2024 PESA WEBINAR SERIES: Forward Modelling for Stratigraphic and Structural Analysis in Complex Mini-Basins, Offshore Sureste Basin, Mexico (Fugro)

Structurally active mini-basins characterize continental margins such as deep-water Angola, Brazil, North Borneo, and the Gulf of Mexico, and the stratal architecture of these mini-basins is dominantly controlled by the interplay of structural growth and sediment supply. We simulate and reproduce the observed stratal geometry using a reduced-complexity, fast computational model (Onlapse-2D), and through a process of iteration the model output is matched to available subsurface control (well logs, 3D seismic data).

Focusing on the late Miocene tectonostratigraphic evolution of a complex mini-basin in the offshore Sureste Basin, Mexico. Two cross-sections were chosen to intersect the existing well, one parallel to the axis of the minibasin and the other perpendicular to it, and two Onlapse models were generated from each. A good first-pass match between model output and geological observations was obtained, which allowed us to identify and separate the effects of two distinct phases of compressional folding and a longer-lasting episode of salt withdrawal/diapirism, and to determine the timing of these events.
Reduced-complexity simulation is an efficient and effective approach to understand the tectonostratigraphic evolution of complex deep-water minibasins. Onlapse models use real seismic interpretations of real active structures and by matching the forward model to the existing well data, it can provide insight into the geometry and timing of the controlling structural processes; demonstrate the changing proportion of background vs. sediment-gravity-flow deposits; and aid in the identification of key erosional or constructional surfaces within the stratigraphy.