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Evaluation of the Shallow Gas Hydrate Production Based on the Radial Drilling-Heat Injection-Back Fill Method

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Journal of Ocean University of China 2024年第1期23卷 119-128页

作者： CHEN Qiang WAN Yizhao wu nengyou SUN Jianye WANG Jian LIU Changling LI Yanlong LI Chengfeng HU Gaowei Key Laboratory of Gas Hydrate Ministry of Natural ResourcesQingdao 266071China Laboratory for Marine Mineral Resources Laoshan LaboratoryQingdao 266071China CNPC Offshore Engineering Company Limited Beijing 100028China Technology Innovation Center for Marine Methane Monitoring Ministry of Natural ResourcesQingdao 266071China

It has been evidenced that shallow gas hydrate resources are abundant in deep oceans worldwide.Their geological back-ground,occurrence,and other characteristics differ significantly from deep-seated hydrates.Because of the high risk of well construction and low production efficiency,they are difficult to be recovered by using conventional oil production methods.As a result,this paper proposes an alternative design based on a combination of radial drilling,heat injection,and backfilling methods.Multi-branch holes are used to penetrate shallow gas hydrate reservoirs to expand the depressurization area,and heat injection is utilized as a supplement to improve gas production.Geotechnical information collected from an investigation site close to the offshore production well in the South China Sea is used to assess the essential components of this plan,including well construction stability and gas production behavior.It demonstrates that the hydraulic fracturing of the 60mbsf overburden layer can be prevented by regulating the drilling fluid densities.However,the traditional well structure is unstable,and the suction anchor is advised for better mechanical performance.The gas produc-tion rate can be significantly increased by combining hot water injection and depressurization methods.Additionally,the suitable produc-tion equipment already in use is discussed.

关键词： shallow gas hydrate trail production radial drilling-heat injection-back fill method experimental and numerical simulation

Gas hydrate formation in fine sand

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Science China Earth Sciences 2013年第3期56卷 549-556页

作者： ZANG XiaoYa LIANG DeQing wu nengyou Key Laboratory of Renewable Energy and Gas Hydrate Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Guangzhou Center for Gas Hydrate Research Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

Gas hydrate formation from two types of dissolved gas (methane and mixed gas) was studied under varying thermodynamic conditions in a novel apparatus containing two different natural media from the South China Sea. The testing media consisted of silica sand particles with diameters of 150-250 μm and 250-380 μm. Hydrate was formed (as in nature) in salt water that occupies the interstitial space of the partially water-saturated silica sand bed. The experiments demonstrate that the rate of hydrate formation is a function of particle diameter, gas source, water salinity, and thermodynamic conditions. The initiation time of hydrate formation was very short and pressure decreased rapidly in the initial stage. The process of mixed gas hydrate formation can be divided into three stages for each type of sediment. Sand particle diameter and water salinity also can influence the formation process of hydrate. The conversion rate of water to hydrate was different under varying thermodynamic conditions, although the formation processes were similar. The conversion rate of methane hydrate in the 250-380 μm sediment was greater than that in the 150-250μm sediment. However, the sediment grain size has no significant influence on the conversion rate of mixed gas hydrate.

关键词：水合物形成天然气水合物细砂混合气体水合物热力学条件甲烷水合物沉积物转化率

Molecular dynamics simulations of the mechanisms of thermal conduction in methane hydrates

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Science China Chemistry 2012年第1期55卷 167-174页

作者： WAN LiHua LIANG DeQing wu nengyou GUAN JinAn Guangzhou Institute of Energy Conversion Chinese Academy of SciencesKey Laboratory of Renewable Energy and Gas HydrateChinese Academy of SciencesGuangzhou 510640China

The thermal conductivity of methane hydrate is an important physical parameter affecting the processes of methane hydrate exploration,mining,gas hydrate storage and transportation as well as other applications.Equilibrium molecular dynamics simulations and the Green-Kubo method have been employed for systems from fully occupied to vacant occupied sI methane hydrate in order to estimate their thermal conductivity.The estimations were carried out at temperatures from 203.15 to 263.15 K and at pressures from 3 to 100 MPa.Potential models selected for water were TIP4P,TIP4P-Ew,TIP4P/2005,TIP4P-FQ and TIP4P/Ice.The effects of varying the ratio of the host and guest molecules and the external thermobaric conditions on the thermal conductivity of methane hydrate were studied.The results indicated that the thermal conductivity of methane hydrate is essentially determined by the cage framework which constitutes the hydrate lattice and the cage framework has only slightly higher thermal conductivity in the presence of the guest molecules.Inclusion of more guest molecules in the cage improves the thermal conductivity of methane hydrate.It is also revealed that the thermal conductivity of the sI hydrate shows a similar variation with temperature.Pressure also has an effect on the thermal conductivity,particularly at higher pressures.As the pressure increases,slightly higher thermal conductivities result.Changes in density have little impact on the thermal conductivity of methane hydrate.

关键词：分子动力学模拟甲烷水合物传导机制导热系数天然气水合物客体分子温度变化物理参数

Effect of thermal stimulation on gas production from hydrate deposits in Shenhu area of the South China Sea

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Science China Earth Sciences 2013年第4期56卷 601-610页

作者： SU Zheng HUANG Li wu nengyou YANG ShengXiong Key Laboratory of Renewable Energy and Gas Hydrate Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Guangzhou Center for Gas Hydrate Research Chinese Academy of Sciences Guangzhou Marine Geological Survey

The Shenhu area on the northern continental slope of the South China Sea (SCS) is one of the promising fields for gas hydrate exploitation. The hydrate-bearing layer at drilling site SH2 is overlain and underlain by permeable zones of mobile water. In this study a vertical well was configured with a perforated Interval I for producing gas and a coiled Interval II for heating sediment. The hydrate is dissociated by a small depressurization at Interval I and a thermal stimulation at Interval II. The numerical simulations indicate that the thermal stimulation has a significant effect on gas release from the hydrates in the production duration and improves the gas production in the late period. The gas released by thermal stimulation cannot be produced as quickly as the production gets operated because of the hard pathway for fluids to flow in the sediments. The gas production is enhanced due to the heating for 7242 m 3 in the whole production. Increasing heating temperature at Interval II can improve gas production and restrain water output, and advance the arrival time of the gas flow from the zone at Interval II. The absolute criterion and relative criterion suggest that the thermal stimulation in the production schemes is pronounced for releasing gas from the hydrate deposit, but the production efficiency of gas is limited by the sediment of low permeability. The study provides an insight into the production potential of the hydrate accumulations by thermal stimulation with depressurization in two wells, and a basis for analyzing economic feasibility of gas production from the area.

关键词：海域天然气水合物天然气生产中国南海热刺激矿床气体释放加热温度狐

Alcohol compounds in Azolla imbricata and potential source implication for marine sediments

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Science China Earth Sciences 2017年第2期60卷 348-359页

作者： MAO ShengYi ZHU XiaoWei wu nengyou JIA GuoDong SUN YongGe GUAN HongXiang wu DaiDai Key Laboratory of Gas Hydrate Guangzhou Institute of Energy ConversionChinese Academy of SciencesGuangzhou 510640China Key Laboratory of Marginal Sea Geology South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China The Key Laboratory of Gas Hydrate Ministry of Land andResourcesQingdao Institute of Marine GeologyQingdao 266071China School of Ocean and Earth Sciences Tongji UniversityShanghai 200092China Department of Geosciences Zhejiang UniversityHangzhou 310037China Guangzhou Center for Gas Hydrate Research Chinese Academy of SciencesGuangzhou 510640China

This study investigated the composition of long-chain alkyl diols,triols,sec-alcohols,hydroxyl acids,and other hydroxylated compounds in Azolla imbricata and compared the organic alcohol components of Azolla filiculoides,Azolla microphylla,and South China Sea(SCS)sediments in order to investigate the possible indication of Azolla being the biological source of diols and triols in SCS sediment.Large amounts of diols,monohydroxy acids,and sec-alcohols with internal hydroxy groups atω20 were detected in the three types of Azolla.Among these,1,ω20-diol andω20-hydroxy acid exhibited strong even-odd predominance distribution,whereasω20-sec-alcohol exhibited strong odd-even predominance distribution.In addition,small amounts of diols,triols,and dihydroxy acids with internal hydroxy groups at 9,10 orω9,ω10 were detected,among which the chain length of C_(29)was predominate.Compounds having similar structures as those in Azolla reflected a similar biosynthetic pathway:ω20-hydroxy acid exhibiting even-odd predominance distribution is decarboxylated toω20-sec-alcohol exhibiting odd-even predominance distribution and converted to 1,ω20-diol with even-odd predominance distribution by acyl reduction;ω9,ω10-hydroxy acid is converted to 1,20,21(1,ω9,ω10)-triol by acyl reduction,and then converted to 9,10-diol by hydrogenation and dehydration.The alcohol components in A imbricata were clearly not the biological source of 1,13/1,14/1,15-C_(28,30,32)diols and 1,3,4-C_(27-29)triols in the SCS sediment.Certain marine diatoms might be the source of 1,14-C_(28,30)diol in inshore sediment,but the biological source of diols and triols in the SCS sediment requires further investigation.

关键词：羟基化合物沉积物源海洋硅藻满江红二醇生物合成途径羟基酸近岸沉积物

Cobalt doping amount determines dominant reactive species in peroxymonosulfate activation via porous carbon catalysts co-doped by cobalt and nitrogen

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Journal of Environmental Sciences 2024年第4期138卷 212-226页

作者： Xiang Li Limeng wu Aiqin Zhang Shaohua wu Yan Lin Chunping Yang Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle Nanchang Hangkong UniversityNanchang 330063China Academy of Environmental and Resource Sciences School of Environmental Science and EngineeringGuangdong University of Petrochemical TechnologyMaoming 525000China College of Environmental Science and Engineering Hunan University and Key Laboratory of Environmental Biology and Pollution Control(Hunan University)Ministry of EducationChangsha 410082China

Switching the reaction routes in peroxymonosulfate(PMS)-based advanced oxidation processes have attracted much attention but remain challenging.Herein,a series of Co-N/C catalysts with different compositions and structures were prepared by using bimetallic zeolitic imidazolate frameworks based on ZIF-8 and ZIF-67(x Zn/Co-ZIFs).Results show that Co doping amount could mediate the transformation of the activation pathway of PMS over CoN/C.When Co doping amount was less than 10%,the constructed x Co-N/C/PMS system(x≤10%)was singlet oxygen-dominated reaction;however further increasing Co doping amount would lead to the generation and coexistence of sulfate radicals and high-valent cobalt,besides singlet oxygen.Furthermore,the nitrogen-coordinated Co(Co-NX)sites could serve as main catalytically active sites to generate singlet oxygen.While excess Co doping amount caused the formation of Co nanoparticles from which leached Co ions were responsible for the generation of sulfate radicals and high-valent cobalt.Compared to undoped N/C,Co doping could significantly enhance the catalytic performance.The 0.5%Co-N/C could achieve the optimum degradation(0.488 min^(-1))and mineralization abilities(78.4%)of sulfamethoxazole among the investigated Co-N/C catalysts,which was superior to most of previously reported catalysts.In addition,the application prospects of the two systems in different environmental scenarios(pH,inorganic anions and natural organic matter)were assessed and showed different degradation behaviors.This study provides a strategy to regulate the reactive species in PMS-based advanced oxidation process.

关键词： Peroxymonosulfate Sulfate radical Singlet oxygen Cobalt Zeolitic imidazolate framework Advanced oxidation process

The physiological role of the unfolded protein response in the nervous system

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Neural Regeneration Research 2024年第11期19卷 2411-2420页

作者： Shuangchan wu Wensheng Lin Department of Neuroscience University of MinnesotaMinneapolisMNUSA Institute for Translational Neuroscience University of MinnesotaMinneapolisMNUSA

The unfolded protein response(UPR)is a cellular stress response pathway activated when the endoplasmic reticulum,a crucial organelle for protein folding and modification,encounters an accumulation of unfolded or misfolded proteins.The UPR aims to restore endoplasmic reticulum homeostasis by enhancing protein folding capacity,reducing protein biosynthesis,and promoting protein degradation.It also plays a pivotal role in coordinating signaling cascades to determine cell fate and function in response to endoplasmic reticulum stress.Recent research has highlighted the significance of the UPR not only in maintaining endoplasmic reticulum homeostasis but also in influencing various physiological processes in the nervous system.Here,we provide an overview of recent findings that underscore the UPR’s involvement in preserving the function and viability of neuronal and myelinating cells under physiological conditions,and highlight the critical role of the UPR in brain development,memory storage,retinal cone development,myelination,and maintenance of myelin thickness.

关键词： myelin neuron oligodendrocyte Schwann cell unfolded protein response

Methane seepage intensities traced by sulfur isotopes of pyrite and gypsum in sediment from the Shenhu area,South China Sea

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Acta Oceanologica Sinica 2018年第7期37卷 20-27页

作者： ZHANG Mei LU Hongfeng GUAN Hongxiang LIU Lihua wu Daidai wu nengyou Key Laboratory of Gas Hydrate Guangzhou Institute of Energy ConversionChinese Academy of SciencesGuangzhou 510640China Guangzhou Marine Geological Survey Guangzhou 510760China Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266061China Key Laboratory of Gas Hydrate Qingdao Institute of Marine GeologyMinistry of Land and ResourcesQingdao 266071China

The northern slope of the South China Sea is a gas-hydrate-bearing region related to a high deposition rate of organic-rich sediments co-occurring with intense methanogenesis in subseafloor environments.Anaerobic oxidation of methane（AOM） coupled with bacterial sulfate reduction results in the precipitation of solid phase minerals in seepage sediment,including pyrite and gypsum.Abundant aggregates of pyrites and gypsums are observed between the depth of 667 and 850 cm below the seafloor（cmbsf） in the entire core sediment of HS328 from the northern South China Sea.Most pyrites are tubes consisting of framboidal cores and outer crusts.Gypsum aggregates occur as rosettes and spheroids consisting of plates.Some of them grow over pyrite,indicating that gypsum precipitation postdates pyrite formation.The sulfur isotopic values（δ^34 S） of pyrite vary greatly（from –46.6‰ to –12.3‰ V-CDT） and increase with depth.Thus,the pyrite in the shallow sediments resulted from organoclastic sulfate reduction（OSR） and is influenced by AOM with depth.The relative high abundance and δ^34 S values of pyrite in sediments at depths from 580 to 810 cmbsf indicate that this interval is the location of a paleo-sulfate methane transition zone（SMTZ）.The sulfur isotopic composition of gypsum（from–25‰ to –20.7‰） is much lower than that of the seawater sulfate,indicating the existence of a 34 S-depletion source of sulfur species that most likely are products of the oxidation of pyrites formed in OSR.Pyrite oxidation is controlled by ambient electron acceptors such as MnO2,iron（Ⅲ） and oxygen driven by the SMTZ location shift to great depths.The δ^34 S values of gypsum at greater depth are lower than those of the associated pyrite,revealing downward diffusion of 34 S-depleted sulfate from the mixture of oxidation of pyrite derived by OSR and the seawater sulfate.These sulfates also lead to an increase of calcium ions from the dissolution of calcium carbonate mineral,which will be favor to the formation of gypsum.Overall,the mineralogy and sulfur is

关键词： pyrite tube authigenic gypsum sulfur isotopes methane seepage northern South China Sea

Detection and indication of 1,3,4-C27-29 triol in the sediment of northern South China Sea

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Science China Earth Sciences 2016年第6期59卷 1187-1194页

作者： ZHU XiaoWei MAO ShengYi wu nengyou JIA GuoDong SUN YongGe GUAN HongXiang wu DaiDai Key Laboratory of Marginal Sea Geology South China Sea Institute of OceanologyCASGuangzhou 510301China Key Laboratory of Marginal Sea Geology Guangzhou Institute of GeochemistryCASGuangzhou 510640China Key Laboratory of Gas Hydrate Guangzhou Institute of Energy ConversionCASGuangzhou 510640China Department ofGeosciences Zhejiang UniversityHangzhou 310037China Guangzhou Center for Gas Hydrate Research CASGuangzhou 510640China

After the detection of the 1,20,21-C_(29) long-chain triol in some sediments and freshwater pteridophytes, in this study, a new homologous long-chain triol, 1,3,4-C_(27-29), is detected for the first time in the Site4 B core sediment in the northern South China Sea. The hydroxyl location and length of the carbon chain of this newly discovered triol differ from those of 1,20,21-C_(29) triol. The test results of its molecular distribution and individual carbon isotope reveal that 1,3,4-C_(29) triol has a good correlation with n-C_(26-30) even carbon-numbered long-chain fatty alcohols, with R^2(n=68) values of 0.905, 0.929 and 0.903, respectively, and its carbon isotope composition, at –32.3‰±1.9‰, is similar to that of n-C_(26-30), at –29.13‰±0.87‰, –32.98‰±1.28‰, and –32.98‰±1.28‰. 1,3,4-C_(29) triol from the Site4 B core sediment and terrigenous long-chain fatty alcohol(n-C_(26-34)) show highly consistent distribution trends in the entire section; thus, the former could serve as a proxy indicator of the terrigenous input. Considering that the 1,20,21-C_(29) triol in previous research belongs to Azolla, which are fresh water pteridophytes, the 1,3,4-C_(27-29) triol identified in this study might have similar biogenetic derivation. Thus, determination of its biogenic area and growing environment could provide potential organic geochemical evidence supporting the terrigenous input and source in the northern South China Sea.

关键词：南海北部长链醇沉积物检测长链脂肪醇单体碳同位素碳同位素组成地球化学证据