Evaluation of the reservoir permeability of anthracite coals by geophysical logging data

Permeability is one of the most significant reservoir parameters. It is commonly obtained by experiment, history simulation, injection/falloff well test and geophysical logging. Among these, geophysical logging remains as the most economic and efficient technique in evaluating coal permeability in the vicinity of an open-hole. In this paper, geophysical logging data are used to evaluate the coal reservoir permeability for the No. 3 coal seam in the southern Qinshui Basin (Fanzhuang and Zhengzhuang coal zones). Ideally coal reservoirs consist of coal matrix and fracture networks that can be represented by a model called a collection of sheets. Based on the model, coal reservoir permeability can be quantitatively calculated using the theoretical formula of k_f = 8.50 × 10^− 4 w²φ_f, in which fracture width (w) and fracture porosity (φ_f) were obtained by dual laterolog and density logging data, respectively. Calculative results show that coal reservoir permeability ranged from 0.017 mD to 0.617 mD for the Fanzhuang coal zone and from 0.047 mD to 1.337 mD for the Zhengzhuang coal zone. The permeability decreases with coal burial depth, reflecting variations in penetration capability of coal reservoirs at varying depths. Comparing results with those from injection/falloff well tests, however, shows that the model-calculated permeability is slightly higher. This is expected because the model did not include the influence from coal anisotropy.     

Thermal equation of state of CaIrO<Subscript>3</Subscript> post-perovskite

The pressure–volume–temperature (P–V–T) relation of CaIrO₃ post-perovskite (ppv) was measured at pressures and temperatures up to 8.6 GPa and 1,273 K, respectively, with energy-dispersive synchrotron X-ray diffraction using a DIA-type, cubic-anvil apparatus (SAM85). Unit-cell dimensions were derived from the Le Bail full profile refinement technique, and the results were fitted using the third-order Birth-Murnaghan equation of state. The derived bulk modulus \( K_{T0} \) at ambient pressure and temperature is 168.3 ± 7.1 GPa with a pressure derivative \( K_{T0}^{\prime } \) = 5.4 ± 0.7. All of the high temperature data, combined with previous experimental data, are fitted using the high-temperature Birch-Murnaghan equation of state, the thermal pressure approach, and the Mie-Grüneisen-Debye formalism. The refined thermoelastic parameters for CaIrO₃ ppv are: temperature derivative of bulk modulus \( (\partial K_{T} /\partial T)_{P} \) = ?0.038 ± 0.011 GPa K^?1, \( \alpha K_{T} \) = 0.0039 ± 0.0001 GPa K^?1, \( \left( {\partial K_{T} /\partial T} \right)_{V} \) = ?0.012 ± 0.002 GPa K^?1, and \( \left( {\partial^{2} P/\partial T^{2} } \right)_{V} \) = 1.9 ± 0.3 × 10^?6 GPa² K^?2. Using the Mie-Grüneisen-Debye formalism, we obtain Grüneisen parameter \( \gamma_{0} \) = 0.92 ± 0.01 and its volume dependence q = 3.4 ± 0.6. The systematic variation of bulk moduli for several oxide post-perovskites can be described approximately by the relationship K _T0  = 5406.0/V(molar) + 5.9 GPa.     

1976年和林格尔6.3级地震前后震兆特征分析

从时空变化特征、震源参数、地震波谱特征，b值，Vp/Vs,Q值，持续时间衰减比，Ap/As等方面对1976年4月6日和林格尔6．3级地震进行了较为全面的分析，着重分析了地震前后2年左右出现的运动学和动力学变化特征，以提取和林格尔6．3级地震的短临信息，分析后认为此次地震出现的震兆特征与包头6．4级地震，张北6．级地震某些方面有相似处，对探讨分析未来阴山、燕山地震带浅源中强震的孕育过程及提取临震信息，具有参考意义。     

应用模式识别法选拔学术带头人

讨论了与学术带头人培养、选拔有关的几个主要问题,并探讨了利用模式识别方法选拔学术带头人的可能性。     

吉林省汪清县闹枝金矿床黄铁矿的找矿矿物学研究

黄铁矿是闹枝金矿的主要载金矿物之一,不同成矿阶段的黄铁矿在晶体形态、化学成分以及热电性等方面各有其特点,特别是黄铁矿的热电性特征,在金矿的找矿勘探中具有重要的指导意义。     

青藏高原造山带的某些特征

以昆仑中央断裂为界，青藏高原可分为南、北两部分。北部的造山带是在刚性基底地壳上发育起来的。造山前期是裂陷槽发展阶段，并以简间的碰合褶皱成山。造山期后构造变形也简单，以逆冲、叠覆构造为主。南部的造山带是在柔性基底地壳上发育起来的。它的特点是活动性强，经我旋回开、合造山前期出现有连贯性较好的洋盆及两侧广阔的陆缘沉积，造山期后变形复杂，除逆冲、叠覆构造外，出现大量平移断层。这一部的构造格局形成了青藏高原造山带一系列独有的特征。     

Olivine as an in situ piezometer in high pressure apparatus

The deviatoric stress produced in a large-volume, high-pressure apparatus of the girdle-anvil type has been estimated from the density of free dislocations induced in natural olivine single crystals (initial density of 2×10⁶ cm^?2). Experiments at maximum pressure P=40 kbar and temperature T=1050°C for t=1 h in NaCl cell assemblies and various P-T paths yield specimens whose dislocation densities are unchanged from this initial value, implying that the deviatoric stress was less than 140 bar. In BN cell assemblies, the recovered specimen from high P-T experiments exhibit much higher densities of dislocations (～10⁹ cm^?2) which have been produced by steady-state plastic deformation of the olivine crystals under a deviatoric stress of ～3 kbar. This value of deviatoric stress in BN has been corroborated by observations of the subgrain size and recrystallized grain size in specimens of longer run duration (3 h).     

Separation of P- and S-wavefields from wide-angle multicomponent OBC data for a basalt model

Wide-angle multicomponent ocean-bottom cable (OBC) data should further enhance sub-basalt imaging by using both compressional and converted shear wavefields. The first step in analysing multicomponent OBC data is to decompose the recorded wavefields into pure P- and pure S-wavefields, and extract the upgoing P- and S-waves. This paper presents a new scheme to separate P- and S-wavefields from wide-angle multicomponent OBC data in the τ–p domain. By considering plane-wave components with a known horizontal slowness, the P- and S-wavefields are separated into the directions of observed P- and S-wave oscillations using the horizontal and vertical components of the data. The upgoing P- and S-waves are then extracted from the separated P- and S-wavefields. The parameters used in the separation are the seismic wave velocities and the density at the receiver location, which can be estimated from the first reflection phase observed on the horizontal and vertical components. Numerical tests on synthetic data for a plane-layered model show good performance and demonstrate the accuracy of the scheme. Separation of wavefields from a basalt model is performed using synthetic wide-angle multicomponent OBC data. The results show that both near-offset and wide-angle reflections and conversions from within and below basalt layers are enhanced and clearly identified on the separated wavefields.     

大陆地震观测中连续震颤波信号的定位

针对大陆地震观测中的连续震颤波,根据其信号特征和观测特点,在准确识别震颤波信号、提高信噪比、缩小信号范围等原则基础上,参考国际上对间歇式震颤的定位方法,对信号的识别、处理及定位方法和技术进行整合、改进,提出对这类信号采用的定位技术和方法流程,并应用该方法对中国大陆地震观测中几个由台风引发的连续震颤波信号进行定位和效果检验。结果表明,这些技术和方法是可行的,其定位结果合理可信。     

京沪高铁天津地区地表沉降空间插值方法研究

京沪高速铁路天津、沧州地区存在不同程度的地表沉降。以京沪高速铁路天津地区沿线的水准观测数据为研究对象,采用反距离加权法、径向基函数法与泛克里格插值法对研究对象进行了空间插值分析,通过精度评定与结果检验发现泛克里格方法能够较好地反映地表趋势面,可以作为研究该区域地表沉降的一种方法。