Papers by Dr.Mohamed ِ A L I Alrashedi
Iraqi Geological Journal, 2023
Shiranish Formation at three localities in Northern Iraq (Pulkana, Dokan, and Sufaya) was studied... more Shiranish Formation at three localities in Northern Iraq (Pulkana, Dokan, and Sufaya) was studied to determine hydrocarbon generation potential and conditions of the depositional environment. For this purpose, 15 rock samples were collected from subsurface sections (Pulkana and Sufaya oil fields) and 5 surface samples from the Shiranish outcrop in the Dokan area. These samples were subjected to Rock-Eval pyrolysis analysis, in addition to biomarker analysis of the bitumen extract of one sample. Total organic carbon, S2, and hydrogen index values of the Formation samples from the Sufaya oil field, and the Dokan outcrop were generally low; indicating that Shiranish Formation is non-hydrocarbon source rocks. On the other hand, the Total organic carbon, S2, and HI of the Shiranish Formation for Pulkana oilfield samples are generally high; indicating that Shiranish Formation can be regarded as a fair source of rocks. Tmax and biomarker data indicate that the organic matter of the Shiranish Formation is immature-early mature. Moreover, the hydrogen index, oxygen index, and biomarker data indicate that the Shiranish Formation contains type II and II/III and was deposited under an anoxic depositional environment at Pulkana. At Sufaya and Dokan, Shiranish Formation contains type III and IV kerogen deposited in a more oxic environment.
Journal of African Earth Sciences, 2024
The Shiranish Formation represents one of the most important fractured reservoirs in northern Ira... more The Shiranish Formation represents one of the most important fractured reservoirs in northern Iraq. In this work, the petrophysical properties of the formation have been fully characterised using microscopy, core analysis, and well log analysis using conventional methods as well as new quantitative diagenetic approaches. During this work we have developed methods to quantify a petrophysical heterogeneity index (χ), reservoir quality indicator (RQI), and fracture effect index (FEI) for each of the stratigraphic units of the formation. The FEI was calculated by dividing the difference between the mean permeability of the wireline log data and the mean permeability of the unfractured core plug samples by the difference between the mean porosity of the wireline log data and the mean porosity of the unfractured core plug samples. This study shows that the Shiranish Formation has a fracturing pore system in all the characterised units, but it is particularly well developed in U.4, which shows the best reservoir quality (A and B). The new methods developed in this study can be applied to any carbonate formation to provide a trustworthy way to obtain a reservoir quality indicator linked to the petrophysical heterogeneity of the studied formation.
Iraqi Geological Journal, 2023
The idea of the current work was the combination of the organic geochemical analyses, and the stu... more The idea of the current work was the combination of the organic geochemical analyses, and the study of sedimentology characteristics of the source rock samples collected from the Ispartaçay Formation (Cretaceous period) between the city of Antalya and the city of Isparta, southwestern Turkey. Total Organic Carbon analysis and Rock-Eval pyrolysis were performed on the 24 samples taken from the study area, in order to evaluate quantitatively, and qualitatively organic matter and thermal maturity to determine the potential for hydrocarbon production. As well as studying the petrographic features (component and diagenesis), microfacies analysis, and sedimentary environment of the Ispartaçay Formation. The successions of the Ispartaçay Formation are poor to fair organic matter content and consist of dark grayish limestone, marly limestone, shale, massive cherty limestone, and thin-bedded radiolarian limestone. Total Organic Carbon values indicate that Ispartaçay Formation rocks are fair potential. Besides this, most of the samples from the Ispartaçay Formation contain mature to pot-mature (Type III-Type IV) kerogen. Petrographically, the particle portion of the Ispartaçay sediments is composed mainly of radiolarians, and planktonic foraminifera, In addition to the presence of a proportion of benthic foraminifera, whereas the groundmass is composed of micrite. Generally, the present sediments are subjected to some diagenetic processes like silicification, cementation, and dissolution. The microfacies analysis revealed that the succession of the Ispartaçay Formation is composed of alternations of two major microfacies, namely lime mudstone and lime wackestone microfacies. Depending on the facies and petrographic evidence, Ispartaçay Formation represents sediments deposited in the mid to outer ramp environment.
IRAQI BULLETIN OF GEOLOGY AND MINING (IBGM), 2023
Aqra Formation is a shallow marine deposit of the late-Cretaceous sedimentary cycle. According to... more Aqra Formation is a shallow marine deposit of the late-Cretaceous sedimentary cycle. According to the field lithological description, the two studied sections of the Aqra Formation are subdivided into three units. Based on sedimentological characteristics and fossils assemblage eleven facies have been recognized in both studied sections, their alternated association points to a wide range of depositional environments extended from tidal flat, back reef, reef, to fore-reef. Based on the fossil's appearance, the studied sections comprised two fossils biozone {Orbitoides media zone (part) and Liftusia morgani zone}, it is age determined to be late Campanian-Early Maastrictian in both studied sections. Sequence stratigraphic analysis, as calibrated by sedimentary facies and biostratigraphy delineated one sequence (Aqra sequence 1) of 2nd order, and their MFI correlation result with MFS studies in the Arabian platform indicated to maximum flooding stage dominated on the Arabian plate at the Latest Campanian.
Geochemistry, Depositional Environment, and Provenance of the Cretaceous Radiolarian Chert in Northeastern Kurdistan, Iraq
Iraqi geological journal, Dec 31, 2022
The radiolarian chert rocks are one of the most important indications of the existence of ophioli... more The radiolarian chert rocks are one of the most important indications of the existence of ophiolites because they are a source of silica supply. These rocks have been studied to refute and reject the idea that ophiolites do not existed. The Si/(Si+Al+Fe+Ca) ratio in the radiolarian chert indicates that the silica is of biogenic origin and adds SiO2 from the shale fraction through diagenetic processes. The high values of Fe2O3 content indicate the hydrothermal effect during precipitation. This effect is controlled by the distance between the sediments and the mid-oceanic ridge or sea floor metamorphism. The phosphorus could be a direct result of volcanic activity associated with ophiolitic rocks, whereas, the negative correlation coefficient of phosphorous with calcium (r = -0.53) supports the idea that the source of phosphorous is volcanic activity that is not related to the carbonate fluorapatite mineral. REEs shows a basic difference as a positive cerium anomaly in section Q2 and a negative cerium anomaly in section Q1. The Al-Fe-Mn diagram shows that all samples fall into the field I non-hydrothermal zone, but in the SiO2 vs Al2O3 diagram the samples of the Q1 section fall into the hydrothermal field, and samples of the Q2 section fall into the non-hydrothermal field. The input materials in Qulqula radiolarian chert come from terrigenous sediments in both sections. On the other hand, the Al/(Al+Fe+Mn) ratio range, (between 0.61 to 0.70), is very close to the average shale composite value, (0.6.19), which may reflect the contribution from continental and non-hydrothermal sediments, while the lower values of this ratio reflect hydrothermal source input. The MnO2 /TiO2 ratios ranged between 0.06 to 2.37 in section Q1 which represents typical characteristics of the deep ocean, trenches, and basaltic plateau sediments.
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Papers by Dr.Mohamed ِ A L I Alrashedi