Research in Morocco

Moroccan Atlantic Margin has experienced km-scale vertical movements during its post-rift evolution. Uplifts have controlled the distribution of sedimentary systems and the origin of the sediments delivered to the margin. Untangling the complex post-rift evolution of the NW African margin is fundamental to constraining the behaviour of the shallow-marine to fluvial transition zone as well as the formation and distribution of potential reservoirs

The Lower Cretaceous shallow-marine to fluvial coarse siliciclastic successions of the Agadir Essaouira Basin are an exploration target offshore. However, limited success in recent drilling campaigns reflects the poor understanding of the depositional systems from source to sink. and its links to the eroding hinterland. This highlights the need of a more holistic approach, tracing sediment routing and the main input points through time.

This integrated study aims to develop the first regional paleogeographic and tectonostratigraphic Source-to-Sink model of North-West Africa by deciphering the controls, timing and volume of the sediment supply to the margin and by constraining the importance of sediment recycling, mixing and storage. The main focus is on the late Early Cretaceous marine regression that is associated with substantial input of clastic sediment into the deep-water basins.

The study is currently focusing on source discrimination based on the heavy mineral populations of the potential source areas and on the sampled sandstones in combination with apatite and zircon geochronology.

This study is carried out under the supervision of Stefan Schroeder and Jonathan Redfern (University of Manchester), Shane Tyrrell (NUI Galway) and Giovani Bertotti (TU Delft)

An interdisciplinary and multi-scale research project to characterize and evaluate the evolution of the Cretaceous depositional systems Onshore Morocco along the Atlantic Seaboard, extending offshore along the Morocco passive margin. To improve understanding of the depositional systems, facies modeling and basin evolution, with the implications for petroleum systems and modeling reservoirs, source distribution , generation and migration, and seal. The research will undertake detailed analysis of onshore outcrops to develop improved sedimentological models and establish depositional facies distributions through time, provenance, diagenesis and improved chronostratigraphy.

This project commenced in January 2014, and 1^st results have been delivered to the sponsors. The project will be integrated with analysis of available offshore subsurface data provided by ONHYM, including an offshore 2D seismic grid and access to well data and reports. NARG has singed an MOU with ONHYM to cooperate ion this study, building on the very strong links over the last 10 years. Additional data will be provided by sponsoring companies, to assist in mapping the offshore in order to constrain the source to sink models, and assess the evolution of the Cretaceous system and controls on sedimentation (salt tectonics) and basin evolution.

Research team comprises 6 PhDs (Tim Luber, Angel Arantegui, Tu Anh Ngyeun (Schlumber Scholarship), and Leonardo Muniz Pichel (Brazilian Gov Scholarship) based in Manchester and Remi Charton in TuDelft. Academic staff supervision from Prof Jonathan Redfern, Prof Giovanni Bertotti and Prof Joep Storms from Manchester, TU Delft and Amsterdam (VUA).

The study will focus on stratigraphic architecture, paleogeography and facies trends of Jurassic carbonates along the Moroccan Atlantic Margin, as well as age relationships in the basin.

Part of the work will be outcrop-based, by conducting a regional stratigraphic-sedimentological study. Results will be integrated with subsurface datasets, seismic and well data.

The study will have impact on active oil and gas exploration, in the light of hydrocarbon discoveries in Jurassic carbonates both in Morocco and in the conjugate basins of Canada. Reconnaissance studies of the Jurassic Outcrops north of Agadir have already been conducted.

Students are being interviewed for an early January start. In addition ONHYM are funding one of their staff to undertake an MRes at Manchester as part of this study.

This project being undertaken by PhD studentJianpang Wang (Chinese Gov. Scholarship) has commenced, supervised by Prof Kevin Taylor and Prof Jonathan Redfern.

The aims are to characterise the Cenomanian/ Turonian source rocks outcropping onshore Morocco and correlate with the offshore penetrations. Geochemical data will be collated and new data produced from examination of outcrop and cuttings data.

The study will address the controls and processes of source rock development and enrichment. It is anticipated this will extend south along the Atlantic margin and also include an element of basin modelling. This will contribute to the NARG Source Rock Hunter project.

These projects were run as a lead collaborator in the Atlantic Triassic Project, combining the research power of the Universities of Manchester, Aberdeen and UCD Dublin (Prof Pat Shannon). NARG researchers were Nadine Mader (PhD completed 2008, currently with Maersk) and Ivan Fabuel Perez (PhD completed 2009 currently with Exxon) and Xavier Van lanen (funded by Shell and currently with Statoil). Academic staff from NARG working on this project included Prof Jonathan Redfern, Dr David Hodgetts and Prof Brian Williams. Dr Cat Baudon worked on the project as a PostDoc at Manchester, and the students were also supported by Dr Sophie Leleu from Aberdeen University. This involved an integrated analysis of Late Triassic rift sequences in Canada, Morocco and the North Atlantic (and seismic data from Norway and W Britain). Manchester led the research use of LiDAR and field sedimentology in Morocco, characterising reservoirs in the systems, and also looking at the structural controls using field based analysis in the High Atlas of Morocco, the Argana Basin Morocco and Fundy Basin Canada. A number of publications have come out from this research.

Publications:

Redfern, J., Hodgetts, D. & Fabuel-Perez, I. (2007). Digital analysis brings renaissance for petroleum geology outcrop studies in North Africa. In: First Break 25, pp. 81-87.

Fabuel-Perez, I., Hodgetts, D., & Redfern, J., (2009), A new approach for outcrop characterization and geostatistical analysis of a low-sinuosity fluvial-dominated succession using digital outcrop models; Upper Triassic Oukaimeden Sandstone Formation, central High Atlas, Morocco AAPG Bulletin, 93, 6, pp. 795-827

Fabuel-Perez, I.; Redfern, J.; Hodgetts, D., (2009), Sedimentology of an intra-montane rift- controlled fluvial dominated succession: The Upper Triassic Oukaimeden Sandstone Formation, Central High Atlas, Morocco, Sedimentary Geology, v. 218, iss. 1-4, pp. 103-140.

Baudon, C., Fabuel-Perez, I. and Redfern, J. ( 2009). "Structural style and evolution of a Late Triassic rift basin in the central High Atlas, Morocco; controls on sediment deposition." Geological Journal, 44(6): pp. 677-691.

Van Lanen, X.M.T., Hodgetts, D., Redfern, J., Fabuel-Perez, I. (2009). " Applications of digital outcrop models; two fluvial case studies from the Triassic Wolfville Fm., Canada and Oukaimeden Sandstone Fm., Morocco." Geological Journal, 44(6): 742-760.

Fabuel-Perez, I., Hodgetts, D. and Redfern, J. (2010). " Integration of digital outcrop models (DOMs) and high resolution sedimentology; workflow and implications for geological modelling; Oukaimeden Sandstone Formation, High Atlas (Morocco)." Petroleum Geoscience, 16, 133-154.133-154.

Redfern, J., Shannon, P.M., Williams, B.P.J., Tyrell, S., Leleu, S., Fabuel Perez, I., Baudon, C., Stolfova, K., Hodgetts, D., Speksnijder, A., Haughton, P.D.W, Daly, J.S. , ( 2011) An integrated study of Permo-Triassic basins along the North Atlantic passive margin: implication for future exploration. Geological Society, London, Petroleum Geology Conference series, v. 7, p. 921-936, doi: 10.1144/?0070921

Mader, N. K. and Redfern, J. (2011). A sedimentological model for the continental Upper Triassic Tadrart Ouadou Sandstone Member: recording an interplay of climate and tectonics (Argana Valley; South-west Morocco), Sedimentology, 1365-3091 DOI:10.1111/j.1365-3091.2010.01204.x

Baudon, C., Redfern, J & Van Den Driessche P; J, (2012), Permo-Triassic structural evolution of the Argana Valley and implications on the kinematics and impact of the Atlantic rifting in the High Atlas, Journal of African Earth Sciences, 65, 91-104.

Rarity, F. X. M. T. van Lanen, D. Hodgetts, R. L. Gawthorpe, P. Wilson, I. Fabuel-Perez, and J. Redfern (2013), LiDAR-based digital outcrops for sedimentological analysis: workflows and techniques. Geological Society, London, Special Publications, 387, doi:10.1144/SP387.5

PhD Theses:

2006: Dr Nadine Mader (now working for Maersk): Sedimentology, third order sequence stratigraphy and controlling factors on facies distribution in the Triassic of North Africa. NARG Funded

2009: Dr Ivan Fabuel Perez (now in Exxon): 3D Modelling of Late Triassic Continental mixed fluvial systems; integrating LIDAR with high resolution sedimentology of fluvial facies: High Atlas, Morocco NARG Funded

2011: Dr Xavier Van Lanen (now with Statoil): Quantitative Outcrop Analysis / Integrated Reservoir Modelling of Triassic Fluvial Facies, Minas Basin, Nova Scotia, Canada. Shell International funded.

Early work on regional source rocks was undertaken by postdoctoral researcher Dr Sebastian Luning, supported by Stefan Lubeseder and Dr Jonathan Redfern. This work aimed to assess the source rock quality of Palaeozoic shales from outcrop studies, that had proved difficult to quantify due to intense weathering. The project included the analysis of a number of methods to allow more accurate regional mapping of source rock facies including surface exposures. Based on their characteristic uranium gamma-radiation and pyrite framboid distribution, the original organic richness of the Silurian / Upper Devonian shales in weathered outcrops was mapped in Libya. A model for the distribution of the rich source rocks was developed. Fieldwork was carried in the Moroccan Anti-Atlas where the Frasnian and Silurian hot shales were studied at outcrop using a portable gamma-ray spectrometer. The unit is typically marked by enrichment in uranium. Additional fieldwork was carried out on the Silurian Tannezuft Shales outcrops documented in Ghat (SW Libya) and Algeria for the Silurian and Devonian source facies.

The project was continued by Dr Alvaro Jimenez Berracosso (now with Repsol). New field investigations were carried out in north central Tunisia, examining the organic-rich sediments of the Bou Dabbous Fm (lower Eocene). The research addressed the controls on the development of the organic richness and assess its distribution stratigraphicaly and aerially, in order to improve source rock quality predictions.

Other research (oncluding proprietary consulting projects) has focused on the Silurian (Tanezuft Shales) in Libya and Morocco, Cenomanian/ Turonian and Toarcian source rocks.

Future work will initially focus on the Cenomanian / Turonian in Morocco, with Prof Kevin Taylor from the University of Manchester. These outcrops, integrated with available offshore well and seismic data, will provide an analogue for offshore source intervals along the Atlantic margin. Development of the online database is continuing for all the main source horizons and potentially significant intervals.

NARG has also been working on basin modelling projects, integrated to petroleum system analysis, since its inception. We have access to the lasts basin modelling software, and through collaborations, can undertake heat flow and subsidence history analysis (FT, Vr etc). The capability is enhanced now through the membership of TU Delft.

Publications:

Burwood R., Redfern J., and Cope M. (2003) Geochemical evaluation of East Sirte Basin (Libya) petroleum systems and oil provenance. In Petroleum Geology of Africa: New Themes and Developing Technologies, Vol. 207 (ed. T. J. Arthur, D. S. MacGregor, and N. R. Cameron), pp. 203-204. Geological Society of London Special Publication.

Lüning, S., Craig, J., Loydell, D. K., Storch, P. & Fitches, W. R. (2000): Lowermost Silurian 'hot shales' in North Africa and Arabia: Regional Distribution and depositional model. Earth Science Reviews 49: 121-200.

Lüning, S., Adamson, K., Craig, J. (2003a): Frasnian 'Hot Shales' in North Africa: Regional Distribution and Depositional Model. In: Arthur, T. J., Macgregor, D. S., Cameron, N. (Eds.), Petroleum Geology of Africa: New Themes and developing technologies, Geol. Soc. (London) Sp. Publ. 207: 165-184.

Lüning, S., S. Kolonic, D. Loydell, J. Craig (2003b): Reconstruction of the original organic richness in weathered Silurian shale outcrops (Murzuq and Kufra basins, southern Libya). GeoArabia 8: 299-308.

Lüning, S., S. Kolonic, E. M. Belhadj, Z. Belhadj, L. Cota, G. Baric, T. Wagner (2004): Integrated depositional model for the Cenomanian-Turonian organic-rich strata in North Africa. Earth-Science Reviews 64: 51-117.

Underdown, R., and Redfern, J., (2007), The importance of constraining regional exhumation in basin modelling: a hydrocarbon maturation history of the Ghadames Basin, North Africa., Petroleum Geoscience, V 13, p 1-19

Underdown, R., and Redfern J., (2007), Constraining the burial history of the Ghadames Basin, North Africa: An integrated analysis using sonic velocities, vitrinite reflectance data and apatite fission track ages. Basin Research, Volume 19, Number 4, pp. 557-578 (22)

Underdown, R., and Redfern, J., (2008), Petroleum Generation and Migration in the Ghadames Basin, North Africa: A 2D Basin Modelling Study, AAPG Bulletin, V. 92, No. 1 , pp. 53-76.

Bodin S., E. Mattioli, S. Frohlich, J.D. Marshall, L. Boutib, S. Lahsini, J.Redfern (2010). "Toarcian carbon isotope shifts and nutrient changes from the Northern margin of Gondwana (High Atlas, Morocco, Jurassic): Palaeoenvironmental implications." Palaeogeography, Palaeoclimatology, Palaeoecology, 297, pp 377-390.

Reports:

Additional reports are available of the Jurassic source rocks of Fuerteventura, and regional source rock analysis of the Silurian in Morocco and Libya.

PhD Thesis:

2006: Dr Ruth Underdown (now a school teacher): Assessing the impact of regional unconformities on the maturation and migration of hydrocarbons within the Ghadames Basin, North Africa. NARG Funded.

The influence of dolomitisation on Late Cretaceous carbonates in North Africa is often critical to reservoir development. The study has analysed the superbly exposed section along the Jeffara escarpment of southern Tunisia, together with analogue outcrops in Northern Spain.  These outcrops provide an excellent opportunity to study the extensively dolomitised Upper Albian-Lower Turonian shallow water carbonates of the Zebbag Formation (Rhadouane, Kerker and Gattar Members), and similar facies in Spain, which are potential outcrop analogues for reservoirs currently under production and appraisal in North Africa. This study comprised a multi-disciplinary, multi-scale approach using field, petrographical and geochemical data to better constrain the depositional history, diagenetic history and source of diagenetic fluids.

Publications:

3 papers in preparation.

PhD Thesis:

Richard Newport (2014), passed viva and currently undertaking minor correction prior to final submission. The thesis will be available in early 2015.