Gas Hydrates Phase Equilibrium with CaBr2 and CaBr2 + MEG at Ultra-High Pressures

Abstract We report methane (structure I) and methane/ethane (structure II) hydrate phase equilibrium data with calcium bromide (32 wt%) and a mixture of calcium bromide (20 wt%) + monoethylene glycol (20 wt%) solutions for pressures up to 200 MPa. As expected for thermodynamic hydrate inhibitors, the salt and glycol cause the hydrate phase equilibrium boundary to shift to lower temperatures and higher pressures. These data are the first to be reported for these systems, which are particularly useful as calcium bromide is widely used in drilling fluids and hydrate formation is a growing concern in well completion and workover fluids. The measured experimental data were compared with commonly used hydrate prediction tools to assess their reliability.