TY - JOUR A1 - Shekhar, R. A1 - Sahni, I. A1 - Benson, Gregory S. A1 - Agar, Susan M. A1 - Amour, Frédéric A1 - Tomas, Sara A1 - Christ, Nicolas A1 - Alway, Robert A1 - Mutti, Maria A1 - Immenhauser, A. A1 - Karcz, Z. A1 - Kabiri, L. T1 - Modelling and simulation of a Jurassic carbonate ramp outcrop, Amellago, High Atlas Mountains, Morocco JF - Petroleum geoscience N2 - Carbonate reservoirs pose significant challenges for reservoir modelling and flow prediction due to heterogeneities in rock properties, limits to seismic resolution and limited constraints on subsurface data. Hence, a systematic and streamlined approach is needed to construct geological models and to quickly evaluate key sensitivities in the flow models. This paper discusses results from a reservoir analogue study of a Middle Jurassic carbonate ramp in the High Atlas Mountains of Morocco that has stratigraphic and structural similarities to selected Middle East reservoirs. For this purpose, high-resolution geological models were constructed from the integration of sedimentological, diagenetic and structural studies in the area. The models are approximately 1200 x 1250 m in size, and only faults (no fractures) with offsets greater than 1 m are included. Novel methods have been applied to test the response of flow simulations to the presence or absence of specific geological features, including proxies for hardgrounds, stylolites, patch reefs, and mollusc banks, as a way to guide the level of detail that is suitable for modelling objectives. Our general conclusion from the study is that the continuity of any geological feature with extreme permeability (high or low) has the most significant impact on flow. Y1 - 2014 U6 - https://doi.org/10.1144/petgeo2013-010 SN - 1354-0793 VL - 20 IS - 1 SP - 109 EP - 123 PB - Geological Soc. Publ. House CY - Bath ER - TY - JOUR A1 - Scheffler, Franziska A1 - Oberhänsli, Roland A1 - Pourteau, Amaury A1 - Immenhauser, A. A1 - Candan, O. T1 - Sedimentologic to metamorphic processes recorded in the high-pressure/low-temperature Mesozoic Rosetta Marble of Anatolia JF - International journal of earth sciences N2 - Anatolia’s high-pressure metamorphic belts are characterized in part by a Neotethyan stratigraphic succession that includes a mid-Cretaceous hemi-pelagic marble sequence. This unit contains, towards its stratigraphic top, dm-to-m-long radiating calcitic rods forming rosette-like textures. Here, we refer to these features as “Rosetta Marble”. The remarkable textural similarity of non-metamorphic selenite crystals and radiating calcite rods in the Rosetta Marble strongly suggests that these textures represent pseudomorphs after selenites. Metamorphosed hemi-pelagic limestones, dominated by Rosetta selenite pseudomorphs, are alternating with siliceous meta-sediments containing relictic radiolaria tests. This stratigraphic pattern is indicative of transient phases characterized by evaporites precipitated from basinal brines alternating with non-evaporative hemi-pelagic deposition from normal-marine seawater. The regional distribution of Rosetta Marble exposures over 600 km is indicative of basin-scale evaporitic intervals. High-pressure, low-temperature metamorphism of these rocks is witnessed by Sr-rich (up to 3500 ppm), fibrous calcite pseudomorphs after aragonite and isolated aragonite inclusions in quartz. Peak metamorphic conditions of 1.2 GPa and 300–350 °C are attested by high-Si white mica thermobarometry. The Rosetta Marble case example examines the potential to unravel the complete history from deposition to diagenesis and metamorphism of meta-sedimentary rocks. KW - Gypsum KW - High-pressure metamorphism KW - Neotethys KW - Anatolia Y1 - 2016 U6 - https://doi.org/10.1007/s00531-015-1214-y SN - 1437-3254 SN - 1437-3262 VL - 105 SP - 225 EP - 246 PB - Springer CY - New York ER - TY - JOUR A1 - Agada, S. A1 - Chen, F. A1 - Geiger, S. A1 - Toigulova, G. A1 - Agar, Susan M. A1 - Shekhar, R. A1 - Benson, Gregory S. A1 - Hehmeyer, O. A1 - Amour, Frédéric A1 - Mutti, Maria A1 - Christ, Nicolas A1 - Immenhauser, A. T1 - Numerical simulation of fluid-flow processes in a 3D high-resolution carbonate reservoir analogue JF - Petroleum geoscience N2 - A high-resolution three-dimensional (3D) outcrop model of a Jurassic carbonate ramp was used in order to perform a series of detailed and systematic flow simulations. The aim of this study was to test the impact of small- and large-scale geological features on reservoir performance and oil recovery. The digital outcrop model contains a wide range of sedimentological, diagenetic and structural features, including discontinuity surfaces, shoal bodies, mud mounds, oyster bioherms and fractures. Flow simulations are performed for numerical well testing and secondary oil recovery. Numerical well testing enables synthetic but systematic pressure responses to be generated for different geological features observed in the outcrops. This allows us to assess and rank the relative impact of specific geological features on reservoir performance. The outcome documents that, owing to the realistic representation of matrix heterogeneity, most diagenetic and structural features cannot be linked to a unique pressure signature. Instead, reservoir performance is controlled by subseismic faults and oyster bioherms acting as thief zones. Numerical simulations of secondary recovery processes reveal strong channelling of fluid flow into high-permeability layers as the primary control for oil recovery. However, appropriate reservoir-engineering solutions, such as optimizing well placement and injection fluid, can reduce channelling and increase oil recovery. Y1 - 2014 U6 - https://doi.org/10.1144/petgeo2012-096 SN - 1354-0793 VL - 20 IS - 1 SP - 125 EP - 142 PB - Geological Soc. Publ. House CY - Bath ER -