Keeping Subsea Pipelines Free from Wax and Hydrate Deposits by Use of a Subsea Cooler Unit

Abstract

This paper presents the "cold flow" technology and tests performed to qualify a subsea concept as a step towards taking the technology into use. By combining subsea cooling and the traditional cold flow seeding method with a novel inductive heating mechanism, all hydrate and wax potential can be converted into small and inert solid particles in a subsea cooler downstream of the wellhead. The particles will travel suspended in the bulk flow at ambient seabed temperature towards the host facility without any additional flow assurance measures, like pipeline insulation, heating, or chemical injection. The paper contains a description of the Empig cold flow technology, and the initial concept launched by SINTEF. Furthermore, a description of a hydrocarbon flow loop used in the testing of the technology together with a brief description of test results. A subsea cooler unit used for a pit test is then presented. This section contains a discussion on its design principles, a description of the marinized heating system, and test results.