MacCulloch Field; Improving Reservoir Characterisation Through Time Lapse Analysis.

The MacCulloch field lies in Block 15/24b in the Central North Sea. The field has been on production since 1997. The primary reservoir is Lower Palaeocene turbidite sandstones of the Upper Balmoral Sandstone unit in the Lower Palaeocene Lista Formation. It is connected to a large aquifer in the underlying Lower Balmoral Sandstone unit. The field is made up of a number of individual turbidite flows predominantly characterised by clean, high porosity and permeability, high net/gross sandstones. These discrete depositional units can be distinguished on the seismic data and examination of the time-lapse response of these units shows that they have acted as a primary control on the depletion of the field. The objective of the core display is to show differences between individual massive reservoir sand units from different flow episodes and illustrate some of the more minor reservoir facies encountered in possible overbank deposits or margins to individual flow packages.