Gas Hydrates - Arctic Unconventional Resources

Anatoly Dmitrievsky¹, Inna Balanyuk², Sergey Shapovalov², and Olga Chaikina^2
1Russian Academy of Sciences, Institute of Oil and Gas Problems RAS, Moscow, Russian Federation.
²Russian Academy of Sciences, P.P.Shirshov Institute of Oceanology, Moscow, Russian Federation.

The largest among known gas hydrate accumulations is discovered at the boundary of the Barents and Norwegian Seas. Arctic shelf is really unique reserve of discovered and predicted hydrocarbon resources of Russia. Recoverable hydrocarbon resources exceed 100 billion tons of oil equivalent. In the Western sector of Russian Arctic a giant oil and gas shelf province containing 70% of initial recoverable resources of Russian shelf has been stricken.

The most essential criteria of the sea bed stability are the development of the geodynamically active zone of the Barents Sea rift, faults tectonics, geothermic regime, gas breath of industrial deposits, modern sedimentation and gas hydrates formation in the Barents Sea conditions. The Barents Sea rift development was accompanied by vigorous tectonic activity, propagation of deep faults, deep fractured zones that played an important role in fluid dynamic and thermobaric regime of the whole region. It played a substantial role in formation of unique fields as Stokman, Prirazlomnoe and others, created prerequisites for possible gas outbursts into near-surface sediments of the Barents Sea that could result, in some cases, in gas hydrate formation.

Hydrodynamic conditions of the region led to kick up of hydrocarbons water solubility that creates preconditions for gas hydrates formation. Gas hydrates are meta-stable formations and exist in the nature in the conditions which are about their phase stability limits. Minor changes of temperature and pressure could result in inconvertible decomposition process with release of vast amounts of methane and water into the environment followed by landslides and downfalls. Wide spread occurrence of gas hydrates in the bottom sediments of seas and oceans is, in the same time, a positive factor of increasing of hydrocarbons resource and a serious industrial and ecological problem. Some of the serious engineering problems in the sea bed instability conditions are marine fields operation, oil platforms construction and pipelining. Gas engineers faced this kind of problems while pipeline “Russia-Turkey” was under construction.

The major processes that controlled a structure of the friable sedimentary cover of Arctic shelves appear on the seismic acoustic records as chaotic effect of cryolite genesis (permafrost, themokarst, glades, paleo-riverbeds and so on) and hydrocarbons migration (gas hydrates, gas saturated sediments, gas sipping, etc.). Such phenomena are the main components of geo-risks for oil and gas fields development in Arctic Seas and are, together with the gas hydrates deposits, the top priority objects of seismic acoustic measurements.

AAPG Search and Discovery Article #90130©2011 3P Arctic, The Polar Petroleum Potential Conference & Exhibition, Halifax, Nova Scotia, Canada, 30 August-2 September, 2011.