Case Study - Arbroath - an Integrated Petrophysical and Seismic Elastic Inversion Process for De-risking Infill Drilling

The Arbroath field is located in UKCS block 22/17 and produces 38o API oil from the Forties Sandstone turbidite reservoir at approximately 2500m TVDSS. Production began in 1990 and the field still produces significant oil volumes today. In 2006, a re-appraisal of 1993 and 2000 vintage 4D seismic data over the field was initiated to de-risk infill drilling targets. This included a petrophysical and petroacoustic review, 4D seismic re-processing, relative elastic impedance inversion, and a related sand failure study. During the petrophysics and sand failure analysis, a multi-dimensional clustering technique was employed and compared with other statistical log prediction techniques. As a pre-conditioning for elastic inversion, frequency split structurally oriented filtering was used to de-noise critical low frequency components of the elastic stacks in order to expand the low frequency bandwidth. This paper presents the integrated progression from seismic data review with petrophysical and petroacoustic analysis leading to prediction of un-swept oil, and assisting infill well placement and design. We highlight the innovative technology used during each of the stages.