Reducing Source Rock Uncertainties using Forward Stratigraphic Modelling – a Guiana Basin Offshore Suriname Case Study

Source rock prediction in frontier deepwater basins is fundamentally limited by sparse well control and the complex interplay of factors governing organic matter production and preservation. The Cenomanian-Turonian (C-T) interval in the Guiana Basin, offshore Suriname, is a prime example. Despite its recognized petroleum system significance, its lateral extent and quality remain poorly defined outside a handful of ODP drill sites and industry wells. Forward Stratigraphic Modelling (FSM) offers a process-based approach to bridge this gap, simulating primary productivity, sediment supply, accommodation, and bottom-water oxygen conditions to predict TOC, Hydrogen Index, and source rock thickness and distribution across the basin. We apply this workflow to the C-T interval of the Guiana Basin, building a basin-scale FSM model constrained by well and seismic data. FSM models, however, are deterministic and non-unique: different parameter combinations can produce equally plausible outcomes, all matching the calibration data. In frontier settings, key inputs such as organic matter paleo-productivity, accommodation influencing depositional environments, and oxygen conditions governing preservation carry substantial uncertainty. Capturing the full range of possible source rock configurations requires running hundreds of simulations, which rapidly becomes computationally prohibitive. The response surface methodology, a mathematical proxy built from a Latin Hypercube Sampling experimental design that reproduces FSM behavior at a fraction of the cost, allows thousands of realizations to be generated instantaneously. This yields sensitivity rankings, P10/P50/P90 property maps, and probabilistic assessments of source rock presence above economic thresholds. Calibration of the FSM TOC output against the Staatsolie GeoAtlas well dataset shows good spatial consistency, with the model reproducing the overall trend of increasing TOC toward the deepwater depocenter, reflecting the transition from oxic shelf to anoxic bottom-water preservation in the northeast. Sensitivity analysis highlights paleo-bathymetry and primary productivity as the dominant controls on source rock development, with nutrient supply and sediment dilution playing important secondary roles. Sedimentation rate shows a nonlinear influence, with optimal TOC preservation at intermediate rates balancing organic flux against mineral dilution and oxic exposure. Continental nutrient supply from large catchments emerges as a key factor in enhancing primary productivity and source rock thickness. Risk analysis indicates variable probability of source rock presence across the basin, with highest confidence near known occurrences and increasing uncertainty toward less constrained areas. The probabilistic outputs support charge risk ranking and integration with petroleum system assessment frameworks, providing a practical approach to source rock de-risking in data-sparse deepwater frontier settings.