注浆加固与含水层改造底板采动效应孔巷电阻率CT探测研究

底板注浆加固与含水层改造是承压水体上煤层安全开采底板岩溶水害防治的有效方法之一.为了评价注浆加固和含水层改造底板的采动效应特征.以皖北恒源煤矿Ⅱ615工作面为研究对象,采用孔巷电阻率CT法,按照采动底板活动规律设计观测方案.进行了注浆底板破坏深度的动态电阻率CT探测试验.获得了Ⅱ615工作面底板强破坏带深度为8.0 m.裂隙带深度为14.0 m以及煤层底板采动裂隙演化过程的电阻率响应特征.结果表明:孔巷间电阻率的变化较好地反映了底板岩体的受力状态、结构变化以及破坏程度,探测结果直观准确;注浆后底板采动影响范围和破坏深度均减小,反映了注浆后底板抗破坏能力增强,提高了承压水体上煤层开采的安全性.     

中国东部煤矿深部开采中的地质勘探技术

中国东部煤矿已经进入深部开采阶段,高产高效矿井要求查明煤层中落差5m左右的断层、幅度5m左右的褶曲、陷落柱和采空区的空间分布形态,同时查明与水文地质条件密切相关的煤层顶、底板岩性.本文概述了煤矿深部开采中的地质勘探技术,给出了利用不同勘探方法查明地质构造、岩溶裂隙发育带的应用实例,指出煤矿深部开采地质勘探技术的发展方向是将地球物理方法、基础地质勘探手段与地理信息系统技术进行有机结合.     

浅层次脆性变形域中煤层韧性剪切带微观分析

在研究煤层层间剪切与韧性流变的基础上提出浅层次脆性变形域中的煤层韧性剪切带. 煤层韧性剪切带的宏、微观特征不仅有煤层揉流褶皱、煤层糜棱岩带、煤层韧性面理构造等, 而且微观特征还表现为不同的光性组构与煤镜质组各向异性、煤化学结构的变化和有机地球化学成分的改变等. 分析了煤层韧性剪切带的形成机制, 并探讨了其应变环境: 在地壳浅层次脆性变形域中, 煤层受力后容易变形, 煤层不仅产生脆性变形, 而且也产生韧性剪切变形. 在简单剪切应力作用下煤层及其围岩间发生层间滑动或煤层发生韧性流动. 因此, 地壳浅层(< 5 km)能形成众多的煤层韧性剪切带.     

煤层冲刷带地震响应特征及其与煤层瓦斯突出的相关性分析

阳泉新景煤矿生产实践发现3#煤层发生的煤与瓦斯突出事故大部分位于煤层冲刷带.三维地震勘探记录地层连续性好、控制精度高,是识别煤层冲刷带最常用的技术手段.本文以新景矿芦南二区为研究区,建立二维正演模型,研究煤层的地震响应规律,发现其振幅和相位属性对煤层冲刷带响应明显.利用该区现有的三维地震资料,综合瞬时振幅属性特征、地震相分类特征及声波阻抗响应特征,圈定冲刷带平面位置及分布范围.运用有限元分析软件对煤层冲刷带应力分布进行三维正演模拟,结合煤样测试结果,对区内应力异常带的煤层瓦斯和煤体结构等进行分析.研究发现煤层冲刷带过渡区段突出危险性最大,是圈定冲刷带的关键部位,研究成果与实际突(喷)出点位置吻合度较高.总之:1)煤层冲刷作用是导致瓦斯地质条件差异性的主要因素之一,过渡区段为重点防突区域;2)综合多种地震岩性信息响应特征在准确识别煤层冲刷带位置及分布范围方面效果显著.     

利用地震P波方位属性评价瓦斯富集区

以往研究表明煤层具有弱各向异性,为正交各向异性介质,因此利用P波的方位各向异性属性来进行煤层裂隙裂缝检测、预测煤层瓦斯富集带是行之有效的方法.本文对山西阳泉新景佛洼区的三维地震资料进行处理,得到4个方位的偏移数据体,并提取与煤层裂隙裂缝相关的多种地震属性.通过计算得到裂隙裂缝的相对密度,进而对煤层瓦斯的富集带进行预测.     

地震槽波方法试验与研究

<正> 在采煤过程中,一些预料不到的（落差近似等于煤厚）小断层、煤层冲蚀、煤层变薄带、陷落柱等小型地质变化,常常会妨碍甚至中断机械化或综合机械化采煤工作面的生产,给煤矿带来严重的经济损失。为了保证煤炭生产的正常进行,必须及时探明工作面的开采地质条件。西德克雷教授提出的地震槽波法是有效解决这一问题的新手段,因此该法受到了国内外煤田地球物理工作者的普遍重视。     

薄煤层综采工作面高产高效开采方法探讨

本文主要研究了如何对薄煤层进行高产高效的开采,随着中厚煤层的濒临枯竭,薄煤层开始进入大众视野,所谓薄煤层是指厚度在1.3m以下的煤层,现在该煤层存在的优势是储量极大,但是缺陷也是有的,薄煤层开采会受到工作面空间的限制,开采难度比较大,而且危险度极高,于此表明薄煤层综采高产高效的重要性,所以如何才能使薄煤层的开采变的高产高效是至关重要的。     

黄陵矿区2号煤层构造应力场分析

煤层构造应力场与煤与瓦斯突出和煤层裂隙分布带范围密切相关.黄陵矿区煤层中瓦斯含量较高,分布不均是矿井安全生产的重要隐患.基于该区地震、地质和测井数据,本文对三维地震数据体进行精细的构造解释,用反演法建立了地质力学模型,并确定岩石力学参数,运用有限元理论和弹性计算力学对矿区三维构造应力场进行了数值模拟,得到黄陵矿区2号煤层地质构造带应力场分布特征,模拟结果与井田宏观及微观构造信息一致.这对预测该区裂隙分布带,煤与瓦斯突出等具有重要的指导意义.     

温度作用下煤层瓦斯解吸渗流规律数值模拟

如何提高煤层气渗透率是目前煤层气开采研究中的重要课题。基于煤层瓦斯渗流规律数学模型,利用COMSOL Multiphysics软件,对流-固-热耦合条件下的非等温煤层气解吸、渗流变化规律进行了数值模拟。结果表明,在注热条件下,煤层气渗流压力随着温度的增加而下降,且下降速度加剧,压力差越大,气体从高压区域流向低压区域的渗流速度越快。气体在煤层中径向流向井口,井口附近压力的梯度增大,气体渗流速度较快;在未受到加热影响的区域,煤层气不受外加热量影响,煤层气解吸速率保持不变;注热后煤层温度升高,可以加快煤层气渗流速度、提高渗透率、增加煤层气产量。研究成果可为煤层中注热开采煤层气的工程实践提供相应的理论依据。     

基于粗糙集及最小二乘支持向量机的煤层厚度预测

煤层厚度是煤矿设计与开采必不可少的数据,准确地预测煤层厚度,能够给煤矿生产提供有力的地质保障,煤层在地震勘探中属于薄层,其薄层厚度预测一直是公认的难题之一,传统的预测方法是利用钻孔资料的内插对比获得,精度比较低.本文提出了基于三维地震属性数据的粗糙集(RS)-最小二乘支持向量机(LS-SVM)算法模型,用于预测煤层厚度.利用粗糙集对地震属性数据所包含的大量干扰数据进行简约,减少样本维数,将简约后属性数据作为LS-SVM的输入预测煤层厚度.并运用PSO算法优化获得核函数的核参数及最佳正则化参数.实际钻孔数据试验验证了算法模型的可行性,并对整个研究区进行了煤层厚度预测,取得了较好的效果,最后探讨了VTK支持下的煤层可视化技术,对煤层实现了三维展示,达到了预期效果.     

THE INFLUENCE OF OBLIQUELY DIPPING DISCONTINUITIES ON THE USE OF RAYLEIGH CHANNEL WAVES FOR THE IN-SEAM SEISMIC REFLECTION METHOD *

The geological sequence rock-coal-rock represents a seismic low-velocity channel. Channel waves generated in a coal seam and their reflections from discontinuities can be used for proving the minability of the seam. To investigate the process of reflection, two-dimensional models of the sequence rock-coal-rock have been investigated by means of the ultrasonic transducer technique. Two-dimensional models have the advantage that the wave field can be observed at an arbitrarily chosen point of the model plate. Thus, by means of these models the direct and the reflected Rayleigh channel wave can be observed along their path of propagation. From the geophysical point of view the various types of discontinuities of a coal seam can be divided into two basic types: one is restricted to the seam, the other includes in addition a fractured zone in the adjoining rock. The investigation of the symmetrical Rayleigh channel wave reflected by a discontinuity yields the following results: For dip angles γ between approximately 90° and approximately 60° the reflectivity is virtually independent of the type of discontinuity. This does not hold for the limiting case of γ= 90° (vertical dip) for which the reflectivity increases with increasing influence of the fractured zone. For dip angles γ between approximately 60° and approximately 40° the reflectivity is still independent of the fractured zone but the shape of the reflected wave deteriorates with increasing influence of the fractured zone. For dip angles γ below approximately 40° the reflected wave deteriorates such that the application of the in-seam seismic reflection method will be difficult or even impossible. The conversion of the direct wave of the symmetrical fundamental mode into a reflected wave of the antisymmetrical fundamental mode has been observed.     

THE INFLUENCE OF AN ASYMMETRY IN THE SEQUENCE ROCK/COAL/ROCK ON THE PROPAGATION OF RAYLEIGH SEAM WAVES*

Small offsets in hard coal seams can be detected with the aid of seam (channel) waves. Transmission and reflection of seam waves depend, among other parameters, upon the symmetry properties of the sequence rock/coal/rock. Two typical unsymmetrical sequences are found in European coal deposits: (i) coal seams with roof and floor of differing acoustic impedance and (ii) coal seams interlayered with rock and soil. Two-dimensional analog models with appropriate impedance contrasts are used to study the effect of the unsymmetrical layers upon the propagation of Rayleigh seam waves. Data analysis is based upon amplitude measurements both parallel and perpendicular to the layers and dispersion curves. The effect of unsymmetrical roof (rock 1) and floor (rock 2) was studied with models containing homogeneous coal seams. Leaky mode wave groups with phase velocities (c_R) in the range between the SV-wave velocities (β_{r1, 2}) of the two rock materials, i.e. β_r1≥c_R > β_r2, form a characteristic part of the Rayleigh seam wave signal. Using Knott's energy coefficient calculations it is shown that in that range energy leakage into the surrounding rock by refracted SV-waves is restricted to only one of the two interfaces, namely coal/rock 2. At the other interface, coal/rock 1, all waves are totally reflected. Thus, the high amplitudes of these leaky mode wave groups are explained by “quasi-normal mode” features. The influence of a dirt bed on wave propagation was studied in models where the roof and the floor have the same elastic properties. The maximum thickness of the dirt bed did not exceed 20% of the total seam thickness. The effect of the bed's location within the seam was also investigated. For all recorded normal-mode wave groups either the total seam or the coal layers could be regarded as wave guides. This was shown by the fact that the phases could be associated with the phase velocity dispersion curves calculated for the symmetrical sequence rock/coal/rock. These curves are relevant under the condition that the thickness of the coal layer assumed under the calculation coincides with the thickness of the effective wave guide of the respective wave groups. Wave groups guided in the total seam are not influenced by either the thickness or the position of the dirt bed. On the other hand, for wave groups guided in the coal layers, the quotient of signal amplitudes in the coal layers is influenced by the position of the dirt bed.     

煤矿冲击地压的微地震监测研究

为了研究煤矿冲击地压与岩层在三维空间破裂之间的关系，进而探索依据岩层破裂规律预测和预报冲击地压的可能性，文中采用自行研制的防爆型微地震定位监测（MS）系统，基于定位原理，监测了山东华丰煤矿冲击地压煤层（四层煤）及其解放层（六层煤）开采过程中的岩层破裂过程和二次应力场分布变化的过程，得到了如下结论：冲击地压的发生与岩层破裂密切相关，四层煤下顺槽处于六层煤顶板破裂区的外边缘时，正处于高应力区内，在此处掘进容易引发冲击地压，必须将六层煤下顺槽位置向实体煤侧移动20 m以上，或将四层煤下顺槽位置内移20 m以上，才能消除四层煤的冲击地压；六层煤和四层煤开采时，工作面前方断层活化的距离分别为250 m和350 m左右，根据这一距离，及时对断层带进行卸压处理，可以消除由断层带引发的冲击地压；监测显示了工作面周围岩层的三维破裂形态和范围，为矿井确定防水煤柱的高度提供了可靠的依据；监测证明了厚层砾岩的破裂、断层活化、采场附近关键层的破裂是引起冲击地压的主要原因，证明了所研制的硬件和定位软件具有较高的精度和实用性，可以在煤矿和边坡、隧道等领域应用.     

微小盆地倾斜煤层采空区瞬变电磁法探测

为研究微小含煤盆地倾斜煤层采空区的瞬变电磁法探测效果,以云南省新近系向斜盆地采空区为研究对象,从数值模拟与现场实测两方面对瞬变电磁探测效果展开研究。首先,针对研究区微小盆地构造条件建立倾斜煤层地电模型,以正演模拟和电阻率计算论证理论可行性;其次,根据模拟结果设置工作参数进行现场数据采集,以倾斜含煤段作为电性标志层追踪电阻率异常并推断采空区分布范围;最后,采用井下超前钻探对推断的采空区进行验证。结果表明,瞬变电磁法适用于探测微小盆地的构造变化而引起的地电结构的改变,探测结果清晰显示盆地倾斜含煤地层的起伏变化,能准确反映采空区的分布。      

ON THE ABSORPTION-DISPERSION CHARACTERISTICS OF CHANNEL WAVES PROPAGATING IN COAL SEAMS OF VARYING THICKNESS1

The WKB-method is used for the derivation of both the complex dispersion relation and displacement functions for Love channel-waves that propagate in a coal seam of varying thickness. The constant Q-model is used to describe the anelastic friction. With numerical solutions of the absorption-dispersion relation, the influence of thickness changes on the phase velocity and absorption coefficient of Love seam-waves is analysed at various frequencies. It is shown that the changes in the seam thickness can be optimally detected around the average Airy-phase frequency. An equivalence is pointed out between the wave guide structures: homogeneous with varying seam thickness and horizontally inhomogeneous with constant seam thickness.     

地震反射法中薄煤层分辨能力的研究

本文以非线性地震层状构造理论为基础,对薄层分辨率进行了研究,研究中采用理论计算和合成地震记录,并用超声地震模型试验加以验证。结果表明,薄层可检测性准则,应是它的复合反射波的振幅不小于围岩中较强反射波的振幅。由Farr提出的可检测薄层的极限厚度为λ/12（λ为薄层中地震波波长）,是在薄层顶、底界面反射系数很小时的近似值。指出,当薄层顶、底界面反射系数较大时,如煤层,其可检测性高于Farr定义,且随界面反射系数的增大或频率的提高而提高;适当地提高地震反射波的频率,就能得到厚2-3m薄煤层的大振幅、高信噪比的反射波。上述结论均用煤田地震勘探实例证实。     

含小断层煤层Rayleigh型槽波波场和频散分析

煤层隐伏小断层在煤田地质勘探期间能否查明,是影响煤矿安全生产的主要地质因素.煤层中传播的地震槽波,非常适用于探测煤田异常构造.本文利用谱元法模拟计算了含断层模型Rayleigh型地震槽波的产生、传播过程,对于直达槽波、反射槽波、透射槽波进行了波场特征分析,频散特征分析,频谱特征分析.根据不同小落差断层模型（垂直断距分别为1/4、1/2、3/4、1个煤厚;断层倾角分别为90°、60°、45°）,分析了Rayleigh型槽波传播过程中断层对反射槽波、透射槽波能量、频谱的影响效应.基于以上分析,对于小断层模型中的Rayleigh型地震槽波取得了一些规律性认识,并对Rayleigh型地震槽波的勘探应用做了一些探讨.     

井间地震技术在松南油气开发中的初步应用研究

为了研究松南地区陆相砂泥岩薄互层储层岩石物性横向变化、微构造等对油气聚集的影响和探索利用高分辨率井间地震技术直接指示油气分布的可能性,开展了井间地震及地面小三维地震、VSP、测井等立体地震观测．使用了自行研制的井中炸药震源和常规地震记录仪器．采用层析成像方法、反射资料叠前偏移成像方法等对采集到的资料进行研究,得到了不同分辨率的地下构造和岩石物性信息,展示出不同方法技术在分辨薄储层能力上的差异．高分辨率的井间地震成果较好地实现了井间地层对比,查清了两井间储层横向变化和油气分布情况．层析速度与构造信息等的综合应用解释了两井油气产能差异的原因,建立了油气地质模型．所得成果显示出井间地震技术在油气开发中的潜力．     

井间地震物理模拟研究

井间地震资料具有极高的分辨率,但是,其波场十分复杂,特别是有效一次反射波场能量较弱,且往往被管波等强相干干扰淹没,波场的识别与分离难度较大.地震物理模拟技术是认识复杂地震波场的有效手段.我们通过单一地质体模型、复杂地质体模型和真实井间模拟模型等多种逼真地质模型的物理模拟,揭示了井间地震观测下直达波、透射波、反射波、折射波,多次波和导波等各类波型的特征.物理模拟试验表明,在炮检域平面上分析直达波的信噪比与能量分布,可以使处理人员对旅行时的误差有更直观的认识.所以识别初至与拾取旅行时间时,不仅要在共震源点道集(CSG)上分析拾取,而且还要在共炮检距道集(COG)上分析拾取,这样就提高了直达波识别的可靠性与拾取时间的精度.     

Dispersion features of transmitted channel waves and inversion of coal seam thickness

In-seam seismic survey currently is a hot geophysical exploration technology used for the prediction of coal seam thickness in China. Many studies have investigated the relationship between the group velocity of channel wave at certain frequency and the actual thickness of exposed coal beds. But these results are based on statistics and not universally applicable to predict the thickness of coal seams. In this study, we first theoretically analyzed the relationship between the depth and energy distribution of multi-order Love-type channel waves and found that when the channel wave wavelength is smaller than the thickness of the coal seam, the energy is more concentrated, while when the wavelength is greater than the thickness, the energy reduces linearly. We then utilized the numerical simulation technology to obtain the signal of the simulated Love-type channel wave, analyzed its frequency dispersion, and calculated the theoretical dispersion curves. The results showed that the dispersion characteristics of the channel wave are closely related to the thickness of coal seam, and the shear wave velocity of the coal seam and its surrounding rocks. In addition, we for the first time realized the joint inversion of multi-order Love-type channel waves based on the genetic algorithm and inversely calculated the velocities of shear wave in both coal seam and its surrounding rocks and the thickness of the coal seam. In addition, we found the group velocity dispersion curve of the single-channel transmitted channel wave using the time–frequency analysis and obtained the phase velocity dispersion curve based on the mathematical relationship between the group and phase velocities. Moreover, we employed the phase velocity dispersion curve to complete the inversion of the above method and obtain the predicted coal seam thickness. By comparing the geological sketch of the coal mining face, we found that the predicted coal seam thickness is in good agreement with the actual thickness. Overall, adopting the channel wave inversion method that creatively uses the complete dispersion curve can obtain the shear wave velocities of the coal and its surrounding rocks, and analyzing the depth of the abruptly changed shear wave velocity can accurately obtain the thickness of the coal seam. Therefore, our study proved that this inversion method is feasible to be used in both simulation experiments and actual detection.