THE DISTRIBUTION OF APTIAN SANDSTONES IN THE CENTRAL AND NORTHERN NORTH SEA (UK SECTOR) ‐ A LOWSTAND SYSTEMS TRACT PLAY

Abstract

In this paper, we discuss the distribution in the Central and Northern North Sea (UK sector) of the Late Aptian sandstones of reservoir potential which are assigned to members of the Sola Formation. An exploration strategy for these sandstones is proposed, based on sequence‐stratigraphic and palaeogeographic models derived from the examination of numerous wells. The sandstones were deposited by mass‐flow processes as a consequence of a major, tectonically‐induced or enhanced, Late Aptian fall in relative sea‐level. The distribution of these lowstand sandstones, and the facies developed, was controlled by the structure and palaeogeography that existed in the study area both before and after this sea‐level fall.The pattern of faulting in the study area during Sola Formation deposition is related to Jurassic and older tectonism, which is associated with the development of the proto‐North Atlantic and the thermal subsidence of the North Sea rift system. Faults controlled the areas of sandstone provenance, and also determined the routes by which reworked sediments were transported into depocentres.We have mapped the distribution of these sandstones using both well and seismic data. Maps of fault patterns, basinal and high areas, and facies distributions have been generated for the top‐ Valhall Formation level (i. e. immediately beneath the Sola Formation), and also for the Sola Formation itself. These maps were used to model the distribution of Aptian lowstand sandstones and prospects in the UK Central and Northern North Sea. This modelling exercise is of relevance for the identification of lowstand sandstones with reservoir potential elsewhere on the NE Atlantic margin.