Pub Date : 2021-07-01DOI: 10.30495/IJES.2021.682867
Baseer Ahmad Barahouei, M. Noura, M. E. Moslempour, R. Dabiri
Hydrogeochemical characteristics of groundwater and its suitability for domestic and irrigation, purposes were evaluated in Konaro ophiolitic area. Heavy metals pollution is accounted for a major pollution in the natural environment are that can pose a serious threat to ecosystems because of their biodegradation potential, toxicity and sustainability (Moslempour and Shahdadi 2013) 8 representative groundwater samples were collected from wells and qanat and analyzed for major cations and anions. The order of dominance of cation and anions were Na> HCO3> SO4 > Mg> Cl> Ca> K, respectively. The rock weathering and dissolution of minerals processes, especially ophiolitic rocks minerals are dominant in controlling the groundwater quality in the study area. Electrical conductivity (EC) and total dissolved solid (TDS) show high positive correlation with total Hardness (TH), K, Na, and SO4-. As per the WHO standards for domestic water purposes, majority of samples show that the groundwater is suitable for drinking. The spatial distribution maps of physicochemical parameters were prepared in ArcGIS. The suitability of groundwater for agriculture purpose was evaluated from EC, TDS, sodium adsorption ratio (SAR) and Na% which ranges from excellent to not suitable, so majority of the groundwater samples are suitable for irrigation. The results revealed that the GQI quality index varied between 89% and 91% in the Konaro area, which in terms of quality rating, the water samples from these resources laid in appropriate to acceptable range. Moreover, based on examining the zoning map, the GQI quality index accounted for the lowest value in the east direction of the study area. Thus, most of the groundwater samples from this study (sample W2) confirm the beneficial use of aquifers in the area for domestic, agricultural, and irrigation purposes.
{"title":"Evaluation of groundwater suitability for the domestic and irrigation purposes in Konaro Ophiolitic Area, Iranshahr, SE Iran","authors":"Baseer Ahmad Barahouei, M. Noura, M. E. Moslempour, R. Dabiri","doi":"10.30495/IJES.2021.682867","DOIUrl":"https://doi.org/10.30495/IJES.2021.682867","url":null,"abstract":"Hydrogeochemical characteristics of groundwater and its suitability for domestic and irrigation, purposes were evaluated in Konaro ophiolitic area. Heavy metals pollution is accounted for a major pollution in the natural environment are that can pose a serious threat to ecosystems because of their biodegradation potential, toxicity and sustainability (Moslempour and Shahdadi 2013) 8 representative groundwater samples were collected from wells and qanat and analyzed for major cations and anions. The order of dominance of cation and anions were Na> HCO3> SO4 > Mg> Cl> Ca> K, respectively. The rock weathering and dissolution of minerals processes, especially ophiolitic rocks minerals are dominant in controlling the groundwater quality in the study area. Electrical conductivity (EC) and total dissolved solid (TDS) show high positive correlation with total Hardness (TH), K, Na, and SO4-. As per the WHO standards for domestic water purposes, majority of samples show that the groundwater is suitable for drinking. The spatial distribution maps of physicochemical parameters were prepared in ArcGIS. The suitability of groundwater for agriculture purpose was evaluated from EC, TDS, sodium adsorption ratio (SAR) and Na% which ranges from excellent to not suitable, so majority of the groundwater samples are suitable for irrigation. The results revealed that the GQI quality index varied between 89% and 91% in the Konaro area, which in terms of quality rating, the water samples from these resources laid in appropriate to acceptable range. Moreover, based on examining the zoning map, the GQI quality index accounted for the lowest value in the east direction of the study area. Thus, most of the groundwater samples from this study (sample W2) confirm the beneficial use of aquifers in the area for domestic, agricultural, and irrigation purposes.","PeriodicalId":44351,"journal":{"name":"Iranian Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47533666","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 : 2021-07-01DOI: 10.30495/IJES.2021.682865
Behzad Saeedi Razavi
Core data analysis of one well from the Karanj oil field, southwestern Iran, allowed us to precise the biostratigraphy, microfacies and paleoecology of the Asmari Formation. Analysis of thin section from this cored well permitted identification of 28 genera and 20 species of benthic and planktic foraminifera respectively. Subsequently four benthic foraminiferal assemblage biozones were identified, as follows: (1) Lepidocyclina-Operculina-Ditrupa Assemblage zone, (2) Archaias asmaricus-Archaias hensoni-Miogypsinoides complanatus Assemblage zone, (3) Miogypsina-Peneroplis farsensis–Elphidium sp. 14 Assemblage zone and (4) Borelis melo curdica-Borelis melo melo Assemblage zone; indicating an Oligocene (Rupelian-Chattian) to early Miocene (Aquitanian to Early Burdigalian) age for the Asmari Formation. Microfacial study of depositional textures led to characterizing 12 microfacies types, indicating environments in five different settings: restricted lagoon, open lagoon, shoal, slope, and basin mostly in the upper Asmari Formation. These sediments had been deposited under 3 different salinity levels (from 34 to more than 50 psu) in an environment ranging from aphotic to oligophotic and to euphotic zones, and under oligotrophic to eutrophic conditions from the Chattian to the Burdigalian on a carbonate platform (homoclinal ramp). In the studied well, the Asmari Formation had been deposited in a marine environment with normal salinity during the Rupelian-Chattian interval and in a marine environment with high salinity during the Aquitanian to the Burdigalian times.
{"title":"Biostratigraphy, Paleoecology, Microfacies and Depositional environment of the Asmari formation (Oligocene-Early Miocene) in Karanj oil field, SW Iran","authors":"Behzad Saeedi Razavi","doi":"10.30495/IJES.2021.682865","DOIUrl":"https://doi.org/10.30495/IJES.2021.682865","url":null,"abstract":"Core data analysis of one well from the Karanj oil field, southwestern Iran, allowed us to precise the biostratigraphy, microfacies and paleoecology of the Asmari Formation. Analysis of thin section from this cored well permitted identification of 28 genera and 20 species of benthic and planktic foraminifera respectively. Subsequently four benthic foraminiferal assemblage biozones were identified, as follows: (1) Lepidocyclina-Operculina-Ditrupa Assemblage zone, (2) Archaias asmaricus-Archaias hensoni-Miogypsinoides complanatus Assemblage zone, (3) Miogypsina-Peneroplis farsensis–Elphidium sp. 14 Assemblage zone and (4) Borelis melo curdica-Borelis melo melo Assemblage zone; indicating an Oligocene (Rupelian-Chattian) to early Miocene (Aquitanian to Early Burdigalian) age for the Asmari Formation. Microfacial study of depositional textures led to characterizing 12 microfacies types, indicating environments in five different settings: restricted lagoon, open lagoon, shoal, slope, and basin mostly in the upper Asmari Formation. These sediments had been deposited under 3 different salinity levels (from 34 to more than 50 psu) in an environment ranging from aphotic to oligophotic and to euphotic zones, and under oligotrophic to eutrophic conditions from the Chattian to the Burdigalian on a carbonate platform (homoclinal ramp). In the studied well, the Asmari Formation had been deposited in a marine environment with normal salinity during the Rupelian-Chattian interval and in a marine environment with high salinity during the Aquitanian to the Burdigalian times.","PeriodicalId":44351,"journal":{"name":"Iranian Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48989243","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 : 2021-07-01DOI: 10.30495/IJES.2021.682866
M. Fouladi, Mirsattar Meshinchi Asl, M. Mehramuz, N. Nezafati
In the current study, we have developed a new method called the third- order moving average method to estimate the shape and depth of residual magnetic anomalies. This method, calculates a nonlinear relationship between depth and shape factor, at seven points with successive window length. It is based on the computing standard deviation at depths that are determined from all residual magnetic anomalies for each value of the shape factor. The method was applied to the synthetic model by geometrical shapes both as horizontal cylinder and combination of horizontal cylinder, sphere and thin sheet approaches, with and without noise. It was tested by real data in Geological Survey of Iran (GSI). In this study, least square methods were applied to interpret the magnetic field so that we can compare the results of this methods with the third- order moving average method. This method is applied to estimate the depth using second horizontal derivative anomalies obtained numerically from magnetic data with successive window lengths. This method utilizes the variance of the depths as a scale for calculation of the shape and depth. The results showed that the third- order moving average method is a powerful tool for estimating shape and depth of the synthetic models in the presence and absence of noise compared to least square method. Moreover, the results showed that this method is very accurate for real data while the least square method did not lead to feasible results. In this study, least square methods were applied to interpret the magnetic field so that we can compare the results of this methods with the third- order moving average method. This method is applied to estimate the depth using second horizontal derivative anomalies obtained numerically from magnetic data with successive window lengths. This method utilizes the variance of the depths as a scale for calculation of the shape and depth.The results showed that the third- order moving average method is a powerful tool for estimating shape and depth of the synthetic models in the presence and absence of noise compared to least square method. Moreover, the results showed that this method is very accurate for real data while the least square method did not lead to feasible results.
{"title":"Comparison of the Third- order moving average and least square methods for estimating of shape and depth residual magnetic anomalies","authors":"M. Fouladi, Mirsattar Meshinchi Asl, M. Mehramuz, N. Nezafati","doi":"10.30495/IJES.2021.682866","DOIUrl":"https://doi.org/10.30495/IJES.2021.682866","url":null,"abstract":"In the current study, we have developed a new method called the third- order moving average method to estimate the shape and depth of residual magnetic anomalies. This method, calculates a nonlinear relationship between depth and shape factor, at seven points with successive window length. It is based on the computing standard deviation at depths that are determined from all residual magnetic anomalies for each value of the shape factor. The method was applied to the synthetic model by geometrical shapes both as horizontal cylinder and combination of horizontal cylinder, sphere and thin sheet approaches, with and without noise. It was tested by real data in Geological Survey of Iran (GSI). In this study, least square methods were applied to interpret the magnetic field so that we can compare the results of this methods with the third- order moving average method. This method is applied to estimate the depth using second horizontal derivative anomalies obtained numerically from magnetic data with successive window lengths. This method utilizes the variance of the depths as a scale for calculation of the shape and depth. The results showed that the third- order moving average method is a powerful tool for estimating shape and depth of the synthetic models in the presence and absence of noise compared to least square method. Moreover, the results showed that this method is very accurate for real data while the least square method did not lead to feasible results. \u0000In this study, least square methods were applied to interpret the magnetic field so that we can compare the results of this methods with the third- order moving average method. This method is applied to estimate the depth using second horizontal derivative anomalies obtained numerically from magnetic data with successive window lengths. This method utilizes the variance of the depths as a scale for calculation of the shape and depth.The results showed that the third- order moving average method is a powerful tool for estimating shape and depth of the synthetic models in the presence and absence of noise compared to least square method. Moreover, the results showed that this method is very accurate for real data while the least square method did not lead to feasible results.","PeriodicalId":44351,"journal":{"name":"Iranian Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46989173","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 : 2021-07-01DOI: 10.30495/IJES.2021.682869
Asiyeh Arampour, M. Afghah, M. P. Shirazi
In the easternmost part of the Izeh Zone of the Zagros Mountains, the Kazhdumi Formation of upper Aptian-middle Albian interval is superbly exposed in three-main exposures as argillaceous carbonate facies. The main bioclastic components of the Kazhdumi Formation are Orbitolinid and other larger benthic foraminifers, planktonic foraminifera and calcareous algae. The depositional system in the study area during the upper Aptian-middle Albian corresponds to a shaly carbonate ramp. Two depositional sequences are determined, as prograding system from west to east. Comparison of the proposed depositional sequences with those reported in the Arabian Plate and adjacent areas suggests a correlation with the global sea-level curve. The Lower Cretaceous, Aptian carbonates of Kazhdumi Formation contain nine microfacies, which were deposited on a ramp system deepened in both directions (west and east). Stratigraphic sequence led to recognize two third-order sequences. On the other hand, rudstone and boundstone lithofacies of the studied formation have higher reservoir potential and were deposited during Apt 3 and Apt 5 sequences of the Arabian Plate. The Kazhdumi Formation in the study area was deposited in an intrashelf basin that should be classified as an independent basin in the future paleogeographic maps of the southwest Iran. We interpret the Kazerun Fault, as a crustal warping of basement faults of the Arabian Plate boundary, which were responsible for the creation of the intrashelf basin in the study area.
{"title":"Biostratigraphy and depositional architecture of the Kazhdumi formation (Aptian-Albian) in the Izeh zone, Zagros mountains, SW Iran","authors":"Asiyeh Arampour, M. Afghah, M. P. Shirazi","doi":"10.30495/IJES.2021.682869","DOIUrl":"https://doi.org/10.30495/IJES.2021.682869","url":null,"abstract":"In the easternmost part of the Izeh Zone of the Zagros Mountains, the Kazhdumi Formation of upper Aptian-middle Albian interval is superbly exposed in three-main exposures as argillaceous carbonate facies. The main bioclastic components of the Kazhdumi Formation are Orbitolinid and other larger benthic foraminifers, planktonic foraminifera and calcareous algae. The depositional system in the study area during the upper Aptian-middle Albian corresponds to a shaly carbonate ramp. Two depositional sequences are determined, as prograding system from west to east. Comparison of the proposed depositional sequences with those reported in the Arabian Plate and adjacent areas suggests a correlation with the global sea-level curve. The Lower Cretaceous, Aptian carbonates of Kazhdumi Formation contain nine microfacies, which were deposited on a ramp system deepened in both directions (west and east). Stratigraphic sequence led to recognize two third-order sequences. On the other hand, rudstone and boundstone lithofacies of the studied formation have higher reservoir potential and were deposited during Apt 3 and Apt 5 sequences of the Arabian Plate. The Kazhdumi Formation in the study area was deposited in an intrashelf basin that should be classified as an independent basin in the future paleogeographic maps of the southwest Iran. We interpret the Kazerun Fault, as a crustal warping of basement faults of the Arabian Plate boundary, which were responsible for the creation of the intrashelf basin in the study area.","PeriodicalId":44351,"journal":{"name":"Iranian Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45933122","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 : 2021-07-01DOI: 10.30495/IJES.2021.682864
Hadayat Ullah, P. Khalid, M. Mehmood, Saad Ahmed Mashwani, Zaheer Abbasi, Muhammad Jehangir Khan, E. Haq, G. M. Shah
The Eastern Suleiman Fold and Thrust Belt comprises of a thick cover of sedimentary sequences. Despite of presence of complete petroleum system source, reservoir and seal rocks less attention was paid by the exploration and production companies to prospect. An integrated approach is adopted to delineate reservoir potential and net pay zones in the clastic reservoirs of the Cretaceous age widely distributed in the area. Wireline logs and migrated seismic reflection data were used for field development and optimization. Petrophysical analysis reveals that Pab Sandstone of the Cretaceous age is acting as a reservoir rock, whereas the Ghazij Shales of the Eocene age are acting as a regional seal rock. A complete workflow is proposed for formation evaluation, and structural interpretation of the subsurface geology. Based on wireline logs it is interpreted that the thickness of the Pab Sandstone varies from 250 m to 350 m in the entire study area. The sandstone is massive with high porosity and intercalated layers of shales. Faulted anticlinal structures are present in the study area which are favorable for the accumulation of hydrocarbon. 3D structural models and various seismic attribute models were prepared to analyze the reservoir character of this clastic reservoir. Based on wireline logs and seismic data clean sand, shaly sand and shale are marked as dominant facies in the study area. However, clean sand facies are more favorable to act as potential net pay zone.
{"title":"Reservoir potential, net pay zone and 3D modeling of Cretaceous Pab Formation in Eastern Suleiman Range, Pakistan","authors":"Hadayat Ullah, P. Khalid, M. Mehmood, Saad Ahmed Mashwani, Zaheer Abbasi, Muhammad Jehangir Khan, E. Haq, G. M. Shah","doi":"10.30495/IJES.2021.682864","DOIUrl":"https://doi.org/10.30495/IJES.2021.682864","url":null,"abstract":"The Eastern Suleiman Fold and Thrust Belt comprises of a thick cover of sedimentary sequences. Despite of presence of complete petroleum system source, reservoir and seal rocks less attention was paid by the exploration and production companies to prospect. An integrated approach is adopted to delineate reservoir potential and net pay zones in the clastic reservoirs of the Cretaceous age widely distributed in the area. Wireline logs and migrated seismic reflection data were used for field development and optimization. Petrophysical analysis reveals that Pab Sandstone of the Cretaceous age is acting as a reservoir rock, whereas the Ghazij Shales of the Eocene age are acting as a regional seal rock. A complete workflow is proposed for formation evaluation, and structural interpretation of the subsurface geology. Based on wireline logs it is interpreted that the thickness of the Pab Sandstone varies from 250 m to 350 m in the entire study area. The sandstone is massive with high porosity and intercalated layers of shales. Faulted anticlinal structures are present in the study area which are favorable for the accumulation of hydrocarbon. 3D structural models and various seismic attribute models were prepared to analyze the reservoir character of this clastic reservoir. Based on wireline logs and seismic data clean sand, shaly sand and shale are marked as dominant facies in the study area. However, clean sand facies are more favorable to act as potential net pay zone.","PeriodicalId":44351,"journal":{"name":"Iranian Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45807496","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 : 2021-04-01DOI: 10.30495/IJES.2021.681579
Fatemeh Morovati, M. M. Ataabadi, M. Arian, A. Zohdi, Mohsen Al-e Ali
Sea cows are exceptional fossil vertebrates recently discovered in the deposits of the Qom Formation. Yet, the Sirenia-bearing limestones are still poorly understood in terms of detail paleoenvironmental and micropaleontological investigations. In order to distinguish the temporal and paleoenvironmental context of the Sirenia (sea cow) bearing deposits of the Qom Formation in central Iran, three stratigraphic sections were studied in Hamedan (Ivak and Shirinsu) and Isfahan (Chahriseh) provinces. A total number of 47 thin sections were studied for micropaleontology, biozonation and carbonate microfacies analysis, as well as sedimentary environment recounstruction. Biostratigraphical investigations suggest that the Sirenia-bearing deposits are Aquitanian/Burdigalian in age, which implies restriction of sea cows remains to the Lower Miocene. We recognized nine microfacies (n=8 correspond to carbonate; n=1 correspond to siliciclastic) in the study areas. They are systematically grouped into two microfacies settings, representing inner and middle ramp environments. This is based on the facies associations and the distribution of skeletal components and rock textures. The Sirenia-bearing limestone consists of peloid/algae bearing wackstone/packstone/floatstone. A carbonate (inner) ramp system under shallow water conditions is interpreted as the habitats of the Sirenian mammals during the Aquitanian/Burdigalian in Central Iran. This paleoenvironmental setting could be utilized for further exploration of Qom Formation deposits for discovering sea cows.
{"title":"Age, microfacies and sedimentary environments of the Sirenia-bearing deposits of the Qom Formation in Central Iran","authors":"Fatemeh Morovati, M. M. Ataabadi, M. Arian, A. Zohdi, Mohsen Al-e Ali","doi":"10.30495/IJES.2021.681579","DOIUrl":"https://doi.org/10.30495/IJES.2021.681579","url":null,"abstract":"Sea cows are exceptional fossil vertebrates recently discovered in the deposits of the Qom Formation. Yet, the Sirenia-bearing limestones are still poorly understood in terms of detail paleoenvironmental and micropaleontological investigations. In order to distinguish the temporal and paleoenvironmental context of the Sirenia (sea cow) bearing deposits of the Qom Formation in central Iran, three stratigraphic sections were studied in Hamedan (Ivak and Shirinsu) and Isfahan (Chahriseh) provinces. A total number of 47 thin sections were studied for micropaleontology, biozonation and carbonate microfacies analysis, as well as sedimentary environment recounstruction. Biostratigraphical investigations suggest that the Sirenia-bearing deposits are Aquitanian/Burdigalian in age, which implies restriction of sea cows remains to the Lower Miocene. We recognized nine microfacies (n=8 correspond to carbonate; n=1 correspond to siliciclastic) in the study areas. They are systematically grouped into two microfacies settings, representing inner and middle ramp environments. This is based on the facies associations and the distribution of skeletal components and rock textures. The Sirenia-bearing limestone consists of peloid/algae bearing wackstone/packstone/floatstone. A carbonate (inner) ramp system under shallow water conditions is interpreted as the habitats of the Sirenian mammals during the Aquitanian/Burdigalian in Central Iran. This paleoenvironmental setting could be utilized for further exploration of Qom Formation deposits for discovering sea cows.","PeriodicalId":44351,"journal":{"name":"Iranian Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45841314","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 : 2021-04-01DOI: 10.30495/IJES.2021.681581
J. Jafari, A. Mahboubi, R. Moussavi-Harami
The Oligocene-Lower Miocene Asmari Formation shows considerable reservoir heterogeneity because of variations in the lithology, depositional facies and diagenesis. This paper aim to investigate reservoir heterogeneities using seismic, core and well logs data. Twelve carbonate microfacies and three siliciclastic petrofacies are identified in the Asmari Formation based on well log and core data from 7 wells in the Marun field, which generally indicate a shallowing-up profile. Microfacies changes suggest that the Asmari Formation was deposited in a restricted lagoonal and carbonate ramp setting with periodic clastic sediment supply due to relative sea level fall. Six third-order sequences are recognized in the Asmari Formation from studies of core and well log data, while interpretation of 3D seismic data shows that the formation consists of two second-order seismic sequences. The lowest sequence boundary between the Pabdeh and Asmari Formations (SBI) is a type-2 boundary, and the six others are type-1 sequence boundaries. Six distinct packages of reflectors are interpreted on seismic data through the Cenozoic. The Pabdeh and Asmari Formations can be divided into three packages. Package 1 corresponds to transgressive and highstand systems tract deposits, which mainly consist of shales, marls, and carbonates with interbedded sandstones. This package is overlain by mounded and lenticular seismic facies (package 2) and high-amplitude and continuous seismic reflectors (package 3). Package 2 is predominantly sandstone with interbedded shale, and package3 mainly consists of carbonates. Inversion of seismic data shows that high-porosity zones are present in the western and southern Marun field. A lower high-porosity zone corresponds to lowstand fluvial-deltaic sediments and the upper zone to the beach and shallow marine sandstones.
{"title":"Seismic and sequence stratigraphy of the Oligocene-Miocene Asmari reservoir in the Marun oilfield, SW Iran","authors":"J. Jafari, A. Mahboubi, R. Moussavi-Harami","doi":"10.30495/IJES.2021.681581","DOIUrl":"https://doi.org/10.30495/IJES.2021.681581","url":null,"abstract":"The Oligocene-Lower Miocene Asmari Formation shows considerable reservoir heterogeneity because of variations in the lithology, depositional facies and diagenesis. This paper aim to investigate reservoir heterogeneities using seismic, core and well logs data. Twelve carbonate microfacies and three siliciclastic petrofacies are identified in the Asmari Formation based on well log and core data from 7 wells in the Marun field, which generally indicate a shallowing-up profile. Microfacies changes suggest that the Asmari Formation was deposited in a restricted lagoonal and carbonate ramp setting with periodic clastic sediment supply due to relative sea level fall. Six third-order sequences are recognized in the Asmari Formation from studies of core and well log data, while interpretation of 3D seismic data shows that the formation consists of two second-order seismic sequences. The lowest sequence boundary between the Pabdeh and Asmari Formations (SBI) is a type-2 boundary, and the six others are type-1 sequence boundaries. Six distinct packages of reflectors are interpreted on seismic data through the Cenozoic. The Pabdeh and Asmari Formations can be divided into three packages. Package 1 corresponds to transgressive and highstand systems tract deposits, which mainly consist of shales, marls, and carbonates with interbedded sandstones. This package is overlain by mounded and lenticular seismic facies (package 2) and high-amplitude and continuous seismic reflectors (package 3). Package 2 is predominantly sandstone with interbedded shale, and package3 mainly consists of carbonates. Inversion of seismic data shows that high-porosity zones are present in the western and southern Marun field. A lower high-porosity zone corresponds to lowstand fluvial-deltaic sediments and the upper zone to the beach and shallow marine sandstones.","PeriodicalId":44351,"journal":{"name":"Iranian Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45303266","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 : 2021-04-01DOI: 10.30495/IJES.2021.681578
M. Rajabi, S. Senemari, M. P. Shirazi, Maryamnaz Bahrammanesh Tehrani
The carbonate sequence of the Asmari Formation is the most important oil reservoir formed in the Zagros Basin, southwestern Iran. In order to interpret the sedimentary environment, the Makhmal-Kuh and Kaka-Reza sections in the Lorestan province were investigated. These sections were compared with some other outcrops in the Zagros Basin. Twenty one genera and species were identified in the Makhmal-Kuh section, and 20 genera and species in the Kaka-Reza section. Among foraminifera, Miogypsina sp ., Amphistegina sp., Elphidium sp., Operculina sp., Nephrolepidina sp., Eulepidina sp., Heterostegina sp., Nummulites fichtelli, Nummulites vascus and Nummulites intermedius are the most important species. Based on the identification of co-occurrence taxa, two assemblage zones are introduced in the Makhmal-Kuh section, and one faunal assemblage zone in the Kaka-Reza section. Petrographic analysis also led to the recognition of twelve microfacies types in the Makhmal-Kuh section and five microfacial types in the Kaka-Reza section. Based on these microfacial types, three sub-environments were determined in the Makhmal-Kuh section and two settings in the Kaka-Reza section: Outer ramp, in the aphotic zone, dominated by planktic foraminifera, bryozoan, and echinoids; the mid ramp, in the oligophotic zone, characterized with benthic foraminifera and planktic foraminifera; the shallower waters of the mesophotic-euphotic zone dominated by benthic foraminifera and coralline red algae in the inner ramp. Therefore, the depositional sub-environments along with biotic assemblages represent warm waters of tropical regions under photic variable conditions in a homoclinal ramp. Based on the distribution of co-occurrence fossils, the Asmari Formation is dated as Rupelian to the Aquitanian.
{"title":"Depositional environment and microfacies analysis: An example of the Asmari Formation in West Zagros Basin, Lorestan province (Iran)","authors":"M. Rajabi, S. Senemari, M. P. Shirazi, Maryamnaz Bahrammanesh Tehrani","doi":"10.30495/IJES.2021.681578","DOIUrl":"https://doi.org/10.30495/IJES.2021.681578","url":null,"abstract":"The carbonate sequence of the Asmari Formation is the most important oil reservoir formed in the Zagros Basin, southwestern Iran. In order to interpret the sedimentary environment, the Makhmal-Kuh and Kaka-Reza sections in the Lorestan province were investigated. These sections were compared with some other outcrops in the Zagros Basin. Twenty one genera and species were identified in the Makhmal-Kuh section, and 20 genera and species in the Kaka-Reza section. Among foraminifera, Miogypsina sp ., Amphistegina sp., Elphidium sp., Operculina sp., Nephrolepidina sp., Eulepidina sp., Heterostegina sp., Nummulites fichtelli, Nummulites vascus and Nummulites intermedius are the most important species. Based on the identification of co-occurrence taxa, two assemblage zones are introduced in the Makhmal-Kuh section, and one faunal assemblage zone in the Kaka-Reza section. Petrographic analysis also led to the recognition of twelve microfacies types in the Makhmal-Kuh section and five microfacial types in the Kaka-Reza section. Based on these microfacial types, three sub-environments were determined in the Makhmal-Kuh section and two settings in the Kaka-Reza section: Outer ramp, in the aphotic zone, dominated by planktic foraminifera, bryozoan, and echinoids; the mid ramp, in the oligophotic zone, characterized with benthic foraminifera and planktic foraminifera; the shallower waters of the mesophotic-euphotic zone dominated by benthic foraminifera and coralline red algae in the inner ramp. Therefore, the depositional sub-environments along with biotic assemblages represent warm waters of tropical regions under photic variable conditions in a homoclinal ramp. Based on the distribution of co-occurrence fossils, the Asmari Formation is dated as Rupelian to the Aquitanian.","PeriodicalId":44351,"journal":{"name":"Iranian Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44517093","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 : 2021-04-01DOI: 10.30495/IJES.2021.681580
Maryam Pourabdollahi, A. Dorostian, H. Rahimi, Attieh Eshaghi
The aim of this study is to investigate the strong ground motion generation of destructive earthquake in Kermanshah with the moment magnitude of 7.3 using Empirical Green’s function (EGF) method. To simulate the ground-motion can be helpful for understanding seismic hazard and reduce fatalities due to lack of real ground motion. We collected the seismograms recorded at seven strong motion stations with good quality to estimate the source parameters at frequencies between 0.1 and 10.0 Hz. By minimizing the root-mean-square (rms) errors to obtain the best source parameters for the earthquake. The earthquake fault was divided into seven sub-faults along the strike and seven sub-faults along the slope. The asperity of 21×10.5 km was obtained. The rupture starting point has been located in the northern part of the strong motion seismic area. The coordinates of the rupture starting point indicate that the rupture propagation on the fault plan was unilateral from north to south. The simulated ground motions have a good correlation with observed records in both frequency and time domain. The results are in well agreement with the Iranian code of practice for seismic resistant design of buildings, however, the calculated design spectrum of Sarpol-e Zahab station is higher than the design spectrum of the Iranian code which suggest that the Iranian code may need to be re-evaluated for this area.
{"title":"Ground-motion simulation for the 2017 Mw7.3 Ezgeleh earthquake in Iran by using the Empirical Green's Function Method","authors":"Maryam Pourabdollahi, A. Dorostian, H. Rahimi, Attieh Eshaghi","doi":"10.30495/IJES.2021.681580","DOIUrl":"https://doi.org/10.30495/IJES.2021.681580","url":null,"abstract":"The aim of this study is to investigate the strong ground motion generation of destructive earthquake in Kermanshah with the moment magnitude of 7.3 using Empirical Green’s function (EGF) method. To simulate the ground-motion can be helpful for understanding seismic hazard and reduce fatalities due to lack of real ground motion. We collected the seismograms recorded at seven strong motion stations with good quality to estimate the source parameters at frequencies between 0.1 and 10.0 Hz. By minimizing the root-mean-square (rms) errors to obtain the best source parameters for the earthquake. The earthquake fault was divided into seven sub-faults along the strike and seven sub-faults along the slope. The asperity of 21×10.5 km was obtained. The rupture starting point has been located in the northern part of the strong motion seismic area. The coordinates of the rupture starting point indicate that the rupture propagation on the fault plan was unilateral from north to south. The simulated ground motions have a good correlation with observed records in both frequency and time domain. The results are in well agreement with the Iranian code of practice for seismic resistant design of buildings, however, the calculated design spectrum of Sarpol-e Zahab station is higher than the design spectrum of the Iranian code which suggest that the Iranian code may need to be re-evaluated for this area.","PeriodicalId":44351,"journal":{"name":"Iranian Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48782837","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}
The Kohat Foreland Basin is an outcome of continental collision between Indian and Eurasian plates defining the southern edge of Himalayan Orogenic System in the north-western Pakistan. This study constrains the structural geometry and kinematics in 2-D and 3-D workflow, evaluation of the role of multiple detachments and the structural correlation between surface and sub-surface geology of the western Kohat Foreland Basin. The structural style of the western Kohat Foreland Basin evinces the thin skin deformation associated with a couple of structural detachments i.e. i) base-Eocene shale/ evaporite sequence ii) the upper interface of crystalline basement. These detachments separate the outcropping and buried stratigraphic sequence of the Kohat Foreland Basin into upper and lower structural-stratigraphic domains. The lower domain has a series of north-dipping or south-verging fold-thrust assemblages incorporating a rigid rock sequence of EoCambrian to Paleocene. The comparatively more ductile rocks of the upper domain comprising of Eocene to Pliocene are deformed into tight, overturned, doubly plunging and internally faulted anticlines intervened by broad synclines. The two domains dictate different deformational behavior and structural style, deforming in total disharmony; hence the structural geometry of shallow units does not match the sub-surface rocks. The total 37% of shortening in the sedimentary cover was revealed by structural balancing in 2-D and 3-D kinematic modelling. Stress analysis of Gurguri Fault unveiled 40% failure susceptibility and recorded positive values of effective normal stress (σn) with an orientation of maximum principle stress (σ1) as N17°.
{"title":"Geological constraints on the Western Kohat foreland basin, Khyber Pakhtunkhwa, Pakistan: Implication from 2D and 3D structural modelling","authors":"Syed Ahsan Hussain Gardezi, Sajjad Ahmad, Gohar Rehman, Nawaz Ikram","doi":"10.30495/IJES.2021.678954","DOIUrl":"https://doi.org/10.30495/IJES.2021.678954","url":null,"abstract":"The Kohat Foreland Basin is an outcome of continental collision between Indian and Eurasian plates defining the southern edge of Himalayan Orogenic System in the north-western Pakistan. This study constrains the structural geometry and kinematics in 2-D and 3-D workflow, evaluation of the role of multiple detachments and the structural correlation between surface and sub-surface geology of the western Kohat Foreland Basin. The structural style of the western Kohat Foreland Basin evinces the thin skin deformation associated with a couple of structural detachments i.e. i) base-Eocene shale/ evaporite sequence ii) the upper interface of crystalline basement. These detachments separate the outcropping and buried stratigraphic sequence of the Kohat Foreland Basin into upper and lower structural-stratigraphic domains. The lower domain has a series of north-dipping or south-verging fold-thrust assemblages incorporating a rigid rock sequence of EoCambrian to Paleocene. The comparatively more ductile rocks of the upper domain comprising of Eocene to Pliocene are deformed into tight, overturned, doubly plunging and internally faulted anticlines intervened by broad synclines. The two domains dictate different deformational behavior and structural style, deforming in total disharmony; hence the structural geometry of shallow units does not match the sub-surface rocks. The total 37% of shortening in the sedimentary cover was revealed by structural balancing in 2-D and 3-D kinematic modelling. Stress analysis of Gurguri Fault unveiled 40% failure susceptibility and recorded positive values of effective normal stress (σn) with an orientation of maximum principle stress (σ1) as N17°.","PeriodicalId":44351,"journal":{"name":"Iranian Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2021-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49276511","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}
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