--> Abstract: Gas-hydrate Systems in Petroleum Provinces, by Jurgen Mienert; #90177 (2013)

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Gas-hydrate Systems in Petroleum Provinces

Jurgen Mienert

Both the Gulf of Mexico and Barents Sea are petroleum provinces that host potentially large areas of gas- hydrate-bearing rocks. Significant gas resources in gas hydrate accumulations are found in a range of geological settings in deep water areas such as the Gulf of Mexico. While successful gas-hydrate drilling by Joint Industry Partners (JIPS) in 2009 and 2012 proved the existence of gas hydrate in petroleum provinces in the Gulf of Mexico, such campaigns are lacking in the shallow Barents Sea. Here we present evidence for significant leakages of hydrocarbons generated in deep-source rocks to the shallow subsurface in the SW Barents Sea. Giant gas chimneys (GGC) are the most evident features connected to shallow high-amplitude acoustic anomalies suggesting migration and trapping of fluids. The evidence for large fluid-flow features and trapped fluids exists especially close to known hydrocarbon fields such as Snøhvit, Skrugard, and Havis, a relationship that is particularly evident at major deep-seated faults and GGCs. The eminent correlation between deep-seated faults, source rocks and the shallow trapped fluids and the missing control of net erosion on fluid-flow locations suggest that structural elements, tectonics and glaciations may have played major roles in the activity and timing of the fluid leakage and gas hydrate formation. Today's gas hydrate formation areas are inferred from 2D and 3D seismic data and gas-hydrate-stability modeling. Mixing of methane with higher order thermogenic hydrocarbon gases such as ethane and propane lead to changes in the depth of the hydrate stability zone in petroleum provinces so that the base of the hydrate stability zone is deeper than if pure methane is present. Seismic interpretations of trapped fluid areas are analysed together with gas hydrate stability zone models providing new knowledge about gas hydrate systems in petroleum provinces of the SW Barents Sea. This is a contribution by the Centre for Arctic Gas Hydrate, Environment and Climate (CAGE), a research centre of excellence (SFF) funded by The Research Council of NO, and located at the University of Tromsø. CAGE will address and integrate major scientific objectives in Arctic gas hydrate, environment and climate research with a 10 year scope.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013