Challenges in using heavy crude oil: formation of stable emulsions and difficulties in pipeline transportation

Dwindling of conventional oil reserves and increasing global demands have caused increased exploitation of heavy crudes accounting for a large fraction of the world's crude oil resources. Formation of stable water-in-crude oil emulsions in hydrocarbon reservoirs or in production processes are inevitable increasing environmental problems as well as costs of transportation and refining. Heavy crude oil viscosity also makes several problems during extraction and transportation. Viscosity reduction processes of heavy crude oil for pipeline transportation have been subject of many researches. In this paper, challenges involved in use of these energy resources have been evaluated using a comprehensive literature review.