Modeling Two-Step Mechanism of Thermodynamic Hydrate Inhibitor Injection for Gas Hydrate Plug Dissociation

Gas hydrate blockage in oil and gas flowlines is a major flow assurance issue that results in operational disruptions, safety hazards, and economic losses. Typically, one-sided depressurization (1SD) is deployed, followed by the injection of a thermodynamic hydrate inhibitor (THI) to accelerate the...

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Bibliographic Details
Published in:Energy & fuels 2024-07, Vol.38 (14), p.12586-12594
Main Authors: Kannan, Seetharaman Navaneetha, Ravichandran, Sriram, Estanga, Douglas, Turner, Douglas J., Grasso, Giovanni, Sloan, E. Dendy, Koh, Carolyn A.
Format: Article
Language:English
Subjects:
Traditional Fossil Fuels
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Summary:Gas hydrate blockage in oil and gas flowlines is a major flow assurance issue that results in operational disruptions, safety hazards, and economic losses. Typically, one-sided depressurization (1SD) is deployed, followed by the injection of a thermodynamic hydrate inhibitor (THI) to accelerate the plug dissociation process. This study introduces a novel two-step mechanistic model for predicting gas hydrate plug dissociation time, addressing a critical challenge in deepwater production operations. The model uniquely integrates field 1SD and the subsequent injection of THI, incorporating simultaneous heat and mass transfer changes across the plug. The model highlights that in horizontal pipes, axial convection is the primary mechanism for THI-induced plug dissociation with rates influenced by plug characteristics (permeability, porosity, and plug length), fluid properties, and dilution due to water liberated from dissociating hydrates. The model considers the effect of the THI flow rate and THI dilution across the plug due to water liberation from dissociating hydrates. The model addresses the safe operating conditions for hydrate plug depressurization and the influence of major variables contributing to hydrate plug dissociation with THI. The advancement of this model lies in its ability to offer a realistic representation of field conditions that aids operational and design engineers in establishing safety protocols for hydrate plug remediation strategies.
ISSN:0887-0624
1520-5029
DOI:10.1021/acs.energyfuels.4c01517