Three-dimensional characterization and mechanics of brittle deformation in thrust fault related folds

This thesis addresses the proposition that a better understanding of fractures will aid in the optimization of hydrocarbon recovery in thrust fault related folds.; Fault planes, stratigraphic layers, and stratigraphic growth features interpreted within a three-dimensional volume of seismic reflection data collected over the Elk Hills Oil Field, Kern County, CA are integrated with mechanical models to develop a four-dimensional fault evolution history that is structurally, stratigraphically, and mechanically consistent. The developed fault chronology has direct implications for the migration and emplacement of hydrocarbons. The method introduced here, by which structural and stratigraphic interpretations are incorporated into a sequence of forward mechanical models, represents an effective means of constraining the structural evolution of a fault network that developed within a syn-depositional tectonic setting.; The development of fractures in the sedimentary layers of Sheep Mountain anticline, a Laramide asymmetric fault-cored fold of the Bighorn Basin of Wyoming, is documented and interpreted as a method of constraining the kinematic evolution of the fold. The relative chronology, mode of formation (opening vs. shearing), and structural locations of these fractures provide the following constraints interpretations of fold kinematics: there was little or no lateral fold propagation and no hinge migration; limb rotation or limb flexure and stretching operated at different structural locations during folding.; Field observations of sheared fractures in various structural locations across Sheep Mountain document the role of fracture reactivation. Differences in observations of shearing constrain spatial and temporal variations of the stress state across the anticline during folding. Differences in both the formation and reactivation of fracture sets in the forelimb and backlimb indicate that the stress state in the forelimb was significantly influenced by the underlying fault.; The coupling of fracture mapping with analysis of high precision GPS positions collected across patches of bedding surfaces at Sheep Mountain provides insight into the curvature-fracture relationship. Comparison of principal curvature magnitudes with fracture measurements indicates that greater curvature correlates with greater spherical variance of fracture sets. Fracture intensities, however, correlate only loosely with curvature, so fracturing mechanisms other than flexure must be taken into account.