As an important source of low-carbon,clean fossil energy,natural gas hydrate plays an important role in improving the global energy consumption structure.Developing the hydrate industry in the South China Sea is impor...As an important source of low-carbon,clean fossil energy,natural gas hydrate plays an important role in improving the global energy consumption structure.Developing the hydrate industry in the South China Sea is important to achieving‘carbon peak and carbon neutrality’goals as soon as possible.Deep-water areas subjected to the action of long-term stress and tectonic movement have developed complex and volatile terrains,and as such,the morphologies of hydrate-bearing sediments(HBSs)fluctuate correspondingly.The key to numerically simulating HBS morphologies is the establishment of the conceptual model,which represents the objective and real description of the actual geological body.However,current numerical simulation models have characterized HBSs into horizontal strata without considering the fluctuation characteristics.Simply representing the HBS as a horizontal element reduces simulation accuracy.Therefore,the commonly used horizontal HBS model and a model considering the HBS’s fluctuation characteristics with the data of the SH2 site in the Shenhu Sea area were first constructed in this paper.Then,their production behaviors were compared,and the huge impact of the fluctuation characteristics on HBS production was determined.On this basis,the key parameters affecting the depressurization production of the fluctuating HBSs were studied and optimized.The research results show that the fluctuation characteristics have an obvious influence on the hydrate production of HBSs by affecting their temperatures and pressure distributions,as well as the transmission of the pressure drop and methane gas discharge.Furthermore,the results show that the gas productivity of fluctuating HBSs was about 5%less than that of horizontal HBSs.By optimizing the depressurization amplitude,well length,and layout location of vertical wells,the productivity of fluctuating HBSs increased by about 56.6%.展开更多
The analytical mathematical solutions of gas concentration and fractional gas loss for the diffusion of gas in a cylindrical coal sample were given with detailed mathematical derivations by assuming that the diffusion...The analytical mathematical solutions of gas concentration and fractional gas loss for the diffusion of gas in a cylindrical coal sample were given with detailed mathematical derivations by assuming that the diffusion of gas through the coal matrix is concentration gradient-driven and obeys the Fick’s Second Law of Diffusion.The analytical solutions were approximated in case of small values of time and the error analyses associated with the approximation were also undertaken.The results indicate that the square root relationship of gas release in the early stage of desorption,which is widely used to provide a simple and fast estimation of the lost gas,is the first term of the approximation,and care must be taken in using the square root relationship as a significant error might be introduced with increase in the lost time and decrease in effective diameter of a cylindrical coal sample.展开更多
Natural gas hydrate(NGH)is an important future resource for the 21st century and a strategic resource with potential for commercial development in the third energy transition.It is of great significance to accurately ...Natural gas hydrate(NGH)is an important future resource for the 21st century and a strategic resource with potential for commercial development in the third energy transition.It is of great significance to accurately predict the productivity of hydrate-bearing sediments(HBS).The multi-phase seepage parameters of HBS include permeability,porosity,which is closely related to permeability,and hydrate saturation,which has a direct impact on hydrate content.Existing research has shown that these multi-phase seepage parameters have a great impact on HBS productivity.Permeability directly affects the transmission of pressure-drop and discharge of methane gas,porosity and initial hydrate saturation affect the amount of hydrate decomposition and transmission process of pressure-drop,and also indirectly affect temperature variation of the reservoir.Considering the spatial heterogeneity of multi-phase seepage parameters,a depressurization production model with layered heterogeneity is established based on the clayey silt hydrate reservoir at W11 station in the Shenhu Sea area of the South China Sea.Tough+Hydrate software was used to calculate the production model;the process of gas production and seepage parameter evolution under different multi-phase seepage conditions were obtained.A sensitivity analysis of the parameters affecting the reservoir productivity was conducted so that:(a)a HBS model with layered heterogeneity can better describe the transmission process of pressure and thermal compensation mechanism of hydrate reservoir;(b)considering the multi-phase seepage parameter heterogeneity,the influence degrees of the parameters on HBS productivity were permeability,porosity and initial hydrate saturation,in order from large to small,and the influence of permeability was significantly greater than that of other parameters;(c)the production potential of the clayey silt reservoir should not only be determined by hydrate content or seepage capacity,but also by the comprehensive effect of the two;and(d)time scales need to be considered when studying the effects of changes in multi-phase seepage parameters on HBS productivity.展开更多
强直性脊柱炎(ankylosing spondylitis,AS)是一种主要累及中轴骨的与多种因素和多种基因相关的非特异性炎症疾病,该病通常先发于骶髂关节,逐渐沿脊柱中轴向上至椎旁韧带、关节突及外周关节,发展到后期,椎间盘及韧带出现骨化,多节段融合...强直性脊柱炎(ankylosing spondylitis,AS)是一种主要累及中轴骨的与多种因素和多种基因相关的非特异性炎症疾病,该病通常先发于骶髂关节,逐渐沿脊柱中轴向上至椎旁韧带、关节突及外周关节,发展到后期,椎间盘及韧带出现骨化,多节段融合,并逐渐演变成一个类似长骨的杆状结构,导致严重的脊柱畸形及关节强直。随着AS病程的进展,患者脊柱的弹性、顺应性逐渐降低,力学平衡逐渐丧失,同时长期的慢性炎症导致骨质疏松、骨脆性增加,使得AS患者脊柱发生骨折的风险显著高于正常人。2013年,由Robinson等进行的包含17764例患者的队列研究发现,AS患者发生脊柱骨折的概率约为正常人的3.3倍。同时,处于相对固定的胸椎与活动的颈椎之间连接部的下颈椎,因其解剖特点及生物力学特性,是脊柱骨折最高发的部位,约占73%。笔者针对强直性脊柱炎患者下颈椎骨折(ankylosing spondylitis with the lower cervical fracture,ASLCF)的治疗进展进行文献回顾,以期为临床医师选择合适的治疗方法提供思路。展开更多
目的分析颅底凹陷合并难复性寰枢椎脱位术后齿状突下移程度与术后神经功能恢复的关系。方法回顾性分析2010—2018年在我院诊断为颅底凹陷合并难复性寰枢椎脱位并行后路减压治疗的患者19例,其中男10例,女9例;平均(41.89±14.27)岁;...目的分析颅底凹陷合并难复性寰枢椎脱位术后齿状突下移程度与术后神经功能恢复的关系。方法回顾性分析2010—2018年在我院诊断为颅底凹陷合并难复性寰枢椎脱位并行后路减压治疗的患者19例,其中男10例,女9例;平均(41.89±14.27)岁;病程持续(42.61±70.71)个月。10例合并寰枕融合,7例合并Klippel-Feil综合征,4例合并椎动脉发育畸形,无病例合并小脑扁桃体疝及脊髓空洞等。测量术前及末次随访寰齿前间隙(anterior atlantodental interval,AADI)、斜坡齿突角(clivo-axial angle,CXA)及齿状突上移程度(the distance of the tip of odontoid to the McRae line,McRL),采用日本骨科协会评分(Japanese orthopaedic association scores,JOA)评估神经功能。对JOA评分改善率与齿状突下移率(odontoid descent rate,ODR)、寰齿前间隙变化(△AADI)和斜坡齿突角变化(△CXA)进行相关性分析。结果本组患者获得随访时间10~79个月,平均随访时间(20.42±8.24)个月。术前JOA为(11.21±2.62)分,末次随访JOA为(14.53±2.19)分,平均JOA改善率为(58.75±24.43)%。JOA评分改善率与ODR存在相关关系(R=0.88,P<0.05),与△AADI(R=0.07,P=0.77)及△CXA(R=-0.04,P=0.98)无明显相关性。结论难复性寰枢椎脱位合并颅底凹陷的手术疗效与齿状突复位率相关。展开更多
基金supported by the National Natural Science Foundation of China(Nos.42276224 and 42206230)the Jilin Scientific and Technological Development Program(No.20190303083SF)+1 种基金the International Cooperation Key Laboratory of Underground Energy Development and Geological Restoration(No.YDZJ202102CXJD014)the Graduate Innovation Fund of Jilin University(No.2023CX100).
文摘As an important source of low-carbon,clean fossil energy,natural gas hydrate plays an important role in improving the global energy consumption structure.Developing the hydrate industry in the South China Sea is important to achieving‘carbon peak and carbon neutrality’goals as soon as possible.Deep-water areas subjected to the action of long-term stress and tectonic movement have developed complex and volatile terrains,and as such,the morphologies of hydrate-bearing sediments(HBSs)fluctuate correspondingly.The key to numerically simulating HBS morphologies is the establishment of the conceptual model,which represents the objective and real description of the actual geological body.However,current numerical simulation models have characterized HBSs into horizontal strata without considering the fluctuation characteristics.Simply representing the HBS as a horizontal element reduces simulation accuracy.Therefore,the commonly used horizontal HBS model and a model considering the HBS’s fluctuation characteristics with the data of the SH2 site in the Shenhu Sea area were first constructed in this paper.Then,their production behaviors were compared,and the huge impact of the fluctuation characteristics on HBS production was determined.On this basis,the key parameters affecting the depressurization production of the fluctuating HBSs were studied and optimized.The research results show that the fluctuation characteristics have an obvious influence on the hydrate production of HBSs by affecting their temperatures and pressure distributions,as well as the transmission of the pressure drop and methane gas discharge.Furthermore,the results show that the gas productivity of fluctuating HBSs was about 5%less than that of horizontal HBSs.By optimizing the depressurization amplitude,well length,and layout location of vertical wells,the productivity of fluctuating HBSs increased by about 56.6%.
基金provided by the Science and Technology Grant of Huainan City of China (No.2013A4001)the Key Research Grant of Shanxi Province of China (No.201303027-1)
文摘The analytical mathematical solutions of gas concentration and fractional gas loss for the diffusion of gas in a cylindrical coal sample were given with detailed mathematical derivations by assuming that the diffusion of gas through the coal matrix is concentration gradient-driven and obeys the Fick’s Second Law of Diffusion.The analytical solutions were approximated in case of small values of time and the error analyses associated with the approximation were also undertaken.The results indicate that the square root relationship of gas release in the early stage of desorption,which is widely used to provide a simple and fast estimation of the lost gas,is the first term of the approximation,and care must be taken in using the square root relationship as a significant error might be introduced with increase in the lost time and decrease in effective diameter of a cylindrical coal sample.
基金supported by the National Natural Science Foundation of China(Grant Nos.42276224,and 42206230)the Jilin Scientific and Technological Development Program(Grant No.20190303083SF)+2 种基金the International Cooperation Key Laboratory of Underground Energy Development and Geological Restoration(Grant No.YDZJ202102CXJD014)the Interdisciplinary Integration and Innovation Project of JLU(Grant No.JLUXKJC2021ZZ18)the Graduate Innovation Fund of Jilin University(Grant No.2023CX100)。
文摘Natural gas hydrate(NGH)is an important future resource for the 21st century and a strategic resource with potential for commercial development in the third energy transition.It is of great significance to accurately predict the productivity of hydrate-bearing sediments(HBS).The multi-phase seepage parameters of HBS include permeability,porosity,which is closely related to permeability,and hydrate saturation,which has a direct impact on hydrate content.Existing research has shown that these multi-phase seepage parameters have a great impact on HBS productivity.Permeability directly affects the transmission of pressure-drop and discharge of methane gas,porosity and initial hydrate saturation affect the amount of hydrate decomposition and transmission process of pressure-drop,and also indirectly affect temperature variation of the reservoir.Considering the spatial heterogeneity of multi-phase seepage parameters,a depressurization production model with layered heterogeneity is established based on the clayey silt hydrate reservoir at W11 station in the Shenhu Sea area of the South China Sea.Tough+Hydrate software was used to calculate the production model;the process of gas production and seepage parameter evolution under different multi-phase seepage conditions were obtained.A sensitivity analysis of the parameters affecting the reservoir productivity was conducted so that:(a)a HBS model with layered heterogeneity can better describe the transmission process of pressure and thermal compensation mechanism of hydrate reservoir;(b)considering the multi-phase seepage parameter heterogeneity,the influence degrees of the parameters on HBS productivity were permeability,porosity and initial hydrate saturation,in order from large to small,and the influence of permeability was significantly greater than that of other parameters;(c)the production potential of the clayey silt reservoir should not only be determined by hydrate content or seepage capacity,but also by the comprehensive effect of the two;and(d)time scales need to be considered when studying the effects of changes in multi-phase seepage parameters on HBS productivity.
文摘强直性脊柱炎(ankylosing spondylitis,AS)是一种主要累及中轴骨的与多种因素和多种基因相关的非特异性炎症疾病,该病通常先发于骶髂关节,逐渐沿脊柱中轴向上至椎旁韧带、关节突及外周关节,发展到后期,椎间盘及韧带出现骨化,多节段融合,并逐渐演变成一个类似长骨的杆状结构,导致严重的脊柱畸形及关节强直。随着AS病程的进展,患者脊柱的弹性、顺应性逐渐降低,力学平衡逐渐丧失,同时长期的慢性炎症导致骨质疏松、骨脆性增加,使得AS患者脊柱发生骨折的风险显著高于正常人。2013年,由Robinson等进行的包含17764例患者的队列研究发现,AS患者发生脊柱骨折的概率约为正常人的3.3倍。同时,处于相对固定的胸椎与活动的颈椎之间连接部的下颈椎,因其解剖特点及生物力学特性,是脊柱骨折最高发的部位,约占73%。笔者针对强直性脊柱炎患者下颈椎骨折(ankylosing spondylitis with the lower cervical fracture,ASLCF)的治疗进展进行文献回顾,以期为临床医师选择合适的治疗方法提供思路。
文摘目的分析颅底凹陷合并难复性寰枢椎脱位术后齿状突下移程度与术后神经功能恢复的关系。方法回顾性分析2010—2018年在我院诊断为颅底凹陷合并难复性寰枢椎脱位并行后路减压治疗的患者19例,其中男10例,女9例;平均(41.89±14.27)岁;病程持续(42.61±70.71)个月。10例合并寰枕融合,7例合并Klippel-Feil综合征,4例合并椎动脉发育畸形,无病例合并小脑扁桃体疝及脊髓空洞等。测量术前及末次随访寰齿前间隙(anterior atlantodental interval,AADI)、斜坡齿突角(clivo-axial angle,CXA)及齿状突上移程度(the distance of the tip of odontoid to the McRae line,McRL),采用日本骨科协会评分(Japanese orthopaedic association scores,JOA)评估神经功能。对JOA评分改善率与齿状突下移率(odontoid descent rate,ODR)、寰齿前间隙变化(△AADI)和斜坡齿突角变化(△CXA)进行相关性分析。结果本组患者获得随访时间10~79个月,平均随访时间(20.42±8.24)个月。术前JOA为(11.21±2.62)分,末次随访JOA为(14.53±2.19)分,平均JOA改善率为(58.75±24.43)%。JOA评分改善率与ODR存在相关关系(R=0.88,P<0.05),与△AADI(R=0.07,P=0.77)及△CXA(R=-0.04,P=0.98)无明显相关性。结论难复性寰枢椎脱位合并颅底凹陷的手术疗效与齿状突复位率相关。
