Iranian Journal of Earth Sciences最新文献

{"title":"Improving the accuracy of fracture modeling in carbonate reservoirs X-field in SW of Iran","authors":"S. R. M. Madani, H. Hassani, B. Tokhmechi","doi":"10.30495/IJES.2020.673334","DOIUrl":"https://doi.org/10.30495/IJES.2020.673334","url":null,"abstract":"Fracture modeling is one of the most important steps in the study of fractured reservoirs. Due to the high cost of imaging logs and their absence in most wells of the study area, it is often attempted to use other available data to detect fractures. This paper attempts to investigate the relationship between the lithology and fractures of rocks. For this purpose, the Image, Neutron, Density, Litho-density, and NGS logs have used to simulate the lithology. Based on this feature, the studied area was divided into six homogeneity part, and the fracture probability was determined in each section to improve the accuracy of fracture modeling. Recently, an intelligent method has been proven as an efficient tool for modeling complex and non-linear phenomena. In this paper, neural network methods has been used in fracture modeling. The results show that the division of the field based on lithological studies will  improves the accuracy of fracture modeling in the studied area up to 7 percent without increasing the cost of image logging.","PeriodicalId":44351,"journal":{"name":"Iranian Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43665065","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}

{"title":"Biostratigraphy of Devonian-Carboniferous boundary in Tuyeh-Darvar section, north of Iran","authors":"M. Najjarzadeh, A. Ashouri, M. Yazdi, A. Bahrami","doi":"10.30495/IJES.2020.673332","DOIUrl":"https://doi.org/10.30495/IJES.2020.673332","url":null,"abstract":"Devonian-Carboniferous boundary is not clear in the Eastern Alborz Mountains. In the current study Tuyeh-Darvar section with about 170 m, thickness is selected. In this investigation, the primary goal is revision of Devonian/Carboniferous Boundary (known as DCB) and the other goal is the redefinition of the DCB as a famous necessity (based on ICS program in 2008 for defining the boundary and to find a new GSSP). According to Conodont data from acid-leaching 53 carbonate samples(by acid acetic) that obtained from Late Devonian and Early Carboniferous deposits in this section, and based on standard conodont Zonation 6 Zone are recognized;1. Bi.ultimus/or Si.praesulcata Zone, 2. Pr.kockeli /or Si.sulcata Zone, 3. Si.duplicata to Si.sandbergi bio interval, 4. Si.crenulata Zone, 5.Gnathodus-P.inornatus Zone, and 6.Ps.multistriatus Zone. Considering to the Conodont Zones above mentioned, Conodont faunas and other evidences, in the Tuyeh-Darvare section the DCB, is located within cream to grey silt stone beds, which are lies between K6 limestone and K8 dark carbonate beds (about 7.10 m above the base of recent studied section).","PeriodicalId":44351,"journal":{"name":"Iranian Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42203509","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}

{"title":"Water types and carbonate saturation model of groundwater in middle Governorate (Gaza strip, Palestine)","authors":"Khalid Fathi Ubeid, M. Al-Agha","doi":"10.30495/IJES.2020.673331","DOIUrl":"https://doi.org/10.30495/IJES.2020.673331","url":null,"abstract":"This study was carried out in the Middle Governorate of Gaza Strip, Palestine. The coastal aquifer is the main source of water for domestic, agricultural, and industrial purposes in the study area. During the last three decades the aquifer has deteriorated to a high degree in the quality and quantity due to the over-pumping and the encroachment of seawater.  Hydrogeochemical analysis for groundwater samples from 21 domestic wells were done in 2015. The major cations and anions (Na+, K+, Ca2+, Mg2+, Cl-, SO42-, NO3-, and HCO3-) that influence the water quality were determined. The results of analysis show that the groundwater was chemical highly enriched with Na+ and Cl- an indication of seawater intrusion into the aquifer, while K+ and SO42- sourced from fertilizers and wastewater. The regression analysis show significant positive correlation (more than +0.80) between the hydrochemical parameters Na+, K+, Ca2+, Mg2+, Cl-, and SO42. Due to main cations and anions five water types were distinguished in studied wells: (1) Na-Mg-Cl, (2) Na-Cl, (3) Na-Mg-Cl-SO4, (4) Na-Cl-SO4, and (5) Na-Ca-Cl. They represent around 48%, 19%, 19%, 10% and 5% respectively of the total wells. The calcite and dolomite were assessed in terms of the saturation index, where they show mainly negative values indicating under-saturation. The hydrogeochemical behavior is rather complicated and is affected by both anthropogenic and natural parameters.","PeriodicalId":44351,"journal":{"name":"Iranian Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42493617","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}

{"title":"Assessment of the potential areas for underground dam construction in Roomeshgan, Lorestan province, Iran","authors":"S. Baharvand, J. Rahnamarad, S. Soori","doi":"10.30495/IJES.2020.671655","DOIUrl":"https://doi.org/10.30495/IJES.2020.671655","url":null,"abstract":"One of the methods for dealing with the problem of water shortage and the decline of groundwater levels in the arid areas is the construction of underground dams. It is difficult to make a decision about suitable locations for the construction of underground dams because of the necessity to consider numerous factors. Some of these criteria are hydrological, geological and geomorphologic characteristics of the area. By applying the GIS and AHP methods, this study attempted to introduce the suitable locations for construction of underground dams in Roomeshgan area in Lorestan Province, Iran. For this purpose, factors such as slope, lithology, land use, alluvium thickness, water quality, and distance from the well, fault and stream and rivers network were used. Using the Analytic Hierarchy Process (AHP) for the possibility of considering various qualitative and quantitative criteria, the process can be one way to select the appropriate location for constructing an underground dam. In this study, after the assessment of the used layers in the Expert Choice software, weight mapping of each layer was prepared. Then, the map of suitable areas for construction of the underground dam was prepared by overlapping the weight mappings of each layer in ArcGIS software. According to the results, 15.87 %, 11.96 %, 35.75 %, 33.23 % and 3.18 % of the region are located in very poor, poor, moderate, suitable and very suitable areas, respectively. After several field surveys of the area with three percent, six locations were selected for underground dam construction. The results show that the factors mentioned above have the most important role in locating the underground dam construction and the chosen method has high accuracy.","PeriodicalId":44351,"journal":{"name":"Iranian Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70076996","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}

{"title":"Study of micro-textures and chemistry of feldspar minerals of East Sarbisheh volcanic complex (Eastern Iran), for evidence of magma chamber process","authors":"M. Jamshidibadr, Sahar Tarabi, Kazem Qolizadeh","doi":"10.30495/IJES.2020.671654","DOIUrl":"https://doi.org/10.30495/IJES.2020.671654","url":null,"abstract":"The Eocene-Oligocene Sarbisheh volcanic complex is a part of the Lut-Sistan Zone that outcrops in eastern Iran. In the east of this complex, three groups of volcanic rocks (i.e., andesite, dacite, and rhyolite) exist. Plagioclase as the main mineral of these rocks is found with varying micro-textures. Based on a changing trend in the concentration of anorthite, the developed micro-textures (coarse/fine-sieve, fine-scale oscillatory zoning, and resorption surfaces) are not affected by the chemical composition of the magma. Rather, such changes can occur by temperature variations during magma crystallization or H2O fugacity changes in the magmatic system. The recharge of basic magma leads to a temperature rise, partial melting of the central part of the crystal, and formation of sieve texture, and resorption surfaces. Consequently, the chemical changes of magma in the chamber cause the formation of An-enrichment in the outer layer of the plagioclase crystal and formation of oscillatory zoning. In addition, the morphological micro-textures (i.e., glomerocryst, synneusis, swallow-tailed, microlite, and broken crystals) are developed by the influence of dynamic behavior of the crystallizing magma and magmatic differentiation. The thermobarometry evaluation using pyroxene and biotite chemistry showed that the temperature ranges between 700 and 1150°C and the pressure were less than 2 kbar.","PeriodicalId":44351,"journal":{"name":"Iranian Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70076981","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}

{"title":"Recurrent seismicity in Rajasthan State in the tectonically stable NW Indian Craton","authors":"H. Kumar, M. Pandit","doi":"10.30495/IJES.2020.671653","DOIUrl":"https://doi.org/10.30495/IJES.2020.671653","url":null,"abstract":"Indian peninsular region comprises several Archean cratonic blocks (Dharwar, Bastar, Singhbhum, Aravalli – Bundelkhand), bordered by Proterozoic mobile belts. Therefore, this region is considered as tectonically stable and designated as the least vulnerable region to earthquake hazard except the still active Central Indian Tectonic Zone (CITZ). The latter is a major suture between southern and northern Indian blocks. Seismicity in India is common along its northern and northeastern (Himalayan) region defining the Indian Plate margin, in collision with the Eurasian (Tibetan) Plate. Being tectonically active, this region has a documented record of frequent earthquakes including some high magnitude and devastating ones. The northwestern Indian block is amongst the relatively stable Precambrian regions of India and categorized under Zone – II by the Indian Meteorology Department, one of the seismically least vulnerable regions. However, the region has been a site of recurring low to moderate magnitude earthquakes. Compilation of the earthquake data from the Rajasthan State in NW India documents at least 45 earthquakes in this region during the last one and a half decades. Several of these have remained unnoticed because of their low magnitude. The NE –SW trending Aravalli Mountain Region (AMR), running across the eastern half of Rajasthan State represents the most significant tectonomorphic feature of NW India. The AMR is an ensemble of Proterozoic age Aravalli and Delhi Supergroup rocks (metasediments, volcanics and intrusives) that overlie an Archean basement (Banded Gneissic Complex – BGC). These Proterozoic mobile belts have evolved through several episodes of deformation that have shaped its present day geomorphology. The western part of the State, the Marwar Block, is relatively younger in age and was accreted to the AMR during the 1 Ga subduction event. The western margin of AMR, also called as the Western Margin Fault, represents a major suture between the two terranes. However, the entire region was cratonized by end Proterozoic and has remained tectonically stable during the Phanerozoic Eon. The Archean basement and overlying Proterozoic cover rocks are infested with several major and minor faults and shear zones. The most prominent ones are the NE-SW trending major lineaments corresponding with the regional tectonic grain and several minor ones across. The earthquake epicenter distribution pattern shows a close spatial association with these lineaments. In the absence of any significant tectonic activity in the region and rise in pore pressure either due to magmatism or excessive rainfall, we attribute recurrence of earthquakes in the region to reactivation of such old sutures/weaker zones as a response to stress build-up along the northern margin of the Indian Plate resulting from ongoing northward convergence of the Indian Plate. Some of the faults in western part are traceable into the Cambay Basin active faults in the south that may ha","PeriodicalId":44351,"journal":{"name":"Iranian Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70076925","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}