Lower Cretaceous reservoir development in the North Sea Central Graben, and potential analogue settings in the Southern Permian Basin and South Viking Graben

Abstract

Much of the future hydrocarbon exploration potential in the North Sea lies in locating stratigraphic traps and discrete reservoir intervals. This study assesses the potential for Lower Cretaceous reservoirs, with particular focus on the Norwegian Central Graben and proposed methods to identify future prospects over a wider area. Seismic interpretation and well data reveal the structure and sedimentology of the study area. Although the region was isolated from a large hinterland in the Early Cretaceous, potential local sediment sources, sediment transport routes and areas with possible reservoir development are identified. The greater Mandal High area, where Lower Cretaceous shoreface deposits and submarine fan systems are postulated, is suggested for primary focus. Similar deposits may have developed around the other exposed highs in the region, although several were drowned towards the end of the Early Cretaceous. Detailed seismic and stratigraphic analysis will be necessary to identify individual reservoir units. Since similar settings may have occurred in the adjacent South Viking Graben and Southern Permian Basin regions during the Early Cretaceous, further reservoir assessment is recommended for the North Sea in general.

Stepwise basin evolution of the Middle Jurassic–Early Cretaceous rift phase in the Central Graben area of Denmark, Germany and The Netherlands

“…The entire area, including the plateau areas, then acted as one structural province subjected to regional subsidence. This caused the sea to transgress much further onto the mainland of the Friesland Platform and the West Netherlands basins, where marginal-marine sandstone deposition prevailed (Jeremiah et al 2010;Zwaan 2018).…”

New insights into salt tectonics in the northern Dutch offshore: a framework for hydrocarbon exploration

“…The precise depositional area of KN is uncertain, here it is assumed that the interval had an approximately constant thickness, but with localized thickening onto the Schill Grund Platform and within the Dutch Central Graben. This variability is based on the palaeogeographical maps of Ziegler (1982), which suggest a transition from paralic to deep-marine deposition from platform to graben (see also Zwaan 2018).…”

“…For example, this model could be applied to define the depositional and preserved extent of Jurassic (Posidonia/Kimmeridge) source rocks, to investigate the timing of subsequent hydrocarbon charge though salt windows or to understand the distribution of shallow gas occurrences above salt diapirs. Understanding rim-syncline development can also help with the definition of reservoir distribution in Upper Triassic, Jurassic and Cretaceous strata (see also Bouroullec, this volume, in press;Verreussel, this volume, in press;Zwaan 2018). Zechstein salt movement also impacts other plays in this area, including the Triassic Volpriehausen play (charge through salt windows from Carboniferous source rocks, salt-controlled traps and lateral seals, and the risk of halite reservoir cementation: e.g.…”

Mesozoic resource potential in the Southern Permian Basin area: the geological key to exploiting remaining hydrocarbons whilst unlocking geothermal potential

“…Steuber et al 2005), led to an evolution from a clastic-dominated succession (marine shorefaces/pelagic mudstones/deepwater sandstones: e.g. Milton-Worssell et al 2006;Jeremiah et al 2010;Vis et al 2018;Zwaan 2018) to chalk-rich seas (including important reservoir units across the region: e.g. van Lochem 2018).…”