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Farhad Ehya - One of the best experts on this subject based on the ideXlab platform.
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Rare earth element and stable isotope (O, S) geochemistry of barite from the Bijgan deposit, Markazi Province, Iran
Mineralogy and Petrology, 2012Co-Authors: Farhad EhyaAbstract:The Bijgan barite deposit, which is located northeast of Delijan in Markazi Province of Iran, occurs as a small Lenticular Body at the uppermost part of an Eocene volcano-sedimentary rock unit. The presence of fossiliferous and carbonaceous strata suggests that the host rocks were deposited in a quiet marine sedimentary environment. Barite, calcite, iron oxides and carbonaceous clay materials are found as massive patches as well as thin layers in the deposit. Barite is marked by very low concentrations of Sr (1-2%) and total amounts of rare earth elements (REEs) (6.25-17.39 ppm). Chondrite-normalized REE patterns of barite indicate a fractionation of light REEs (LREEs) from La to Sm, similar to those for barite of different origins from elsewhere. The La(CN)/Lu(CN) ratios and chondrite-normalized REE patterns reveal that barite in the Bijgan deposit is enriched in LREE relative to heavy rare earth elements (HREEs). The similarity between the Ce/La ratios in the barite samples and those found in deep-sea barite supports a marine origin for barite. Lanthanum and Gd exhibit positive anomalies, which are common features of marine chemical sediments. Cerium shows a negative anomaly in most samples that was inherited from the negative Ce anomaly of hydrothermal fluid that mixed with seawater at the time of barite precipitation. The delta(18)O values of barites show a narrow range of 9.1-11.4aEuro degrees, which is close to or slightly lower than that of contemporaneous seawater at the end of the Eocene. This suggests a contribution of oxygen from seawater in the barite-forming solution. The delta(34)S values of barites (9.5-15.3aEuro degrees) are lower than that of contemporaneous seawater, which suggests a contribution of magmatic sulfur to the ore-forming solution. The oxygen and sulfur isotope ratios indicate that submarine hydrothermal vent fluids are a good analog for solutions that precipitated barite, due to similarities in the isotopic composition of the sulfates. The available data including tectonic setting, host rock characteristics, REE geochemistry, and oxygen and sulfur isotopic compositions support a submarine hydrothermal origin for the Bijgan barite deposit. At the seafloor, barite deposition occurred where ascending Ba-bearing hydrothermal fluids encountered seawater. Sulfate was derived from the sulfate-bearing marine waters, and, to a lesser extent, by oxidized H(2)S, which was derived from magmatic hydrothermal fluids.
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Rare earth element and stable isotope (O, S) geochemistry of barite from the Bijgan deposit, Markazi Province, Iran
Mineralogy and Petrology, 2012Co-Authors: Farhad EhyaAbstract:The Bijgan barite deposit, which is located northeast of Delijan in Markazi Province of Iran, occurs as a small Lenticular Body at the uppermost part of an Eocene volcano-sedimentary rock unit. The presence of fossiliferous and carbonaceous strata suggests that the host rocks were deposited in a quiet marine sedimentary environment. Barite, calcite, iron oxides and carbonaceous clay materials are found as massive patches as well as thin layers in the deposit. Barite is marked by very low concentrations of Sr (1–2%) and total amounts of rare earth elements (REEs) (6.25–17.39 ppm). Chondrite-normalized REE patterns of barite indicate a fractionation of light REEs (LREEs) from La to Sm, similar to those for barite of different origins from elsewhere. The La_CN/Lu_CN ratios and chondrite-normalized REE patterns reveal that barite in the Bijgan deposit is enriched in LREE relative to heavy rare earth elements (HREEs). The similarity between the Ce/La ratios in the barite samples and those found in deep-sea barite supports a marine origin for barite. Lanthanum and Gd exhibit positive anomalies, which are common features of marine chemical sediments. Cerium shows a negative anomaly in most samples that was inherited from the negative Ce anomaly of hydrothermal fluid that mixed with seawater at the time of barite precipitation. The δ^18O values of barites show a narrow range of 9.1–11.4‰, which is close to or slightly lower than that of contemporaneous seawater at the end of the Eocene. This suggests a contribution of oxygen from seawater in the barite-forming solution. The δ^34S values of barites (9.5–15.3‰) are lower than that of contemporaneous seawater, which suggests a contribution of magmatic sulfur to the ore-forming solution. The oxygen and sulfur isotope ratios indicate that submarine hydrothermal vent fluids are a good analog for solutions that precipitated barite, due to similarities in the isotopic composition of the sulfates. The available data including tectonic setting, host rock characteristics, REE geochemistry, and oxygen and sulfur isotopic compositions support a submarine hydrothermal origin for the Bijgan barite deposit. At the seafloor, barite deposition occurred where ascending Ba-bearing hydrothermal fluids encountered seawater. Sulfate was derived from the sulfate-bearing marine waters, and, to a lesser extent, by oxidized H_2S, which was derived from magmatic hydrothermal fluids.
U N Jingye - One of the best experts on this subject based on the ideXlab platform.
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reservoir forming mechanism and models for sandstone Lenticular Body oil gas reservoir
Petroleum Geology & Oilfield Development in Daqing, 2004Co-Authors: U N JingyeAbstract:The oil/gas reservoir of sandstone Lenticular-Body is a type of lithologic reservoir, so far its reservoir-forming mechanism is a problem that has no eomplete solution, even there are a lot of disagreements in recognition. Based on deep theory research on simulated experimental result in formation mechanism lab of lithologic hydrocarbon reservoir, applying the new theory of migration of oil/gas, and combining exploration practice, this paper discusses the lithologic hydrocarbon reservoir of sandstone Lenticular-Body. According to the contact relationship of sand-shale, the seven kinds of reservoir-forming models of lithologic hydrocarbon reservoir are constructed, the four kinds of models in accordance with advan-lageous degree are classified, (he phenomenon that not all sandstone Lenticular-Body can form reservoir in shale (oil source rock) is explained, which is found in the process of exploration. Further more, a new concept that can seek "small-scale oil reservoir groups" is put forward, the good achievement is obtained during the application in Yingtai region, Bayanchagan region, etc.
Un Jing-ye - One of the best experts on this subject based on the ideXlab platform.
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Reservoir-forming mechanism and models for sandstone Lenticular-Body oil/gas reservoir
Petroleum Geology & Oilfield Development in Daqing, 2020Co-Authors: Un Jing-yeAbstract:The oil/gas reservoir of sandstone Lenticular-Body is a type of lithologic reservoir, so far its reservoir-forming mechanism is a problem that has no eomplete solution, even there are a lot of disagreements in recognition. Based on deep theory research on simulated experimental result in formation mechanism lab of lithologic hydrocarbon reservoir, applying the new theory of migration of oil/gas, and combining exploration practice, this paper discusses the lithologic hydrocarbon reservoir of sandstone Lenticular-Body. According to the contact relationship of sand-shale, the seven kinds of reservoir-forming models of lithologic hydrocarbon reservoir are constructed, the four kinds of models in accordance with advan-lageous degree are classified, (he phenomenon that not all sandstone Lenticular-Body can form reservoir in shale (oil source rock) is explained, which is found in the process of exploration. Further more, a new concept that can seek "small-scale oil reservoir groups" is put forward, the good achievement is obtained during the application in Yingtai region, Bayanchagan region, etc.
Gao Ning - One of the best experts on this subject based on the ideXlab platform.
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Oil and gas accumulation mechanism of S_(2+3) oil layer in west slope region
Journal of Daqing Petroleum Institute, 2020Co-Authors: Gao NingAbstract:There are five types of oil or gas reservoirs of S_(2+3) oil layer in west slope region,they are oil or gas reservoirs of anticline,structural lithology,updip pinch out of lithology,Lenticular Body and fault seal.They mainly distribute on the Taikang uplift and its surroundings.There are the characteristics of oil and gas in the same layer and gas in the upper layer and oil in lower layer.Oil of S_(2+3) oil layer was from the K1qn and K_1n_1 source rocks in Qijiagulong sag through oil-source correlation.The formation of oil or gas reservoirs experienced two main periods,first was at the end of K1_n sedimentary period,second was from the end of K_2m sedimentary period to the early of Eogene system sedimentary period.this paper summarized three oil or gas accumulation models,they are the accumulation model of oil or gas in the traps of sandstone updip pinching,structure and structure-lithology and fault seal.Taikang uplift and its surroundings are the most favorable oil or gas exploration area of S_(2+3) oil layer in west slope region and those traps on the main direction of oil or gas migration are the most favorable oil or gas exploration targets through comprehensive analysis.
Zhu Zhi-feng - One of the best experts on this subject based on the ideXlab platform.
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Research on the type of Oil &gas reservoir and the mode of reservoir-formed on Chang-6 oil reservoir in yongjing area of the southern of zhidan oil field,ordos basin
Inner Mongolia Petrochemical Industry, 2020Co-Authors: Zhu Zhi-fengAbstract:with a large number of logging,drilling,core logging,test oil such as test-mining information,combined with a variety of testing methods and analysis tools,thoroughly and systematically studied on the area stratigraphy,tectonics,sedimentary microfacies types and distribution characteristics,reservoir characteristics,etc.But also for the Chang 6 oil gas reservoirs for a comprehensive and integrated analysis,pointed out that the major types of Chang-6 oil gas reservoirs are as follows: ① Up-lip pinch-out sandstone lithology reservoir;② Sandstone Lenticular-Body lithology reservoir;③ Barrier heterogeneity lithologic reservoir;④ Structure-lithology composite reservoir.Based on comprehensive study,the final,summed up and established the Chang 6 oil gas reservoir-formed mode.