Marine shale gas exploration targets are reaching into shallow to deep or ultradeep burial depths. Rock microstructure and reservoir quality emerge as the main risk considerations for a profitable reservoir at these large depths. Shallow to deep marine shales occur in the Silurian Longmaxi Formation of the Weiyuan Block, which is located on the southwestern margin of the Sichuan Basin. However, few details of the characteristics of the Longmaxi shales in this Block have been reported. In this study, five wells approximately 3500 m deep were drilled. Field emission scanning electron microscopy, low-pressure gas adsorption and core plug porosity-permeability measurements are conducted on 6 shallow (2651–2940 m) and 11 deep (3539–3575 m) Longmaxi samples to obtain the organic geochemical characteristics, mineral constitutions, pore structures and petrophysical properties, and they are the major controls on reservoir quality. The results show similar mineralogical and organic geochemical characteristics in all samples from the various depths. Both shallow and deep shales are mainly composed of quartz, carbonate and clays and have a total organic carbon (TOC) content more than 2 wt.% and a mean S1 + S2 value more than 52 mg/g. Source rock quality criteria using the TOC and S1 + S2 suggest most shale samples fall excellent source rocks. The samples are mostly siliceous rocks that contain organic pores, intraparticle dissolution pores, interparticle quartz pores and interparticle clay pores and they play a positive role in improving reservoir quality. Pore surface area and pore volume increase with increasing TOC, indicating that the porous organic fraction is a major control on pore structure and porosity. We suggested that siliceous deep Longmaxi formation in Weiyuan Block belongs to a high-quality shale with an average TOC value of 3.9 wt.% and well-developed pore networks, which should be the important target for deep shale gas exploration.
海相页岩气勘探目标向浅层至深层或超深层延伸。在这些大深度，岩石微观结构和储层质量成为考虑盈利油藏的主要风险因素。四川盆地西南缘威远地块志留系龙马溪组发育浅-深海相页岩。然而，有关龙马溪组页岩特征的详细报道较少。在这项研究中，共钻了5口约3500米深的井。对龙马溪浅部(2651 ~ 2940 m) 6个样品和深部(3539 ~ 3575 m) 11个样品进行了场发射扫描电镜、低压气体吸附和岩心塞孔渗透率测量，获得了有机地球化学特征、矿物组成、孔隙结构和岩石物理性质，这些是控制储层质量的主要因素。结果表明，不同深度样品的矿物学和有机地球化学特征相似。浅部和深层页岩均以石英、碳酸盐和粘土为主，总有机碳(TOC)含量均大于2 wt。%，平均S1 + S2值大于52 mg/g。采用TOC和S1 + S2的烃源岩质量标准表明，大多数页岩样品属于优质烃源岩。样品多为硅质岩，含有机质孔、颗粒内溶蚀孔、颗粒间石英孔和颗粒间粘土孔，对提高储层质量具有积极作用。孔隙表面积和孔隙体积随有机质含量的增加而增大，表明孔隙有机质组分是孔隙结构和孔隙度的主要控制因素。认为威远地块深部龙马溪组硅质页岩为优质页岩，平均TOC值为3.9 wt。孔隙网络发育，应成为深部页岩气勘探的重要目标。
{"title":"Reservoir characterization of the shallow to deep Longmaxi formation in the Weiyuan Block, southwestern Sichuan Basin","authors":"Y. Hao, Yi-Zhen Li, Qing Zhang, Wei Jiang, Xusheng Liang, Benqiang Wang, Yanjun Lu, Hongjian Zhu","doi":"10.1177/01445987231188067","DOIUrl":"https://doi.org/10.1177/01445987231188067","url":null,"abstract":"Marine shale gas exploration targets are reaching into shallow to deep or ultradeep burial depths. Rock microstructure and reservoir quality emerge as the main risk considerations for a profitable reservoir at these large depths. Shallow to deep marine shales occur in the Silurian Longmaxi Formation of the Weiyuan Block, which is located on the southwestern margin of the Sichuan Basin. However, few details of the characteristics of the Longmaxi shales in this Block have been reported. In this study, five wells approximately 3500 m deep were drilled. Field emission scanning electron microscopy, low-pressure gas adsorption and core plug porosity-permeability measurements are conducted on 6 shallow (2651–2940 m) and 11 deep (3539–3575 m) Longmaxi samples to obtain the organic geochemical characteristics, mineral constitutions, pore structures and petrophysical properties, and they are the major controls on reservoir quality. The results show similar mineralogical and organic geochemical characteristics in all samples from the various depths. Both shallow and deep shales are mainly composed of quartz, carbonate and clays and have a total organic carbon (TOC) content more than 2 wt.% and a mean S1 + S2 value more than 52 mg/g. Source rock quality criteria using the TOC and S1 + S2 suggest most shale samples fall excellent source rocks. The samples are mostly siliceous rocks that contain organic pores, intraparticle dissolution pores, interparticle quartz pores and interparticle clay pores and they play a positive role in improving reservoir quality. Pore surface area and pore volume increase with increasing TOC, indicating that the porous organic fraction is a major control on pore structure and porosity. We suggested that siliceous deep Longmaxi formation in Weiyuan Block belongs to a high-quality shale with an average TOC value of 3.9 wt.% and well-developed pore networks, which should be the important target for deep shale gas exploration.","PeriodicalId":11606,"journal":{"name":"Energy Exploration & Exploitation","volume":"23 1","pages":"2058 - 2077"},"PeriodicalIF":2.7,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87207292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-12DOI: 10.1177/01445987231184595
Ziwen Jiang, C. Cai
The Mesoproterozoic Xiamaling Formation (∼1.4 Ga) is considered to be a set of promising strata for shale oil and gas exploration and production in the Yanliao Basin, North China Craton. This study aimed to investigate the organic matter accumulation mechanism, and hydrocarbon generation and expulsion characteristics of the Xiamaling Formation, using various methods, including scanning electron microscopy, rock-eval pyrolysis, and elemental geochemistry. Multiple geochemical proxies indicate that Unit 3—Unit 1 of the Xiamaling Formation was deposited in a climate that alternated between highly humid and semiarid conditions, with the strong-to-weak terrigenous influx. The redox conditions of bottom water were undulatory oxic in Unit 3 and the upper part of Unit 1, but anoxic in Unit 2 and the lower part of Unit 1. Sulfurization of organic matter was the main reason for the high TOC content in Unit 3. However, the high TOC content in Unit 2 and the lower part of Unit 1 was caused by an oxygen-deficient water column. Unit 2 and the lower part of Unit 1 exhibit a significant shale oil potential owing to low maturity, high hydrogen index (HI) values, and prevalence of type Ⅰ, II1, and II2 kerogens.
{"title":"Organic matter accumulation mechanisms and source rock potential of the Mesoproterozoic Xiamaling Formation, Yanliao Basin, North China","authors":"Ziwen Jiang, C. Cai","doi":"10.1177/01445987231184595","DOIUrl":"https://doi.org/10.1177/01445987231184595","url":null,"abstract":"The Mesoproterozoic Xiamaling Formation (∼1.4 Ga) is considered to be a set of promising strata for shale oil and gas exploration and production in the Yanliao Basin, North China Craton. This study aimed to investigate the organic matter accumulation mechanism, and hydrocarbon generation and expulsion characteristics of the Xiamaling Formation, using various methods, including scanning electron microscopy, rock-eval pyrolysis, and elemental geochemistry. Multiple geochemical proxies indicate that Unit 3—Unit 1 of the Xiamaling Formation was deposited in a climate that alternated between highly humid and semiarid conditions, with the strong-to-weak terrigenous influx. The redox conditions of bottom water were undulatory oxic in Unit 3 and the upper part of Unit 1, but anoxic in Unit 2 and the lower part of Unit 1. Sulfurization of organic matter was the main reason for the high TOC content in Unit 3. However, the high TOC content in Unit 2 and the lower part of Unit 1 was caused by an oxygen-deficient water column. Unit 2 and the lower part of Unit 1 exhibit a significant shale oil potential owing to low maturity, high hydrogen index (HI) values, and prevalence of type Ⅰ, II1, and II2 kerogens.","PeriodicalId":11606,"journal":{"name":"Energy Exploration & Exploitation","volume":"45 1","pages":"2016 - 2035"},"PeriodicalIF":2.7,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72509789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present-day in-situ stresses affect the drilling design, well pattern deployment, well completion modification, hydraulic fracturing and water injection of tight-oil sandstones. The measurement data of these stresses are commonly unavailable because of their high costs and limited core samples, therefore employing conventional logs for these stress determination is imperative for tight-oil sandstones. Firstly, the suitable calculation models for the present-day in-situ stress calculation by conventional logs were selected according to the geological characteristics of the sixth member of the Yanchang Formation (Chang 6) in Heshui area of the southern Ordos Basin, China. Then, the dynamic rock mechanical parameters were determined by conventional logs, and corrected by the static rock mechanical parameters obtained from the triaxial rock mechanical tests. Moreover, the pore fluid pressure was determined by the empirical formula method. Finally, the maximum and minimum horizontal compressive stresses (σH and σh), and the vertical stress (σv) of six wells were calculated according to the selected models of these stresses, respectively. The present-day in-situ stresses, determined by the proposed method in the paper, were verified by those obtained from acoustic emission tests and finite-element numerical simulations with the relative errors of less than 10%. The results show that the magnitudes of σH, σh and the horizontal differential stress (σH−h) in the study area mainly range from 32 to 43 MPa, 23 to 37 MPa and 5 to 8 MPa, respectively. The magnitude of the three-dimensional present-day in-situ stress increases with the increase of depth. The average gradients of σH, σv and σh are 0.018, 0.014 and 0.015 MPa/m, respectively, that is σH>σv>σh. In this stress state, the hydraulic fractures, with a trend of little expansion towards multiple directions, are commonly developed at a small angle intersecting with the direction of σH in the study area.
{"title":"Determining the present-day in-situ stresses of tight-oil sandstones by conventional logs: An approach in the Triassic Yanchang Formation, southern Ordos Basin","authors":"Wenya Lyu, Chen Hui, Lianbo Zeng, Leifei Wang, Jianming Fan, Yanxiang Liu, Jian Liu, Haonan Wang, Mao Zhe","doi":"10.1177/01445987231188064","DOIUrl":"https://doi.org/10.1177/01445987231188064","url":null,"abstract":"The present-day in-situ stresses affect the drilling design, well pattern deployment, well completion modification, hydraulic fracturing and water injection of tight-oil sandstones. The measurement data of these stresses are commonly unavailable because of their high costs and limited core samples, therefore employing conventional logs for these stress determination is imperative for tight-oil sandstones. Firstly, the suitable calculation models for the present-day in-situ stress calculation by conventional logs were selected according to the geological characteristics of the sixth member of the Yanchang Formation (Chang 6) in Heshui area of the southern Ordos Basin, China. Then, the dynamic rock mechanical parameters were determined by conventional logs, and corrected by the static rock mechanical parameters obtained from the triaxial rock mechanical tests. Moreover, the pore fluid pressure was determined by the empirical formula method. Finally, the maximum and minimum horizontal compressive stresses (σH and σh), and the vertical stress (σv) of six wells were calculated according to the selected models of these stresses, respectively. The present-day in-situ stresses, determined by the proposed method in the paper, were verified by those obtained from acoustic emission tests and finite-element numerical simulations with the relative errors of less than 10%. The results show that the magnitudes of σH, σh and the horizontal differential stress (σH−h) in the study area mainly range from 32 to 43 MPa, 23 to 37 MPa and 5 to 8 MPa, respectively. The magnitude of the three-dimensional present-day in-situ stress increases with the increase of depth. The average gradients of σH, σv and σh are 0.018, 0.014 and 0.015 MPa/m, respectively, that is σH>σv>σh. In this stress state, the hydraulic fractures, with a trend of little expansion towards multiple directions, are commonly developed at a small angle intersecting with the direction of σH in the study area.","PeriodicalId":11606,"journal":{"name":"Energy Exploration & Exploitation","volume":"26 1","pages":"2036 - 2057"},"PeriodicalIF":2.7,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78421394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-10DOI: 10.1177/01445987231185850
Yuzhong Liao, Wei Zhang, Yuwei Rong, Feng Liu, S. Wei, Long Li, Zirui Zhao, Manhong Li
The lithospheric thermal structure has a profound indicative significance for the potential evaluation and exploration of geothermal resources. The Linyi geothermal field, located in the southern section of the Yishu fault in Shandong Province, boasts abundant geothermal resources. However, its origin is still unclear. This study analyzed the characteristics of terrestrial heat flow using the temperature logging of geothermal wells and measurements of thermal conductivity and heat production. Combined with the geophysical information of the Xiangshui (Jiangsu Province)-Mandula (Nei Mongol) geoscience transect and the lithology revealed by the geothermal wells, this study built a conceptual model of the lithospheric thermal structure using the one-dimensional steady-state heat conduction equation. Based on this model, the heat flow is 64.9 mW/m2, indicating a high geothermal setting in the study area. Furthermore, the ratio of crustal to mantle heat flow is < 1 (0.67), implying that surface heat flow originates predominantly from the mantle. The Yishu fault probably acts as a pathway for heat transfer from the mantle. The temperature of the Moho boundary in the study area was estimated to be 614.8 °C. The Curie depth was calculated to be 29.5 km (585 °C), which is consistent with the depth estimated using the aeromagnetic data. In sum, the Linyi geothermal field has a high geothermal setting, which contributes to the formation of geothermal resources.
{"title":"A high geothermal setting in the Linyi geothermal field: Evidence from the lithospheric thermal structure","authors":"Yuzhong Liao, Wei Zhang, Yuwei Rong, Feng Liu, S. Wei, Long Li, Zirui Zhao, Manhong Li","doi":"10.1177/01445987231185850","DOIUrl":"https://doi.org/10.1177/01445987231185850","url":null,"abstract":"The lithospheric thermal structure has a profound indicative significance for the potential evaluation and exploration of geothermal resources. The Linyi geothermal field, located in the southern section of the Yishu fault in Shandong Province, boasts abundant geothermal resources. However, its origin is still unclear. This study analyzed the characteristics of terrestrial heat flow using the temperature logging of geothermal wells and measurements of thermal conductivity and heat production. Combined with the geophysical information of the Xiangshui (Jiangsu Province)-Mandula (Nei Mongol) geoscience transect and the lithology revealed by the geothermal wells, this study built a conceptual model of the lithospheric thermal structure using the one-dimensional steady-state heat conduction equation. Based on this model, the heat flow is 64.9 mW/m2, indicating a high geothermal setting in the study area. Furthermore, the ratio of crustal to mantle heat flow is < 1 (0.67), implying that surface heat flow originates predominantly from the mantle. The Yishu fault probably acts as a pathway for heat transfer from the mantle. The temperature of the Moho boundary in the study area was estimated to be 614.8 °C. The Curie depth was calculated to be 29.5 km (585 °C), which is consistent with the depth estimated using the aeromagnetic data. In sum, the Linyi geothermal field has a high geothermal setting, which contributes to the formation of geothermal resources.","PeriodicalId":11606,"journal":{"name":"Energy Exploration & Exploitation","volume":"34 1","pages":"1899 - 1918"},"PeriodicalIF":2.7,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75849895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-06DOI: 10.1177/01445987231186689
Wenchao Shen, Cunliang Zhao, Jingsen Zhang, S. Arbuzov, D. Spears
This work describes a Ge-bearing mineral in the Carboniferous medium-ash, high-sulfur and low-volatile bituminous coal of the Yuzhou Coalfield, southern part of the North China Basin. Germanium (Ge) in the investigated coals ranges from 10.4 to 57.6 μg/g, with an average of 32.8 μg/g. Average concentrations of Ge in coal samples are about 16 times higher than that of world hard coals (2.4 μg/g). Ge-bearing mineral was found in the coal sample. It occurs as a vein and is closely associated with copper zinc tin sulfide, and illite. To the best of our knowledge, this is the first record of this mineral in coal. The average chemical composition based on the electron microprobe analyses is (in wt. %): Al 23.42, Ge 32.92, O 35.24, F 7.82, total 99.39, corresponding to (Al1.97Ge0.03)2GeO4(F0.93, OH)1.93. Krieselite has the ideal chemical formula Al2GeO4(F, OH)2, and is most likely the Ge-bearing mineral found in the investigated coal sample. The appearance of Ge-bearing mineral indicates an origin later than peat deposition and also demonstrates that Ge mineralization could take place during coalification.
研究了华北盆地南部禹州煤田石炭系中灰、高硫、低挥发性烟煤中的一种含锗矿物。锗(Ge)含量在10.4 ~ 57.6 μg/g之间，平均为32.8 μg/g。煤样中Ge的平均浓度约为世界硬煤的16倍(2.4 μg/g)。煤样中发现含锗矿物。它呈脉状，与铜锌锡硫化物和伊利石密切相关。据我们所知，这是煤中首次记录到这种矿物。电子探针分析的平均化学成分为(wt. %): Al 23.42, Ge 32.92, O 35.24, F 7.82, total 99.39，对应于(Al1.97Ge0.03)2GeO4(F0.93, OH)1.93。Krieselite具有理想的化学式Al2GeO4(F, OH)2，并且最有可能是在所调查的煤样品中发现的含锗矿物。含Ge矿物的出现表明其成因晚于泥炭沉积，也表明在煤化过程中可能发生Ge矿化。
{"title":"Discovery of Ge-bearing mineral in a Carboniferous coal from the Yuzhou Coalfield, southern part of the North China Basin","authors":"Wenchao Shen, Cunliang Zhao, Jingsen Zhang, S. Arbuzov, D. Spears","doi":"10.1177/01445987231186689","DOIUrl":"https://doi.org/10.1177/01445987231186689","url":null,"abstract":"This work describes a Ge-bearing mineral in the Carboniferous medium-ash, high-sulfur and low-volatile bituminous coal of the Yuzhou Coalfield, southern part of the North China Basin. Germanium (Ge) in the investigated coals ranges from 10.4 to 57.6 μg/g, with an average of 32.8 μg/g. Average concentrations of Ge in coal samples are about 16 times higher than that of world hard coals (2.4 μg/g). Ge-bearing mineral was found in the coal sample. It occurs as a vein and is closely associated with copper zinc tin sulfide, and illite. To the best of our knowledge, this is the first record of this mineral in coal. The average chemical composition based on the electron microprobe analyses is (in wt. %): Al 23.42, Ge 32.92, O 35.24, F 7.82, total 99.39, corresponding to (Al1.97Ge0.03)2GeO4(F0.93, OH)1.93. Krieselite has the ideal chemical formula Al2GeO4(F, OH)2, and is most likely the Ge-bearing mineral found in the investigated coal sample. The appearance of Ge-bearing mineral indicates an origin later than peat deposition and also demonstrates that Ge mineralization could take place during coalification.","PeriodicalId":11606,"journal":{"name":"Energy Exploration & Exploitation","volume":"1 1","pages":"2007 - 2015"},"PeriodicalIF":2.7,"publicationDate":"2023-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88935056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-03DOI: 10.1177/01445987231185150
C. Dong, Dejiang Li, Ye Zhang, Dahua Li, Man Liu, Zhongxi Han
Wufeng Formation shale is an important source rock of unconventional hydrocarbons in the Lower Paleozoic shales of Sichuan Basin. However, the study on its provenance and paleoclimate is still relatively limited. In this study, mineralogical and geochemical data of the shales from the Upper Ordovician Wufeng Formation in southwestern China has been used to interpret the provenance and conditions of weathering and paleoclimate. The Wufeng shales have intermediate to high SiO2 (57.72–82.38 wt. %, av. = 68.84 wt. %) and Al2O3 (5.26–16.17 wt. %, av. = 10.62 wt. %), are rich in transition metal elements (i.e. V, Ni, Cu, Co and Cr) and Y as well as moderate depletion in Na2O and Sr, relative to the concentrations of the upper continental crust (UCC). In the chondrite-normalized (CN) rare earth elements (REE) distributions, these rocks display light REE (LREE) enrichment (La/YbCN = 6.69–12.63, av. = 9.28), flat heavy REE (HREE) (Gd/YbCN = 1.35–2.41, av. = 1.70), and clearly negative Eu anomalies (Euan = 0.50–0.66, av. = 0.58), showing similar characteristics with the CN post-Archean Australian Average Shales (PAAS). Wufeng Formation shales are immature composition without evident recycling sediments, and they are originated from an intermediate-felsic igneous source composed of tonalite–trondhjemite–granodiorite (TTG), granitic and andesitic igneous rocks. The chemical weathering conditions of studied shales decreased from moderate to low in the provenance region, suggesting a gradual cooling trend of the climate at Late Ordovician Thus, this article will be helpful to discern the provenance and variations of chemical weathering conditions and paleoclimate of Wufeng Formation shales.
五峰组页岩是四川盆地下古生界页岩中重要的非常规烃源岩。但对其物源和古气候的研究还比较有限。本文利用西南地区上奥陶统五峰组页岩的矿物学和地球化学资料，对其物源、风化条件和古气候进行了解释。五峰页岩SiO2含量为中高(57.72 ~ 82.38 wt)。%， av = 68.84 wt。%)和Al2O3 (5.26-16.17 wt。%， av = 10.62 wt。(%)，相对于上大陆地壳(UCC)的浓度，具有丰富的过渡金属元素(即V、Ni、Cu、Co和Cr)和Y，以及Na2O和Sr的适度损耗。在球粒归一化稀土元素(REE)分布中，稀土元素(LREE)轻富集(La/YbCN = 6.69 ~ 12.63, av. = 9.28)，重稀土元素(HREE)平富集(Gd/YbCN = 1.35 ~ 2.41, av. = 1.70)， Eu负异常明显(Euan = 0.50 ~ 0.66, av. = 0.58)，与CN太古宙后澳大利亚平均页岩(PAAS)特征相似。五峰组页岩为未成熟成分，无明显的再循环沉积，其源岩为中长英质火成岩，由闪长岩-闪长岩-花岗闪长岩(TTG)、花岗质和安山岩火成岩组成。研究区页岩化学风化条件由中到低，表明晚奥陶世气候呈逐渐降温趋势，有助于辨明五峰组页岩化学风化条件和古气候的物源及变化。
{"title":"Geochemistry and mineralogy of the Upper Ordovician Wufeng formation, Southwestern China: Implications for Paleoclimate construction","authors":"C. Dong, Dejiang Li, Ye Zhang, Dahua Li, Man Liu, Zhongxi Han","doi":"10.1177/01445987231185150","DOIUrl":"https://doi.org/10.1177/01445987231185150","url":null,"abstract":"Wufeng Formation shale is an important source rock of unconventional hydrocarbons in the Lower Paleozoic shales of Sichuan Basin. However, the study on its provenance and paleoclimate is still relatively limited. In this study, mineralogical and geochemical data of the shales from the Upper Ordovician Wufeng Formation in southwestern China has been used to interpret the provenance and conditions of weathering and paleoclimate. The Wufeng shales have intermediate to high SiO2 (57.72–82.38 wt. %, av. = 68.84 wt. %) and Al2O3 (5.26–16.17 wt. %, av. = 10.62 wt. %), are rich in transition metal elements (i.e. V, Ni, Cu, Co and Cr) and Y as well as moderate depletion in Na2O and Sr, relative to the concentrations of the upper continental crust (UCC). In the chondrite-normalized (CN) rare earth elements (REE) distributions, these rocks display light REE (LREE) enrichment (La/YbCN = 6.69–12.63, av. = 9.28), flat heavy REE (HREE) (Gd/YbCN = 1.35–2.41, av. = 1.70), and clearly negative Eu anomalies (Euan = 0.50–0.66, av. = 0.58), showing similar characteristics with the CN post-Archean Australian Average Shales (PAAS). Wufeng Formation shales are immature composition without evident recycling sediments, and they are originated from an intermediate-felsic igneous source composed of tonalite–trondhjemite–granodiorite (TTG), granitic and andesitic igneous rocks. The chemical weathering conditions of studied shales decreased from moderate to low in the provenance region, suggesting a gradual cooling trend of the climate at Late Ordovician Thus, this article will be helpful to discern the provenance and variations of chemical weathering conditions and paleoclimate of Wufeng Formation shales.","PeriodicalId":11606,"journal":{"name":"Energy Exploration & Exploitation","volume":"6 1","pages":"1983 - 2006"},"PeriodicalIF":2.7,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73203078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-03eCollection Date: 2023-01-01DOI: 10.3897/zookeys.1168.100798
Yanmeng Hou, Lingchen Zhao, Feng Zhang
The genus Catatemnus Beier, 1932 is reported for the first time from China and includes six new species: C.huaesp. nov. from Hainan Island, C.laminosussp. nov., C.ramussp. nov., C.scabersp. nov., and C.tengchongensissp. nov. all from Yunnan Province, and C.tibetanussp. nov. from Xizang Autonomous Region. Descriptions and illustrations of all the new species are provided.
{"title":"First record of the genus <i>Catatemnus</i> Beier, 1932 from China, with the description of six new species (Pseudoscorpiones, Atemnidae).","authors":"Yanmeng Hou, Lingchen Zhao, Feng Zhang","doi":"10.3897/zookeys.1168.100798","DOIUrl":"10.3897/zookeys.1168.100798","url":null,"abstract":"<p><p>The genus <i>Catatemnus</i> Beier, 1932 is reported for the first time from China and includes six new species: <i>C.huae</i><b>sp. nov.</b> from Hainan Island, <i>C.laminosus</i><b>sp. nov.</b>, <i>C.ramus</i><b>sp. nov.</b>, <i>C.scaber</i><b>sp. nov.</b>, and <i>C.tengchongensis</i><b>sp. nov.</b> all from Yunnan Province, and <i>C.tibetanus</i><b>sp. nov.</b> from Xizang Autonomous Region. Descriptions and illustrations of all the new species are provided.</p>","PeriodicalId":11606,"journal":{"name":"Energy Exploration & Exploitation","volume":"11 1","pages":"295-327"},"PeriodicalIF":1.3,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10848838/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87563198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-29DOI: 10.1177/01445987231183178
Feng Gu, Zhaowei Zhu, Q. Shi, R. Li
This study performs the simulation and energy, exergy, and economic analyses of an organic Rankine cycle (ORC) integrated with a natural gas combined cycle. Working fluids studied in this research are ammonia, isobutane, R-11, R-113, and R-141b. The power plant and ORC are simulated using Aspen HYSYS software. The results show that using the ORC leads to an improvement in the thermo-economic indexes of the combined cycle power plant. The sensitivity analysis also demonstrated that using ammonia and isobutane as working fluids results in the highest exergy destruction and the lowest exergy and energy efficiencies; therefore, they are unsuitable. On the other hand, a comparison of thermo-economic results illustrated that among the studied working fluids, R-113 is the desirable selection. According to the simulation, it is deduced that employing R-113 working fluid leads to the net power generation of the plant increasing by 2.48%, the cost of electricity decreasing by 10.75%, and the total energy efficiency of the power plant increasing by 6.02%.
{"title":"Thermodynamic and economic analyses of natural gas combined cycle power plants with and without the presence of organic Rankine cycle","authors":"Feng Gu, Zhaowei Zhu, Q. Shi, R. Li","doi":"10.1177/01445987231183178","DOIUrl":"https://doi.org/10.1177/01445987231183178","url":null,"abstract":"This study performs the simulation and energy, exergy, and economic analyses of an organic Rankine cycle (ORC) integrated with a natural gas combined cycle. Working fluids studied in this research are ammonia, isobutane, R-11, R-113, and R-141b. The power plant and ORC are simulated using Aspen HYSYS software. The results show that using the ORC leads to an improvement in the thermo-economic indexes of the combined cycle power plant. The sensitivity analysis also demonstrated that using ammonia and isobutane as working fluids results in the highest exergy destruction and the lowest exergy and energy efficiencies; therefore, they are unsuitable. On the other hand, a comparison of thermo-economic results illustrated that among the studied working fluids, R-113 is the desirable selection. According to the simulation, it is deduced that employing R-113 working fluid leads to the net power generation of the plant increasing by 2.48%, the cost of electricity decreasing by 10.75%, and the total energy efficiency of the power plant increasing by 6.02%.","PeriodicalId":11606,"journal":{"name":"Energy Exploration & Exploitation","volume":"42 1","pages":"1956 - 1982"},"PeriodicalIF":2.7,"publicationDate":"2023-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73828953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-27DOI: 10.1177/01445987231176306
Nan Jiang, Xingzhi Wang, Dong Xiao, Ran Liu, Wei Wang, Li-ke Zhao, Xiaofang Wang
Sucrosic dolomite, an important hydrocarbon reservoir, has long been the focus of carbonate sedimentological and reservoir geological studies. This study investigated a kind of heterogeneous sucrosic dolomite in the Lower Permian Qixia Formation of NW Sichuan Basin, which has recently been the location of giant natural gas discoveries. The heterogeneous sucrosic dolomite is characterized by coexistence of porous euhedral dolomite and tight anhedral dolomite, and it is mainly distributed in the platform-marginal shoal facies with a quasi-layered structure. Further geochemical analysis, including C, O, and Sr isotopes as well as rare earth elements, reveals that the euhedral dolomite and anhedral dolomite have similar geochemical properties to the matrix limestone representing coeval seawater, and they were mainly generated from dolomitization by the closed marine-related fluid (left-leaning REE and δPr < 1) in the shallow burial. The difference in crystal morphology, porosity, and permeability between the euhedral dolomite and anhedral dolomite is mainly related to the compositional and textural heterogeneities of the host rocks. Due to the dissolution of meteoric water (relatively flat REE and low Y/Ho) in the early diagenetic stage caused by high frequent exposures, quasi-layered vugs and caves were formed in the grainstones. In the process of shallow burial dolomitization, the loose-filled carbonate sands formed the porous euhedral dolomite due to sufficient space, while the matrix limestone formed the tight anhedral dolomite due to relatively poor porosity and permeability. Accordingly, the paleogeomorphic highland controlled platform-marginal shoal superimposed by meteoric water dissolution in the early diagenetic stage is the main factor for the formation of Qixia Formation reservoirs, while dolomitization is mainly manifested as the inheritance and adjustment of pre-existing pores in the host rock. Therefore, the exploration direction for dolomite reservoirs in the Qixia Formation in the Sichuan Basin should be shifted to the favorable sedimentary facies-controlled reservoir model, which can also be referential for other cases under similar geological setting.
{"title":"The origin of heterogeneous sucrosic dolomite reservoir of the lower Permian Qixia Formation, NW Sichuan Basin, China","authors":"Nan Jiang, Xingzhi Wang, Dong Xiao, Ran Liu, Wei Wang, Li-ke Zhao, Xiaofang Wang","doi":"10.1177/01445987231176306","DOIUrl":"https://doi.org/10.1177/01445987231176306","url":null,"abstract":"Sucrosic dolomite, an important hydrocarbon reservoir, has long been the focus of carbonate sedimentological and reservoir geological studies. This study investigated a kind of heterogeneous sucrosic dolomite in the Lower Permian Qixia Formation of NW Sichuan Basin, which has recently been the location of giant natural gas discoveries. The heterogeneous sucrosic dolomite is characterized by coexistence of porous euhedral dolomite and tight anhedral dolomite, and it is mainly distributed in the platform-marginal shoal facies with a quasi-layered structure. Further geochemical analysis, including C, O, and Sr isotopes as well as rare earth elements, reveals that the euhedral dolomite and anhedral dolomite have similar geochemical properties to the matrix limestone representing coeval seawater, and they were mainly generated from dolomitization by the closed marine-related fluid (left-leaning REE and δPr < 1) in the shallow burial. The difference in crystal morphology, porosity, and permeability between the euhedral dolomite and anhedral dolomite is mainly related to the compositional and textural heterogeneities of the host rocks. Due to the dissolution of meteoric water (relatively flat REE and low Y/Ho) in the early diagenetic stage caused by high frequent exposures, quasi-layered vugs and caves were formed in the grainstones. In the process of shallow burial dolomitization, the loose-filled carbonate sands formed the porous euhedral dolomite due to sufficient space, while the matrix limestone formed the tight anhedral dolomite due to relatively poor porosity and permeability. Accordingly, the paleogeomorphic highland controlled platform-marginal shoal superimposed by meteoric water dissolution in the early diagenetic stage is the main factor for the formation of Qixia Formation reservoirs, while dolomitization is mainly manifested as the inheritance and adjustment of pre-existing pores in the host rock. Therefore, the exploration direction for dolomite reservoirs in the Qixia Formation in the Sichuan Basin should be shifted to the favorable sedimentary facies-controlled reservoir model, which can also be referential for other cases under similar geological setting.","PeriodicalId":11606,"journal":{"name":"Energy Exploration & Exploitation","volume":"9 1","pages":"2101 - 2120"},"PeriodicalIF":2.7,"publicationDate":"2023-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87036251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-26DOI: 10.1177/01445987231181919
Q. Abu Al-haija, Omar Mohamed, Wejdan Abu Elhaija
Energy demand forecasting has been an indispensable research target for academics, which has led to creative solutions for energy utilities in terms of power system design, control, and planning. The usefulness of energy demand forecasting is confined to the power engineering industry but globally exceeds such outcomes to contribute to the environment and health sectors. Despite the large number of research projects published on this topic, the challenge of energy demand forecasting still exists, especially with the developments in modeling concepts via artificial intelligence, which motivates more attractive solutions for the variables involved in energy demand forecasting. Mathematical correlation or extrapolation-like methods cannot be effective in all situations; however, when a time series neural network is presented, most statistical, empirical, and theoretical problems can be easily handled. This paper presents a simple and easy-to-understand method for the next decade of energy demand forecasting based on a nonlinear autoregressive (NAR) neural network. From its time series past values, NAR structurally is an optimal predictor for a future variable. A publicly available data set for global energy consumption has been used to construct the network model with sufficiently accurate results. The evidence has appeared in precisely following the exponential trend of energy consumption as well as the regressions for training, testing, and validation, which ensures the model's robustness and avoids getting involved in overfitting. The proposed model concepts and results can be easily used in undergraduate engineering education, training graduates, and future research.
{"title":"Predicting global energy demand for the next decade: A time-series model using nonlinear autoregressive neural networks","authors":"Q. Abu Al-haija, Omar Mohamed, Wejdan Abu Elhaija","doi":"10.1177/01445987231181919","DOIUrl":"https://doi.org/10.1177/01445987231181919","url":null,"abstract":"Energy demand forecasting has been an indispensable research target for academics, which has led to creative solutions for energy utilities in terms of power system design, control, and planning. The usefulness of energy demand forecasting is confined to the power engineering industry but globally exceeds such outcomes to contribute to the environment and health sectors. Despite the large number of research projects published on this topic, the challenge of energy demand forecasting still exists, especially with the developments in modeling concepts via artificial intelligence, which motivates more attractive solutions for the variables involved in energy demand forecasting. Mathematical correlation or extrapolation-like methods cannot be effective in all situations; however, when a time series neural network is presented, most statistical, empirical, and theoretical problems can be easily handled. This paper presents a simple and easy-to-understand method for the next decade of energy demand forecasting based on a nonlinear autoregressive (NAR) neural network. From its time series past values, NAR structurally is an optimal predictor for a future variable. A publicly available data set for global energy consumption has been used to construct the network model with sufficiently accurate results. The evidence has appeared in precisely following the exponential trend of energy consumption as well as the regressions for training, testing, and validation, which ensures the model's robustness and avoids getting involved in overfitting. The proposed model concepts and results can be easily used in undergraduate engineering education, training graduates, and future research.","PeriodicalId":11606,"journal":{"name":"Energy Exploration & Exploitation","volume":"117 1","pages":"1884 - 1898"},"PeriodicalIF":2.7,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75242632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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