Carbonate diagenesis of the mixed clastic–carbonate Galala Formation, North Eastern Desert, Egypt

Ghar, Mohamed S. Abu El; Khalifa, M.A.; Hussein, Ahmed W.

doi:10.1007/s12517-014-1349-3

Cited by 12 publications

(7 citation statements)

References 23 publications

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“…Quartz-feldspar-lithic ternary plot showing distribution of samples from three measured sections for the classification of sandstone of the Chhidru Formation (adapted from Dickinson et al, 1983). The presence of minerals like (b) muscovite, (c) zircon, (d) tourmaline, and (e) oxidized biotite in the Chhidru Formation moulds and deposition of granular mosaic cement within the pore spaces of wackestone and packstone are strong clues for meteoric diagenesis (El Ghar, Khalifa, & Hussein, 2015;Flügel, 2012;Mahboubi, Moussavi-Harami, Carpenter, Aghaei, & Collins, 2010). The diagenesis has significantly enhanced and reduced the reservoir quality by extensive dissolution of allochems and cementation of pore spaces, respectively (Wadood et al, 2021b).…”

Section: Diagenetic Evolution and Impacts On Reservoir Potentialmentioning

confidence: 99%

The Late Permian clastic–dominated carbonate shelf, Northwestern Pakistan: Implications for palaeoenvironments, palaeoclimate, and reservoir modelling

et al. 2021

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The Indus Basin of Pakistan has archived thick and laterally extensive Permian carbonates. The current study focuses on constraining the palaeoenvironments, reservoir potential, and ambient climatic conditions during the deposition of Late Permian clastic-dominated carbonates of the Chhidru Formation, Indus Basin, Pakistan. At outcrop, the unit shows laterally variable thicknesses of dominantly thick-bedded, fossiliferous, channelized calcareous sandstone, and sandy limestone. The microscopic textural, compositional, and biotic attributes divulged four microfacies, arguing for the deposition in a range of diverse depositional environments including lagoonal to deltadominated middle shelf. The deposition of clastic-rich carbonates of the Chhidru Formation on the underlying pure carbonates of the Wargal Formation hints strongly towards a sea-level fall on the northwestern margin of the Indian Plate. The regression tightly correlates with the stratigraphic record of the adjacent continents, including South China, the Persian Gulf, and northern Gondwana regions. The abundance of detrital material indicates terrestrial influx to the basin, inhibiting the benthic activity and consequently resulting in poor microfossil content. Nevertheless, 11 agediagnostic foraminiferal taxa were identified, suggesting a Late Wuchiapingian to Changhsingian age. The X-ray diffraction analysis of argillaceous horizons revealed several climate-sensitive clay minerals. Based on the dominance of illite, palygorskite, sepiolite, and chlorite, an extremely arid and cold climate is suggested for the region during the time of deposition of the Chhidru Formation. Petrographic observations suggest reworking of sediments shed from the Indian Shield of the Aravalli system and MalaniRange. The petrography, scanning electron microscopy, and energy dispersive X-ray spectroscopy revealed multiple diagenetic phases including marine, meteoric, and burial that have shaped the unit into a poor to moderate reservoir.

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Section: Diagenetic Evolution and Impacts On Reservoir Potentialmentioning

confidence: 99%

The Late Permian clastic–dominated carbonate shelf, Northwestern Pakistan: Implications for palaeoenvironments, palaeoclimate, and reservoir modelling

et al. 2021

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“…11b, e, h). This type of diagenetic feature represents the meteoric-phreatic diagenetic realm (Khalifa et al, 2009;El Ghar et al, 2015); the second phase is where cement has filled the fractures (Fig. 11a) and shows undulatory extinction, which is an indicative feature of burial diagenesis realm (Vincent et al, 2007).…”

Section: Cementationmentioning

confidence: 99%

Reservoir Quality Assessment of the Upper Permian Chhidru Formation, Salt and Surghar Ranges, Pakistan

Zahir

Awais

Ghani

et al. 2021

Acta Geologica Sinica (Eng)

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The Late Permian succession of the Upper Indus Basin in northeastern Pakistan is represented by the carbonate‐dominated Zaluch Group, which consists of the Amb, Wargal and Chhidru formations, which accumulated on the southwestern shelf of the Paleo‐Tethys Ocean, north of the hydrocarbon‐producing Permian strata of the Arabian Peninsula. The reservoir properties of the mixed clastic‐carbonate Chhidru Formation (CFm) are evaluated based on petrography, using scanning electron microscopy (SEM), energy dispersive x‐ray spectroscopy (EDX) and x‐ray diffraction (XRD) techniques. The diagenetic features are recognized, ranging from marine (isopachous fibrous calcite, micrite), through meteoric (blocky calcite‐I, neomorphism and dissolution) to burial (poikilotopic cement, blocky calcite‐II‐III, fractures, fracture‐filling, and stylolites). Major porosity types include fracture and moldic, while inter‐ and intra‐particle porosities also exist. Observed visual porosity ranges from 1.5%–7.14% with an average of 5.15%. The sandstone facies (CMF‐4) has the highest average porosity of 10.7%, whereas the siliciclastic grainstone microfacies (CMF‐3) shows an average porosity of 5.3%. The siliciclastic mudstone microfacies (CMF‐1) and siliciclastic wacke‐packestone microfacies (CMF‐2) show the lowest porosities of 4.8% and 5.0%, respectively. Diagenetic processes like cementation, neomorphism, stylolitization and compaction have reduced the primary porosities; however, processes of dissolution and fracturing have produced secondary porosity. On average, the CFm in the Nammal Gorge, Salt Range shows promise and at Gula Khel Gorge, Trans‐Indus, the lowest porosity.

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“…In meteoric water environment, the low Mg 2+ content enhances precipitation of calcite (granular/blocky shape) and indicates fresh water diagenesis. In meteoric phreatic zone, the pores space principally filled with water, where cement is more even with crystal growth that yielded large crystal size of blocky calcite cement (El Ghar, Khalifa, & Hussein, 2015; Flügel, 2010; Khalifa, 2005; Tucker & Wright, 1990; Zhang et al, 2006). The filling the macropores with the coarse crystalline cements are interpreted as the burial cementation (Guo et al, 2016).…”

Section: Diagenetic Processesmentioning

confidence: 99%

“…Marine diagenetic environments are recognized by first generation of micritization, non‐ferron‐isopachous fibrous cements (El Ghar et al, 2015; Khalifa, 2005; Mahboubi, Moussavi‐Harami, Carpenter, Aghaei, & Collins, 2010; Taghavi, Mørk, & Emadi, 2006; Vincent et al, 2007). Micritization is the most striking diagenetic feature that is identified in the Fort Member limestones, likely to be formed in marine environment.…”

Section: Diagenetic History (Paragenesis)mentioning

confidence: 99%

“…The granular calcite cement, early stage of blocky calcite cement, micritic cement, dissolution of moulds as well as neomorphism (polymorphic transformation of primary minerals) are all the indication of meteoric‐phreatic diagenetic realms (El Ghar et al, 2015; Melim et al, 2002; Vincent et al, 2007). During the meteoric stages, metastable skeletal (bioclasts) and non‐skeletal grains are dissolved, generated secondary fabric‐ and non‐fabric selective porosity such as inter‐crystalline, intra‐particles, and moldic/solution porosities (Figure 6h).…”

Section: Diagenetic History (Paragenesis)mentioning

confidence: 99%

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Microfacies and diagenetic overprints in the limestones of Middle Jurassic Fort Member (Jaisalmer Formation), Western Rajasthan, India: Implications for the depositional environment, cyclicity, and reservoir quality

2020

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The present study investigates the microfacies and the effects of diagenetic processes on the reservoir quality of limestones of the Fort Member, Jaisalmer Formation, Western Rajasthan. The study interpolates an integrated approach including field studies, petrography, staining, and X‐ray diffraction techniques. The Fort Member is composed of medium‐ to thick‐bedded, nodular highly fossiliferous limestones, which are fine‐ to medium‐grained, poorly‐ to very well‐sorted, and comprise angular‐ to well‐rounded grains of low to high sphericity. These limestones contain abundant skeletal (bivalves, brachiopods, echinoderms, foraminifera, algae, gastropods, sponge, coral, and calcispheres) and non‐skeletal grains (intraclasts, ooids, and peloids). On the basis of detailed petrographic investigations, eight microfacies have been recognized including: bioclastic wackestone, whole‐fossil wackestone, bioclastic lithoclastic packstone, aggregate grainstone, peloidal grainstone, ooidal grainstone, bioclastic grainstone, and coated bioclastic grainstone. Based on the microfacies analysis, the limestones of the Fort Member are inferred to have been deposited in shoal, lagoon, and open marine environments. The diagenetic overprints of the Fort Member limestones is characterized by the several diagenetic features such as micritization, cementation, dolomitization, compaction, dissolution, silicification, neomorphism (aragonite to calcite transformation and development of microspar), and secondary porosity. Such main diagenetic features affecting the carbonates are developed in marine phreatic, meteoric phreatic, mixed meteoric phreatic and burial diagenetic environments. Micritization of allochems, dolomitization of lime muds, and cementation by isopachous calcite, granular calcite cement, neomorphism, and recrystallization of bioclasts are developed in meteoric‐phreatic diagenesis. The meteoric‐vadose diagenesis led to prevalence of dissolution process and sparry calcite infilling the fractures. Dolomitization, blocky calcite cement, and silicification processes were developed during the burial diagenesis. These diagenetic processes have direct effects on the modification of both intergranular and intragranular/crystalline porosity. In this manner, it is found that the calcite cementation, micritization, and compaction were responsible for the reduction of the pore spaces, whereas dolomitization, dissolution, formation of moldic pores, and fracturing increased the pore volumes. Therefore, the enhanced pore volumes improved the carbonate reservoir characteristics, suggesting the limestones of the Fort Member to be a better carbonate reservoir for hydrocarbon accumulation.

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Carbonate diagenesis of the mixed clastic–carbonate Galala Formation, North Eastern Desert, Egypt

Cited by 12 publications

References 23 publications

The Late Permian clastic–dominated carbonate shelf, Northwestern Pakistan: Implications for palaeoenvironments, palaeoclimate, and reservoir modelling

The Late Permian clastic–dominated carbonate shelf, Northwestern Pakistan: Implications for palaeoenvironments, palaeoclimate, and reservoir modelling

Reservoir Quality Assessment of the Upper Permian Chhidru Formation, Salt and Surghar Ranges, Pakistan

Microfacies and diagenetic overprints in the limestones of Middle Jurassic Fort Member (Jaisalmer Formation), Western Rajasthan, India: Implications for the depositional environment, cyclicity, and reservoir quality

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