Geological and Geophysical Inversion by Hierarchical Classification – Combining Seismic Stratigraphic and AVO Attributes

摘要

We present a case study in which both texture facies and fluid prediction are linked by performing a hierarchical classification and estimation scheme whereby a multiattributes volume, which captures seismic stratigraphy and texture information, is combined with AVO attributes to map fluid response into a single, coherent seismostratigraphic and reservoir facies volume.The benefits of the application of seismic attributes classification in subsurface studies have been widely published. From horizon-based facies classification maps to more recent 3D multiattribute classification volumes, the approach is usually the same and driven by a twostep procedure. First, an unsupervised classification aims at revealing the natural clustering of the data, and second, a supervised scheme is applied where training and validation data are used to redefine the class cloud point centers based on well log data flagging a specific fluid or lithology. Recent advances in computing power enable the generation of multitrace or texture attributes, which capture the stratigraphic or structural elements of seismic data. In these workflows, the focus is always either, on the seismic texture facies for seismostratigraphic purposes or, on the reservoir facies for fluid and potential lithology detection and discrimination. The downside of these approaches is that they are not combined into a single common paradigm. We present a case study in which both texture facies and fluid prediction are linked by performing a hierarchical classification and estimation scheme whereby a multiattributes volume, which captures seismic stratigraphy and texture information, is combined with AVO attributes to map fluid response into a single, coherent seismostratigraphic and reservoir facies volume. This methodology is applied for exploration data screening in offshore Borneo in the Greater Samarang sub-block (East Baram Delta, offshore Sabah, Malaysia). In this case study, geological framework, seismic geomorphology, seismic stratigraphy, and combined fluid response from AVO data calibrated with well data facilitate the development of new play concepts in the highstand system tracts and in the morphology generated by incisions in the shoreface deposits during the low stands.