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The lower Silurian black Shales from the Ahnet basin (SW Algerian Saharan platform): a comprehensive mineralogical study and paleoenvironmental implications

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Abstract

Shale gas reservoirs witnessed an increasing interest in the last few years, due to their abundant reserves and the increasing of worldwide demand on energy. Algeria is an oil-rich country and hosts one of the largest unconventional shale gas reservoirs in the world. This study focuses on unraveling paleoclimatic and paleoenvironmental conditions of lower Silurian formation (Llandovery) from the Ahnet basin (south of Algeria), being considered as one of important prospects under-evaluation for unconventional shale gas resources. In this study, a detailed mineralogical investigation of shale minerals using various techniques such as X-ray diffraction (XRD) on oriented aggregates clays and scanning electron microscopy (SEM–EDX) in addition to spectroscopy natural gamma (SNG). The results show that the dominant facies is black shale with a ratio of Th/U (˂ 4) deposited in a marine sedimentation environment manifested by a low Th/K and U/K values (average = 10.40 ppm/pct and 14.41 ppm/pct, respectively). The mineralogical assemblage of black shales deduced from Th versus K cross-plots represented illite and kaolinite. The XRD analysis performed on oriented slides showed the trend of kaolinite, illite, and chlorite. The chlorite mineral is relatively constant (~ 5%). The distribution of kaolinite and illite shows an inverse change. An increase in the percentage of kaolinite and decrease in illite from upper Llandoverian (illite ~ 73 to ~ 68%, kaolinite: ~ 19 to ~ 28%) to lower Llandoverian (illite ~ 64 to ~ 48%; kaolinite ~ 31 to ~ 46%) reflects the evolution to a deep marine environment and humid climatic conditions; moreover, it confirmed by SEM–EDX results, they have further argued the evolution toward deep marine environments, as they show a dispersion of sulfides which can be shown with the mineral pyrite on the other hand absence of carbonate minerals. Paleoenvironmental studies of the lower Silurian period of the Ahnet basin show that the shales of the Llandoverian epoch characterized by adequate conditions allow the preservation of organic matter and the generation of hydrocarbons. In addition, the mechanical characteristics of the stable structures of illite and kaolinite allow maintaining the hydraulic fracturing in good quality.

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References

  • Adams JAS, Weaver CE (1958) Thorium-to-uranium ratios as indicators of sedimentary processes: example of concept of geochemical facies. Am Asso Petrol Geol Bull 42:387–430

    Google Scholar 

  • Akrad OM, Miskimins JL, Prasad M (2011) The effects of fracturing fluids on shale rock mechanical properties and proppant embedment. In: SPE annual technical conference and exhibition. Society of Petroleum Engineers, Denver. https://doi.org/10.2118/146658-MS

  • Aldridge RJ, Schönlaub HP (1989) Conodonts. In A global standard for the Silurian System, edited by C.H. Holland and M.G Bassett. Natl Mus Wales Geol Ser 9:274–279

    Google Scholar 

  • Arab, M., and Djezzar S., 2011. Sonatrach/Division, Exploration gas potential evaluation of Reggane basin, south-western Algeria

  • Askri, H., Belmecheri, A., Benrabah, B., Boudjema, A., Boumendjel, K., Daoudi, M., Drid M., Ghalem T., Docca A. M., Ghandriche H., Ghomari A., Guellati N., Khennous M., Lounici, R., Naili, H., Takherist, D., Terkmani, M.. 1995. Geology of Algeria. Sonatrach Exploration, p. 32.

  • Asses, A., 1987. Analysis of borehole logs, sedimentary sequences and paleogeography of the clayey-sandstone series deposited at the Silurian-Devonian Passage in the East Saharan synecline. : Illizi basin and Algerian part of the Ghadames basin. University. Pau, 1 vol. p. 331.

  • Berry, W.B.N., Boucot, AJ., 1973. Correlation of the African silurian rocks. Geol. Soc. Amer. Special paper. 147, 1 vol, 2 pl. ht, 1 carte, p. 83.

  • Berstad S, Dypvik H (1982) Sedimentological evolution and natural radioactivity of Tertiary sediments from the central North Sea. J Pet Geol 5:77–88

    Article  Google Scholar 

  • Beuf S, Biju-Duval B, Charpal O, Rognon P, Gariel O, Bennacef A (1971) The Lower Paleozoic Sandstones in the Sahara: sedimentation and discontinuities. Structural evolution of a Craton, Paris, p 464

    Google Scholar 

  • Black R, Caby R, Moussine-pouchkine A, Bayer R, Bertrand JM, Boullier AM, Faber J, Lesquer A (1979) Evidence for late Precambrian plate tectonics in west African. Nature 278(5701):223–227

    Article  Google Scholar 

  • Black R, Liegeois JP (1993) Craton, mobile blets, alkaline rocks, and continental lithospheric mantle. The pan-african testimony. J Geol Soc London 150(1993):89–98

    Article  Google Scholar 

  • AJ Boucout 1990 Silurian Biogeography Silurian Biogeography https://doi.org/10.1144/GSL.MEM.1990.012.01.17

  • Boudjema, A., 1987. Structural evaluation of the oil basins (Triassic) of the North Western Sahara (Algeria). thesis. univ, Orsay, 1 vol, p. 290.

  • Caby, R., Bertrand, J.M.L., Black, R., 1981. Pan-African closure and continental collision in the Hoggar – Iforas segment, central sahara – In Precambrian plate tectonics (A. kroner ed), Elsevier, p. 407–434.

  • Cailliere, Henin et Rautureau, 1982. Minéralogie des argiles. 2. Classification et nomenclature. Masson.

  • Chamley H. (1989) Clay formation through weathering. In: Clay sedimentology. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-85916-82

  • Claret J, Tempere C (1965) The palaeozoic of the Tamensa basin (south of Ahggar). zdeutsch. Geol Ges 117:460–468

    Google Scholar 

  • Conrad J, Lemosquet Y (1984) From the craton to its margin; sedimentary and structural evolution of the Ahnet-Timimimoun-Bechar basin (Agerian Sahara) during the Carboniferous; paleoclimatic data. Trav Lab Sci Terre 7 XXVI(6):987–994. https://doi.org/10.2113/gssgfbull.S7-XXVI.6.987

    Article  Google Scholar 

  • Corapcioglu H, Miskimins J, Prasad M (2014) Fracturing fluid effects on Young’s modulus and embedment in the niobrara formation. In: SPE annual technical conference and exhibition. Society of Petroleum Engineers, Amsterdam. https://doi.org/10.2118/170835-MS

  • Craig, J., Rizzi, C., Said, F., Thusu, B., Lüning, S., Asbali, A.I., Keeley, M.L., Bell, J.F., Durham, M.J., Eales, M.H., Beswetherick, S., Hamblett, C., 2008. Structural styles and prospectivity in the Precambrian and Palaeozoic hydrocarbon systems of North Africa. In: Salem, M.J., Oun, K.M., Essed, A.S. (Eds.), The Geology of East Libya, vol. 4, p. 51e122.

  • Dunoyer De Segonzac G (1969) Les minéraux argileux dans la diagenèse, passage au métamorphisme. Thèse de doctorat Es Science Naturelles, Strasbourg

    Google Scholar 

  • Ehrenberg, Svana (2001) Use of spectral gamma-ray signature to interpret stratigraphic surfaces in carbonate strata: an example from the Finnmark carbonate platform (Carboniferous–Permian) Barents Sea. AAPG Bulletin 85:295–308. https://doi.org/10.1306/8626C7C1-173B-11D7-8645000102C1865D

    Article  Google Scholar 

  • Engstrøm, F., 1981. Fortolkningsgrundlag for SNG-log, Unpublished Ph.D. thesis, Danmarks Tekniske Universitet, Lyngby, Danmark, p. 469.

  • Eveline VF, Akkutlu IY, Moridis GJ (2016) Impact of hydraulic fracturing fluid damage on shale gas well production performance. In: SPE annual technical conference and exhibition. Society of Petroleum Engineers, Dubai. https://doi.org/10.2118/181677-MS

  • Fabre, J., 1976. Geological introduction of the Algerian Sahara and neighbouring regions: Phanerozoic cover. Soc.nat. Ed. Diff. Alger, p. 422.

  • Fabre, J., Kazi-Tani, N., 2005. Geology of Western and Central Sahara, Tervuren African Geoscience Collection, p. 211–212.

  • Fabre J, Petit-maire N (1988) Holocene climatic evolution at 22–23°N from tow paleolakes in the Taoudeni area (north Mali). Pal. Pal. Pal. 65. Elsevier, Amsterdam 1988:133–148

    Google Scholar 

  • Fabricius IL, Fazladic LD, Steinholm A, Korsbech U (2003) The use of spectral natural gamma-ray analysis in reservoir evaluation of siliciclastic sediments : a case study from the Middle Jurassic of the Harald Field, Danish Central Graben. Geol Survey Denmark Greenland Bull 1:349–366

    Article  Google Scholar 

  • Fertl WH (1979) Gamma ray spectral data assists in complex formation evaluation. Log Anal 20(05):337

    Google Scholar 

  • Follot, J., 1952. Ahnet and Mouydir. XIXth International Geological Congress. Regional Monographs, 1st series: Algeria 1, Algiers, p 79.

  • S Galeazzi O Point N Haddadi J Mather D Druesne 2010 Regional Geology and Petroleum Systems of the Illizi-Berkine Area of the Algerian Saharan Platform: an Overview https://doi.org/10.1016/j.marpetgeo.2008.10.002

  • Gould KM, Piper DJW, Pe-piper G, Macrae RA, 2014. Facies, provenance and paleoclimate interpretation using spectral gamma logs application to the Lower Cretaceous of the Scotian Basin. (57):445–454. doi: https://doi.org/10.1016/j.marpetgeo.2014.06.008

  • Haddoum H, Guiraud R, Moussine-Pouchkine A (2001) Hercynian compressional deformations of the Ahnet-Mouydir Basin. Algerian Saharan Platform: Far-Field Stress Effects Late Palaeozoic Orogeny. https://doi.org/10.1046/j.1365-3121.2001.00344.x

    Article  Google Scholar 

  • Hassan, M., Hossin, A., Combaz, A., 1976. Fundamentals of the differential gamma ray log – interpretation technique. Society of Professional Well Log Analysts, p.18.

  • Hurst, A., 1990. Natural gamma-ray spectroscopy in hydrocarbonbearing sandstones from the Norwegian continental shelf. In: Hurst, A., Lovell, M.A., & Morton, A.C. (eds): Geological applications of wireline logs. Geological Society Special Publication (London) 48, p. 211–222.

  • Hurst, A., Milodowski, A., 1994. Characterization of clays in sandstones: thorium content and spectral log data. Society of Professional Well Log Analysts 16th European Formation Evaluation Symposium, October 11–13, 1994. Transactions, Paper S, p. 18.

  • Iriarte J, Tutuncu AN (2018) Geochemical and geomechanical alterations related to rock–fluid–proppant interactions in the Niobrara Formation. In: Paper presented at the SPE international conference and exhibition on formation damage control, Lafayette. Society of Petroleum Engineers. https://doi.org/10.2118/189536-MS

  • Jeppson L (1990) An oceanic model for lithological and faunal changes tested on the Silurian record. Jour Geol Soc London 147:663–674

    Article  Google Scholar 

  • John A., Quirein John S., Gardner John T., Watson, Schlumberger, 1982. Well services combined natural gamma ray spectral/litho-density measurements applied to complex lithologies, SPE-11143-MS, https://doi.org/10.2118/11143-MS

  • Johnson H (1996) Dangerous domains. Violence Against Women Canada 44(2):189–190. https://doi.org/10.7202/706701ar

    Article  Google Scholar 

  • Johnson ME., McKerrow WS., Road P., 1991. Historical biology, an International Journal of Paleobiology Sea level and faunal changes during the latest Llandovery and earliest Ludlow (Silurian), p. 153–169. https://doi.org/10.1080/10292389109380398

  • Kazi-Tani, N., Boumendjel, Kh., 1998. curve of the eustatic variation 435 – 375 Ma SONATRACH, unpublished.

  • Klaja, J., Dudek, L., 2016. Geological interpretation of spectral gamma ray (SGR) logging in selected boreholes. NAFTA GAZ.

  • Klett, T.R., 2000. Total petroleum systems of the Grand Erg/Ahnet Province, Algeria and Morocco-the Tanezzuft-Timimoun, Tanezzuft-Ahnet, Tanezzuft-Sbaa, Tanezzuft-Mouydir, Tanezzuft-Benoud, and Tanezzuft-Béchar/Abadla. U.S. Geological Survey Bulletin, vol. 2202 B, p. 144.

  • Leggett JK, Mckerrow WS, Cocks RB (1981) Rickards. Periodicity in the early Palaeozoic marine realm. J Geol Soc 138:167–176. https://doi.org/10.1144/gsjgs.138.2.0167

    Article  Google Scholar 

  • Legrand, Rh., 1995. evidence and concerns with regard to the late Ordovician in north African. In Ordovician odyssey. Cooper. Drosey. And finney (eds)., pacific soc. Sed. Geol., fullerton, California.

  • Lessard, L., 1959. preliminary note on the geology of the Tassili ouan - Ahaggar (southern sahara). C.R. som. Soc. Geol. Fr, p. 151 -152.

  • Loydell DK (1998) Early Silurian sea-level changes. Cambridge Univ Press 135(4):447–471. https://doi.org/10.1017/S0016756898008917

    Article  Google Scholar 

  • Luning S, Craig J, Loydell DK, Storch P, Fitches B (2000) Lower Silurian ‘hot shales in North Africa and Arabia : regional distribution and depositional model. Earth Sci Rev 49(1–4):121–200. https://doi.org/10.1016/S0012-8252(99)00060-4

    Article  Google Scholar 

  • Luo Q, Zhong N, Dai N, Zhang W (2016) Derived organic matter in the Wufeng – Longmaxi Formations (Upper Ordovician – Lower Silurian) of southeastern Chongqing, China : implications for gas shale evaluation. Int J Coal Geol 153:87–98. https://doi.org/10.1016/j.coal.2015.11.014

    Article  Google Scholar 

  • Makhous M, Galushkin YI, Curie M (2003) Burial history and thermal evolution of the northern and eastern Saharan basins. Am Assoc Petr Geol Mem 87:1623–1651. https://doi.org/10.1306/04300301122

    Article  Google Scholar 

  • Massa, D., 1988. Paleozoic of Western Libya. Stratigraphy and paleography. Thesis, D. Sc. univ nice, 2 vol, p. 554.

  • Massa D, Jaeger H (1971) stratigraphic data on the Silurian of western Libya. Thesis BRGM 73:313–321

    Google Scholar 

  • Zielinski M (2012) Conodont thermal alteration patterns in Devonian and Carboniferous rocks of the Ahnet and Mouydir basins (southern Algeria). Mar Pet Geol 38(1):166–176. https://doi.org/10.1016/j.marpetgeo.2012.08.014

    Article  Google Scholar 

  • McKerrow, W.S., Lambert, R.St.J., Cocks, L.R.M., 1985. The Ordovician, Silurian, and Devonian periods. In The Chronology of the geological record. Geological Society, London Memoir, No. 10, edited by N.J. Snelling, p. 73–80.

  • Mckerrow, W.S., Scotese, C.R., 1990. Palaeozoic palaeogeography and biogeography, (eds), Geological Society Memoir No. 12, p. 191–196.

  • Murray HH, Leininger RK (1955) Effect of weathering on clay minerals. Clays Clay Miner 4:340–347. https://doi.org/10.1346/CCMN.1955.0040138

    Article  Google Scholar 

  • Mwenifumbo, C.J., Killeen, P.G., 1987. Natural gamma ray logging in volcanic rocks: the mudhole and clementine base metal prospect. In: Kirkham, R.V. (Ed.), Buchans geology, newfoundland. Geological Survey of Canada, pp. 263–272 Paper 86–24.

  • Nielsen, B.L., Løvborg, L., Sørensen, P., Mose, E., 1987. Gammaray analysis for U, Th and K on bulk cutting samples from deep wells in the Danish Subbasin and the North German Basin, Unpublished report, Risø National Laboratory, Denmark, p. 82.

  • North CP, Boering M (1999) Spectral Gamma-ray logging for facies discrimination in mixed fluvial-eolian successions: a cautionary tale. AAPG Bull 83:155–169

    Google Scholar 

  • Odin, G.S., Odin, Ch., 1994. Geological time scale. C.R. Acad Sci. Paris. 318 II, p. 59–71.

  • Pe-Piper G, Dolansky L, Piper DJW (2005) Sedimentary environment and diagenesis of the mid-Cretaceous Chaswood Formation, Elmsvale Basin, Nova Scotia. Sediment Geol 178:75–97

    Article  Google Scholar 

  • Pusch, R., 1994. Waste disposal in rock. Developments in Geotechnical Engineering, 76. Elsevier Amsterdam.

  • Pusch, R., 2006 Mechanical properties of clays and clay minerals, Handbook of clay science edited by F. Bergaya, B.K.G. Theng and G. Lagaly Developments in Clay Science, Vol. 1 https://doi.org/10.1016/S1572-4352(05)01006-8

  • Rickards, R.B., 1989. Exploitation of graptoloid cladogenesis in Silurian stratigraphy. In A global standard for the Silurian System. National Museum of Wales, Geological Series 9, edited by C.H. Holland M.G. Bassett, p. 267–274.

  • Ross, C.A., Ross, J.R.P., 1996. Silurian sea-level fluctuations. In: Witzke, B.J., Ludvigson, G.A., Day, J. _Eds.., Paleozoic sequence stratigraphy: views from the North American Craton. Geol. Soc. Am., Special Paper 306, p. 187–192.

  • Schlumberger, 1982. Natural gamma-ray spectrometry. Essentials of N.G.S. interpretation,. Houston, Texas: Schlumberger Educational Services, p. 69.

  • Schlumberger (1995) Log interpretation charts Schlumberger wireline and testing. Sugarland, Texas

    Google Scholar 

  • Schnyder J, Ruffell A, Deconinck JF, Baudin F (2006) Conjunctive use of spectral gamma-ray logs and clay mineralogy in defining late Jurassic-early Cretaceous palaeoclimate change (Dorset, U.K.). Palaeogeogr Palaeoclimatol Palaeoecol 229:303–320

    Article  Google Scholar 

  • Soleimani B (2009) Paleoclimate Reconstruction during Pabdeh, Gurpi, Kazhdumi and Gadvan Formations (Cretaceous-Tertiary) based on clay mineral distribution. Int J Civil Environ Eng 1:59–63

    Google Scholar 

  • Thiry, M., Carrillo, N., Franke, C., et al. 2013. Technique for the preparation of clay minerals for X-ray diffraction analysis and introduction to the interpretation of diagrams To cite this version : HAL Id : hal-00872214.

  • Vecoli M, Videt B, Paris F (2008) First biostratigraphic (palynological) dating of Middle and Late Cambrian strata in the subsurface of northwestern Algeria, North Africa : implications for regional stratigraphy. Rev Palaeobot Palynol 149(1–2):57–62. https://doi.org/10.1016/j.revpalbo.2007.10.004

    Article  Google Scholar 

  • Wendt J, Kaufmann B, Belka Z, Klug C, Lubeseder S (2006) Sedimentary evolution of a Palaeozoic Basin and ridge system : the Middle and Upper Devonian of the Ahnet and Mouydir (Algerian Sahara). Geol Mag 143(3):269–299. https://doi.org/10.1017/S0016756806001737

    Article  Google Scholar 

  • Wendt J., Kaufmann B., Belka Z., Korn D., 2009. Carboniferous stratigraphy and depositional environments in the Ahnet Mouydir area (Algerian Sahara). (55): 443–472. https://doi.org/10.1007/s10347-008-0176-y

  • Zhou Z, Hoffman BT, Bearinger D, Li X (2014) Experimental and numerical study on spontaneous imbibition of fracturing fluids in shale gas formation. In: SPE/CSUR unconventional resources conference—Canada. Society of Petroleum Engineers, Calgary. https://doi.org/10.2118/17160 0-MS

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Acknowledgements

The authors would like to thank the national company of SONATRACH for the help in collecting the necessary data to carry out this work. The National School of Mines and Metallurgy Amar Laskri Annaba and Mohamed Kheider Biskra University are warmly thanked for analysis facilities. The Editor and anonymous reviewers are particularly thankful for their carful and constructive revision greatly improved the paper.

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  1. Laboratoire Des Réservoirs Souterrains: Pétroliers, Gaziers Et Aquifères, Université Kasdi Merbah, 30000, Ouargla, Algeria

    Abdelmadjid Allaoui, Mohamed Salah Belksier, Ouafi Ameur-Zaimeche, Rabah Kechiched, Abdellatif Remita & Lahcene Fellah

  2. Laboratoire Géodynamique Et Ressources Naturelles, Université Med Kheider Biskra Algérie, B.P 145 RP, Biskra, Algeria

    Bachir Lamouri

  3. Laboratoire Mines, Métallurgie Et Matériaux, Département de Génie, Minier École Nationale Supérieure Des Mines Et de La Métallurgie Amar Laskri Annaba, Sidi Amar, Algeria

    Sameh Habes

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Communicated by Santanu Banerjee.

Highlights

• Unraveling Llandoverian paleoclimatic and paleoenvironmental conditions based on clay minerals variation.

• Spectroscopy natural gamma, X-ray diffraction and scanning electron microscopy were documented.

• Black shales with a ratio of Th/U ˂ 4 were deposited in relatively deep marine environment.

• The Llandoverian epoch yields adequate conditions to preserve organic matter and allow generation of hydrocarbons.

• The Llandoverian clay minerals are commonly represented by illite and kaolinite presenting good mechanical properties for hydraulic fracturing.

Appendix

Appendix

The percentages of each mineral are calculated by the semi-quantitative method according to the following algebraic equation:

$$\left[\left(PI\right)\times \left(MF\right)/S\right]\times 100$$
(1)

PI, peak intensity; MF, multiplier factor; S, the multiplier sum of (PI) × (MF) of different minerals (Table 1).

Table 1 Method of calculating the percentages of different minerals; illite, kaolinite, and chlorite of each sample.
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Allaoui, A., Belksier, M.S., Ameur-Zaimeche, O. et al. The lower Silurian black Shales from the Ahnet basin (SW Algerian Saharan platform): a comprehensive mineralogical study and paleoenvironmental implications. Arab J Geosci 15, 1103 (2022). https://doi.org/10.1007/s12517-022-10388-9

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