Differential scanning calorimetry: a new technique to characterize hydrate formation in drilling muds

摘要

With the increasing number of deep offshore drilling operations, operators and service companies are confronted to more and more complex technical challenges. Extreme conditions encountered at these depths require an adaptation of the drilling muds. In particular, range of temperature and pressure (up to -1 deg C and 400 Bars) are favorable conditions fromed from water and gas: water contained in drilling muds wil form under certain temperature and pressure conditions, a solid cage which entraps the gas molecules. Formation of these solid gas hydrates is liable to plug kill and choke lines as well as the annular, and may cause interrruption of the drilling operation and even destruction of rig equipment. Deep offshore drilling operators are aware of this problem and some operational solutions and drilling mud formulations are proposed and utilized, but when extreme water depths are attained, classical inhibitors solutions alone may be ineffiective. The usual way to determine the thermodynamic conditions of the formation of hydrates in drilling mud formulations is to use PVT cell. This technique required heavy instrumentation and often does not permit to work with a whole formulation (specially in the presence of solids). Moreover. PVT cells do not give a quantitative evaluation of the kinetic properties of hydrate formation.