Unravelling the history of a complex hydrocarbon play through petroleum systems modelling – Catcher area development (CAD), UK Central North Sea region

Significant uncertainty exists with regards to the migration history of hydrocarbons in the Catcher Area Development (CAD) region, West Central Shelf, UK Central North Sea. In this study, petroleum system modelling is carried out to understand the pathways, timing and processes involved in hydrocarbons migration from the Jurassic Kimmeridge Clay to the injectite dominated sandstone reservoirs of the CAD region. The Cromarty sandstones are identified as the lateral carrier of hydrocarbons from the graben area to the CAD reservoirs. Out of the six CAD fields, five were charged along a fill spill chain. During the charging process, the CAD system was mostly seal limited, with significant hydrocarbon leakage into the overburden. Hydrocarbon migration and gas leakage in the region continues today. The present-day accumulations of the CAD region are spill limited suggesting the potential for more discoveries westward. This study provides an understanding of why gas chimneys are widespread in the CAD region and how the quality of hydrocarbons in the different fields relates to one another and those of the wider region. It also supports the presence of prospects further SW of the CAD region. • Application of Petroleum Systems Modelling to defining hydrocarbon migration pathways in complex systems. • Determination of the structural and stratigraphic settings of a petroleum system using seismic and well data. • Formation and structure of sand injection complexes.