Basic Framework, Deformation, and Petroleum in Middle East: ABSTRACT

Abstract

The most prolific oil-producing area of the Middle East lies on the southern flank or extension of the ancient Asiatic Tethyan geosyncline and was at least partly subjected to the same tectonic forces which produced the Alpine-Taurus-Himalayan Mountains. The importance of these tectonics is second only to depositional conditions in the Arabian-Persian Gulf geosyncline during which occurred the proper distribution of salt and anhydrites in time and place. To emphasize the importance of the evaporites, most if not all of the large gentle structures of Arabia and the southern gulf are salt-generated and the remaining structures in Iran and Iraq were created or modified by plastic deformation of salt and anhydrite. The Hith Anhydrite caps Jurassic oil in Arabia; the Fars Anhydrite caps Cretaceous-Miocene oil in Iran and Iraq. Late Tertiary deformation and fracturing of the Cretaceous Bangestan and Miocene Asmari Limestones created the long lines of story-book folds of the Zagros Mountains and oil reservoirs in Iran and Iraq. Fractured Bangestan oil reservoirs leaked much of their contents upward into fractured Asmari reservoirs where oil finally was trapped by the plastic Fars Formation. End_Page 469------------------------------ Zagros deformation not only determined the size and shape of reservoirs but also their permeability and porosity. The economic importance of this area is obvious. The Middle East, especially the Arabian-Persian Gulf and its periphery, is presently producing more than one third of the world's oil. Recent discoveries and extensions of known reservoirs have increased production to the point that the area produces more than North America. More than half of the world's proved reserves are in this area. Communist-block countries, in spite of tremendous potential, are contributing less than one-sixth of total world oil. Doubtless this is partly a result of the fact that these countries still have not attained the same wide use of petroleum products as the free world. Also, oil commerciality depends on the proper balance between a stable growing market and cheap transportation. The unique accessibility and availability of Middle East oil from this gulf guarantees its rising importance in world-energy needs. A plethora of oil is here and available; transportation is cheap. Extensive oil discoveries in new, inaccessible, or distant inland areas, even in the Middle East, world conditions permitting, should in no way threaten this source for many years to come. End_of_Article - Last_Page 470------------