The Jurassic Depositional System of Morocco; Geology and Exploration Play Concepts

By

Mohamed Dakki¹, M. Hssain¹, M. El Alji¹, M. Nahim¹, M. Zaidi¹, M. El Mostaine¹

(1) Onarep, Rabat, Morocco

 The Jurassic depositional system of Morocco occurred in two distinct geographic domains: (1) Along a complex zone located at the westernmost portion of the Tethys seaway and (2) at the eastern margin of the central Atlantic margin.

Sedimentary deposits resulted, essentially, from the relative sea level changes during the complex successive tectonic phases of continental collision and plate divergence inducing the deposition of various facies ranging from continental and lagoonal carbonate and clastic to open marine deposits. Carbonate, often reefal dominated, were deposited within platforms and along existent shelf edges.

From tectonic point of view, normal faults initiated during the rifting period were reactivated into high to medium angle reverse faults, during Late Cretaceous to Early Tertiary time, inducing the formation of various imbricates and structures within the Mesozoic series. Recent integrated studies based on seismic interpretation, well data and outcrops, have permitted to assess the hydrocarbon potential of the Jurassic depositional system of Morocco.

Geochemical analyses carried out on samples from drilled wells and outcrops show that rich and mature source rocks are developed within Palaeozoic, Jurassic and Cretaceous series.

Combination of structural assessment with geochemical results and seismic interpretation has permitted to map various kitchens and to define new play concepts within viable petroleum systems. The developed concepts such as sub-thrust have never been tested yet.