Institute of Petroleum Engineering

Centre for Gas Hydrate Research Publications

Abstract 127
Gas Hydrates: Source of Energy or a Serious Problem to the Oil and Gas Industry
Masoudi, R., and Tohidi, B.
4th Iranian National Congress on Energy and Economy, Tehran, Iran, 28 Feb to 1st March (2005).
In gas and petroleum exploration and production operations, gas hydrates, clathrates, pose a serious economic and safety concern. Low seabed temperatures combined with high fluid pressures promote formation of clathrates in reservoir hydrocarbon-water fluid mixtures. Hydrates can make costly and dangerous blockages in the oil and gas pipelines, subsea transfer lines, and surface separation facilities. It is speculated that, in some parts of Iran in particular in the Caspian Sea, the naturally formed hydrates in marine sediments (and possibility of hydrate formation during offshore drilling) are a very important concerns to any exploration and production operations in such area. Although hydrate formation can pose serious flow assurance problems in oil and gas industry, gas hydrates have great potential for positive applications as sources of energy -� turning a long-standing problem into a potential benefit. Two important properties of hydrates are their very high gas to solid ratio, 1m3 of hydrate may contain up to 175m3 of gas (at standard conditions), and self preservation effects which make them feasible to be transported at atmospheric pressure. They thus present a novel means for gas storage, transportation and delivery, with consequent potential applications in a wide variety of areas, including exploitation of remote gas fields, natural gas processing, capturing associated gas, CO2 mitigation/sequestration, desalination and water treatment, volatile organic compounds (VOC) recovery, etc. In this communication, we give an extensive overview on the challenges and opportunities which gas hydrates make to the oil and gas industry in Iran. This will include various strategies for hydrate formation and prevention scenarios with particular emphasize on this issue in Caspian Sea (Tohidi et al., 2003; Masoudi et al., 2004). In addition, the feasibility of gas capturing in form of hydrate, as a source of energy which is formally called gas-to-solid technology, is discussed and compared to other alternatives such as CNG and LNG for application of gas storage and transportation. For this purpose the preliminarily promising results of series of tests carried out on natural gas hydrate formation/production is presented along with an evaluation of its preservation effect at atmospheric pressure.