Abstract The Huntington Field is located in Block UK 22/14b in the UK Central North Sea. The reservoir is the Tertiary Forties Formation (a deep-sea fan interval), which has been produced since 2013. Pre-production well data indicate that hydrocarbons (oil) are present outside structural closure as recorded by direct pressure data and wireline-derived fluid contacts, and indicated by seismic attribute data. These observations in other parts of the world (e.g. Mad Dog Field, Miocene Gulf of Mexico) have been attributed to the presence of a hydrodynamic reservoir. This paper aims to reconcile these observations from seismic data, logs and pressure data with competing models to explain the hydrocarbon distribution. Combining the interpretations above with the additional observations that (a) there are no sedimentological barriers or identifiable faulting between wells, (b) the surrounding fields (Everest and Forties) have been actively producing for decades, but that calculated flow rates in the Huntington Field agree with published data for other virgin hydrodynamic systems, and (c) measured regional and local overpressure gradients indicate fluid flow to the NW where hydrocarbons are present outside the structure indicates that a hydrodynamic model is the most probable solution to explain the fluids and their present distribution.