No the oil shipped on the Keystone XL is not corrosive to the pipeline. Although some of the oil will be derived from the oil sands, only oil is shipped. The sand is separated at the source.
A Battelle study (July 2012), confirms that the oil is not corrosive. Rather, according to the study, it is comparable to other heavy crude oils, “such as those produced in Venezuela, Mexico, and California, which have been transported and refined in U.S. for decades.”
Most recently Natural Resources Canada (NRC) released a report that also highlighted that bitumen-derived crude oil is no more corrosive to pipelines than conventional crudes. International standards for measuring the corrosiveness of crude oil in pipelines have been developed, providing us with an objective and credible system that can be used by researchers and engineers to improve pipeline safety and reliability around the world. The conclusion of the NRC study – that bitumen-derived crude oils are no more corrosive than any other crude oils – backs up the same results found in several other studies and the decades of experience pipeline companies have in safely transporting crude oil produced in Canada. The NRC study also points out that all crude oils must meet strict specifications for water, sediment and other chemical content before they are allowed to go into a pipeline.
For more information: See the Battelle study. Additional information is available in Section 6.3 of the NDEQ “Draft Evaluation Report on the Keystone XL Pipeline Nebraska Reroute,” available from the NDEQ homepage. Information is also available in the Final EIS, Section 3.13.