Slope-fan depositional architecture from high-resolution forward stratigraphic models. (March 2018)

• Record Type: Journal Article
• Authors: Hawie, Nicolas; Covault, Jacob A.; Dunlap, Dallas; Sylvester, Zoltán
• Is Part Of: Marine and petroleum geology. Volume 91(2018)
• Page Start: 576
• Page End: 585
• Publication Date: 2018-03
• Subjects: Submarine fan -- Stratigraphic model -- Deep-water -- Channel -- Lobe -- Compensational stacking; Submarine geology -- Periodicals; Petroleum -- Geology -- Periodicals; Géologie sous-marine -- Périodiques; Pétrole -- Géologie -- Périodiques; Petroleum -- Geology; Submarine geology; Periodicals; Electronic journals; 551.468
• DOI: 10.1016/j.marpetgeo.2017.12.033
• Languages: English
• ISSNs: 0264-8172

Abstract

Abstract: Submarine fans in tectonically active continental-slope basins are targets of petroleum exploration and production. These slope fans commonly comprise compensationally stacked sandy and muddy architectural elements, including mass-transport deposits, weakly confined to distributary channel-and-lobe deposits, and leveed-channel deposits. The lateral continuity and vertical connectivity of these architectural elements are important uncertainties in reservoir characterization that influence fluid-flow behavior during hydrocarbon production. Here, we use a simple forward stratigraphic model to simulate the stratigraphic patterns and illuminate the likely distribution of fine-scale, sub-seismic heterogeneity in a slope fan. We used published seismic-reflection horizons from the tectonically active Columbus basin, offshore Trinidad, to define the top and base of a Pleistocene submarine fan. We then simulated the stratigraphic evolution of the slope fan with a series of DionisosFlow™ forward stratigraphic models. All variables were kept constant during the simulations in order to test the hypothesis that the autogenic evolution of the surface topography alone, as a result of erosion and deposition, can produce compensational-stacking patterns common in submarine fans. A reference-case model is similar to the thickness trend of published isochron maps of the Trinidad slope fan. The reference-case model also produced patterns of compensational stacking. Varying the time step impacts the heterogeneity of the model. Shorter time steps are characterized by less sediment accumulation, which results in less sediment diversion during the subsequent time step, more gradual migration of channel deposits, shorter offset distances of depocenters, and shorter length-scale heterogeneity compared to longer time steps. Thus, a key characteristic of slope-fan deposits is autogenic compensational stacking, without any external forcing, which governs heterogeneity in these reservoirs. Furthermore, our results suggest that relatively simple diffusion-based models can produce realistic compensation patterns and future work will be focused on higher-resolution model calibration to seismic-reflection data and the influence of input variables on heterogeneity of channel-and-lobe deposits of slope fans. Highlights: First high-resolution DionisosFlow forward stratigraphic model to reproduce stratigraphic patterns and illuminate sub-seismic heterogeneity in a tectonically active deep-water slope fan. Model reproduces thickness trend and compensational stacking of channel-and-lobe deposits. Varying time step impacted model heterogenetiy; shorter time steps are characterized by shorter length-scale heterogeneity compare to longer time steps. Autogenic evolution of the surface topography produces realistic compensational-stacking patterns of slope-fan deposits.