Salt Tectonics and Sub-salt Exploration Plays in the Essaouira Basin, Morocco.

The Essaouira Basin forms part of the main Moroccan Salt Basin of the Central Atlantic Province. The salt is interpreted to have been deposited during rifting at ca. 200 Ma, as there are CAMP volcanics above and below the salt. The salt was particularly mobile in this basin, with large allocththonous sheets extruded, which are 1-2 km in thickness, and extrude up to 20 km away from vertical feeders. Sheet extrusion mainly occurred in the early Upper Cretaceous ca. 85 to 95 Ma. The salt canopy itself is interpreted to be folded on a wavelength of 10 km and amplitude of 700m, with a sediment cover of approximately 1.5 km of growth strata above the salt. This folding phase took place from late Oligocene? to Miocene times, and through to present day. The sea bed is folded, but is also undergoing extensional collapse where the sea floor has oversteepened. The recent folding has blown a lot of the shallow anticlinal traps and pre-salt targets are particularly attractive where the top seal will have remained intact. There is a perceived lack of reservoir potential in the deep salt basin, after two recent dry holes. However, new seismic data has been acquired with a 10 km long streamer length and this has enabled very good imaging below the complex allocththonous salt sheets. We have identified several important channel input points which contain pre-Santonian sandstones. These reservoirs have undergone later folding below the allocththonous salt sheet. Numerous truncation and sub-salt anticlinal traps have been identified, and the basin is considered to have good potential for a working Jurassic (oil)-Early Cretaceous(reservoir) petroleum system. We will present new high quality seismic data of the Lower Cretaceous pre-salt play, which has yet to be tested.