Wettability of Petroleum Pipelines: Influence of Crude Oil and Pipeline Material in Relation to Hydrate Deposition

Pipeline plugging by gas hydrates causes problems during petroleum production. In the present work, various solid surfaces and crude oils have been used to study the effect of material and crude oil composition on the wettability of pipeline-mimicking surfaces. The subsequent effect on deposition of hydrates to the pipeline wall is discussed. The results show that both the pipeline wall material and crude oil composition influence the wettability of the system. The surfaces with the lowest surface free energy represent the most oil-wet systems, with the lowest adhesion energy between water and the solid surface in crude oil. To study the influence of crude oil composition on wettability, several compositional parameters have been combined using multivariate data analysis. Nonplugging oils, suggested to create oil-wet hydrates, also create oil-wet solid surfaces, indicating that the same components influence both the hydrate and pipeline surface. The compositional feature most significantly indicating nonplugging properties is a high content of acids compared to bases.