This work depends on detailed petrographic and diagenetic processes studies of collected cutting rock samples, from the Late Jurassic Naokelekan Formation from Ajil-8, Balad-1 and Baiji-1 wells. Based on the thin sections study, the formation contains various petrographic components represented by pelecypods, calcispheres, planktonic and benthonic foraminifera, in addition to the groundmass of micrite and microspars. Many diagenetic processes affected the rock successions such as, compaction, micritization, authigenic minerals (pyrite), cementation, neomorphism, dissolution, porosity, replacement and dolomitization. The detailed microfacies analysis reveals that the rock successions consist mainly of three microfacies including; lime mudstone, which is divided into non-fossiliferous lime mudstone, bioclastic lime mudstone and planktonic foraminiferal lime mudstone, lime wackestone which also divided into calcispheres lime wackestone, benthonic lime wackestone, and pelcypodal lime wackestone, and lime packstone include, bioclastic lime packstone, peloidal lime packstone, and calcispheres lime packestone. The overall characters of these microfacies indicate the formation was deposited in two different environments: (1) shallow marine subtidal environment at the lower and upper parts (2) outer shelf in an euxinic environment at its middle part
This work were carried out on 193 thin sections from Middle Jurassic Sargelu Formation. These samples are from three wells (Ajil-8, Balad-1 and Baiji-1). Petrographically, the Sargelu Formation composed of skeletal component (radiolaria, pelecypods, calcispheres, planktonic, benthonic foraminifera and ostracods), in addition non-skeletal such as pellets, groundmass of micrite and recrystallized microspars. Many diagenetic processes affected this formation the main which have been recognized are: compaction, micritization, cementation, neomorphism, dissolution, fractures and veins, silicifaction and dedolomitization in addition authigenic minerals (pyrite). Depending on the petrographic studies the following microfacies have been recognized: Lime Mudstone Microfacies which was divided into three submicrofacies (Pelecypodal Lime Mudstone, Radiolarian Lime Mudstone and Planktonic Foraminiferal Lime Mudstone), Wackestone Microfacies which was divided into four submicrofacies (Radiolarian Lime Wackestone, Halobia Wackestone, Calcispheres Wackestone and Planktonic Foraminiferal Wackestone) and Packstone Microfacies (Halobia Lime Packstone and Peloidal Lime Packstone). The overall characters of these microfacies indicate that the formation was deposited in two different environments: (1) upper Bathyal environment at the lower part (2) Outer shelf environment at the upper part.
This study deals with the minerology of Injana Formation (Late Miocene- Pliocene) at Zawita and Daigala sections, north of Iraq. A total of 13 samples are collected from Injana Formation. The heavy minerals assemblages include opaque minerals, orthopyroxenes, clinopyroxenes, zircon, rutile, epidotes, garnet, amphiboles, tourmaline, chlorite, biotite, kyanite, muscovite and staurolite. The source rocks of these assemblages of heavy minerals are mafic igneous and metamorphic rocks principally as well as acidic igneous and old sedimentary rocks. The ZTR indices indicate the Injana sandstone is mineralogically immature .The tectonic origins of Injana Formation is characterized as lithic recycled of recycled orogeny .The mudstone consists of mixture of clay and silt percentage variable. The major clay minerals are chlorite, kaolinite, illite and smectite. The non-clay minerals are calcite, quartz and subordinate feldspars. The mineralogy of the clay fraction of Injana mudstone leads to be climate arid to semi-arid
To interpret the provenance 0f Injana Formation, 20 sandstone samples of Injana Formation were collected from Zawita and Dekala areas north Iraq (10 for each sections ), then thin section have been done sildes. The petrographic study showed that the sedimentary, metamorphic and igneous rock fragments, quartz (mono&polycrystalline) and feldspars (microcline, orthoclase and plagioclase) make up the main grain components of the sandstone. Carbonate cement is more common cementing minerals, and the matrix is subordinate. The percentage of mono-quartz and sedimentary, igneous rock fragments are greater than the amounts of feldspar and poly-quartzand metamorphic fragments. A diagenetic processes were represented by the carbonate, iron oxides and evaporite cements, as well as compaction, cementation, and dissolution. The majority of the rocks of Injana Formation’s provenances are sedimentary and igneous, with minor amounts of subordinate metamorphic rocks. These sandstones are considered to be immature and classified as immature Litharenites type. The tectonic provenances that are extrapolated from petrographical results are transitional and lithic with effect of uplifting of Alpaine oroging recycled origin which are derived from the order rocks during the Miocene age.
The reservoir characterization of Lower Qamchuqa (Shu'aiba) Formation (Aptian) is studied at the well BH-86 of Bai- Hassan Oilfield in Kirkuk area, Northern Iraq. The lithological study (of 91 thin sections) revealed that the formation consists of shaly limestone, a thin bed of marl within the limestone, and dolomitic limestone. Four petrographic microfacies were noticed Lime mudstone microfacies, Dolomudstone microfacies, Lime wackestone microfacies, subdivided into benthonic foraminifera lime wackestone submicrofacies and bioclasts lime wackestone submicrofacies, and the last microfacies is the Lime packstone microfacies, which is subdivided into pelloidal lime packstone submicrofacies and Orbitolina lime packstone microfacies. Shale content is calculated from the gamma-ry log, showing that the formation is mainly of low shale content (less than 35%). The porosity determined from sonic, density, and neutron logs reflect that the range between <1 and 15% and in some intervals about 6% is secondary porosity type. The estimated permeability ranges between <0.01 and 2.0mD, reflecting low permeability. The formation is subdivided into six reservoir units according to the shale content, average porosity, and permeability. The unit RU-5 has the best reservoir properties among the identified units with an average shale content of about 3.15%, about 6.2% porosity, and about 1.75mD average permeability. On the other hand, the least reservoir property is noticed in the unit RU-1 with average 9.48% shale content, 3.64% porosity, and 0.5mD average permeability. The research indicates that the fractures contribute to the flow within the Lower Qamchuqa Formation. Fluids flow through the formation in four unique Hydraulic Flow Units (HFU). Only about 8% of the gross 146m of the formation is expected to have the required reservoir properties for oil production and about 68% for gas production. The actual productive thickness for oil is only about 2.8% of the gross thickness of the studied section, and it’s more than 50% of the gross thickness for gas.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.