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Application of 3-D Structural Analogue Modeling to Hydrocarbon Exploration: Examples From Subandean Bolivia, the Gulf of Mexico and Papua New Guinea


Seismic imaging in foreland thrust belts remains a challenge as often only the syncline geometries are properly characterized. Structural complexity in the fold cores is generally high, particularly considering multiple décollement levels in the pre-tectonic sedimentary section, for instance in Bolivia or Papua New Guinea. The same problem is encountered in salt tectonic provinces, especially for the domains with a succession of mini-basins, such as in the Gulf of Mexico, where the deformation affecting their borders is difficult to observe in detail. Moreover, the accuracy of the observation and thus the interpretation usually decreases with depth. Prior to committing to multi-million $ wells, it is crucial for petroleum exploration companies to know and understand the mechanisms that trigger decoupling and the associated kinematics, in order to better constrain the 3D geometries of the deep target areas. Typically the exploration program commences with interpretative work and the development of 2D and 3D geological models, including forward models and/or balanced and restored cross sections. However, it is often difficult to validate one scenario versus another due to the lack of detail in the complex cores of the structures and to the poor understanding of the structural evolution. Sandbox analogue modeling performed under an X-ray tomography device is a powerful tool to validate or test an interpretation of a complex structural area. It allows the analysis in 3D through time (4D) of analogue structures observed in such areas. Here we present three exploration studies where analogue models provided some key insights into the structural complexity: 1. Subandean Bolivia, where the evolution of a double decollement level system is clearly affected by the process of erosion / sedimentation and well-illustrated by a set of analogue models. 2. The large frontal anticlines of the Papua New Guinea Fold Belt, containing the bulk of the oil and gas reserves, where the internal geometry and the complex structural and tectonic evolution are poorly understood. A set of analogue models illustrates the different possible evolutions of these structures affected by a pre to syn-tectonic basement fault. 3. In the Gulf of Mexico, a set of analogue models illustrates different evolutions of mini-basins affected by surface erosion and sedimentation processes and/or by active compression.