Sulfur Glomeration Mechanism and Critical Velocity Calculation in Sour Gas Well Bore

with the decreasing of temperature and pressure, elemental sulfur may precipitate in wellbore. The diameter of some parts of the wellbore becomes smaller when there are plenty of precipitated sulfurs on the inner side of the wall. The mechanism of sulfuric glomeration and adsorption were investigated and the tendency of sulfuric distribution was analyzed in wellbore, critical gas velocity and sulfur particle mechanical models were established. The results indicate that liquid bridge force, which is produced by the effects of water film between sulfur particles, is the main cause of sulfur glomeration. At the beginning of sour gas reservoir development, when borehole pressure is lower than saturation pressure, the distribution of precipitated sulfur and critical velocity of carrying sulfur are increasing from bottom hole to well head. Sulfur particles are difficultly carried when liquid bridge force is formed. Critical velocity goes up with precipitated sulfur diameter increasing.