The chemical and physical structure of petroleum: effects on recovery operations

In a mixture as complex as petroleum, recovery chemistry can only be generalized because of the intricate and complex nature of the molecular species that make up the crude oil. It is this complexity that leads not only to difficulties in analyzing the recovered material but also in analyzing the original oil in place. Moreover, the incompatibility of crude oil constituents with each other is a continuing issue and the occurrence of suspended organic solids during recovery (especially thermal) reduces the efficiency of a variety of processes. More detailed knowledge of the composition and reactivity of petroleum will help in understanding the means by which models can be applied to understanding recovery processes. The models that are proposed as a means of being applicable to the prediction of sediment (i.e., asphaltene, resin, wax) formation and deposition from petroleum due to changes in pressure, temperature and composition fall somewhat short in their structure. Further modeling needs involve an understanding of the chemistry of these materials and reflect the more modern approach to the physico-chemical structure of petroleum in order to more correctly predict the onset of precipitation as well as the location and amount of the sediment deposition in the producing wells and in oil-transport pipelines.