Unrestricted fluid flow of oil and gas streams is crucial to the petroleum industry. Unless preventative action is taken, gas hydrate plugs form under the high pressure, low temperature conditions inherent to offshore production.
The oil and gas industry is facing increasing costs in inhibiting gas hydrate formation due to the development of offshore gas reservoirs. Recent international estimates of the cost of the conventional inhibitor, methanol, alone are in excess of $150 million/year. Gas hydrates are likely to form in subsea flowlines unless the water is removed down to the lowest dew point encountered, highly effective insulation is in place, or inhibitors are used. Since complete stripping of water from condensates and/or natural gas is prohibitively expensive, and effective insulation is beyond current economic limits, the most effective solution includes the use of hydrate inhibitors. This paper describes the state of the art of hydrate prevention, detailing hydrate structure, conditions and mechanisms of formation, and developing approaches – from the conventional to the cutting-edge – to hydrate inhibition. Its focus on low-dosage inhibitors, including a review of kinetic inhibitors and anti-agglomerants form, function, development, selection, modeling and applications, highlights gaps in current knowledge. Finally, a research agenda addressing both mitigation and deployment strategies is proposed.