Petroleum wellhead burning: A review of the basic science for burn efficiency prediction

摘要

While wellhead burning has been a hazard for generations, the development of reliable, safe capping practices suggests that wellhead burning can be used as an oil spill mitigation tool. But, there are technical issues that need consideration during spill management planning before intentional wellhead ignition is applied as an standard spill response tactic. This review provides an abbreviated historical perspective of recent work, the practical implications of current policy, and then topically examines the maturity of the fundamental science underlying wellhead ignition and burning that scientists, engineers, and policy makers should consider. To anchor to this work to reality, a wellhead blowout scenario is examined over a range of flow rates. The regimes of two-phase pipe flows, their dependence on wellbore velocities and gas-liquid ratios, and how those regimes might influence the burn efficiency, with particular focus on annular flows, are also examined. The current state of the basic research topics underlying wellbore flow, wellhead ejection, and two-phase fuel plume combustion that remain to be fully explored to accurately predict discharge and burn behavior are then examined and discussed. Among the critical findings presented is that the worst-case discharge flow rate cannot be assumed the worst-case spill scenario. An examination of burn efficiency analyses reveals that there is no body of experimental measurements upon which they are based and validated. It was also found that these oft-cited analyses assume the oil is fully entrained, which is the most ideal, instead of considering other possible two-phase flow regimes.