Integrated Fault Seal Analysis
Faults commonly trap fluids such as hydrocarbons and water and therefore are of economic significance. During hydrocarbon field development, smaller faults can provide baffles and/or conduits to flow. There are relatively simple, well established workflows to carry out a fault seal analysis for siliciclastic rocks based primarily on clay content. There are, however, outstanding challenges related to other rock types, to calibrating fault seal models (with static and dynamic data) and to handling uncertainty.
The variety of studies presented here demonstrate the types of data required and workflows followed in today's environment in order to understand the uncertainties, risks and upsides associated with fault-related fluid flow. These studies span all parts of the hydrocarbon value chain from exploration to production but are also of relevance for other industries such as radioactive waste and CO2 containment.
Fault zone architecture and its scaling laws: where does the damage zone start and stop?
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Published:July 17, 2020
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CiteCitation
A. Torabi, T. S. S. Ellingsen, M. U. Johannessen, B. Alaei, A. Rotevatn, D. Chiarella, 2020. "Fault zone architecture and its scaling laws: where does the damage zone start and stop?", Integrated Fault Seal Analysis, S. R. Ogilvie, S. J. Dee, R. W. Wilson, W. R. Bailey
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Abstract
Damage zones of different fault types are investigated in siliciclastics (Utah, USA), carbonates (Majella Mountain, Italy) and metamorphic rocks (western Norway). The study was conducted taking measurements of deformation features such as fractures and deformation bands on multiple 1D scanlines along fault walls. The resulting datasets are used to plot the frequency distribution of deformation features and to constrain the geometrical width of the damage zone for the studied faults. The damage-zone width of a single fault is constrained by identifying the changes in the slope of cumulative plots made on the frequency data. The cumulative plot further shows high deformation frequency by a steep slope (inner damage zone) and less deformation as a gentle slope (outer damage zone). Statistical distributions of displacement and damage-zone width and their relationship are improved, and show two-slope power-law distributions with a break point at c. 100 m displacement. Bleached sandstones in the studied siliciclastic rocks of Utah are associated with a higher frequency of deformation bands and a wider damage zone compared to the unbleached zone of similar lithology. Fault damage zones in the carbonate rocks of Majella are often host to open fractures (karst), demonstrating that they can also be conductive to fluid flow.
- Apennines
- bleaching
- Cache Valley
- carbonate rocks
- Central Apennines
- damage
- deformation
- displacements
- Europe
- fault zones
- faults
- fluid flow
- foot wall
- fractures
- geometry
- Grand County Utah
- Italy
- karst
- mechanical properties
- mechanism
- Mesozoic
- metamorphic rocks
- Moab Utah
- Navajo Sandstone
- normal faults
- Norway
- outcrops
- Paradox Basin
- power law
- scale models
- Scandinavia
- sedimentary rocks
- siliciclastics
- Southern Europe
- statistical analysis
- statistical distribution
- United States
- univariate analysis
- Utah
- Western Europe
- Oygarden Complex
- Sotra Island
- Moab Fault
- Majella Mountain
- Humbug Flats