) pipeline ingress points; 2) pipeline segment pressure drops and operating pressures; and 3) specific sample timings and locations to determine the probable causes of the flow limitations.