Anti Agglomerants Case Study

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3.3.2 Anti-Agglomerants (AA):
Anti-agglomerates (AAs) are surfactants and polymers, which are injected in low dose (generally 1 to 4 % weight of water content), which cause the water phase to be suspended as small droplets. When the suspended water droplets convert to hydrates, the flow characteristics are maintained without blockage. They allow hydrate crystals to form but keep the particles small and well dispersed in the hydrocarbon liquid as slurry. They inhibit hydrate plugging rather than hydrate formation. The dispersion hinders the formation of larger crystals which would then be less likely to cause plugs (Clark et al. 2005). Since hydrate crystal is formed and dispersed, subcooling or residence time limitations has been eliminated, …show more content…

Pipeline operation can also be of importance as dispersion of small hydrate crystals will be favoured by higher velocities. At low flow rates and during shutdown conditions, the crystals may settle out and agglomerate when the oil density difference is sufficient. The anti-agglomerants provide protection up to 40:60 water oil ratios (Chandragupthan et al. 2011). Typical examples of AAs include alkyl aromatic sulphonates or alkylphenylethoxylates (Pickering et al. 2001).

Anti-agglomerates, (AA) inhibitor is an economically attractive option under severe hydrate-forming conditions and is also very effective where production is shut-in for extended periods. AAs can provide relatively high sub-cooling up to 40oF, which is sufficient for deepwater applications and have completed successful field trials in deepwater GoM production systems. AAs have toxicity issues and may transport microcrystals of hydrate into and remain in the condensed/oil phase.

3.3.3 Economical Evaluation of …show more content…

For new field development, production fluids may not be readily available for testing. They also lack an established model for the prediction of their effectiveness, thus posing difficulties for field developers in the application of these chemicals (Pickering et al. 2001; Chandragupthan et al. 2011). KHIs have limited subcooling (time dependent). They interact with other chemical inhibitors (for example corrosion inhibitors) which reduce their effectiveness and this should be accounted for in testing programmes (Graham et al. 2001). They also have limited experiences in oil systems (Chandragupthan et al.

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