Methane Hydrate Blockage in Gas–Water–Sand Systems: Insights from FBRM and PVM Analysis

Hydrate reservoirs are accompanied by a large amount of water migration during the extraction process, leading to severe sand outflow, making sand control and wellbore flow safety a huge challenge. The development and blocking of hydrates in gas–water–sand systems were investigated in terms of shear rates using a high-pressure stirred autoclave equipped with FBRM and PVM probes to estimate the average hydrate particle dimensions and amount of particles related to the hydration volume percent and flow resistance of hydrate slurry. An increment in the measured motor current was first observed when the hydrate volume fraction was around 18 ± 2 vol % with sand concentration varied from 0 to 1.5 wt % and clear changes of hydrate particle size and number were monitored. Initially, the hydrate particle surface area keeps increasing until it reaches a maximum between 2.1 and 13.7 vol % hydrate for shear rate 400–800 rpm, after which it quickly declines to a plateau at 12.1–19.1 vol % in a pure water system and 7.5–22 vol % in a sand-containing system. Aqueous phase hydrate bed development may have started when the value of the plateau is reached. The results may contribute to the development of predictive models for the start of hydrate blocking behavior in gas–water–sand systems.