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基于CDEM的天然气水合物沉积物水力压裂裂纹扩展数值模拟

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Acta Mechanica Sinica 2024年第2期40卷 28-38页

作者：黄宇东王天驹王蕊王昊天鲁晓兵张旭辉 Institutes of Mechanics Chinese Academy of SciencesBeijing100190China School of Engineering Science University of Chinese Academy of SciencesBeijing100049China CPOE Research Institute of Engineering Technology Tianjin300450China CNPC Offshore Engineering Company Limited Beijing100176China

目前,天然气水合物开采存在储层渗透率低和热传导导致生产效率低等问题.作为一种常规油气勘探中有效提高储层渗透率的技术,水力压裂有望用于改善天然气水合物储层的渗透率,提高采收效率.然而,有关含天然气水合物沉积物(GHBS)水力压裂应... 详细信息

目前,天然气水合物开采存在储层渗透率低和热传导导致生产效率低等问题.作为一种常规油气勘探中有效提高储层渗透率的技术,水力压裂有望用于改善天然气水合物储层的渗透率,提高采收效率.然而,有关含天然气水合物沉积物(GHBS)水力压裂应用的研究却很少.本文采用有限元和离散元耦合的连续离散元法(CDEM),对不同地层性质的天然气水合物沉积物(GHBS)的水力压裂过程进行了二维的数值模拟,研究了储层性质和压裂参数对GHBS中裂缝生成的影响.主要结论是,在本研究考虑的压裂参数和沉积物性质中,内摩擦角越小、注入流量越大对产生裂缝越有利;当饱和度和黏聚力处于适当范围时,最有利于产生裂缝;当各方向的地应力相等时,最有利于压裂产生裂缝,但最不利于主要裂缝向更远的方向延伸.

关键词：含天然气水合物沉积物水力压裂离散元法地层性质水合物储层天然气水合物开采内摩擦角裂纹扩展

Formation mechanism of cracks in saturated sand

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Acta Mechanica Sinica 2006年第4期22卷 377-383页

作者： xiaobing lu Zhemin Zheng Yongren Wu Wu Institute of Mechanics Chinese Academy of Sciences. Beijing 100080 China

The formation mechanism of ＂water film＂（or crack） in saturated sand is analyzed theoretically and numerically. The theoretical analysis shows that there will be no stable ＂water film＂ in the saturated sand if the strength of the skeleton is zero and no positions are choked. It is shown by numerical simulation that stable water films initiate and grow if the choking state keeps unchanged once the fluid velocities decrease to zero in the liquefied sand column. The developments of ＂water film＂ based on the model presented in this paper are compared with experimental results.

关键词： Saturated sand Cracks Liquefaction

基于多导体回路法的AT供电方式长回路电容计算方法研究

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电气化铁道 2024年第1期35卷 35-44,50页

作者：邓云川鲁小兵中铁二院工程集团有限责任公司电气化设计研究院

提出了一种基于多导体回路法以接触网和正馈线为传输导体的电气化铁路AT供电方式牵引网长回路电容计算方法。该方法以与电荷唯一对应的回路为基本单元,对复杂多导体传输线系统开展电场描述,实现了AT供电方式牵引网长回路电容的精确计算。

关键词：多导体回路法牵引网电容 AT供电方式长回路

Centrifugal experimental study of suction bucket foundations under dynamic loading

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Acta Mechanica Sinica 2007年第6期23卷 689-698页

作者： xiaobing lu Yongren Wu Bintian Jiao Shuyun Wang Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

Centrifugal experiments were carried out to investigate the responses of suction bucket foundations under horizontal and vertical dynamic loading. It is shown that when the loading amplitude is over a critical value, the sand at the upper part around the bucket is softened or even liquefied. The excess pore pressure decreases from the upper part to the lower part of the sand layer in the vertical direction and decreases radially from the bucket＇s side wall in the horizontal direction. Large settlements of the bucket and the sand layer around the bucket are induced by dynamic loading. The dynamic responses of the bucket with smaller height （the same diameter） are heavier.

关键词： Centrifugal experiments Suction bucket. Dynamic loading. Saturated sand

Thermally induced evolution of phase transformations in gas hydrate sediment

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Science China(Physics,Mechanics & Astronomy) 2010年第8期53卷 1530-1535页

作者： ZHANG XuHui lu xiaobing LI QingPing YAO HaiYuan Key Laboratory for Hydrodynamics and Ocean Engineering Institute of MechanicsChinese Academy of SciencesBeijing 100190China Research Centre China Ocean Oil Co.Beijing 100027China

Thermally induced evolution of phase transformations is a basic physical-chemical process in the dissociation of gas hydrate in sediment (GHS). Heat transfer leads to the weakening of the bed soil and the simultaneous establishment of a time varying stress field accompanied by seepage of fluids and deformation of the soil. As a consequence, ground failure could occur causing engineering damage or/and environmental disaster. This paper presents a simplified analysis of the thermal process by assuming that thermal conduction can be decoupled from the flow and deformation process. It is further assumed that phase transformations take place instantaneously. Analytical and numerical results are given for several examples of simplified geometry. Experiments using Tetra-hydro-furan hydrate sediments were carried out in our laboratory to check the theory. By comparison, the theoretical, numerical and experimental results on the evolution of dissociation fronts and temperature in the sediment are found to be in good agreement.

关键词： gas hydrate dissociation front phase transformation thermal conduction

Adjustable crystalline stereocomplexes from enantiopure gradient polycarbonates

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Science China Chemistry 2016年第11期59卷 1415-1420页

作者： Ye Liu Keke He Weimin Ren Rongrong Li xiaobing lu State Key Laboratory of Fine Chemicals Dalian University of Technology

Stereoselective interaction was observed in the mixture of enantiopure gradient polycarbonate(denoted as PCOPC-g-PCPC, originated from the enantioselective terpolymerization of CO2, 3,4-epoxytetrahydrofuran(COPO) and cyclopentene oxide(CPO)) and various isotactic polycarbonates with opposite configuration in chloroform solution. The resultant crystalline stereocomplexes exhibit enhanced thermal stability and new crystalline behaviors, significantly distinct from their parent polymers. It was found that the cocrystallization selectively occurred between(R)-PCOPC(CO_2/COPO copolymer) and(S)-PCOPC-enriched segment in the gradient terpolymer(S)-PCOPC-g-PCPC, while(R)-PCPC(CO_2/CPO copolymer) selectively complexed with(S)-PCPC-enriched segment. No stereocomplexation was observed between(S)-PCOPC-g-PCPC and(S)-PCOPC or(S)-PCPC. This study is beneficial to finding new routes to prepare various semicrystalline materials having a wide variety of physical properties and degradability.

关键词： crystalline polycarbonates gradient stereocomplex polymer assembly cocrystallization

Numerical study on the deformation of soil stratum and vertical wells with gas hydrate dissociation

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Acta Mechanica Sinica 2016年第5期32卷 905-914页

作者： Xudong Chen Xuhui Zhang xiaobing lu Wei Wei Yaohong Shi Institute of Mechanics Chinese Academy of Sciences Research Institute of Petroleum Exploration and Development-Langfang Marine Environmental and Engineering Geological Survey Guangzhou Marine Geological Survey

Gas hydrate（GH） dissociates owing to thermal injection or pressure reduction from the well in gas/oil or GH exploitation. GH dissociation leads to, for example, decreases in soil strength, engineering failures such as wellbore instabilities, and marine landslides. The FLAC3 D software was used to analyze the deformation of the soil stratum and vertical wells with GH dissociation. The effects of Young＇s modulus, internal friction angle, cohesion of the GH layer after dissociation, and the thickness of the GH layer on the deformation of soils were studied. It is shown that the maximum displacement in the whole soil stratum occurs at the interface between the GH layer and the overlayer. The deformation of the soil stratum and wells increases with decreases in the modulus, internal friction angle, and cohesion after GH dissociation. The increase in thickness of the GH layer enlarges the deformation of the soil stratum and wells with GH dissociation. The hydrostatic pressure increases the settlement of the soil stratum, while constraining horizontal displacement. The interaction between two wells becomes significant when the affected zone around each well exceeds half the length of the GH dissociation zone.

关键词： Gas hydrate Dissociation FLAC3D Soil stratum Well

Experimental investigation of critical suction velocity of coarse solid particles in hydraulic collecting

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Acta Mechanica Sinica 2021年第4期37卷 613-619,I0002页

作者： Yan Zhang xiaobing lu Xuhui Zhang Yuxiang Chen Hong Xiong Lianghua Zhang Institute of Mechanics Chinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China Institute of Deep-Sea Science and Engineering Chinese Academy of SciencesSanya 572000China

Hydraulic collecting and pipe transportation are regarded as an efficient way for exploiting submarine mineral resources such as the manganese nodules and *** particles on the surface of the sea bed are sucked by a pipe during the mining and crushing of the *** this paper,the critical suction velocity for lifting the coarse particles is investigated through a series of laboratory experiments,and the solid-liquid two-phase flow characteristics are *** on the dimensional analysis,the geometric similarity is found between actual exploitation process and model test with the same kind of *** controlling dimensionless parameters such as the hydraulic collecting number,the relative coarse particle diameter,the relative suction height,and the density ratio are deduced and *** results show that the logarithm in base 10 of the hydraulic collecting number increases approximately linearly with the increase of the relative suction height,while decreases with the relative particle diameter.A fitting formula for predicting the critical suction velocity is presented according to the experimental results.

关键词： Hydraulic collecting Critical suction velocity Coarse particles Deep sea mining Dimensional analysis

Numerical Investigation on the Initiation Mechanism of Debris-Flow under Rainfall

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Journal of Mountain Science 2011年第4期8卷 619-628页

作者： lu xiaobing YE Tianli CUI Peng HU Kaiheng CHEN Xiaoqing Institute of Mechanics Chinese Academy of Science Beijing 100084 China Institute of Mountain Hazards and Environment Chinese Academy of Science Chengdu 610041 China

Rainfall is an important factor to trigger the debris *** simulation on the responses of slopes and the initiation of debris flow under rainfall was processed by using the software FLAC2D based on the soil parameters in Weijia Gully,Beichuan County,Sichuan Province,*** effects of the slope angle,rainfall intensity,soil parameters on the developments of the stress and pore pressure and deformation of the slope were *** indicates that large displacements of the slope are mainly located near the slope *** the increase of the rainfall intensity the stability of the slope decreases and so the debris-flow is easy to occur.

关键词： Debris-flow Initiation mechanism Rainfall Numerical simulation