An increasingly common concern made about proposed pipelines built to carry crude oil derived from the oil sands is that the pipes will be more prone to leaks.
Given the intense discussion about the Keystone XL and Northern Gateway pipelines these days, it is hardly surprising that this criticism has been getting a lot of air time of late. The issue being raised by some critics is that the type of crude oil the new pipelines would carry, known as dilbit, is more corrosive than conventional crude.
Dilbit defined
Dilbit is oil sands bitumen that has been reduced in viscosity through addition of a diluent (in effect, a solvent) so it will flow through the pipeline. Trying to move undiluted bitumen through a pipeline would be like trying to suck peanut butter through a straw. (For the record, we are not suggesting you should put bitumen on your toast, in case there was any confusion.)
Diluents are widely used in the industry to thin crude oil (as bitumen is not alone in being too thick to pipe without help). Typically diluents are lighter hydrocarbons, usually pentanes plus, condensates or naphtha.
So is dilbit really riskier to transport than other crudes? Not according to experts who have looked at the issue closely.
Research findings
A fact sheet compiled by the American Petroleum Institute and Association of Oil Pipe Lines includes research findings from the Battelle Memorial Institute, which determined that diluted bitumen is no more corrosive in pipelines than other heavy crude oils.
Battelle came to this conclusion after comparing corrosivity statistics of several types of dilbit against many other crude oils. Most of the dilbit blends actually had a lower corrosivity than crudes which have been transported by U.S. pipelines for four decades.
The Battelle findings concur with those of Alberta Innovates – Energy and Environmental Solutions (AI-EES). AI-EES also performed a review of the corrosivity of dilbit in pipelines in comparison to conventional crude oils (PDF). AI-EES found that the characteristics of dilbit are not unique and are comparable to conventional crude oils during pipeline flow, based on chemical and physical characteristics.
AI-EES also looked at Alberta and U.S. pipeline failure statistics to compare similar crude oil pipeline systems. The comparison indicated that the systems in Alberta (with a large percentage of dilbit lines) had comparable corrosion-related failure rates to the U.S. systems (which carry mostly conventional crudes.)
Pipelines safe, efficient
While these findings validate dilbit as a safely transportable product, there is no room for complacency when it comes to pipelines.
And the energy industry is certainly not complacent about the risks of handling oil sands crude, and indeed all forms of petroleum. Despite what you may read and hear, pipelines remain the safest and most efficient way to transport oil, including the growing volumes produced by Alberta oil sands.
