Abstract

Numerical Study of the Mechanism of Formation of Sodium Chloride Domes in Geological Structures Depending on the Geometrical Sizes of Area

Author(s): T. K. Akhmedzhanov, A. G. Tanirbergenov, Abd A. S. Elmaksoud and B. M. Nuranbaeva

The term “salt” include all rock bodies composed primarily of halite (NaCl). Salt is mechanically weak and flows like a fluid, even at geologically rapid strain rates. Salt is also relatively incompressible so is less dense than most carbonates and all moderately to fully compacted siliciclastic rocks. The primary driving force for salt tectonics is differential loading, which may be induced by gravitational forces, by forced displacement of one boundary of a salt body relative to another, or by a thermal gradient. Buoyancy considered a key driver for salt tectonics, is of secondary importance in many settings. Two factors resist salt flow: strength of the overburden and boundary drag along the edges of the salt body. Salt will move only if driving forces exceed the resistance to flow. Salt domes are diapiric structures involving the upward flow of low-density salt. The circular nature of these features is an indication of the fact that salt domes form as a result of upward flow independent of tectonic activity. The flanks of these structures provide excellent trapping mechanisms for oil and gas. For salt domes to form, thick accumulations of salt must be overlain by sediments of higher density. The exact origin of such a large quantity of salt is not fully understood; however, it is thought that some kind of closed basin of sea water that evaporates is the major mechanism involved. The salt is then buried under unconsolidated Mesozoic and Cenozoic sediments.