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Площадь: 77657.21 км²
Essaouira Basin
Essaouira Basin Lying on the Atlantic coast, this basin has a similar Pre-Tertiary geological history to the Scotian Shelf on the conjugate margin of Canada (Figure 1a). The stratigraphy of the Essaouira Basin can be divided up into the pre-rift Palaeozoic section culminating in the Hercynian compressive events, a syn-rift Triassic to mid-Jurassic section deposited during the Proto-Atlantic opening, and the post-rift Late Jurassic to Late Tertiary section culminating in the Atlassic compressive events. Potential source rocks are located in the SiluroDevonian and Lower Oxfordian shales; however, the true distribution of the source rocks remains uncertain. The principal reservoir rocks are found in fractured Argovian (Middle Oxfordian) carbonates and thinly bedded Upper Triassic fluvial sandstones. Potential reservoirs are found in fractured Devonian carbonates, Ordovician sandstones and Liassic carbonates. Seals are present throughout the succession, but of note above the main reservoirs are the Late Jurassic evaporite/carbonate section, the Upper Triassic Evaporite, basal Triassic shales and Siluro-Devonian shales.
Figure 1: Essaouira Basin onshore and offshore: a) Offshore Morocco Early Cretaceous opening of the Atlantic Ocean. b) Sidi Rhalem onshore field surface anticline – field trip photo. c) Onshore Essaouira fields and pipelines. d) NW–SE geoseismic cross-section.
There has been a resurgence of activity in the offshore area over the past decade where sizeable structures have been drilled. However, the onshore petroleum systems, with Jurassic source rocks and carbonate reservoirs and Cretaceous carbonates and clastics, has remained enigmatic and to date, no commercial successes have been recorded. Onshore, the working Jurassic–Cretaceous petroleum system is illustrated by the small Jurassic Sidi Rhalem field (discovered in 1961, Figures 1b–d). The distribution of mature Oxfordian source rocks is limited (as is the prospectivity of shallow targets) by the generally shallow depth of burial. However, there is a more deeply buried Palaeozoic–Triassic system and Triassic fluvial sands of the TAGI that are productive in the Meskala gas field, discovered in 1977 and operated by the Moroccan National Company, ONHYM. A key element of the Essaouira Basin fields is the Triassic salt providing a seal for Meskala and structural deformation of the overlying strata by halokinesis. However, Jurassic–Cretaceous traps appear to be small to moderate in size and improved seismic coverage is needed to better define drilling targets. The deeper Palaeozoic has yet to become a more popular target for exploration.
Data source:Productive Petroleum Basins of Morocco. STUART HARKER. GEOSCIENCE & TECHNOLOGY EXPLAINED VOL. 18, NO. 5 – 2021
Следующий Бассейн: Souss