Integrated geological and geophysical analysis by hierarchical classification: combining seismic stratigraphic and AVO attributes

The benefits of seismic attribute classification in subsurface studies have been published widely. The approach is usually the same and, in most cases, driven by a two-step procedure – an unsupervised classification and a supervised scheme where training is used to redefine classes based on well-log data flagging a specific fluid or lithology. In parallel to the multi-attribute analysis, interpreters have also benefited from recent advances in computing power, enabling the generation of multi-trace or texture attributes.

In these two workflows, the focus is either on the seismic texture facies for seismic stratigraphic purposes, or on the reservoir facies for fluid and lithology mapping. This paper presents a case study in which both texture facies and fluid prediction are linked by performing a hierarchical classification scheme whereby a multi-attribute-based volume, which captures seismic texture information, is combined with amplitude versus offset (AVO) attributes to map fluid response into a single, coherent reservoir facies volume. This methodology is then applied for exploration data screening in offshore Borneo in the Greater Samarang sub-block (East Baram Delta, offshore Sabah, Malaysia). In this case study, the geological analysis, seismic geomorphology, seismic stratigraphy and combined fluid response from AVO attributes facilitate the development of new play concepts in the highstand system tracts and in the morphology generated by incised valleys in shoreface deposits.