2018 Vol.1(2)

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Original Articles
Deep Continental Scientific Drilling Engineering Project in Songliao Basin: progress in Earth Science research
He-sheng Hou, Cheng-shan Wang, Jiao-dong Zhang, Feng Ma, Wei Fu, Pu-jun Wang, Yong-jian Huang, Chang-chun Zou, You-feng Gao, Yuan Gao, Lai-ming Zhang, Jin Yang, Rui Guo
2018, 1(2): 173-186. doi: 10.31035/cg2018036
[Abstract](3201) [FullText HTML] (1017) [PDF 4507KB](365)
The Songke No.2 well (eastern hole) (referred to as Well SK-2), one of the " two wells and four holes” of the Deep Continental Scientific Drilling Engineering Project in the Songliao Basin, is in Anda City, Heilongjiang Province, and was officially completed on May 26, 2018. The scientific goals of Well SK-2 cover four aspects: paleoclimate research, resource and energy exploration, primary geological research, and development of deep earth exploration techniques. Since the official commencement of drilling in 2014, the Well SK-2 scientific drilling engineering team has organized and implemented drilling for coring, in situ logging, chemical analysis of core elements, and deep structural exploration around the well. Currently, the following preliminary scientific research progress has been made: 4334.81 m in situ core data has been obtained; the centimeter-level high-resolution characterization of the most complete and continuous Cretaceous continental strata ever unearthed has been completed, and the standard profile of continental strata has been initially established; the unconventional natural gas resources and basin-type hot dry rocks in the deep Songliao Basin were found to have good prospects for exploration and development; the climatic evolutionary history of the Cretaceous continental strata was rebuilt for the first time, covering hundreds of thousands to millions of years, and the major events of Cretaceous climate fluctuations have been discovered; all these reveal strong evidence for the subduction and aggregation of paleo-ocean plates, providing a theoretical basis for the re-recognition of the genesis of the Songliao Basin and for deep earth oil and gas exploration. The implementation of the Deep Continental Scientific Drilling Engineering Project in the Songliao Basin is of great significance for exploring the mysteries of the Earth and solving major problems such as those related to the deep energy environment. It is a solid step along the road of "going deep into the Earth".
Main technical innovations of Songke Well No.2 Drilling Project
Yong-yi Zhu, Wen-shi Wang, Xiao-ming Wu, Heng-chun Zhang, Jie Xu, Jia Yan, Long-long Cao, Heng-qian Ran, Jin-chang Zhang
2018, 1(2): 187-201. doi: 10.31035/cg2018031
[Abstract](4784) [FullText HTML] (1567) [PDF 41171KB](68)
Songke Well No.2, one of the main part of the scientific drilling project in Songliao Basin, which was drilled 7018 m and acquired the part of cores continuously from the Low Cretaceous to the Carboniferous and the Permian from the 2843 m deep, can be considered as the deepest continental drilling project in Asia. Aiming at the features of longer well sections, larger diameters and multiple spud-ins for coring of Songke Well No.2, this project broke through the " coring in small diameter and reaming in large diameter” spud-in drilling-completion procedures which are always used in large-diameter-well coring for continental scientific drilling projects in domestic and overseas and the drilling method of short-single-cylinder roundtrip footage. At the same time, " coring in the same diameter and completing drilling at one single diameter” was achieved at all φ311 mm and φ216 mm coring sections of more than one thousand meters long, high-efficient operation with " drilling long footage with drill tools combined in multi-cylinders” was achieved at deep coring section. Four world drilling records were created which include more than a thousand meters continuous coring at φ311 mm, and the footage per roundtrip footage at φ311 mm, φ216 mm and φ152 mm is all more than 30 m, all of these breakthroughs reduced at least 300 days for this project; moreover, considering the characteristics of formations that the geothermal gradient is high in the drilled sections and the inside-well temperature is over 240°C after drilling completion, a formate-polymer water-based mud system was developed by compounding attapulgite and sodium bentonite and by adding independently developed high-temperature stabilizer, which can provide critical technical support for successful well completion at 7018 m in the super-high-temperature environment It is the first time that the water-based mud is operated at the working temperature higher than 240°C in China; Besides, considering the high-quality requirement on cores imposed by the project, the method " mechanical cored is charge” to discharge core nondestructively on the ground was worked out, and more than 4000 m scatheless cores were discharged out of the drill pipes while maintaining original stratum structures.
Preliminary results of environmental monitoring of the natural gas hydrate production test in the South China Sea
Jian-liang Ye, Xu-wen Qin, Hai-jun Qiu, Qian-yong Liang, Yi-fei Dong, Jian-gong Wei, Hai-long Lu, Jing-an Lu, Yao-hong Shi, Chao Zhong, Zhen Xia
2018, 1(2): 202-209. doi: 10.31035/cg2018029
[Abstract](2360) [FullText HTML] (321) [PDF 10799KB](161)
Natural gas hydrate (NGH) is considered as one of the new clean energy sources of the 21st century with the highest potential. The environmental issues of NGH production have attracted the close attention of scientists in various countries. From May 10 to July 9, 2017, the first offshore NGH production test in the South China Sea (SCS) was conducted by the China Geological Survey. In addition, environmental security has also been effectively guaranteed via a comprehensive environmental monitoring system built during the NGH production test. The monitoring system considered sea-surface atmosphere methane and carbon dioxide concentrations, dissolved methane in the sea water column, and the seafloor physical oceanography and marine chemistry environment. The whole process was monitored via multiple means, in multiple layers, in all domains, and in real time. After the production test, an environmental investigation was promptly conducted to evaluate the environmental impact of the NGH production test. The monitoring results showed that the dissolved methane concentration in seawater and the near-seabed environment characteristics after the test were consistent with the background values, indicating that the NGH production test did not cause environmental problems such as methane leakage.
Episodic crustal growth in the Tanzania Craton: evidence from Nd isotope compositions
Kai Sun, Lin-lin Zhang, Zhi-dan Zhao, Fu-qing He, Sheng-fei He, Xing-yuan Wu, Lei Qiu, Xiao-dong Ren
2018, 1(2): 210-224. doi: 10.31035/cg2018025
[Abstract](5211) [FullText HTML] (1082) [PDF 4974KB](57)
The analysis of available Nd isotope data from the Tanzania Craton places important constraints on the crust-mantle separation ages, and events marking juvenile crustal addition and crustal recycling. Nd model ages date the oldest crust extraction to 3.16 Ga in the Tanzania Craton, although a rock record of such antiquity is yet to be found there. The most significant period of juvenile crustal addition as well as crustal recycling is 2.7–2.6 Ga. The Nd isotopes of mafic samples show that chemical heterogeneity existed in the mantle beneath the Tanzania Craton, with some samples originating from significantly depleted mantle, and most samples originating from the mixture of primitive mantle and depleted mantle. The Nd isotope section reveals significant differences in Nd isotopes between the north craton and central craton; compared to the north craton, the central craton yields a Nd model age that is approximately 100 Ma older, and itsεNd(t) values are more negative, indicating that the two parts of the craton have different mantle source regions. Different types of granitoids are distributed in the Tanzania Craton, such as high-K and low-Al granite, calc-alkaline granite, peraluminous granite and transitional types of tonalite-trondhjemite-granodiorites (TTGs). Most of the granitoids formed later than the mafic rocks in syn-collision and post-collision events.
Origin of natural sulfur-metal chimney in the Tangyin hydrothermal field, Okinawa Trough: constraints from rare earth element and sulfur isotopic compositions
Hong Cao, Zhi-lei Sun, Chang-ling Liu, En-tao Liu, Xue-jun Jiang, Wei Huang
2018, 1(2): 225-235. doi: 10.31035/cg2018023
[Abstract](3608) [FullText HTML] (739) [PDF 30067KB](59)
For the first time, we present the rare earth element (REE) and sulfur isotopic composition of hydrothermal precipitates recovered from the Tangyin hydrothermal field (THF), Okinawa Trough at a water depth of 1206 m. The natural sulfur samples exhibit the lowest ΣREE concentrations (ΣREE=0.65×10–6–4.580×10–6) followed by metal sulfides (ΣREE=1.71×10–6–11.63×10–6). By contrast, the natural sulfur-sediment samples have maximum ΣREE concentrations (ΣREE=11.54×10–6–33.06×10–6), significantly lower than those of the volcanic and sediment samples. Nevertheless, the δEu, δCe, (La/Yb)N, La/Sm, (Gd/Yb)N and normalized patterns of the natural sulfur and metal sulfide show the most similarity to the sediment. Most hydrothermal precipitate samples are characterized by enrichments of LREE (LREE/HREE=10.09–24.53) and slightly negative Eu anomalies or no anomaly (δEu=0.48–0.99), which are different from the hydrothermal fluid from sediment-free mid-oceanic ridges and back-arc basins, but identical to the sulfides from the Jade hydrothermal field. The lower temperature and more oxidizing conditions produced by the mixing between seawater and hydrothermal fluids further attenuate the leaching ability of hydrothermal fluid, inducing lower REE concentrations for natural sulfur compared with metal sulfide; meanwhile, the negative Eu anomaly is also weakened or almost absent. The sulfur isotopic compositions of the natural sulfur (δ34S=3.20‰–5.01‰, mean 4.23‰) and metal sulfide samples (δ34S=0.82‰–0.89‰, mean 0.85‰) reveal that the sulfur of the chimney is sourced from magmatic degassing.
Review Articles
Division of tectonic–strata superregions in China
Yang-chun Li, Ke-xin Zhang, Wei-hong He, Ya-dong Xu, Bo-wen Song, Yang Yu, Xue Ke, Xiao-hu Kou, Man-sheng Luo, Hou-tian Xin, Jun-yu Fu, Zhu-liang Yang, Xiao-ming Zhao, Fu-guang Yin, Zhi-pei Li
2018, 1(2): 236-256. doi: 10.31035/cg2018028
[Abstract](2048) [FullText HTML] (360) [PDF 2997KB](126)
The continent of China is grouped into Pan–Cathaysian blocks, Laurasia and Gondwana Continental margins and relics of three oceans-Paleoasian, Tethys, and Pacific as a whole. In detail, the continent of China grew up by coalescence of three blocks or platforms (North China, Tarim and Yangtze) and eight orogenic belts (Altay–Inner Mongolia–Daxinganling, Tianshan–Junggar–Beishan, Qinling–Qilian–Kunlun, Qiangtang–Sanjiang, Gangdisê, Himalaya, Cathaysia, Eastern Taiwan) during the processes of oceanic crust disappearance and acceretionary-collision of continental crusts. In the orogenic belts, six convergent crustal consumption zones (Ertix–Xar Moron, South Tianshan, Kuanping–Foziling, Bangong co–Shuanghu–Nujiang–Changning–Menglian, Yarlung–Tsangpo, Jiangshao–Chenzhou–Qinfang) have been distinguished. Correspondingly, the strata of the continent of China are subdivided into 17 tectonic-strata superregions, which tectonically belong to three blocks or platforms, six convergent crustal consumption zones and eight orogenic series, respectively. This division is based mainly on differences of tectonic environment and tectonic evolution among blocks, zones and belts, including the timing of when the oceanic crusts transferred into continental crusts, the paleobiogeographic features, and the types of strata.
Exploration and research progress of shale gas in China
Gang-yi Zhai, Yu-fang Wang, Zhi Zhou, Shu-fang Yu, Xiang-lin Chen, Yun-xiao Zhang
2018, 1(2): 257-272. doi: 10.31035/cg2018024
[Abstract](3370) [FullText HTML] (381) [PDF 16007KB](135)
There are three types of shale gas resources in China. The resources are present in large amounts and are widely distributed. Marine facies, transitional facies and continental facies resources each account for a third. Based on resource distributions, there are many wells penetrated into the Sinian, Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian strata of the Yangtze plate and its periphery, the North China Craton and the Tarim Basin. Many years of exploration have indicated that the marine Silurian Longmaxi shale gas is widely distributed in south China and has been industrialized in its production in the Sichuan basin. The shale gas from the Cambrian Niutitang Formation and the Sinian Doushantuo Formation are important discoveries in Yichang, Hubei and Zhenba, Shanxi. There are also shale gas resources found within transitional facies and continental facies in different areas in China. The "two element enrichment theory" has been summarized during the exploration process of Silurian marine shale gas in the Sichuan Basin. In addition, horizontal drilling and fracturing technologies up to 3500 m in depth have been developed. Based on the understanding of shale gas accumulation in a complex tectonic zone outside the Sichuan basin, a preliminary summary of the formation of the "converse fault syncline control reservoir" and "paleo uplift control reservoir" model has been constructed. The dominant theory of "Trinity" shale gas enrichment and the high yield of the "deep water Lu Pengxiang sedimentary facies belt, structural preservation conditions and overpressure" is summarized. Guided by the above theories. Anye1 well in Guizhou and Eyangye1 well in Hubei were drilled. "Four storey" oil and shale gas is found in the Permian Qixia group, the Silurian Shiniulan Formation, the Longmaxi Formation and the Ordovician Baota Formation in Anye1 well. Good shale gas has been gound in the Cambrian Niutitang formation inian Doushantuo formation in Eyangye 1well. This paper aims to summarize and review the main progress, theoretical technology and problems of shale gas exploration and development in recent years in China, and predicts the future exploration and development direction for shale gas and possible exploration areas.
Overview on hydrothermal and hot dry rock researches in China
Gui-ling Wang, Wei Zhang, Feng Ma, Wen-jing Lin, Ji-yun Liang, Xi Zhu
2018, 1(2): 273-285. doi: 10.31035/cg2018021
[Abstract](2263) [FullText HTML] (336) [PDF 5386KB](116)
Geothermal energy is a precious resource, which is widely distributed, varied, and abundant. China has entered a period of rapid development of geothermal energy since 2010. As shallow geothermal energy promoting, the depth of hydrothermal geothermal exploration is increasing. The quality of Hot Dry Rock (HDR) and related exploratory technologies are better developed and utilized. On the basis of geothermal development, this paper reviews the geothermal progress during the "12th Five-Year Plan", and summarizes the achievements of hydrothermal geothermal and hot dry rocks from geothermal survey and evaluation aspects. Finally, the authors predict the development trend of the future geothermal research to benefit geothermal and hot dry rock research.
Nanogeology in China: A review
Yi-wen Ju, Cheng Huang, Yan Sun, Cai-neng Zou, Hong-ping He, Quan Wan, Xue-qiu Wang, Xian-cai Lu, Shuang-fang Lu, Jian-guang Wu, Hong-tai Chao, Hai-ling Liu, Jie-shan Qiu, Fei Huang, Hong-jian Zhu, Jian-chao Cai, Yue Sun
2018, 1(2): 286-303. doi: 10.31035/cg2018020
[Abstract](2944) [FullText HTML] (360) [PDF 3989KB](99)
Nanogeology is a subject that is a combination of geology and nanoscale science, and it has been a frontier field in recent years. It is also a new subject with the features of intersectionality and multidisciplinary. Digging deeper into geological problems and nanoscale phenomena helps better revealing the more essential mechanisms and processes in geological science, which is also an evitable path in the development of geology. In this paper, we elaborate the concept, feature and main subdisciplines, and summarize three stages of nanogeology development from preliminary research in the 1990s to subject formation in China. After summarizing the researchers’ achievements in this field, we illustrate some primary research progresses of nanogeology in China as eight subdisciplines. On the basis of the above content, we propose the development prospect of nanogeology in China. There are many geologic problems with scientific values and economic benefits, such as research of geologic fundamental problems, resource exploration and development, mechanism study and prediction of geological activities (disasters), mechanism research and management of environmental pollution and others. Nanogeology has a great potential in China to solve all of these problems. As a result, the theories and methods of nanogeology will become enriching and advanced. It offers important theoretical basis and technological methods to deal with major issues concerning the national economy and the people's livelihoods, such as the prediction of geological activities, as well as resource distribution and its exploration and utilization.
Short Communications
New delineation of two favorable zones for gas hydrate in southern Qinghai and northern Tibet, China
Shuai Zhang, Ping-kang Wang, You-hai Zhu, Rui Xiao, Shou-ji Pang
2018, 1(2): 304-305. doi: 10.31035/cg2018032
[Abstract](3215) [FullText HTML] (747) [PDF 1885KB](57)
New discovery of the permafrost gas hydrate accumulation in Qilian Mountain, China
Zhen-quan Lu, Gang-yi Zhai, You-hai Zhu, Hui Liu, Ting Wang, Hui Fang, Zhong-jun Sun, Shi-qi Tang, Yong-qin Zhang
2018, 1(2): 306-307. doi: 10.31035/cg2018034
[Abstract](3424) [FullText HTML] (1027) [PDF 7471KB](65)
New indications of gas hydrate in the northeastern China permafrost zone
Xing-min Zhao, Fang-yun Song, Jian Deng, Zhu Rao, Zhi-gang Wen, Dao-gong Hu, Li Yi, Chen Liu
2018, 1(2): 308-309. doi: 10.31035/cg2018033
[Abstract](3076) [FullText HTML] (680) [PDF 4415KB](67)
Discovery of the pegmatite lithium veins with predicted super-large size resources in the Sizemuzu district of the Keeryin, China
Xiang-yuan Yue, Xiong Zhou, Yi Zhang, Da-xing Gong, Yu Zhou, Li-ping Luo
2018, 1(2): 310-311. doi: 10.31035/cg2018030
[Abstract](3117) [FullText HTML] (514) [PDF 1844KB](54)
Discovery of the largest Carboniferous manganese deposit in Longtou-Limiao, central Guangxi, China
Xu Chen, Sha Jiang
2018, 1(2): 312-313. doi: 10.31035/cg2018027
[Abstract](3599) [FullText HTML] (827) [PDF 7228KB](67)
News and Highlights
Progress in China’s geological exploration in the first half year of 2018
2018, 1(2): 314-316. doi: 10.31035/cg2018035
[Abstract](1558) [FullText HTML] (1145) [PDF 1766KB](67)
Introduction of the International Research Centre on Global-Scale Geochemistry under the auspice of UNESCO
2018, 1(2): 317-318. doi: 10.31035/cg2018026
[Abstract](1250) [FullText HTML] (832) [PDF 25258KB](23)