A geological survey of the central Saudi Arabia reveals a lot about its structural transition and rock compositions that make it the world’s largest reservoir of oil in the word. Specifically, central Saudi Arabia consists of the world’s richest oil fields that are concentrated in the Greater Ghawar province whose Paleozoic and Jurassic systems of the Arabian Peninsula are largely the sources of oil and gas deposits (Pollastro, 9).
The central part of Saudi Arabia, interior Homocline-central province is composed of gently undulating sedimentary rocks that encroach into Mesopotamia from the Widyan basin registering unexpected breaks at various points in the rock pattern (Pollastro, 11). To the east is a flat lying rock and a basement ridge registered along a latitude of 24? defining the central Arabian Arch.
The region is rich in hydrocarbon particularly the region defined by Paleozoic and Jurassic petroleum systems. The geology or structural settings due to tectonic movements and petrochemical reactions led to the accumulation of large oil deposits in the region (Pollastro, 12).
Structural settings due to tectonic movements within the Arabian Peninsula can be classified into five phases (Pollastro, 12). The initial phase consisted of the Precambrian compression stage which assembled the Arabian plate. It is defined by a micro-continental terrain in an island-arc. The second phase
consists of extensive sediment deposits within the Najd fault system that is located in the intracratonic profile in the Paleo-enthys Sea. On the other hand, the third phase is descriptive of a geological mapping that was characterized by compression and extensional stresses. This stage is commonly referred to as the late Precambria phase that extended to the late Devonian structure.
The fourth phase is characterized by a back arc structure defined partly by a coeval structure predominating the low and latitude of the geostructure of the region. This phase is commonly referred to as the Mid-Permian phase. The fifth phase is descriptive of extensive sedimentation of carbonate evaporative deposits. That translates to the modern day geological map (Moscariello, Spaak, Jourdan & Azzouni, 5).
This geological settlement is characterized by a fore-deep basin defined by chronostratigraphic interactions across the Oman Mountains through the red sea, to Zargos Fold Belts to the Red Sea. This description identifies a framework of hydrocarbon deposits in the central regions of Saudi Arabia.
Predominant deposits in the central part of the country particularly the Pre-Khuff and Khuff regions are characterized by extensive marine environment in the Paleozoic section. Further still the region is geologically defined by epeirogenic uplifts characterized by breaks at regular intervals. The region is also characterized by halokinetics, micacuous sandstones that are shallow in deposition, Infracambrian clastics, arkosic sandstone, and argillaceous sandstones (Pollastro, 20).
The petroleum geochemistry is defined by rock deposits that are organically rich shale facies formed due to upward coarsening material deposits. These consist of upper and lower Qalibar members. These deposits consist of shale, sandstones, and siltstones. These also formed the basis of oil condensation particularly the Paleozoic reservoirs of the central region of Saudi Arabia.
These rocks are belong to the family members described above and consist of abundant deposits of graptolites, chitinozoans, carbonate, sandstones sources, and seal rocks such as Early Silurian Qusaiba Shale (Pollastro, 26). Thus, the geology of the region is a complex mass of rock strata, rock movements, sedimentation, and other organic layers that led to massive deposits of oil apparently the richest in the world.
Pollastro, Richard M. Total Petroleum Systems of the Paleozoic and Jurassic, Greater Ghawar Uplift and Adjoining Provinces of Central Saudi Arabia and Northern Arabian-Persian Gulf. U.S. Department of the Interior U.S. Geological Survey. Anonymous. 1 Dec. 2010.
Moscariello, Andrea Pieter, Spaak, Alain, Jourdan, & Abdul-Hameed Azzouni. The Ordovician Glaciation in Saudi Arabia — Exploration Challenges Part 1. Geology (Outcrop, Subsurface, Analogues).14 May 2010.1 Dec. 2010.