Abstract
The importance of understanding the conditions under which a product maintains stability and acceptable physical properties was highlighted in August of 2021 when Hurricane Ida disrupted operations across many Gulf of Mexico production facilities. The genesis of the storm was poorly forecasted (Beven et al. 2022) and the forecasted intensity and path of this storm dramatically shifted in the days before landfall. Transportation logistics constraints around these uncertainties resulted in operators not having full control over the timelines of evacuation and in some cases, needing to accelerate shut-in procedures to ensure the safety of evacuating personnel.
One instance of this scenario resulted in a facility being evacuated before the crew was able to initiate umbilical maintenance flushing or depressurization of a deepwater subsea paraffin inhibitor (PI) umbilical. Damage to the facility during the storm resulted in a loss of power and hydraulic control for several months in which the product was stagnant and subjected to the seafloor temperature of 4°C and approximately 4,500 psi. A total of 160 days elapsed between the unplanned shut-in and field restart. This unfortunate situation did, however, have a silver lining.
The PI in use on the facility had been developed and qualified under a series of tests developed and implemented between 2015 and 2018 which supplemented the recommendations of API 17TR5 and API 17TR6 with the aim of more effectively screening PI chemistries for stability under edge case field conditions. Until the shut-in caused by Hurricane Ida, none of the PI products developed under this augmented methodology had been exposed to conditions and durations extreme enough to fully validate the efficacy of the changes.
This paper describes the rationale behind the modifications made to the qualification process, specific recommendations related to the evaluation of time-dependent product gelation with an HP Viscometer and evaluation of thermal cycling impacts through a more severe dynamic flow loop, as well as a description of 2 case histories related to the product instability which initiated this project and the successful field test which validated its efficacy in the real world.
