排序方式： 共有67条查询结果，搜索用时 15 毫秒
41.
江苏句容-黄桥地区有机包裹体形成期次和捕获温度、压力的PVTsim模拟计算 总被引：8，自引：0，他引：8
据流体包裹体显微镜观测和石油包裹体群的气体色谱和全烃色谱、色谱-质谱分析结果，句容和黄桥地区三叠系和下二叠系地层中的石油包裹体明显不同，句容地区三叠系灰岩储层中的石油包裹体的个体较大，在透光下为黄色一棕黄色，荧光显微镜下发亮黄色荧光，包裹体中气态烃的C1／C2-5，比值较低，液态烃中三环萜炕、五环三萜烷和规则甾烷系列的生物标志物化合物含量比较丰富，而句容和黄桥地区下二叠系石油包裹体比较细小，发黄色-黄绿色荧光，包裹体中气态烃的C1／C2-5。比值较高，液态烃中均难检测到甾萜烷系列的生物标志物。由流体包裹体均一温度等观测资料与捕获温度、捕获压力的PVTsim的模拟计算结果：句容地区三叠系储层的石油包裹体捕获温度Tr=107．9℃，捕获压力Pr=289bar，约相当于白垩纪晚期（90～83Ma）充注成藏。句容地区下二叠深灰色灰岩中分布的油包裹体的捕获温度Tr=123℃，捕获压力Pr=305．95bar，反映白垩系晚期还有一期温度比较高的含烃流体充注的现象。黄桥地区在含CO2气藏的下二叠系存在有交切关系的，黄色和黄绿色两种荧光性质不同的石油包裹体，前者模拟计算的捕获温度Tr=97．3℃，捕获压力Pr=184．75bar，后者模拟计算的捕获温度Tr=145．5℃，捕获压力Pr=220．05bar，分别相当于白垩纪晚期（95～90Ma）和白垩纪末期（65～60Ma）有合烃流体运聚现象。但是，由于在白垩纪末-第三纪的抬升作用阶段，油气大量散失，因此在喜山期大量无机CO2充注成藏时期，储层中已不合烃类流体。 相似文献
42.
Numerical study of localization in soil systems 总被引：1，自引：0，他引：1
A numerical study of the mechanical behavior of heterogeneous soil systems, consisting of a bulk of sand with embedded stiff gravel inclusions or soft clay inclusions, is performed. A solution scheme using parallel computing is employed when analyzing two different categories of problems. First, a homogenization problem is studied, where use of a single representative volume element subjected to plane strain compression offers the possibility to investigate the coupling between the response at a local scale and at a global scale. Second, a plane strain footing problem with different heterogeneous soil systems is analyzed using a traditional finite element formulation. The material model utilized for the soil is a large deformation formulation of non-associated elasto-plasticity with an isotropic hardening law, able to represent dilation. It was found that the shape of the gravel or clay inclusions in the systems had no significant effect on the global responses, whereas the strain localizations in the two different soil systems, sand–gravel and sand–clay, were found to have different character. The effect of the initial density on the response was clearly observed in the localization patterns. 相似文献
43.
A homogenization strategy for granular materials is presented and applied to a three-dimensional discrete element method (DEM), that uses superellipsoids as particles. Macroscopic quantities are derived from the microscopic quantities resulting from a DEM simulation by averaging over representative volume elements (RVEs). The implementation of an RVE is described in detail regarding the definition and discretization of the RVE boundary. The homogenization strategy is validated by DEM simulations of compression and shear tests of cohesionless granular assemblies. Finally, an elasto-plastic material model is fitted to the resulting stress–strain curves. 相似文献
44.
Fluid inclusions and melt inclusions have been considered as possible guides for mineral exploration by many researchers. However, the minuteness of the fluid inclusions and the multiplicity of generations within the same deposit have always posed serious problems in the proper utilization of fluid-inclusion data in prospecting.Fluid inclusions preserve a valid and comprehensive record of the fluids coexisting with host minerals at the time of crystallization. A careful comparison of fluid-inclusion parameters and deposit characteristics enables one to distinguish between economically significant and insignificant zones of pegmatites.A systematic study of different pegmatites in an area of about 100 km2 in the central part of the Bihar Mica Belt, India, was made. Mineralogical, fluid-inclusion, and melt-inclusion data of the principal mineral constituents like quartz, beryl, and apatite were collected. Thirty-three occurrences were chosen for the study. Pegmatites were grouped into economically significant (commercial) and barren (noncommercial) types. The fluid-inclusion parameters used in this study are size, population, presence of liquid carbon dioxide, salinity, and temperature of homogenization.Economically significant pegmatites and barren pegmatites have distinctly different populations of fluid inclusions. Economic pegmatites show a preponderance of highly saline, polyphase fluid inclusions, commonly with liquid carbon dioxide; these fluid inclusions homogenize over a wide range of temperature. Their size ranges from 50 m to 10 m. On the other hand, quartz of barren pegmatites is characterized by the preponderance of vapor-rich biphase inclusions, which homogenize at a relatively narrower but higher range of temperature. Fluid inclusions that contain halite daughter crystals are rare. The average size of the fluid inclusions in barren pegmatites is smaller (5 m to 20 m). Melt inclusions are more abundant in the barren pegmatites. 相似文献
45.
The transport of a chemical species under the pure action of surface progressive waves in the benthic boundary layer which is loaded with dense suspended sediments is studied theoretically. The flow structure of the boundary layer is approximated by that of a two-layer Stokes boundary layer with a sharp interface between clear water and a heavy fluid. The simplest model of constant eddy diffusivities is adopted and the exchange of matter with the bed is ignored. For a thin layer of heavy fluid, whose thickness is comparable to the surface wave amplitude and the Stokes boundary layer thickness, effective transport equations are deduced using an averaging technique based on the method of homogenization. The effective advection velocity is found to be equal to the depth-averaged mass transport velocity, while the dispersion coefficient can be shown to be positive definite. Explicit expressions for the transport coefficients are obtained as functions of fluid properties and flow kinematics. Physical discussions on their relations are also presented. 相似文献
46.
当前的地面气候观测资料普遍存在非气候性因素导致的非均一性,对气候变化监测和研究结论可靠性造成重要影响。结合观测台站的历史沿革数据,使用ACMANT和Pairwise Comparisons方法以及RHtest V4软件,对北京地区20个台站均一化前的月平均气温序列进行了非均一性检验和订正,最后评估了均一化对北京地区气温序列变化趋势及其城市化偏差估算的影响。结果表明：除元数据中记录的断点外,无元数据记录的断点也会对序列的趋势变化造成明显影响,其中乡村站最显著;经过订正,1958—2018年整个北京地区、乡村站以及城市站增温趋势分别为0.27℃/(10 a)、0.10℃/(10 a)和0.32℃/(10 a),较订正前分别上升了0.03℃/(10 a)、0.06℃/(10 a)和0.02℃/(10 a)。利用均一化资料估算,1958—2018年北京观象台的城市化影响为0.24℃/(10 a),城市化贡献率为70.2%,评估结果较前人结论有所降低。可见,在现有的北京地区气温资料序列中,仍可能存在较明显的非均一性和未被记录的断点,对区域平均气温趋势估算具有显著影响。 相似文献
47.
CCSD主孔中发育有十分丰富的脆性变形现象,按其充填特征大致可划分有石英和方解石充填的微破裂、有矿物薄膜的微破裂和既无矿物充填、又无矿物簿膜的微破裂等3大类.石英微破裂脉和方解石微破裂脉次生包裹体的均一温度分别为110℃～215℃和90℃～190℃,表明前者的形成要早于后者,按现代地热梯度23.4℃/km估算,两者的形成深度分别为4.7～9.2km和3.8～8.1km,9.2km大致可作为宏观上岩石圈发生脆性变形的最大深度或岩石圈由韧性变形域向脆性变形域过渡的界线.片麻岩、榴辉岩和超基性岩微破裂脉的次生包裹体均一温度显示三者由韧性变形域向脆性变形域过渡的深度是不一致的,依次为9.2km、8.5km和8.1km,反映主孔主要岩石类型的脆性变形行为存在有一定差异.根据微破裂的充填物特征和相互切割关系,大致可确定主孔中脆性破裂的形成深度和先后关系:石英微破裂脉,形成最早,深度为4.7～9.2km,方解石微破裂脉的形成深度为3.8～8.1km,8.1km以上开始出现有矿物薄膜的微破裂,既无矿物充填、又无矿物簿膜的微破裂则是地壳深度3.8km以上的主要脆性变形构造类型.可见,微破裂次生包裹体的均一温度或许可作为宏观上建立CCSD主孔脆性变形构造剖面的重要依据之一. 相似文献
48.
We derive a macroscopic model for single-phase, incompressible, viscous fluid flow in a porous medium with small cavities called vugs. We model the vuggy medium on the microscopic scale using Stokes equations within the vugular inclusions, Darcy's law within the porous rock, and a Beavers–Joseph–Saffman boundary condition on the interface between the two regions. We assume periodicity of the medium and obtain uniform energy estimates independent of the period. Through a two-scale homogenization limit as the period tends to zero, we obtain a macroscopic Darcy's law governing the medium on larger scales. We also develop some needed generalizations of the two-scale convergence theory needed for our bimodal medium, including a two-scale convergence result on the Darcy–Stokes interface. The macroscopic Darcy permeability is computable from the solution of a cell problem. An analytic solution to this problem in a simple geometry suggests that: (1) flow along vug channels is primarily Poiseuille with a small perturbation related to the Beavers–Joseph slip, and (2) flow that alternates from vug to matrix behaves as if the vugs have infinite permeability. 相似文献
49.
The effects of oil cracking on fluorescence color, homogenization temperature (Tho) and trapping pressure (Pt) of oil inclusions from deeply buried reservoirs (DBRs) (3672–4359 m) in the northern Dongying Depression were determined based on fluorescence spectroscopy and homogenization temperatures of oil inclusions, kinetic modeling of crude oil cracking, and petroleum inclusion thermodynamics modeling.The modeling results demonstrate that fluorescence color, Tho and predicted Pt have strong relationships with the transformation rate via cracking of oil to gas (Tr), and the formation temperature (Tf) that the inclusions experienced. The fluorescence color is hardly influenced at all during the initial stages of oil cracking (Tr < 13%, Tf < 160 °C), but fluorescence color begins to shift toward shorter wavelengths (blue shift) during progressive oil cracking (Tr < 24%, Tf < 190 °C). With further oil cracking, the fluorescence color may either experience no change or continue its blue shift. Eventually the fluorescence color will disappear as the aromatic compounds are completely cracked. The Tho increases at first (Tr < 24%, Tf < 190 °C), but then decreases or even becomes negative during major oil cracking. The reconstructed Pt values show a corresponding reverse trend.Oil inclusions from DBRs and other shallow reservoirs in the Dongying Depression show an obvious blue shift in fluorescence color at a depth of approximate 4000 m (Tf = 160 °C) and generally contain solid bitumen below 4000 m, supporting the effect of oil cracking on fluorescence variation, consistent with the modeling result. The Tho from DBRs in the Minfeng area increases with increasing burial depth (Tf < 190 °C), which is also consistent with the modeling results. However, the Tho of oil inclusions with blue-white fluorescence from DBRs in the Shengtuo area did not show such a trend. Recent trapping, high trapping pressure and higher-maturity oil may have led to a low-degree of oil cracking, and thus less modification of Tho in the Shengtuo area.Oil cracking results in consistent volume ratios of pyrobitumen to oil inclusions (Fvpy) in the same fluid inclusion assemblage, and the Fvpy value increases with oil cracking level, which can be used to recognize if oil cracking has occurred in oil inclusions and what level of oil cracking they have experienced.As the oil cracking model used in this study did not account for the role of pressure, it is more applicable for oil inclusions that were trapped under normally pressured conditions. Oil inclusions trapped under overpressured conditions will be less influenced by oil cracking. 相似文献
50.
Stability of density-driven flows is a challenging problem with current applications in major areas like energy exploration, water pollution, nuclear and oil industries. The mathematical model for such flows is a system of coupled non linear partial differential equations. To study the physical stability of the system, we consider steady-state flow and perturb the solution of the full system of equations (without Boussinesq approximation) and investigate how it evolves in time: if the solution does not grow indefinitely, the system is called stable. The perturbations are treated as being the result of sub-scale interactions between the velocity field and the solute mass. Making use of a two-scale expansion of the solution, we derived extended stability criteria that include the effects of density, viscosity and flow velocity in flow configurations aligned parallel as well as orthogonal to gravity forces. Numerical simulations with the numerical simulator d3f are presented to test the theoretical stability criteria. 相似文献