The origin of extensional drag folds, distribution of strain, and correlation to fractures with application to the Gilbertown field, Alabama

This dissertation is composed of three papers focusing on the origin of extensional drag folding and its related strain partitioning with application to the Gilbertown graben system in southwest Alabama. A new 2-D numerical growth trishear model and a strain prediction approach are proposed. The trishear model accurately reproduces the geometry of clay models and an extensional drag fold from the Gulf of Suez. Calculated strain ellipses can be used to predict the orientation of fractures. It is shown that the growth trishear model with compaction best predicts the geometry of the drag fold in the Gilbertown field. Strain associated with drag folding is well correlated with the fracture index value calculated from well logs using artificial neural networks.*; *This dissertation includes a CD that is compound (contains both a paper copy and a CD as part of the dissertation). The CD requires the following applications: Windows 95 or higher, WinZip, MS Word.