Arch Structures and Hydrocarbon Exploration

By

 Yahya Ahmed Al Fasatwi¹, K. J. Weber², P. M. van Dijk³

(1) Biruni Remote Sensing Centre, Tripoli, Libya, Tripoli, Libya (2) Department of Applied Earth Sciences, Technology University of Delft (TUD), Delft, the Netherlands, Delft, Netherlands (3) International Institute for Aerospace Survey and Earth Sciences, Enschede, the Netherlands, Enschede, Netherlands

 Arch structures are areas of broad, uplifts on a regional scale. They developed throughout the geologic history of the Earth. It is usually a basement doming. Basement structures such as arches are common features in many foreland basins. They are as important as basins in the tectonic history of the cratons and occupy similar surface areas, and are one of the most important producers of second order basins. In many continents the records indicate that arching was a dominant structural style during Early Paleozoic time. The plaeogeographic effect of arch development in adjacent sedimentary basins is clearly observed in many in many areas. Hydrocarbons are present around many of these arches in both structural and stratigraphic traps. It is recorded that arches or uplifts produce reefal belts in carbonate basins as in the Peace River Arch, Western Canada and will produce pinchouts in the case of clastic sedimentary areas as in Hassi Maessoud, Algeria. These structures are significant controls on the distribution of reservoirs and become focal point for hydrocarbon migration and accumulation. Several structural processes such as faulting and folding characterize areas of arches. This will keep the area of arches higher than the adjacent basins and erosional activity in areas of arches or uplifts than surrounding areas. The analysis includes characteristics of arch structures, occurrences of arches around the world, examples of arches located within different Paleozoic hydrocarbon producing sedimentary basins, and characteristics of oil fields associated with these structures. Al Qarqaf Arch separating west Libya the Ghadamis and Murzuq Basins were used as an example for the influence of arches on hydrocarbon migration and accumulations.