James Wood and Sergio Treviño, Southwest Research Institute (SwRI), USA, introduce a midstream heavy crude oil processing technique for cost-effective pipeline transportation.
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ransporting heavy crude oils through pipeline or by other transportation means is challenging and often requires the petroleum industry to resort to rail transport for inland sources. Heavy and extra-heavy crude oils are difficult to transport via pipelines because of their high viscosities, asphaltene and paraffin deposition, increased content of formation water, salt content, and corrosion issues.1 Heavy crude oil and bitumen production and transport are at least twice as capital- and energy-intensive as the production of conventional oil.2 The expenses and energy requirements associated with the production and transport of heavy crude oil arise from the high viscosity at reservoir conditions, as well as the presence of undesirable compounds such as asphaltenes, heavy metals, and sulfur. This makes heavy crude oils difficult to produce, move by pipeline, and refine.
Pipelines are widely regarded as the most attractive option for transporting crude oils. They offer low costs and relatively low environmental impacts compared to other transport options that require loading and unloading oil in environmentally sensitive places. As such, several technologies have been developed to facilitate the transport of heavy crude oil via pipelines, including heating and injection of flow improvers. Southwest Research Institute® (SwRI®) scientists and engineers have developed a new process for treating heavy crude oils, making pipeline transportation of heavy crude oil and similar commodities more cost-effective and less energy intensive. ‘EZ Flow’ combines hydrodynamic cavitation processing of the heavy crude oil with proprietary addition of chemical formulations to reduce the heavy crude oil’s viscosity by over 60%, helping it flow more easily through existing pipelines.
Background There are several driving forces behind the development of a new process for making heavy crude oils flowable in pipeline. First, heavy crude oil transport is a necessity for petroleum producers worldwide. For example, at least 50% of crude oil reserves in Mexico are heavy and extra-heavy crude oils.3 Canada currently relies on heavy crude oil to meet production needs, producing approximately 700 000 bpd of synthetic crude oil that comes from heavy crude oil, bitumen, and tar sands. These synthetic crudes are transported via pipelines to refineries in Canada and the US.2 The pipeline technologies currently available to transport heavy crudes are expensive, requiring large volumes of chemicals or diluent, and tremendous energy resources in the form of heat. They often HYDROCARBON 51
ENGINEERING
September 2021
