Fault Parameters Controlling Hydrocarbon Accumulation in the Northern North Sea: Insights From 3-D Basin Modelling

Abstract

3D basin modelling of the northern North Sea region has been performed using PETROMOD software in order to understand the petroleum system within the basin. Data integrated and used in building the models include horizon maps, fault intersection maps, erosion/ paleo-thickness maps, stratigraphy data, source rock properties, heat flow maps, paleo-water depth and well data. Fault properties controlling hydrocarbon accumulations in Gullfaks, Visund, Kvitebjørn, and Huldra fields have been analyzed quantitatively to determine the most likely hydrocarbon accumulation models. The results show that oil accumulation in the Gullfaks field is controlled by three main faults. The first fault bounding the field is a non- sealing fault with shale gouge ratio (SGR) of 10%. The second fault located further south in the field is a sealing fault and the third fault located in the north is a non-sealing fault. A NE-SW non-sealing trending fault controls the hydrocarbon accumulation in the Visund field. In the Kvitebjørn field, another NE-SW trending fault surrounding the field with an SGR of 30% controls the hydrocarbon accumulation. The gas in place in the Huldra field is controlled by two N-S trending faults. The first fault is located in the west of the field and is defined by SGR of 40%. The other fault located in the east of the field is a non-sealing fault. The gas accumlation is more sensitive to SGR than oil accumulation. Fault properties affect particularly hydrocarbon migration pathways. Burial history curves of most likely petroleum system model obtained shows that Late Jurassic to Early Cretaceous uplift in the basin is more pronounced in the footwall of the triple rift graben system in the basin. In the same period, axis of the graben system is characterized by non-deposition of sediments. This uplift phase is also evident in paleo-temperature distribution within the basin. Source rocks in the basin, Draupne and Heather Formations, started to be mature at 135Ma and 155Ma and became more mature as burial depth increased. Hydrocarbon generation occurred very early with Draupne Formation generating 120Mtons and Heather Formation generating 18Mtons. This study enhances understanding of the petroleum system in the northern North Sea by providing an integrated 3D basin model of the area, determining properties of major faults controlling hydrocarbon accumulation and providing information on burial history, source rock maturation and generation potential in the basin

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016