AAPG Middle East Region Geoscience Technology Workshop

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Fracture Distribution and Patterns within Phanerozoic Siliciclastic Outcropping Reservoir Equivalent Formations, Saudi Arabia

Abstract

This study investigates the fracture distribution and patterns within Paleozoic siliciclastic outcropping reservoir equivalents in Saudi Arabia. These outcropping units are considered important targets for oil and gas exploration and development in the subsurface in different basinal areas in Saudi Arabia and the region. Revealing fracture patterns might help to reveal their origin, types and controls on their evolution and development and reservoir implication. This study is based on carefully selected outcropping siliciclastic in southern, central and northern Saudi Arabia. The study integrates geological map information, Landsat observation on local and regional scale and detailed high resolution outcrop observation and measurements and analysis. The results of fracture observation and analysis revealed a clear distribution, pattern and orientation in different directions including North-South, East-West, North East-South West and North-West South East. A correlation is noted between regional lineaments and local fracture patterns at outcrop scale. Fracture characteristics (intensity, spacing, opening, orientation and aperture) tend to vary among the studied siliciclastic outcrop formations. Fracture patterns and lithofacies at outcrop scale acted and contributed as structural and depositional barriers and heterogeneities that contributed to reservoir complexity in terms of continuity and connectivity, stratigraphic architecture and potentiality. Our conclusions were supported by previous observation and measurements based on Landsat, outcrops, seismic, well and drilling data within the Arabian platform. Variations in fracture patterns seem to be controlled by both local (intrabasinal) and extrabasinal controls within the Arabian Plate during the Pre-Cambrian and Phanerozoic time. The integration of field outcrop results with subsurface data might help to provide better understanding, revealing challenges and allow to reconstruct robust geological models capable to characterize fractured siliciclastic reservoirs. Consequently, this might help to provide guides for reservoir exploration and exploitation.