龙滩水电站蠕变体B区折断面及折断错滑面成因分 析     

程东幸  刘大安  丁恩保  陈卫红 《工程地质学报》2008,16(1):98-103

通过对广西龙滩水电站左岸边坡蠕变体B区折断面和折断错滑面地质特征,变形特征,滑带充填物特征以及力学参数研究,结合监测,岩体风化以及构造特征、表层岩土体滑移-牵引等特征分析,认为折断面和折断错滑面的形成主要是由于边坡岩性以及河水侵蚀等作用下,岩体的风化差异所造成的,而且在目前有效的工程处理下,由监测资料可知,边坡变形波动较大,变形量值小,没有明显的滑移趋势,稳定性较可靠。  相似文献   

利用方位角道集处理方法预测煤层裂隙     

刘伍  崔若飞钱进 《中国煤炭地质》2008,20(3):59-61

煤层瓦斯含量受多种因素影响,而煤层中的节理裂隙密集带则容易导致瓦斯聚积。在煤田地质勘探中,依据振幅随炮点和检波点入射角的变化可以预测裂隙的发育方向和发育密度。在对淮南地区张集西三煤矿的三维地震数据资料处理时,按不同的方位角增量抽取方位角道集,并对其方位角道集进行速度分析、NMO校正、叠加和偏移,得到6个方位偏移数据体。根据Malick等人的理论模型对其进行计算,获得d、A、B值,并据此预测裂缝发育方向与发育密度。将其预测成果与常规地震解释成果对比,发现两者之间非常吻合,可见利用方位角道集处理方法预测煤层裂隙具有可行性。  相似文献   

复杂岩性油藏精细描述研究进展     

陈欢庆  胡海燕  李文青  邓晓娟 《地球科学与环境学报》2020,(1):99-119

复杂岩性油藏作为目前油田开发中十分重要的油藏类型之一,其精细描述一直受到研究者的关注和重视。为了给有效开发和调整部署提供依据,系统梳理了目前复杂岩性油藏精细描述中存在的主要问题、主要研究内容和技术发展方向,并总结复杂岩性油藏研究进展。从国内复杂岩性油藏精细描述研究现状入手,总结了该项研究存在的6项主要问题,主要包括岩性岩相识别与分类、储层地质成因分析难度大、地层精细划分与对比具有特殊性、裂缝表征难度很大、测井精细二次解释精度低、地质建模井间储层预测准确率低等。基于文献调研和综述,结合科研实践,认为复杂岩性油藏精细描述核心内容包括岩性岩相识别与分类、储层地质成因机制分析、储集空间识别和描述、储层物性精细测井解释和储层地质建模等5个方面。在此基础上,指出了该项研究的发展趋势,主要包括地层精细划分与对比、微观孔隙结构表征、储层裂缝表征、储层综合定量评价和流体识别等。  相似文献   

The role of bedding in the evolution of meso- and microstructural fabrics in fault zones     

《Journal of Structural Geology》2016

To investigate the role of bedding in the evolution of meso- and microstructural fabrics in fault zones, detailed microscopic, mineralogical, and geochemical analyses were conducted on bedding-oblique and bedding-parallel faults that cut a folded Neogene siliceous mudstone that contains opal-CT, smectite, and illite. An analysis of asymmetric structures in the fault gouges indicates that the secondary fractures associated with each fault exhibit contrasting characteristics: those of the bedding-oblique fault are R₁ shears, whereas those of the bedding-parallel fault are reactivated S foliation. The bedding-oblique fault shows the pervasive development of S foliation, lacks opal-CT, and has low SiO₂/TiO₂ ratios only in gouge, whereas the bedding-parallel fault exhibits these characteristics in both gouge and wall rocks. The development of S foliation and the lack of silica can result from local ductile deformation involving the sliding of phyllosilicates, coupled with pressure solution of opal-CT. Although such deformation can occur in gouge, the above results indicate that it may occur preferentially along bedding planes, preceding the formation of a gouge/slip surface. Thus, in sedimentary rocks that contain phyllosilicates and soluble minerals, bedding can influence the rheological evolution of meso- and microstructural fabrics in fault zones.  相似文献   

Simulation of mixed-mode fracture using SPH particles with an embedded fracture process zone     

Yingnan Wang  Hieu T. Tran  Giang D. Nguyen  Pathegama G. Ranjith  Ha H. Bui 《国际地质力学数值与分析法杂志》2020,44(10):1417-1445

This paper focuses on the modelling of mixed-mode fracture using the conventional smoothed particle hydrodynamics (SPH) method and a mixed-mode cohesive fracture law embedded in the particles. The combination of conventional SPH and a mixed-mode cohesive model allows capturing fracture and separation under various loading conditions efficiently. The key advantage of this framework is its capability to represent complex fracture geometries by a set of cracked SPH particles, each of which can possess its own mixed-mode cohesive fracture with arbitrary orientations. Therefore, this can naturally capture complex fracture patterns without any predefined fracture topologies. Because a characteristic length scale related to the size of the fracture process zone is incorporated in the constitutive formulation, the proposed approach is independent from the spatial discretisation of the computational domain (or mesh independent). Furthermore, the anisotropic fracture responses of materials can be naturally captured thanks to the orientation of the fracture process zone embedded at the particle level. The performance of the proposed approach demonstrates its potentials in modelling mixed-mode fracture of rocks and similar quasi-brittle materials.  相似文献   

Thermo-hydro-mechanical modeling of fracturing porous media with two-phase fluid flow using X-FEM technique     

A. R. Khoei  S. M. S. Mortazavi 《国际地质力学数值与分析法杂志》2020,44(18):2430-2472

In this paper, a fully coupled thermo-hydro-mechanical model is presented for two-phase fluid flow and heat transfer in fractured/fracturing porous media using the extended finite element method. In the fractured porous medium, the traction, heat, and mass transfer between the fracture space and the surrounding media are coupled. The wetting and nonwetting fluid phases are water and gas, which are assumed to be immiscible, and no phase-change is considered. The system of coupled equations consists of the linear momentum balance of solid phase, wetting and nonwetting fluid continuities, and thermal energy conservation. The main variables used to solve the system of equations are solid phase displacement, wetting fluid pressure, capillary pressure, and temperature. The fracture is assumed to impose the strong discontinuity in the displacement field and weak discontinuities in the fluid pressure, capillary pressure, and temperature fields. The mode I fracture propagation is employed using a cohesive fracture model. Finally, several numerical examples are solved to illustrate the capability of the proposed computational algorithm. It is shown that the effect of thermal expansion on the effective stress can influence the rate of fracture propagation and the injection pressure in hydraulic fracturing process. Moreover, the effect of thermal loading is investigated properly on fracture opening and fluids flow in unsaturated porous media, and the convective heat transfer within the fracture is captured successfully. It is shown how the proposed computational model is capable of modeling the fully coupled thermal fracture propagation in unsaturated porous media.  相似文献   

Fast multipole displacement discontinuity method (FM‐DDM) for geomechanics reservoir simulations          下载免费PDF全文

Alexander Verde  Ahmad Ghassemi 《国际地质力学数值与分析法杂志》2015,39(18):1953-1974

The displacement discontinuity method (DDM) is frequently used in geothermal and petroleum applications for modeling the behavior of fractures in linear‐elastic rocks. The DDM requires O(N²) memory and O(N³) floating point operations (where N is the number of unknowns) to construct the coefficient matrix and solve the linear system of equations by direct methods. Therefore, the conventional implementation of the DDM is not computationally efficient for very large systems of cracks, often limiting its application to small‐scale problems. This work presents an approach for solving large‐scale fracture problems using the fast multipole method (FMM). The approach uses both the DDM and a kernel‐independent version of the FMM along with a preconditioned generalized minimal residual algorithm to accelerate the solution of linear systems of equations using desktop computers. Using the fundamental solutions for constant displacement discontinuity in a two‐dimensional elastic medium, several numerical examples involving fracture networks representing fractured reservoirs are treated. Numerical results show good agreement with analytical solutions and demonstrate the efficiency of the FMM implementation of the DDM for large‐scale simulations. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Full 3-D numerical modeling of borehole electric image logging and the evaluation model of fracture     

《中国科学D辑(英文版)》2008,(Z2)

A full 3-D finite element method numerical modeling program is written based on the principle and technical specification of borehole electric image well logging tool. The response of well logging is computed in the formation media model with a single fracture. The effect of changing fracture aperture and resistivity ratio to the logging response is discussed. The identification ability for two parallel fractures is also present. A quantitative evaluation formula of fracture aperture from borehole electric image logging data is set up. A case study of the model well is done to verify the accuracy of the for-mula. The result indicates that the formula is more accurate than the foreign one.  相似文献   

南黄海新构造运动   总被引：1，自引：0，他引：1  

侯方辉  张志殉  李三忠  张训华 《海洋地质前沿》2005,21(11):8-10

定义了南黄海新构造运动的概念;提出了南黄海新构造运动的研究方法;阐明了南黄海新构造运动的机理,即受滨西太平洋构造域控制,是在老构造基础上的继承和发展;描述了南黄海新构造运动的基本特征;总结了南黄海新构造运动的研究意义。  相似文献   

冲绳海槽天然气水合物与地质构造的关系   总被引：7，自引：0，他引：7  

方银霞  高金耀  黎明碧  唐勇 《海洋地质与第四纪地质》2005,25(1):85-91

海底天然气水合物大多与通过切穿沉积盖层的断裂的上升烃类流体相关,这些高渗透带包括底辟和泥火山等侵入构造,所以海底断裂、底辟和泥火山等构造周围可能赋存天然气水合物;其次,高沉积速率和巨厚沉积层可使有机质迅速掩埋而保存起来,为天然气水合物的生成提供充足物源,因此,邻近陆坡河谷口的海底沉积扇也是天然气水合物赋存的有利地区;另外,由于陆坡区的水合物沉积层比海盆更容易受外界温压变化的影响发生失稳分解,诱发海底滑坡,所以滑坡与天然气水合物赋存之间的关系也非常密切。冲绳海槽邻近海域具有覆水深、沉积厚度大、沉积速率高和有机质丰富等有利赋存条件,目前的研究已经在该海域发现了天然气水合物赋存的地球物理证据BSR,因此,在现有研究基础上开展断裂、泥火山、海底扇、海底滑坡等与天然气水合物相关的构造研究,可以深入了解天然气水合物在不同地质构造中的分布特征与演化,为更精确地评估其资源潜力提供参考。  相似文献