Seismic geomorphological analysis of channel types: a case study from the Miocene Malay Basin

Abstract

Imaging the subsurface is a major challenge due to many aspects; the most notable is the resolution of the data, which often leads to misinterpretation of reservoir behaviour and depositional environment. Even with the robust tools available to precisely model the subsurface reservoir and depositional architecture, a precise result is still incorrect if derived from an inaccurate subsurface description. Recent advances in 3D seismic geomorphology analytical methods, particularly the application of root mean square (RMS) and frequency decomposition analysis, have enabled detailed imaging, description and classification of subsurface channel networks. Typically, it is easier to image shallow subsurface channels (<500 m depth), but it gets increasingly challenging to recognize channel features at subsurface depths ≥1.5 km. This paper presents the characterization of channel features imaged from such depths within the Miocene section of the Malay Basin, offshore Peninsular Malaysia. An integrated dataset from a selected area in the central region of the Malay Basin was used for this study, including a high-quality 3D seismic cube (1563 km2) and data from one well penetrating the Miocene section of the Malay Basin. We have identified five seismic geobody groups and 10 channel types from both planform and cross-section views. The dimensions, shapes, sinuosities and thicknesses of these channel types vary. Additionally, they display various seismic characteristics in cross-section and planform views. Variability in channel geometries is related to the complex interplay between fluvial and marine processes.