Print this pagePetroleum Provinces and Structural Evolution of Eastern Syria
BREW, GRAHAM, ROBERT LITAK, MUAWIA BARAZANGI, TARIF SAWAF, ANWAR AL-IMAM, and WASIF AL-YOUSSEF
Eastern Syria is dominated by two structural provinces, the Euphrates graben system and the Sinjar/Abd el Aziz uplift. These areas are the site of hydrocarbon production and ongoing exploration. We present a model of tectonic evolution of these mobile zones based on extensive seismic reflection data, well logs and other data. This leads to a regional picture of changing stresses in the northern Arabian platform during the Phanerozoic.
The Euphrates graben system extends some 160 km NW from the Iraqi border to the Palmyrides in central Syria. A complex branching network of numerous grabens and half-grabens is revealed, with no simple rift-bounding faults. The graben system likely formed in a transtensional regime, with estimated total extension of around 5 km. Although deformation initiated in early Senonian time, the main phase of extension occurred during Late Campanian-Maastrichtian. About 30 petroleum fields have been discovered in the Euphrates graben system since 1984, making it one of the major new plays of the decade. Typically, Lower Cretaceous sandstone reservoirs contain light oil in fault traps and are charged by Upper Cretaceous sources.
The east-west striking Sinjar uplift was originally a trough that began subsiding in the Middle Triassic and contains thickened sediments up to Late Cretaceous age. Whilst Late Cretaceous rifting was clearly fault controlled, Early Mesozoic thickening is not so obviously fault related. Compression initiated in the Late Miocene/Pliocene, reactivating normal faults to produce fault-propagation folds. These inverted structures are the traps for production from Mesozoic and Tertiary reservoirs. As in the Euphrates, Paleozoic strata hold promise for future discoveries, yet remain largely untested.
The difference in orientation of the Euphrates and Sinjar caused significant differences in structural evolution. However, both areas represent intraplate response to changing stresses at the boundaries of the Arabian plate.