| Abstract: |
The present work aims to study the sedimentological and petrophysical properties of some Mesozoic rock types, Taba, Sinai.The study area is located at longitudes 34? 52` and 34? 54` E and latitudes 29? 28` and 29? 30` N. The field observation and lithological studies of the studies Cretaceous sequence reveal that the Malha Formation (Albian-Aptian) is unconformably overlies The wata Formation (Turonian) conformably overlies the Galala Formation and consists of limestone with few intercalations of shale, dolostone, gypsum and marl. The thickness of this formation about (126m).The Matulla Formation (Coniacian – Santonian) rests conformably above the Wata Formation and made up of carbonates in the lower part (dolostone-limestone) and sandstone in the upper part. The thickness of this formation is (51m).The Sudr Formation (Campanian-Maastrichtian) which overlies conformably on Matulla Formation. The Sudr Formation consists of snow white chalky limestone with intercalations of marl, claystone and chert bands. The thickness of this formation about (88m).The measured grain size parameters deduced from the mechanical analysis data indicate that the studied sandstone are mainly medium-grained, and rarely coarse-grained, moderately well sorted to poorly sorted, skewed.Plots of various grain size parameters are used to recognize the depositional environment of sandstone samples.Light and heavy mineral analysis are performed on two size fractions of the studied sandstone samples, 0.25-0.125mm and 0.125-0.063mm. The sandstone light minerals of Malha Galala, and Matulla Formations essentially consist of 97% quartz and very rarely fThe opaque mineral are dominate over than the non opaque mineral in both size classes, where the average of this mineral reaches (…………) in the fine sand size and (……….) in the very fine sand size.The non-opaque minerals represented by: zircon, tourmaline, rutile, epidote, garnet, monazite and other minerals.Petrographically: eighty nine thin-section were investigated which represent the Cretaceous sequence at Taba area.Malha Formation consists mainly of sandstone of quartz arenite, quartz wacke, ferruginous quartz arenite, ferruginous quartz wacke, pebbly quartz arenite and sandy siltstone according to the nomenclature of Pettijohn (1973).Galala Formation consists of carbonate and rarely sandstone. The carbonate occurs as biomicrosparite, biodolomicrite biomicrosparite, dolosparite, dolomicrosparite adomicrite and dolosparite.The sandstone occurs in form of dolomitic quartz arenite and glauconitic quartz arenite.The Wata Formation consists of carbonate rocks which includes biodolomicrite, pelintraoobiosparite, dolobiomicrite, biooosparite, biomicrite dolomicrosparite and dolostone.Matulla Formation consists of sandstone and carbonate rocks. The sandstone occurs as dolomitic quartz arenite, quartz arenite and gypsiferous quartz arenite while the carbonate rocks occurs in form of sandy dolobiomicrite, dolobiopelmicrite argillaceous bSudr Formation consists of chakly limestone and some phosphate and chert beds. Petrographically, it represent by forameniferal biomicrite, silicified phosphorite and argillaceous dolostone.The diagenetic aspects for this formations were recorded for sandstone and carbonate rock types. The diagenetic aspects of sandstone rocks include: Physical changes are representing by mechanical compaction and pressure solution, while the chemical procesThe depositional environments were determined for all formations of Cretaceous sequence at Taba area as a following.- Malha Formation: fluvitial (river) according to textural parameters of mechanical analysis.- Galala Formation: the deposition environment is shallow marine according to standard microfacies charts of flugel (1982)- Wata Formation: the environment of sedimentation are suggested to be shallow marine environment- Matulla Formation: shallow marine- Sudr Formation: open-marine depositional environment.The petrophysical analysis of fourty two of Cretaceous sequence samples were studied. The petrophysical studies include: pore geometry and clay mineral types, storange capacity, electrical properties and Acoustic wave velocity. The pore geometry of the stThe clay mineral identification of Cretaceous samples at Taba area include: kaolinite, Illite, Smectite and mixed-layers.The storage capacity were determined which includes porosity permeability and density (bulk density)The porosity was measured from Malha, Galala wata Matulla and sudr Formations. It found to be to , to , to , to , to respectively. The statistical analysis were measured for porosity data.The permeability were measured and found vary from to , to , to , to , to for Malh, Galala, Wata, Matulla and Sudr Formations respectively.Also the bulk density measured and the relation between them were prepared.The study of electrical properties which include, electrical resistivity formation resistivity factor true electric resistivity irreducible water saturation resistivity index, Tortuosity and mounce potential.All these parameters were calculated satistical analysis and correlated
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