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Photomicrographs of Kurra Chine Formation microfacies and diagenetic processes. (a) algal Grainstone microfacies with blue-green algae (red arrow), and occasionally non-skeletal grains like pellets (yellow arrow) (b) dolomitized Wackstone microfacies, characterized by Echinoderm grains with syntaxial rim cement (yellow arrow), and fragmented brachiopod valves (red arrow). (c) dolomitized mudstone microfacies displaying neomorphism (red arrow) (d) dolomitized Wackestone microfacies exhibiting dissolution processes creating secondary porosity. Sp.: Sponges; Bry: Bryozoan; Ost.: Ostracods; Alg.: Algal; Ech.: Echinoderm; D: Dissolution process.
Source publication
Abstract
The study of carbonate petrography is essential for understanding reservoir properties and the quality of rock formations. High-resolution cathodoluminescence spectroscopy and optical microscopy were used to determine the impact of cement on the porosity evolution of carbonate rocks of the Kurra Chine Formation at Sirwan Valley, Northern I...
Context in source publication
Context 1
... skeletal grains have been observed including echinoderms, sponges, brachiopod valves, and algae. Non-skeletal grains, such as pellet and aggregated are also present but have less abundance. According to Dunham (1962), the formation can be classified into three microfacies types: algal grainstone, dolomitized wackestone, and dolomitized mudstone (Fig. ...
Citations
... It is led to changes in the primary depositional shapes [3]. Generally, dolomitization and dissolution increase reservoir quality of carbonate rocks and cementation decrease it [5]. ...
The carbonate rocks of Late Triassic Baluti Formation in Sararu outcrop,
Northern Thrust Zone, Northern Iraqi Kurdistan region consist of brecciated marly
limestone and sandy dolomitic limestone interbedded with shale that characterized
by complex heterogeneity. The microscopic description of the porosity types and
diagenetic processes controlled it were studied in current work. The petrographic
study of 12 thin section of Baluti carbonate displayed that the main skeletal grains
are shallow marine derivative fossils and non-skeletal grains are only
monocrystalline quartz. The main matrix is micrite which sometimes changed to
microspar and sparry calcite. Seven pore types were distinguished in the studied
rocks of the formation from both primary and secondary stages. The primary
porosity are interparticle and intraparticle pores. While, the secondary types were
moldic, intercrystalline, fracture, vuggy and stylolitic porosities. The formation in
studied outcrop was undergone in several diagenetic processes, that enhanced or
reduced the porosity of the Baluti carbonates. Early micritization protect the primary
pores from destroying by compaction. While, solution was assists in creating
different secondary pores in different diagenetic stage of the formation particularly
the dominant moldic porosity. Calcite cements aid in reducing all pore types in the
studied formation. Late dolomitization contribute to formation intercrystalline and
dolomoldic porosities. stylolites with dissolution helps to creating stylolitic
porosity. Neomorphism, silicification and pyritization generally reduced porosity in
the formation.
... The estimation of water saturation relies on the lithology of the formation [5]. The Kurra Chine Formation consists of both clean formations and shale formations. ...
... Hydrocarbon saturation is crucial for oil companies to evaluate hydrocarbon in the reservoir [5]. After identifying water saturation, hydrocarbon saturation is extracted from unity. ...
The Upper Triassic Kurra Chine Formation in the Sarta oil field of the Kurdistan Region of Northern Iraq has garnered limited attention, notwithstanding the keen interest of numerous international oil companies in drilling wells within this geological epoch. This study endeavors to thoroughly investigate the Formation Evaluation and petrophysical properties of the Kurra Chine Formation in the production oil field, with a specific focus on Sarta Well-2 (S-2). The research incorporates diverse methods for formation evaluation and analysis of petrophysical properties, employing conventional wireline logs such as Gamm-Ray, Neutron, Density, Sonic, Resistivity, Caliper, and Bit size.
The research findings reveal that the thickness of the Kurra Chine Formation in S-2 is approximately 380 m. The pay zones of S-2 exhibit an average shale volume of 17 %. The dominant lithology in S-2 comprises Limestone, Dolomite, Anhydrite, Shale, and Sandstone. The average total porosity within the pay zones is determined to be 6 % in S-2. Furthermore, the average effective porosity in reservoir zones of the S-2 is estimated to be 5 %, while the average secondary porosity in these zones is found to be 6 % in S-2. The average permeability in the pay zones of the Sarta well is reported to be 30.6 millidarcy (mD). Additionally, the average water saturation in the pay zones is determined to be 35 % in S-2, whereas the average hydrocarbon saturation is estimated to be 45 % in S-2.
This study furnishes comprehensive descriptions and analyses of the formation evaluation and petrophysical properties of the Kurra Chine Formation in Northern Iraq, shedding light on the characteristics and potential of this oil-bearing formation.
... These studies involved the examination of the cutting and core samples in various wells in the Mosul Block. Previous researchers have also described this Formation in the context of sedimentology, petroleum, source rock, reservoir rock, and depositional environments as documented in (2,4,6,7,8). ...
Palynofacies (PF) analysis was conducted on 34 crushed samples of the Upper Triassic Kurra Chine Formation. These samples were collected from one outcrop sample and two production wells in northern Iraq. A 10μm nylon mesh sieve was used for the concentration of palynomorphs. Four palynofacies types were found in this study. PF1 was characterized primarily by amorphous organic matter (AOM), suggesting a distal suboxic-anoxic depositional environment. PF2 comprised of AOM, along with some Phytoclasts and palynomorphs, indicating a distal dysoxic-oxic shelf depositional environment. PF3 displayed an increasing volume of palynomorphs, signifying a distal dysoxic-anoxic shelf depositional environment. PF4 predominantly consisted of palynomorphs and Phytoclasts, representing a mud-dominated oxic shelf (distal shelf) depositional environment. Kerogen types were identified as type II, which is oil-prone in three palynofacies, and type III which is gas-prone in one palynofacies.
... The estimation of water saturation relies on the lithology of the formation [5]. The Kurra Chine Formation consists of both clean formations and shale formations. ...
... Hydrocarbon saturation is crucial for oil companies to evaluate hydrocarbon in the reservoir [5]. After identifying water saturation, hydrocarbon saturation is extracted from unity. ...
