Under certain conditions of low temperature and high pressure, and in the presence of free water, low-molecular-weight gases such as methane and ethane may crystalize and form gas hydrate clusters. These clusters may accrue in the pipelines and fittings causing partial to complete plugging and restricting the flow of hydrocarbon streams. Dissolving already formed gas hydrate plugs is very challenging. Among different chemicals, only methanol was found to be an effective dissolver of gas hydrate plugs. The main drawback of using methanol as a hydrate dissolver is its low flash point temperature, which makes it unsafe to store in large volumes in hot regions in addition to the need to use large volumes to be able to dissolve the hydrate plug.<br/>Several formulations were recognized as potential alternative to methanol. These formulations possess properties similar to methanol such as low melting point (&lt;50°C) and complete miscibility with water but with flashpoint temperature above 50°C. These formulations were tested as a hydrate dissolver using a gas hydrate autoclave testing cell. These formulations were found to dissolve gas hydrate by employing less volumes comparable to methanol. Three field trials were performed using aqueous based potassium formate formulation where the gas hydrate plug dissolved in less than 30 minutes compared to two hours when methanol was injected at the same injection rate. The results of the field trials accelerated the removal of methanol from the field and to depend on the newly developed, safer, cost effective treatment to dissolve gas hydrate plugs in pipelines.

A safer gas hydrate dissolver: Experimental study and field application

ACS Spring Meeting 2021

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