Pub Date : 2024-01-31DOI: 10.46717/igj.57.1a.12ms-2024-1-23
Mustafa Akbar, Aysar Al-Shama’a
The current research aims to evaluate the hydrogeological characteristics of the water-bearing layers in the study area. Because of the absence of observation wells near the pumping wells, the single pumping test experiment was achieved at seven wells, GW1, GW2, GW8, GW9, GW11, GW13, and GW16, distributed in the study area. The pumping test records were analyzed using Aquifer Test 2016.1 software, which is based on four methods: Theis, Hantush, Cooper-Jacob, and Theis recovery. The average values of transmissivity for the upper aquifer in the study area ranged between 13.4 m2/ day and 279 m2/ day, while the hydraulic conductivity ranged between 0.162 m/day and 4.14 m/day, and the storativity was 0.166 and 0.826. For the lower aquifer, the transmissivity ranges between 11.4 m2/ day and 177 m2/ day, the hydraulic conductivity is 0.214 m/ day and 1.17 m/ day, and the storativity is 0.0791 and 0.99.
{"title":"Evaluation of Hydrogeological Characteristics of Aquifers in Altun Kopri Basin, Northeastern Iraq","authors":"Mustafa Akbar, Aysar Al-Shama’a","doi":"10.46717/igj.57.1a.12ms-2024-1-23","DOIUrl":"https://doi.org/10.46717/igj.57.1a.12ms-2024-1-23","url":null,"abstract":"The current research aims to evaluate the hydrogeological characteristics of the water-bearing layers in the study area. Because of the absence of observation wells near the pumping wells, the single pumping test experiment was achieved at seven wells, GW1, GW2, GW8, GW9, GW11, GW13, and GW16, distributed in the study area. The pumping test records were analyzed using Aquifer Test 2016.1 software, which is based on four methods: Theis, Hantush, Cooper-Jacob, and Theis recovery. The average values of transmissivity for the upper aquifer in the study area ranged between 13.4 m2/ day and 279 m2/ day, while the hydraulic conductivity ranged between 0.162 m/day and 4.14 m/day, and the storativity was 0.166 and 0.826. For the lower aquifer, the transmissivity ranges between 11.4 m2/ day and 177 m2/ day, the hydraulic conductivity is 0.214 m/ day and 1.17 m/ day, and the storativity is 0.0791 and 0.99.","PeriodicalId":14847,"journal":{"name":"Iraqi Geological Journal","volume":"190 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140473934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-31DOI: 10.46717/igj.57.1a.6ms-2024-1-17
Omnia Abd, Najah Abd
One key step when interpreting seismic reflection data is sequence stratigraphy, which has improved with well logs and seismic data. By analyzing the different layers of sediment and rock, we can better understand the geologic history of an area and make more accurate predictions for hydrocarbon exploration. The current research focuses on interpreting seismic lines from the 2D seismic surveys conducted in the Al-Fao area and data from wells in the Siba gas field to construct a stratigraphic model within the Yamama Formation, to identify hydrocarbon traps and determine the most promising zones for hydrocarbon exploration. Yamama Formation is divided into two main units representing transgressive and regressive facies deposited in highstand system tract. Six seismic facies were identified (wavy, mound shape, oblique parallel, sigmoid, chaotic, and parallel), which reflected the deposition of Yamama Formation in a ramp setting with a gentle slope. Instantaneous phase attribute was utilized, which focused on the lateral changes of seismic facies and provided detailed information about the architecture of Yamama Formation depositional basin. The results of the seismic attributes analysis included identifying carbonate buildups and progradation stacking patterns with the presence of direct hydrocarbon indicator. Three main seismic stratigraphic indexes representing potential stratigraphic traps have been identified. These three stratigraphic features reflect the facies of shoal carbonate sediments in the last depositional cycle of Yamama Formation (Highstand). The stratigraphic model showed the best image of the depositional environment of Yamama Formation that corresponds with the seismic data interpretation and identifies the promising hydrocarbon traps.
{"title":"Seismic Sequence Stratigraphic Model and Hydrocarbon Potential of Yamama Formation in Al-Fao Area, Southeastern Iraq","authors":"Omnia Abd, Najah Abd","doi":"10.46717/igj.57.1a.6ms-2024-1-17","DOIUrl":"https://doi.org/10.46717/igj.57.1a.6ms-2024-1-17","url":null,"abstract":"One key step when interpreting seismic reflection data is sequence stratigraphy, which has improved with well logs and seismic data. By analyzing the different layers of sediment and rock, we can better understand the geologic history of an area and make more accurate predictions for hydrocarbon exploration. The current research focuses on interpreting seismic lines from the 2D seismic surveys conducted in the Al-Fao area and data from wells in the Siba gas field to construct a stratigraphic model within the Yamama Formation, to identify hydrocarbon traps and determine the most promising zones for hydrocarbon exploration. Yamama Formation is divided into two main units representing transgressive and regressive facies deposited in highstand system tract. Six seismic facies were identified (wavy, mound shape, oblique parallel, sigmoid, chaotic, and parallel), which reflected the deposition of Yamama Formation in a ramp setting with a gentle slope. Instantaneous phase attribute was utilized, which focused on the lateral changes of seismic facies and provided detailed information about the architecture of Yamama Formation depositional basin. The results of the seismic attributes analysis included identifying carbonate buildups and progradation stacking patterns with the presence of direct hydrocarbon indicator. Three main seismic stratigraphic indexes representing potential stratigraphic traps have been identified. These three stratigraphic features reflect the facies of shoal carbonate sediments in the last depositional cycle of Yamama Formation (Highstand). The stratigraphic model showed the best image of the depositional environment of Yamama Formation that corresponds with the seismic data interpretation and identifies the promising hydrocarbon traps.","PeriodicalId":14847,"journal":{"name":"Iraqi Geological Journal","volume":"215 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140472918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-31DOI: 10.46717/igj.57.1a.3ms-2024-1-14
Nazaneen Amin, A. Al-haleem
The Qamchaq Formation makes up the upper Cretaceous reservoir of the Jambur oil field and is responsible for most of the hydrocarbon production in this complicated carbonate reservoir. The petrophysical characteristics of the rocks and fluids differ in various sections of the region. The first step in constructing an acceptable geological model is to identify reservoir characteristics, geological features, lithological characteristics, and hydrocarbon zones to accurately forecast future reservoir performance during the development phase. The goal of this paper is to describe the petrophysical properties and composition of the upper Qamachq formation based on an analysis of a set of conventional well log data using Techlog 2018 software to make assessment integration easier by offering a variety of functions for processing data and showing results. According to the study, the lithofacies vary from northwest to southeast. The lithology in the northwest is limestone to dolomite; basinal Balambo facies replace it in the southeast of the structure. More parameter estimates include 9% matrix porosity, 51% water saturation, and a net-to-gross ratio of 20%, indicating beneficial petrophysical characteristics in the northwest of the structure that contribute significantly to production, as opposed to the southwest region, which has poor physical characteristics. The permeability derived from log data was inaccurate since the Wyllie-Rose formula's permeability coefficient was designed for sandstone and would not be acceptable for carbonate rock; furthermore, the Coates formula has underestimated the permeability because the permeability coefficient needs to be improved by matching it to the core information for each well.
{"title":"Petrophysical Properties of the Upper Qamchuqa Formation in the Jambur Oil Field","authors":"Nazaneen Amin, A. Al-haleem","doi":"10.46717/igj.57.1a.3ms-2024-1-14","DOIUrl":"https://doi.org/10.46717/igj.57.1a.3ms-2024-1-14","url":null,"abstract":"The Qamchaq Formation makes up the upper Cretaceous reservoir of the Jambur oil field and is responsible for most of the hydrocarbon production in this complicated carbonate reservoir. The petrophysical characteristics of the rocks and fluids differ in various sections of the region. The first step in constructing an acceptable geological model is to identify reservoir characteristics, geological features, lithological characteristics, and hydrocarbon zones to accurately forecast future reservoir performance during the development phase. The goal of this paper is to describe the petrophysical properties and composition of the upper Qamachq formation based on an analysis of a set of conventional well log data using Techlog 2018 software to make assessment integration easier by offering a variety of functions for processing data and showing results. According to the study, the lithofacies vary from northwest to southeast. The lithology in the northwest is limestone to dolomite; basinal Balambo facies replace it in the southeast of the structure. More parameter estimates include 9% matrix porosity, 51% water saturation, and a net-to-gross ratio of 20%, indicating beneficial petrophysical characteristics in the northwest of the structure that contribute significantly to production, as opposed to the southwest region, which has poor physical characteristics. The permeability derived from log data was inaccurate since the Wyllie-Rose formula's permeability coefficient was designed for sandstone and would not be acceptable for carbonate rock; furthermore, the Coates formula has underestimated the permeability because the permeability coefficient needs to be improved by matching it to the core information for each well.","PeriodicalId":14847,"journal":{"name":"Iraqi Geological Journal","volume":"259 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140472895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-31DOI: 10.46717/igj.57.1a.20ms-2024-1-31
A. Al-Zubaidi, Mohammad Mohammad, Ali Al-Barazanjy
The study area is located in the southern desert of Iraq, near the Al-Salman Depression, about 130 km southwest of Al-Samawa City. The Collection of data of this study depends mainly upon field surveys, sample collection of rocks, soil, plants, and animals besides interviews with locals as well as photographing of interesting aspects. The geodiversity of the study area comprises geological features, geomorphological features, soil types, and water resources. The exposed rocks of study area are composed mainly of carbonate rocks, in addition to marl, sandstone, and claystone, which belong to the Middle member of the Dammam Formation (L. Eocene). The main landforms found near the Al-Salman area are flat terrain, depressions (faidhats), wadis, caves, and sinkholes. Three types of soils were recognized; silty clay, clayey silt, and sandy soils. The main water resources are the ephemeral streams (wadis), and water wells in sinkhole, besides the mechanical and hand-dug wells. Geodiversity features formed many habitats in the study area such as Wadi Al-Owja, depressions (faidhats), flat terrain, and sinkhole. The present study reveals that biodiversity includes a wide diversity of plants, invertebrates, and vertebrates. Some species were restricted to certain habitat types in the study area, while other species proved to be more generalist.
{"title":"The Relation between Geodiversity and Biodiversity of Al-Salman Depression, Al-Muthana Governorate, Southern Desert of Iraq","authors":"A. Al-Zubaidi, Mohammad Mohammad, Ali Al-Barazanjy","doi":"10.46717/igj.57.1a.20ms-2024-1-31","DOIUrl":"https://doi.org/10.46717/igj.57.1a.20ms-2024-1-31","url":null,"abstract":"The study area is located in the southern desert of Iraq, near the Al-Salman Depression, about 130 km southwest of Al-Samawa City. The Collection of data of this study depends mainly upon field surveys, sample collection of rocks, soil, plants, and animals besides interviews with locals as well as photographing of interesting aspects. The geodiversity of the study area comprises geological features, geomorphological features, soil types, and water resources. The exposed rocks of study area are composed mainly of carbonate rocks, in addition to marl, sandstone, and claystone, which belong to the Middle member of the Dammam Formation (L. Eocene). The main landforms found near the Al-Salman area are flat terrain, depressions (faidhats), wadis, caves, and sinkholes. Three types of soils were recognized; silty clay, clayey silt, and sandy soils. The main water resources are the ephemeral streams (wadis), and water wells in sinkhole, besides the mechanical and hand-dug wells. Geodiversity features formed many habitats in the study area such as Wadi Al-Owja, depressions (faidhats), flat terrain, and sinkhole. The present study reveals that biodiversity includes a wide diversity of plants, invertebrates, and vertebrates. Some species were restricted to certain habitat types in the study area, while other species proved to be more generalist.","PeriodicalId":14847,"journal":{"name":"Iraqi Geological Journal","volume":"553 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140472591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-31DOI: 10.46717/igj.57.1a.11ms-2024-1-22
Ayat Hassan, Alaa Al-Abadi
The research examines the effectiveness of remote sensing for monitoring drought conditions, specifically focusing on the utilization of satellite missions like GRACE to detect alterations in water levels. The study analyzes GRACE data for 10 Jet Propulsion Laboratory (JPL) grid cells alongside precipitation data from 11 meteorological stations. It employs the DrinC program to calculate the standard precipitation index (SPI) at different time intervals. Non- Non-parametric Mann-Kendall tests and Sen's slope statistics are used to determine the trend and magnitude of the GRACE-based anomaly in terrestrial water storage. The statistical findings reveal a significant decrease in Iraq's terrestrial water storage anomaly between 2007 and 2017, indicating drier climatic conditions. However, there is an increase in anomaly between 2002 and 2006, as well as from 2018 to 2020, indicating wetter conditions. The water storage deficit varies among grid cells, each exhibiting distinct characteristics and patterns. The study also highlights that more intense and prolonged droughts tend to occur in the northern and southern regions of Iraq, while the central region experiences more frequent but less severe droughts. In most grid cells, the Mann-Kendall test illustrates a substantial decrease in the water storage deficit index and a significant increase in SPI-06. On the other hand, only one grid cell shows a noticeable precipitation trend. Comparatively, trends in the water storage deficit index and SPI-06 are similar. Overall, the water storage deficit and its index prove valuable in predicting drought severity in locations lacking hydrological measurements.
{"title":"Hydrological Assessment of Iraq for the Period 2002-2020 Using GRACE Terrestrial Water Storage Deficit","authors":"Ayat Hassan, Alaa Al-Abadi","doi":"10.46717/igj.57.1a.11ms-2024-1-22","DOIUrl":"https://doi.org/10.46717/igj.57.1a.11ms-2024-1-22","url":null,"abstract":"The research examines the effectiveness of remote sensing for monitoring drought conditions, specifically focusing on the utilization of satellite missions like GRACE to detect alterations in water levels. The study analyzes GRACE data for 10 Jet Propulsion Laboratory (JPL) grid cells alongside precipitation data from 11 meteorological stations. It employs the DrinC program to calculate the standard precipitation index (SPI) at different time intervals. Non- Non-parametric Mann-Kendall tests and Sen's slope statistics are used to determine the trend and magnitude of the GRACE-based anomaly in terrestrial water storage. The statistical findings reveal a significant decrease in Iraq's terrestrial water storage anomaly between 2007 and 2017, indicating drier climatic conditions. However, there is an increase in anomaly between 2002 and 2006, as well as from 2018 to 2020, indicating wetter conditions. The water storage deficit varies among grid cells, each exhibiting distinct characteristics and patterns. The study also highlights that more intense and prolonged droughts tend to occur in the northern and southern regions of Iraq, while the central region experiences more frequent but less severe droughts. In most grid cells, the Mann-Kendall test illustrates a substantial decrease in the water storage deficit index and a significant increase in SPI-06. On the other hand, only one grid cell shows a noticeable precipitation trend. Comparatively, trends in the water storage deficit index and SPI-06 are similar. Overall, the water storage deficit and its index prove valuable in predicting drought severity in locations lacking hydrological measurements.","PeriodicalId":14847,"journal":{"name":"Iraqi Geological Journal","volume":"96 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140470524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-31DOI: 10.46717/igj.57.1a.7ms-2024-1-18
Ahmed Alwahab, Ban Mustafa
The current study intends to track and choose geological locations with prospective hydrocarbons at the Ratawi and Mishrif formation levels, in addition to looking for the possibility of showing stratigraphic trapping and assessing probable hydrocarbon resources. The research area is located in southwestern Iraq, within the administrative borders of the Najaf Governorate, in the Western Desert region. Several two-dimensional seismic survey programs Takhaded, Safawi, Qurnain, Glissan first stage and their lines TI, QN, and 1GN were employed, as well as various Glissan-Fourth stage survey lines 4GN. Two systems of faults have been identified within the study area. By performing the Instantaneous phase attribute, also there are two stratigraphic phenomena have been delineated within the Mishrif and Ratawi formations.
{"title":"Structural and Stratigraphic Evolution of Mishrif and Ratawi Formations in Safawi Oil Field, Southern Iraq","authors":"Ahmed Alwahab, Ban Mustafa","doi":"10.46717/igj.57.1a.7ms-2024-1-18","DOIUrl":"https://doi.org/10.46717/igj.57.1a.7ms-2024-1-18","url":null,"abstract":"The current study intends to track and choose geological locations with prospective hydrocarbons at the Ratawi and Mishrif formation levels, in addition to looking for the possibility of showing stratigraphic trapping and assessing probable hydrocarbon resources. The research area is located in southwestern Iraq, within the administrative borders of the Najaf Governorate, in the Western Desert region. Several two-dimensional seismic survey programs Takhaded, Safawi, Qurnain, Glissan first stage and their lines TI, QN, and 1GN were employed, as well as various Glissan-Fourth stage survey lines 4GN. Two systems of faults have been identified within the study area. By performing the Instantaneous phase attribute, also there are two stratigraphic phenomena have been delineated within the Mishrif and Ratawi formations.","PeriodicalId":14847,"journal":{"name":"Iraqi Geological Journal","volume":"331 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140472547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-31DOI: 10.46717/igj.57.1a.4ms-2024-1-15
Qahtan Abdul Aziz, Salih Awadh, H. Al-Mimar
The physical and elastic characteristics of rocks determine rock strengths in general. Rock strength is frequently assessed using porosity well logs such as neutron and sonic logs. The essential criteria for estimating rock mechanic parameters in petroleum engineering research are uniaxial compressive strength and elastic modulus. Indirect estimation using well-log data is necessary to measure these variables. This study attempts to create a single regression model that can accurately forecast rock mechanic characteristics for the Harth Carbonate Formation in the Fauqi oil field. According to the findings of this study, petrophysical parameters are reliable indexes for determining rock mechanical properties having good performance potential. The rock's mechanical characteristics were evaluated using multiple regression analysis (UCS- NPHI, Es- NPHI, VP/VS- NPHI, K- NPHI, and G- NPHI). The UCS-NPHI, obtaining correlation coefficients (R2= 0.74) and for young modulus (R2= 0.85). The expected continuous rock mechanical profile gives a fair indicator of the formation's strength and stability surrounding the wellbore. It can therefore be used to handle problems with wellbore instability, stop sand production, optimize drilling operations, including bit selection and drilling parameters, and perform fracturing operations throughout the Hartha Formation.
{"title":"Estimation of Rock Mechanical Properties of the Hartha Formation and their Relationship to Porosity Using Well-Log Data","authors":"Qahtan Abdul Aziz, Salih Awadh, H. Al-Mimar","doi":"10.46717/igj.57.1a.4ms-2024-1-15","DOIUrl":"https://doi.org/10.46717/igj.57.1a.4ms-2024-1-15","url":null,"abstract":"The physical and elastic characteristics of rocks determine rock strengths in general. Rock strength is frequently assessed using porosity well logs such as neutron and sonic logs. The essential criteria for estimating rock mechanic parameters in petroleum engineering research are uniaxial compressive strength and elastic modulus. Indirect estimation using well-log data is necessary to measure these variables. This study attempts to create a single regression model that can accurately forecast rock mechanic characteristics for the Harth Carbonate Formation in the Fauqi oil field. According to the findings of this study, petrophysical parameters are reliable indexes for determining rock mechanical properties having good performance potential. The rock's mechanical characteristics were evaluated using multiple regression analysis (UCS- NPHI, Es- NPHI, VP/VS- NPHI, K- NPHI, and G- NPHI). The UCS-NPHI, obtaining correlation coefficients (R2= 0.74) and for young modulus (R2= 0.85). The expected continuous rock mechanical profile gives a fair indicator of the formation's strength and stability surrounding the wellbore. It can therefore be used to handle problems with wellbore instability, stop sand production, optimize drilling operations, including bit selection and drilling parameters, and perform fracturing operations throughout the Hartha Formation.","PeriodicalId":14847,"journal":{"name":"Iraqi Geological Journal","volume":"497 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140471686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-31DOI: 10.46717/igj.56.2f.23ms-2023-12-29
A. Al-Jawadi, A. Bety, H. Adeeb, R. Thannoun, Nadhir Al-Ansari
A geological field survey was conducted in Soran District in the Beeston cave located in the Bradost Anticline, northeastern Iraq. The presence of an upper hole in the ceiling of the cave with a diameter of about 3 meters and a main gap dimension is up to 40 x 22 m was found through that. In combination with an analysis of the remote sensing data, a detailed geological survey of the caves with the surrounding areas and an engineering survey were carried out. The geological survey included the stratigraphic sequence of the area between the lowest and highest levels in the study area. It also contains setting and geotechnical parameters for bedding planes and discontinuities. The engineering survey included the measurement of cave dimensions, the distribution of stalactites and stalagmites, and the height of weathering terraces. An analysis of engineering and geological data estimated the approximate timespan of cave formation, and the scenario for cave formation was prepared by adding remote sensing data that could be used in the future to determine other areas where such a cave could be formed. The study reveals the scenario of the cave formation, estimates the age of the cave, and the formation timespan of the cave creation.
{"title":"Geological and Structural Interpretation of the Beeston Cave, Bradost Anticline, NE Iraq","authors":"A. Al-Jawadi, A. Bety, H. Adeeb, R. Thannoun, Nadhir Al-Ansari","doi":"10.46717/igj.56.2f.23ms-2023-12-29","DOIUrl":"https://doi.org/10.46717/igj.56.2f.23ms-2023-12-29","url":null,"abstract":"A geological field survey was conducted in Soran District in the Beeston cave located in the Bradost Anticline, northeastern Iraq. The presence of an upper hole in the ceiling of the cave with a diameter of about 3 meters and a main gap dimension is up to 40 x 22 m was found through that. In combination with an analysis of the remote sensing data, a detailed geological survey of the caves with the surrounding areas and an engineering survey were carried out. The geological survey included the stratigraphic sequence of the area between the lowest and highest levels in the study area. It also contains setting and geotechnical parameters for bedding planes and discontinuities. The engineering survey included the measurement of cave dimensions, the distribution of stalactites and stalagmites, and the height of weathering terraces. An analysis of engineering and geological data estimated the approximate timespan of cave formation, and the scenario for cave formation was prepared by adding remote sensing data that could be used in the future to determine other areas where such a cave could be formed. The study reveals the scenario of the cave formation, estimates the age of the cave, and the formation timespan of the cave creation.","PeriodicalId":14847,"journal":{"name":"Iraqi Geological Journal","volume":"57 13","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139130979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-31DOI: 10.46717/igj.56.2f.12ms-2023-12-18
Mohammed Salman, Thamer Mahdi
The lower Cretaceous sandstones of Zubair and Nahr Umr formations are the main producing reservoirs in Subba oilfield in southern Iraq. Key differences in their petrophysical and depositional attributes exist affecting their reservoir characteristics. The evaluation of well logs and core porosity-permeability data show better reservoir properties in Nahr Formation. The Litho-saturation logs indicate greater thickness of oil-saturated reservoir units for Nahr Unr Formation associated with lower values of shale volume, and higher values of effective porosity. In addition, higher values of permeability for Nahr Umr Formation is suggested by applying porosity-irreducible water saturation cross plot. The reducing reservoir quality of Zubair Formation sandstones is related to finer grains of sandstone reservoirs, higher clay volume, and more effect of compaction resulting from greater depth. A reservoir layering scheme is proposed by sequence stratigraphic analysis leading to the identification of systems tracts and their key surfaces within Zubair and Nahr Umr formations, and forms the basis for predicting of reservoir architecture and quality. Laterally continuous, and thick amalgamated sandstone reservoirs are formed during highstand systems tract in Nahr Umr Formation as a result of low accommodation/sediment supply conditions. Within the transgressive systems tract of Zubair Formation, the sandstone reservoir bodies become isolated as accommodation exceeds sediment supply.
{"title":"A Comparative Reservoir Study of Zubair and Nahr Umr Formations in Subba Oilfield, Southern Iraq","authors":"Mohammed Salman, Thamer Mahdi","doi":"10.46717/igj.56.2f.12ms-2023-12-18","DOIUrl":"https://doi.org/10.46717/igj.56.2f.12ms-2023-12-18","url":null,"abstract":"The lower Cretaceous sandstones of Zubair and Nahr Umr formations are the main producing reservoirs in Subba oilfield in southern Iraq. Key differences in their petrophysical and depositional attributes exist affecting their reservoir characteristics. The evaluation of well logs and core porosity-permeability data show better reservoir properties in Nahr Formation. The Litho-saturation logs indicate greater thickness of oil-saturated reservoir units for Nahr Unr Formation associated with lower values of shale volume, and higher values of effective porosity. In addition, higher values of permeability for Nahr Umr Formation is suggested by applying porosity-irreducible water saturation cross plot. The reducing reservoir quality of Zubair Formation sandstones is related to finer grains of sandstone reservoirs, higher clay volume, and more effect of compaction resulting from greater depth. A reservoir layering scheme is proposed by sequence stratigraphic analysis leading to the identification of systems tracts and their key surfaces within Zubair and Nahr Umr formations, and forms the basis for predicting of reservoir architecture and quality. Laterally continuous, and thick amalgamated sandstone reservoirs are formed during highstand systems tract in Nahr Umr Formation as a result of low accommodation/sediment supply conditions. Within the transgressive systems tract of Zubair Formation, the sandstone reservoir bodies become isolated as accommodation exceeds sediment supply.","PeriodicalId":14847,"journal":{"name":"Iraqi Geological Journal","volume":"109 38","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139134409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-31DOI: 10.46717/igj.56.2f.2ms-2023-12-8
Diaa A. Saadawi, Sherif Kamel, H. Al-Saad, Atef Ibrahim, Ahmed Shalaby
The main focus of this paper is on the sandstones from the Upper Cretaceous period found in the Wadi Feiran area. The study aims to investigate various aspects of the sandstones, including their petrographic characteristics such as textural maturity and mineralogical classification, as well as their paleoenvironment, diagenesis, and chemical composition. The results show that the sandstones are sub-mature and were formed in relatively shallow neritic environments. Based on their mineralogical composition, they are classified as quartz arenite. The paleoenvironmental analysis suggests that the sediments were deposited in an area of mild tectonic stability. During diagenesis, the sandstones underwent various physical and chemical stages. Analysis of their chemical composition indicates that they were deposited under relatively warm and slightly alkaline conditions in a relatively shallow and restricted medium, with major and trace components including Al2O3, SiO2, Fe2O3, CaO, MgO, K2O, Na2O, P2O5, Cl, SO3, Ti, Mn, Cu, Ni, and Sr.
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