Studying the gas hydrate related problems during drilling in south Caspian Sea

Hydrocarbon exploration and exploitation have, over the last decade moved into increasingly more deeper and challenging areas of the world’s continental margins. South Caspian Sea is one of these environments which has been the focus of intense drilling activities for most of the past decade. Harsh conditions in south caspian basin has placed many challenges against drilling engineers. One of these challenges is gas hydrates. Gashydrates have been under close attention because of their significant effect on the safety of drilling operation as a potential hazard, energy resource potential and role in global climate change. In this study the problems related to gas hydrates during drilling in the Caspian Sea was investigated and some solutions was suggested to overcome these problems. Gas hydrates can cause some problems during drilling process like: pluggingthe choke line and kill line, plug formation around the drill string and BOPs, uncontrolled release of free gas trapped beneath the hydrate seal, slope instability, gas kick due to hydrate dissociation and etc. ultra high water depth and existence of mud volcanoes increased the complexity of gas hydrates problem in south caspian sea. Therefore using drilling methods like MPD, using kinetic and thermodynamic inhibitors, drilling inhibitive water based muds like glycol mud, increasing safety factor for designing drilling rig and facilities, drilling all of sections with closed system to preventing gas flow and etc. could be effective in preventing and solving gas hydrate problem during drilling.

Keywords:

Gas Hydrate , Safety , Hazard , Caspian Sea , Gas Kick , Hydrate Dissociation