Transportation of heavy and extra-heavy crude oil by pipeline: A review

The transportation of heavy and extra-heavy crude oils from the head-well to the refinery is becoming important since their production is currently rising all over the world. Such oils are characterized by a low API gravity (< 20) and high viscosity (> 103 cP at 298.15 K) that render difficult oil flow through pipelines. Conventional technology pipelining is designed for light and medium oil crudes, but the pipelining of heavy and extra-heavy crude oils may be challenging because of their high viscosities, asphaltene and paraffin deposition, increasing content of formation water, salt content and corrosion issues. In this paper, the current and innovative technological solutions covering viscosity and friction reduction to move such crude oils from the production site to the processing facilities are thoroughly discussed.