The Northern Gulf of Mexico Basin is part of a small ocean basin characterized by a complex structural framework. The complex structural framework is shaped by the dynamic interaction between salt tectonics and sedimentation. Salt withdrawal mini-basins are among the structural features produced by this interaction and are of particular interest to hydrocarbon exploration. The mini-basins provide significant accommodation in which thick packages of sediments can accumulate. The accumulation of sediments can be very rapid during episodes of high sedimentation such the middle Miocene episodes in the northeastern Gulf of Mexico. Rapid accumulation of sediment in turn changes the local topography of the mini-basin and also lead to significant build up of overpressure. In such settings, the structure and the stratigraphy in the vicinity of mini-basin are influenced by salt movement and the rock properties can be altered due to salt movement and overpressure development. Therefore, the factors of salt movement and overpressure development are crucial in understanding the evolution of the petroleum system in mini-basins. Insights on the roles of these factors in defining the evolution of the petroleum system are beneficial for hydrocarbon exploration. Such insights are of use in addressing practical problems in reservoir characterization, pore pressure prediction and basin and petroleum system modeling (BPSM).
This dissertation establishes insights on the roles of these factors through meticulous quantification of related geologic processes to address some of the stated practical problems above. Chapter 1 quantifies the spatial variations in sediments compaction and clay diagenesis to define spatial trends of elastic properties and use these for seismic reservoir characterization in frontier areas. Chapter 2 studies the impact of high sedimentation and salt movement on the thermal history of a mini-basin to propose a workflow for predicting the effects of smectite to illite diagenesis on overpressure. Chapter 3 investigates the implications of lateral slip along salt-related faults to pressure and thermal history to address the proper application of BPSM techniques in constructing paleo-geometry when modeling these faults. This dissertation focuses on Thunder Horse mini-basin in the Mississippi Canyon area by integrating 3D seismic data with well-logs, biostratigraphic data and borehole measurements of pore pressure and temperature.