Efficient Dissociation of Methane Hydrate Plug by Monoethylene Glycol + Cocoamidopropyl Dimethylamine in the Presence of Oil

Summary Gas hydrate plugging occasionally occurs in oil/gas wellbores and pipelines. Efficient dissociation of the hydrate plug could enable rapid production recovery and reduce revenue losses. In this work, the effectiveness of injecting monoethylene glycol (MEG) and cocoamidopropyl dimethylamine (CAPMA) to dissociate hydrate plug in oil-containing systems was investigated by rocking cell tests. Compared with oil-free systems, the required MEG dosage for hydrate plug dissociation is reduced, and no replug occurs when the MEG injection is insufficient in oil-containing systems. Under the conditions of 276.15 K and 8 MPa, the hydrate plug could be fully dissociated at the MEG volume fraction of 20.4%. Adding 5% CAPMA to MEG further reduced the required MEG volume fraction to 10.4%, decreasing MEG consumption by approximately 50%. The visualization test demonstrates that CAPMA could soften and effectively disperse the hydrate. With CAPMA + MEG, the plug dissociated more efficiently than with MEG alone, and the ice did not float to the liquid interface but instead dispersed throughout the liquid, forming a slurry. Molecular dynamics (MD) simulations indicated that CAPMA may help the exposure of MEG to hydrate by emulsifying the oil barrier into droplets. By using MEG + CAPMA, the cost of chemicals could be reduced by ~42%, alongside time savings. The MEG + CAPMA exhibits strong potential for practical application in hydrate plug dissociation.