--> --> Constraining Basin Models Using Fit-for-Purpose Crustal Architecture Workflows

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Constraining Basin Models Using Fit-for-Purpose Crustal Architecture Workflows


Crustal architecture and plate kinematic models provide boundary conditions and parametric input to basin models and petroleum systems analysis. The location of the Limit of Ocean Crust, craton hingeline, crustal thickness, crustal properties, and age all impact tectonic and basin models. Often, however, we have to choose between various tectonic models early in a project lifecycle before rigorous constraints are available or have been fully analyzed. Here, we investigate how certain crustal architecture elements constrain both rigid and deformable plate models, and demonstrate iterative, fit-for-purpose workflows to investigate crustal architecture, constrain regional tectonic models, and estimate petroleum system uncertainty as a project evolves. Early in a project lifecycle, public domain and vendor global crustal models can be used to generate first pass estimates of these parameters. These can be used, not only to evaluate alternative plate kinematic models, but also to efficiently characterize the 80% confidence range of the expected final crustal architecture and resulting basin models. Subsequent investigation of crustal architecture using available age control, seismic velocity, gravity, and magnetic inversion, as well as subsidence modeling, provides a refined estimate of the timing and location of the rift to drift transition. This estimate is represented quantitatively as the temporal and spatial boundaries between rigid and deformable phases of margin evolution in an improved plate kinematic model. Constructing a viable “full fit” tectonic model requires a rigorous, late stage workflow, where crustal architecture is derived from full synthesis and reconciliation of key geologic and geophysical data, as well as statistical analysis of structural and plate kinematic uncertainty. At each stage in a project lifecycle, the value proposition for further crustal architecture and plate kinematic analysis should be examined, relative to the remaining uncertainties. In complex settings (for example, asymmetric, hyperextended, or convergent margins), tectonic models can and should evolve throughout a project lifecycle in order to reduce uncertainty and constrain more reliable basin and petroleum systems models.