For thermal in-situ oil sands production, it is conventional to think that an emulsion pipeline remains essentially oil-wet. Ideally, an oil coating distributed on the pipe by the produced water-in-oil emulsion from a well pad is expected to give the needed corrosion protection for the operating life of the pipeline.
Practically however, there are conditions under which this ideal scenario becomes no longer feasible, even for low API gravity heavy oil. These parameters affecting protection include but are not limited to water cut, well pad processing, steam cycle phenomena, reservoir characteristics, pipeline operating temperature, partitioning characteristics of the acid gases and their effects on water chemistry and passivation as well as other field operational practices.
From the experience of two case histories at a thermal in-situ oil sands project, this paper elaborates on many of the field parameters and how they influence the integrity of pipeline infrastructure by studying the various corrosion phenomena at play. Corrosion mitigation recommendations for these pipelines will also be presented.
Key words: thermal in-situ, oil sands, asset integrity, corrosion.