HISTORY OF HYDROCARBON CHARGE ON THE ATLANTIC MARGIN - EVIDENCE FROM FLUID-INCLUSION STUDIES, WEST OF SHETLAND

Fluid inclusions in Jurassic reservoir sandstones help us to understan d the history of hydrocarbon charge in the West of Shetland region. Th e sandstones contain both hydrocarbon and aqueous fluid inclusions. Hy drocarbons are present in trails of secondary inclusions through detri tal grains, and as primary inclusions in quartz overgrowths. This is d irect evidence for at least two episodes of hydrocarbon charge before the present oil entered the rock, consistent with indirect evidence fr om burial history modeling and organic geochemistry, Fluorescence colo rs indicate that the two oils are of distinct composition, The first o il was degraded, reflecting an episode of uplift and exposure to near- surface fluids before reburial and migration of a second Live oil, Oil s comparable to these two paleocharges were mixed to produce the oils that are encountered in the current reservoir pores, shelving that the y were preserved despite repeated tectonic events at the Atlantic marg in.