Naslov
Permian and Mesozoic Deposits in Well Mudawara– 1 (Aphamia, Syria): New Sedimentological Data Based on the Core Reinterpretation

Autori
Tišljar, Josip ; Veseli, Vladimir ; Vlahović, Igor ; Koch, Georg

Izvornik
Nafta : exploration, production, processing, petrochemistry (0027-755X) 59 (2008), 4; 180-194

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
sedimentology; lithofacies; sabkha evaporite; early- and late-diagenetic dolomites; Permian and Mesozoic; Mudawara-1 Well; Syria

Sažetak
This paper contains the results of lithofacies and sedimentological interpretations of 6 cores (Fig. 1) from the Mudawara-1 exploration well drilled in the “ Aphamia Block” located in West Central Syria (Fig.2). The oldest part of the deposits is represented by Core-7 (3 077.4 – 3 095.0 m) composed of Lower Permian delta flat shale and sandstone beds characterized by fining upward sequences indicating channel fills (Figs. 3-4). Core– 5 comprises Lower to Middle Carnian deposits of the interval 2 165.0 – 2 193.3 m. They are composed predominantly of carbonate rock – limestone and dolomite – with interbeds of dolomitic shale, and are subdivided into 3 lithofacies units: - The oldest layers (Lithofacies A) were deposited in a shallow marine environment, which at least temporarily, had a connection with open-marine areas ; - Carbonate deposits of Lithofacies B were accumulated within peritidal environments, in the form of shallowing-upward sequences, sporadically with sabkha conditions ; - The youngest part of Core– 5 (Lithofacies C) is represented by early-diagenetic dolomite, indicating early-diagenetic dolomitization in supratidal environments with temporary sabkha conditions ; Core– 4 (2 095.81– 2 123.48 m) comprises Lower to Middle Carnian deposits (Lithofacies D) mostly composed of sabhka dolomite– anhydrite cycles with thin interbeds of dolomitic shale or silty dolomite and late-diagenetic dolomite (Figs. 5-6) ; Core– 3 and Core-2 represent Triassic-Jurassic transition layers drilled between 1 409.30– 1 452.0 m, consisting of late-diagenetic “ sucrosic” dolomite with secondary anhydrite fillings of tectonic fissures, in places with thin interbeds of dolomitic shale (Lithofacies E – Figs. 7-9). Note, that these rocks are reported as Lower to Middle Jurassic, Mulussa – A formation by a Marathon Oil Company study1 ; Core– 1 (1 046.90– 1 056.40 m) comprises a sequence well of Albian– Lower Cenoma¬ ; ; nian age. It is composed of thin-laminated early-diagenetic dolomite which is in places tectonized, almost brecciated. Tectonic fissures and corrosion¬ ; ; voids are filled by a secondary macrocrystalline anhydrite, in places hydratized into gypsum (Lithofacies F) (Figs. 10-11). Anhydrite of Lithofacies E and F is of a secondary, late-diagenetic origin, since it was – along with the replacement of dolomite – precipitated during the post-tectonic phase within tectonic fissures and corroded voids in dolomite from pore solutions oversaturated in Ca-sulfate.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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