ABSTRACT

The failure of sediments as a consequence of lateral motion of a salt sheet is investigated. Variations in behavior are examined due to salt thickness, depth of emplacement, speed of motion in relation to sediment deposition rate and increase of sedimentary elastic constants with depth. Mohr's criterion for failure is typically satisfied two to five thicknesses ahead of the moving salt sheet as well as about a salt thickness or two to the sides of the salt. Failure angles range from acute to obtuse, and a pronounced asymmetry in pattern development is apparent above and below the salt. Inferences are discussed for fractured reservoirs above and below the salt, for detachment surfaces and normal and antithetic faulting, as well as for fracturing acting as an aid to ease the salt motion. The results obtained impact on the understanding of salt sheets as areas of prospective hydrocarbon accumulations.