Narg Newsletter 2019
Total Page:16
File Type:pdf, Size:1020Kb
20 in 2020 View across the Argana Basin, Morocco Fieldwork New Projects New Starts More Early Cretaceous Regional Tectono- Ian Mounteney starts MPhil sections logged and stratigraphy of MSGBC – examining Cretaceous sampled in Morocco for utilising Petrosen and TGS clastic provenance in facies and provenance seismic data Senegal New Sponsors Pierre-Olivier Bruna joins as Triassic Synrift in Eastern PostDoc working on North Africa Research Group Research North Africa Hunt Oil, Mazarine Energy and Morocco – regional fractured reservoirs- Tunisia provenance study Shell join in 2019 Results coming in from TGS Seismic NARG ……….. Senegal Provenance Study MSGBC Basin Study As part of a suite of projects in Senegal and the 20 years of experience working • MSGBC , in collaboration with Petrosen and TGS, we A new PhD will commence in 2019 to across North Africa are undertaking a regional source to sink study, with examine the regional Tectono- MPhil student Ian Mounteney, working at the BGS. stratigraphy of the MSGBC Basin • Over 10 Academic s, 3 PostDocs undertaking regional mapping and and 6 PhDs, 2 MSc/MRes Sampling was completed in 2019, with 135 integrating well data provided by core/cuttings from 19 wells across Senegal (Silurian, students Petrosen with regional seismic data Devonian, Early/Late Cretaceous and Palaeogene). provided by TGS and Spectrum. This Modern river samples were also collected for • Global collaborations with leading build on existing reconnaissance specialists comparison. In total 32 kg of core/cuttings/sand biostratigtphic work and results from produced 4 kg of fine (63-125 micron) sand. Results examining 3D seismic donated by TGS in are expected shortly. See page 5. The Gambia . • Working with local institutions • Active projects underway in New Projects Morocco, Senegal, Mauritania, Tunisia, Egypt, Central Atlantic NARG is constantly starting new projects. In 2019 we move back to Tunisia, to begin reservoir characterisation studies with the appointment of Dr Pierre-Olivier Bruna at • Projects cover all aspects of the Tu Delft. We also have plans in place to undertake new Welcome to our New petroleum system: Depositional studies in Libya and Egypt in 2019/20. fairways, source to sink, clastic Sponsors and carbonate sedimentology, reservoir characterisation, thermo-geochronology Contents Highlights biostratigraphy, landscape evolution and modellling Triassic study …. Page 2 Heavy minerals / Provenance studies…. Page 4 and 5 Carbonates …. Page 7 The Africa Experts Latest publications …. Page 11 Staff and Researcher list …. Page 12 Assessing the provenance and contribution of local vs regional drainage systems for the Upper Triassic fluvial deposits, James Lovell-Kennedy, Jonathan Redfern, [email protected] Challenges 1. Introduction 1. Was there a regional axial rift fluvial system linking Oukaimeden, Kerrouchen, the High Plateaux and the Oujda Mountains during the Upper Triassic? 2. To what extent did local drainage influence sediment deposition during the Upper Triassic? 3. Can proximal, medial and distal fluvial successions be identified and correlated across the Triassic basins across Morocco? Aims of Study A. Analysis of heavy mineral assemblages from Triassic Basins to attempt to recognise signals from distinct source regions. B. Build on previous work on regional uplift to identify Triassic source areas and drainage systems. C. Compare the stratigraphy of the individual Triassic basins to assess the evolution of the depositional system and aid with correlation between basins. D. Perform a High Resolution Heavy Mineral Analysis (HRHMA) to identify the provenance of the Triassic deposits E. Combine heavy mineral analysis with field studies and subsurface data to reconstruct the Triassic paleodrainage and paleogeography Figure 1 : Map of the Triassic Basins, potential source areas and major faults in the study region. 2. Geological Setting and Fieldwork Geological setting Fieldwork Figure 5: Paleocurrent data from Kerrouchen Basin. Units K3 and K4 record a paleoflow flow toward the The inverted Mesozoic rift basins of the Atlas Mountains expose a thick Fieldwork and sampling of coarse clastic NNE, indicating a flow from the Triassic continental red-bed sequence. intervals has been undertaken in the Oukaimeden Basin and Central High Kerrouchen Basin and Oujda Mountains Atlas and towards the Oujda The Triassic basin fill of the Central and Middle Atlas is predominantly to augment previous work done in the Mountains (Figure 6). ephemeral and perennial fluvial deposits, with alluvial fans, occasional Oukaimeden and Argana Basins. The conglomerates of the K2 units aeolian deposits and interbedded lacustrine and, playa mudstones and record variable paleoflows, away from the basinal highs from which rare carbonates deposited in a series of rift basins following the break up of Whilst direct correlation between they are sourced. Pangea. The northern Oujda Mountains records a deltaic plain succession the basins is hampered by the lack with a Carnian transgression of Tethys prior to the establishment of of biostratigraphic data, similar widespread marine conditions in the Jurassic. depositional processes can be identified across the basins such Divergent paleocurrent measurements in the Massif Ancien indicate the as the K3 unit, Kerrouchen, and the F5 presence of a drainage divide, with flow to the west towards Argana and ‘Oukaimeden Sandstone’ within the flow to the east towards Oukaimeden (Figure 6). Oukaimeden Basin. Figure 4: Conglomeritic channels (A) at the base of Unit K3 outcropping in the Kerrouchen Basin, Middle Atlas. The conglomerates are conformably overlain by mud Figure 2: Photo ofT thehe Hercynian Triassic syn-rift continental clastics were deposited at the 140 SE clast conglomerates and stacked fluvial sandstones. The fluvial sands grade into point Unconformity from within the Kerrouchen bar deposits with mud drapes near the top of Unit K3. Basin, Middle Atlas. The basement formed a intra-basinal high.onset Debris flow depositsof rifting. They are proven reservoirs in the Essaouira Basin B (Unit K2) derived from the paleohigh onlap A C Triassic Source to Sink the unconformity.and Unit K3 andthe K4 are recent Sound Energy gas discovery in Tendrara, on the absent at this locality, as they were deposited in basinward lows to the east. The basement andHigh conglomerates Plateaux are Figure 3:, Compositehas logre of- theinvigorated Triassic interest in the play. 1m capped by the massive red mudstones of sequence in the Kerrouchen Basin. 2m 5m Unit K5. Eastern Morocco The reservoirs are tight fluvial sandstones and a key factor is to 3. Future Work betterFigure 6 understand Map of Triassic Source areas and measured and Methodology and Sampling potential paleoflows. 5 potential source areas for reservoirTriassic sediments have quality been identified; After successfully completing his MSc by Research in September 2018Initial heavy, James mineral analysis Lovell will be carried -out on Hercynian Granites, Precambrian Granites, samples from the F5 and K3 units from Metamorphic, Volcanic and Precambrian and Oukaimeden and Kerrouchen, along with deltaic and distribution. Paleozoic sediments. Kennedy, has now commenced a PhD into the provenance of the Triassicplain samples fromfluvial Oujda and samples from the Tendrara Field provided by Sound Energy. Table 1: Table shows the age range of each Tendrara reservoir (TAGI) in Eastern Morocco. During the first year of the PhD, alongside Thepotential sourcesystem for the Triassic has sediments from Discovery These samples are believed to be coeval based on the published literature. For the Precambrian and environment of deposition. Paleozoic sediments, the age range of their detri- potentialtal zircon population isoffshore given. The sedimentary de- training provided by the NERC CDT Oil and Gas, he undertook further field and core posits of the Anti-Atlas contain locally reworked Once the samples have undergone a heavy zircons from the Precambrian inliers. The combi- sampling season in November 2018. More samples have been collectedmineral separation, from a QEMSCAN the will be used to onnation bothof petrographic conjugate analysis of the heavy min- identify the abundance of Apatite, Tourmaline, erals should be able to identify reworked grains, Garnet, Zircon, Rutile, Chrome and Monzonite. The which would help differentiate between a Precam- Kerrouchen Basin, Middle Atlas, and from wells drilled in the High Plateau.ratio of these minerals In (specificallyaddition (ATi, GZi, RZi, Atlanticbrian granitic or sedimentary margin source fors the Trias- CZi and MZi) are provenance sensitive. sic sediment. we have been generously donated data from the Tendrara Block by Sound Energy. wherePotential Source thereRegion Radiometric is Date Range As the potential source areas in the region could Hercynian Granites 275Ma - 326Ma Precambrian and Paleozoic Sedi- 570Ma-2093Ma* Sound Energy and Regional Context of the High have significant overlap between heavy mineral ments *Detrital Zircon populations age populations, petrographic work will be done attempt limitedVolcanoclastic Deposits overburden. 617Ma Metamorphic Units 617Ma – 660Ma These samplesPlateaux are being‘the white space analysed for petrographic…..’ and heavy mineralto identify signatures between reworked and first and cycle grains. Precambrian Granites 617Ma – 2293Ma Acknowledgements: Special thanks to a representative sample selected for detrital zircon geochronology analysisI would