HP DSC investigation of the kinetiks of gas hydrate formation: application to drilling fluids
Abstract
Drilling fluids or muds used in the oil industry play an essential role because of their multiple
functions. Two types of muds can be used: water-base fluids, mainly composed of water, clays,
electrolytes and water soluble polymers, and oil-base fluids which are invert emulsions of brine
into oil containing also various additives. As extreme conditions are now encountered in deep
offshore drilling operations, formation of gas hydrates in these fluids becomes an increasingly
serious problem for operators and service companies. In previous papers, an innovative
calorimetric technique (DSC) was presented, allowing to characterize hydrate formation in drilling
muds. In this study, this work was continued on kinetics properties of hydrate formation in
complex drilling fluids. Experiments were performed with two types of calorimeter i.e., a DSC 111
SETARAM able to work up to 12 MPa, and a new high pressure microcalorimeter (HP
microDSCVII SETARAM) that was specifically developed to allow measurements on gas hydrates
up to 40 MPa. The work was focused on the development of a methodology for studying hydrates
formation in oil-base fluids (water-in-oil emulsions) in isothermal conditions. Kinetics of gas
hydrate formation was investigated at various undercooling degrees and at different gas pressures.
The HP DSC has proven to be a useful tool to characterize kinetics of gas hydrate formation in
complex fluids.