Cold Flow: A Review of a Technology to Avoid Wax Deposition

Off-shore production of crude oil is greatly affected by the formation of solid deposits. These solids range from asphaltenes to gas hydrates and waxes. Long-chain alkanes (with a carbon number > 20) are commonly known as waxes and they are the fraction of petroleum that causes the greatest economical losses in oil recovery. The low temperature of water at the sea bed makes the oil cool down to temperatures below the Wax Appearance Temperature (WAT or Cloud Point), leading to nucleation and adhesion of waxes to the pipe walls. Some patents deal with the remediation of this fouling by generating a slurry in a controlled way, so that it will not adhere to the walls. This article reviews these patents and the experimental evidences that support the hypothesis of Cold Flow.