Laggan Field 3D geological modelling: case study

Abstract

Abstract Drilling of Laggan development wells commenced in summer 2013 and finalization of well locations required updated reservoir models, fully incorporating the 2009 baseline seismic. Consequently, geomodelling workflows have been developed based on the 3D seismic, petrophysical and production test data. The reservoir model building methodology for Laggan consists of the following steps: (1) construction of a classical structural framework using seismic interpreted fault sticks, top reservoir depth surface and the overall reservoir thickness map estimated from seismic data; (2) building of zones model integrating well data, seismic and sedimentological concepts; and (3) generation of a 3D facies and petrophysical model constrained by seismic and well data, including well test results to calibrate the permeability. A reasonable match of the well test data was achieved without any major adjustments to the reservoir model. This methodology has led to the construction of a robust reservoir description, capturing the geological knowledge of the turbidite system and constrained by well and seismic data. The new Laggan model is now considered ‘fit for purpose’ for well locations update, well type and well number confirmation and development of the Reservoir Management Plan.