X-Ray Fluorescence (XRF) data from a series of high-pressure, high-temperature (HPHT) wells drilled in the Shearwater Field, UKCS are presented. These data comprise a total of 789 samples across a series of eight study wells. Chemical stratigraphy was utilised in conjunction with other geological data (i.e. well logs, ditch cutting descriptions and biostratigraphical analyses) to aid real-time stratigraphic placement. Systematic changes in geochemical composition were identified and used to build a chemostratigraphic zonation to aid delineation of lithostratigraphic boundaries.