The application and value of AVO and spectral decomposition for derisking Palaeogene prospects in the UK North Sea

Abstract

Perhaps over a billion barrels of oil, distributed over dozens of mostly small prospects, remain trapped in Palaeogene reservoirs in the UK sector of the North Sea Basin. Here we consider whether traditional amplitude versus offset (AVO) analysis, augmented by spectral decomposition, can provide a useful tool in helping to evaluate which of these prospects are worthwhile targets for drilling. In recent years, exploration drilling in the Palaeogene play fairway of the UK Northern North Sea has had mixed results. Eighty percent of wells drilled since 2000 have failed to encounter hydrocarbons, for reasons that include poor interpretation and evaluation of prospects, lack of AVO analysis, and positioning of wells on poor quality seismic data. Our analysis suggests that AVO analysis and spectral decomposition can be very useful and powerful tools for predicting the presence or absence of hydrocarbons in undrilled Palaeogene prospects in the North Sea. However, the validity of the results depends upon the availability of good quality seismic data with broad frequency content that have been acquired with cable lengths greater than 3 km.