Reservoir modelling - west Nuussuaq

Outcrops, subcrops and seismic facies indicate the presence of both source rocks, reservoir rocks and seals. Oil seeps indicate the presence of 5 distinct oil types representing Upper Cretaceous and Paleocene sources. Within the prospective area the potential reservoir units include mid-Cretaceous fluvio-deltaic sandstones, mid-Cretaceous-Paleocene marine slope channel-sandstones and Paleocene marine canyon sandstones. Diageneses studies suggest, however, that the most promising reservoir intervals are restricted to sandstones of Paleocene age. These generally show porosities higher than 10% and permeabilities of certain units ranging form 20 to 90mD. A palynostratigraphical, lithological and petrophysical evaluation of the c. 3000 m deep GRO-3 well indicates that it penetrates a ?Coniacian-Upper Selandian succession of interbedded marine sandstones and mudstones deposited in a slope apron environment. The Paleocene sandstones are characterised by low shale content and fair porosities (10-15%) and are in particular regarded to be potential reservoir rocks. According to a quantitative interpretation of the logs these sandstones exhibit hydrocarbon saturations of up to 50-70%. However, more reliable estimates require further pertrographic and petro-physical analysis. The combined results from the geophysical surveys, the organic geochemical and diagenesis studies and from the evaluation of GRO-3 have profound implications for future petroleum exploratin activities in the Nuussuaq Basin. The geophysical data indicate that large, rotated fault blocks provide possibilities of major structural traps to be present in the western part of the basin. Source rocks are documented in the succession both from wells and from surface oil seeps. Potential reservoir units occur throughout the sedimentary sucession; especially the Paleocene marine turbiditic sandstones show good reservoir properties. Furthermore, the less consolidated parts of the fluvio-deltaic Cretaceous sandstones may also prove to be prospective reservoirs. The high content of hydrocarbons within the Paleocene sandstones in the GRO-3 well indicates that geological conditions are favourable for discovery of large hydrocarbon accumulations in the western part of the Nuussuaq Basin