Chapter 1. Introduction

Abstract

Abstract Sequence stratigraphy has become a powerful tool in the basin analysis of the North Sea Basin, and will continue to be important in the maximization of the remaining hydrocarbon resources of Jurassic reservoirs in the region, whilst also moving through the energy transition. This chapter provides background to the main theme of this memoir, which is the description of a revised sequence stratigraphy scheme for the Jurassic–lowermost Cretaceous of the region, recognizing 39 stratigraphic sequences (‘J sequences’). The sequences are illustrated by 85 reference wells (56 UK wells, 22 Norway wells and seven Denmark wells), showing chronostratigraphy, lithostratigraphy, wireline logs and key biostratigraphic markers. The reference wells illustrate sequence development, together with their lower and upper boundaries. Comparisons of the North Sea Jurassic sequences with onshore outcrop sections, from the UK, demonstrate that many of the sequences can be recognized onshore. A comparison of the well sequences with seismic sequences is made in 17 illustrated seismic lines, demonstrating the seismic expression of many of the defined sequences. The recognition of a consistent set of stratigraphic sequences across the region allows a much better understanding of the development of the whole area during the Jurassic, which is currently hindered by the existence of multiple local and semi-regional lithostratigraphic schemes, in particular the differing notations that are utilized in the various international offshore jurisdictions that exist across the area.