Geomechanical modeling of simple and high angle breakthrough fault- propagation folds

Document Type : Original Article

Authors

1 Department of Geology,Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran

2 Department of sedimentary and oil basins, Faculty of Earth Sciences, Shahid Beheshti University

3 Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, Iran

4 College of Engineering, Department of Mechanical Engineering, University of Tehran, Tehran, Iran

Abstract

Fault-related folds extend in most tectonics settings and in both extensional and compressional regimes. The widespread importance of such structures in the exploration and extraction of hydrocarbon resources and seismological aspects led to consideration beyond structural geology studies. On the other hand, understanding the geometric evolution of these folds can reveal the geometric relationship of these structures with the processes of placement and migration of hydrocarbon resources. This study uses two 2D finite element models to investigate geometric differences and stress-strain evolution differences in simple and high angle breakthrough fault-propagation folds. Results show that; A) In both types of folding, the plastic strain is concentrated on the surface of the fault, the fault tip, and the forelimb. B) In both types of folding, the pattern of stress-strain at the crest and fold limbs are similar, while it is different from the pattern of stress-strain at the fault surface, although the pattern of stress-strain at different points of faults (tip, middle, and base of the fault) are also similar to each other. C) Despite the similarity of the stress and strain evolution pattern in these two types of folds, three main differences can be identified, 1) reduction of strain-softening interval in the forelimb of breakthrough fault-propagation fold model, 2) increased differential stress in high angle breakthrough fault-propagation folds, and 3) in simple fault- propagation fold model, the strain-hardening interval increases to the fault tip, while in high angle breakthrough fault-propagation folds the reverse is true.

Keywords

Journal of Tectonics
Volume 5, Issue 18
September 2021
Pages 37-55

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