Hydrate Management for Systems with High Salinity Brines at Ultra-High Pressures

Abstract

Reliable prediction of hydrate phase equilibrium is necessary for operations in deepwater oil and gas production which go beyond hydrate management in pipe flow, such as, setting depth of surface-controlled subsurface safety valve (SCSSV) and identification of effective risk mitigation. There are a number of fields being developed and producing with brines with salt concentration near/at saturation, creating conditions where hydrate formation may lead to salt precipitation. High salinity brines coupled with high pressures (> 10,000 psia) are conditions for which no hydrate phase equilibrium data exist in the open literature. This study, funded by DeepStar®, quantified the impact of high salinity brines in the formation of hydrates by the measurements of hydrate stability conditions in saline systems with under-saturated to saturated concentration through newly designed apparatus and development of correlation based on hydrate suppression temperature,providing reliable prediction results for hydrate phase equilibria in both NaCl and CaCl2 systems up to near-saturated concentrations.