Arabian artesian basin

ARABIAN ARTESIAN BASIN (RU: Аравийский артезианский бассейн) is situated on the peninsula of the same name, occupies the largest part of territory of Saudi Arabia. The area is approximately 1.5 million square kilometres.

The basin is confined to the Arabian plate with pre-Cambrian basement. It is limited with mountainous structures at the west and south, with the Mesopotamian basin (the boundary is conventional) at the north and north-west, and opens into the Persian Gulf at the east. The major water-bearing systems are associated with the Paleozoic, Mesozoic, Paleogene, and Neogene depositions, which are represented with terrigenous and carbonatic rocks. The thickness of the Paleozoic depositions is more than 2000 metres, of the Mesozoic ones is more than 3000 metres, the depth of the bedding of the roof is, respectively, down to 4000 metres and down to 1500 metres. The yields of the drilled wells within the Paleozoic depositions are from 0.5 to 32 litres per second (free flow at the east of the basin). The mineralization at the west is approximately 1 gram per litre, the composition is HCO3- and SO42- and Ca2+, the mineralization increases toward the east, the composition changes to Cl- and Na+; the temperature of water (at the depth of 400 metres) is approximately 38 degrees Celsius. The yield of the drilled wells within the Triassic depositions is up to 55 litres per second; the mineralization is 1.1-1.25 grams per litre, the composition is SO42- and HCO3- and Ca2+; the temperature is 52-53 degrees Celsius. The waters of the limestones of the Upper Jurassic and Lower Cretaceous are used with the pumping out from the karst sinkholes, the yield is from 240 to 730 litres per second; the mineralization of the water ranges from 1 gram per litre at the west of the basin to 3-10 grams per litre at the east, the composition at the west is SO42- and HCO3- and Ca2+, at the east is Cl- and Na+.

The Paleogene aquifer system is represented mainly with depositions of carbonatic rocks; the pressurized waters are unsealed at the depth from 150 to 250 metres; the yields of the water spring sources are from 0.5-2 to 528 litres per second; the yields of the drilled wells are from 0.1 to 79 litres per second (the drilled wells are gushing at the east); the mineralization of the water does not exceed 3 grams per litre at the north-west, and increases to 55 grams per litre toward the east. The thickness of the terrigenous-carbonatic depositions of Neogene is up to 1000 metres; the pressurized waters are unsealed at the depth of from 30 to 125 metres; the yields of the water spring sources are from 0.1 to 500 litres per second, of the drilled wells are up to 50 litres per second, within the Al-Hasa oasis are 227 litres per second; the mineralization of the water is 1.3-1.5 grams per litre, the composition is SO42- and Ca2+.

The main area of the feeding of the basin is situated at the west (along the periphery of the Arabian-Nubian shield), the regional area of the discharge is the Persian Gulf. The major source of the replenishment of the underground water resources are the condensed moisture and the infiltration of the atmospheric precipitation. They use the underground waters for the water supply of the populated places and industrial enterprises, for the watering irrigation.