Structural study of Nahr Umr Oil Field in Southern Iraq

Abstract

Nahr Umr oil field is one of the important productive southern Iraqi oil fields. This studyfocuses on the type of fold and faults of the Nahr Umr oil field. A structural analysis(geometric and genetic analyses) performed to identify its type, origin and to find its relevanceto main regional tectonic events. The structural classifications employed well and geophysicaldata through using structure contour maps, cross sections, and seismic section.The structural analysis inferred that fold of Nahr Umr oil field classified as antiform, upright,non-plunge, gentle, supratenous, dome feature, and asymmetrical. The limbs are unequalwhereas the length of left limb shorter than the right limb and its dip is greater than right limb.In addition, the thickness of crest is less than the thickness of limbs. Pattern of faults classifiedas compound, parallel, conjugates and radial with graben structure and these faultsconcentrated on crest of fold. The fold axis is almost N-S at early cretaceous and then clearlyturns to NW-SE and this may due to counterclockwise rotation of Arabian plate. Geophysicalinterpretations and results of structural analysis stated that Nahr Umr oil field formed by threecombined forces which are tectonic movements, reactivated basement, and salt structures.