Study on Distribution Characteristics of Mining Stress and Elastic Energy Under Hard and Thick Igneous Rocks

In the coal measure strata, igneous rocks are often invaded, and their occurrence, size, and distribution form play an important role in mining safety. The breakage of hard and thick igneous rocks easily induces dynamic disasters, such as rock burst, mine seismicity, gas outburst, and surface subsidence, which seriously threaten mine safety production. In view of the working face with overlying hard and thick igneous rocks, the evolution characteristics of mining stress and energy distribution under hard and thick igneous rocks were investigated. Furthermore, the influence law of different horizons and thicknesses of igneous rock on overlying strata movement law, stress distribution, and energy distribution was analyzed based on FLAC3D numerical simulation. Results show that no evident subsidence of the overlying strata exists before the igneous rock is broken. Additionally, the subsidence amount of the overburden is suddenly increased after the igneous rock is broken, thereby showing significant mutability. Before the igneous rock breaks, a high stress area is formed around the goaf, and the stress concentration gradually increases with the increase of the mining scope. After the igneous rock breaks, the coal under high stress is prone to induce dynamic disasters under the action of strong dynamic load. However, the advanced abutment pressure and stored energy rapidly decreased. The accuracy of the numerical simulation is verified by field monitoring. Results of the study are of considerable significance for safe mining of working face under similar geological conditions.     

浸泡作用下砂岩断裂力学特性及劣化机理

岩石的断裂韧度对于定量评价工程的安全及稳定具有重要意义, 而岩石的破坏常常有水参与, 在库水长期浸泡作用下, 岩石的断裂力学特性将如何变化值得深入研究.基于此, 以库岸边坡典型砂岩为研究对象, 设计了长期浸泡试验, 并基于断裂韧度、变形破坏特征和微观结构变化进行综合分析.试验结果表明: (1)浸泡作用下, 砂岩的断裂韧度具有明显的劣化趋势, 而且劣化幅度有一个先增大后减小的趋势, 浸泡5~6月后, 劣化趋势逐渐减缓;(2)砂岩三点弯曲试验的P-CMOD关系曲线可以比较明显地分成3个阶段: 弹性阶段、屈服阶段、裂纹开展及破坏阶段, 随着浸泡时间的增长, 弹性阶段逐渐变短, 屈服阶段逐渐变长, 裂纹开展阶段曲线下降趋势逐渐变缓, 而且达到开裂峰值荷载对应的切口张开位移逐渐增大, 砂岩有逐渐“变软”趋势, 脆性逐渐减弱, 塑性逐渐增强;(3)浸泡作用导致的润滑、软化和砂岩内部微观结构的变化, 特别是微观裂纹、裂隙的发展是导致砂岩断裂韧度及其他力学参数劣化的根本原因.研究成果对于把握库水长期浸泡作用下砂岩断裂力学特性具有比较重要的参考价值.      

低渗透砂岩油藏沉积物粒度分布特征研究

利用MS 2000激光粒度仪,对胜利油区砂岩油藏中112口井的3000多块样品进行测试分析。实验发现低渗透砂岩油藏与中高渗透油藏不同,其沉积物粒度分布主要存在三种方式,每种方式都有其特定的粒度分布特征,并且与一定的沉积作用相联系。研究表明,沉积岩粒度中值分布、泥质含量、分选性等是影响油藏岩石渗透能力的重要因素,正态分布和混合正态分布能较好地描述低渗透砂岩油藏中沉积物的粒度分布特征。     

疏松砂岩储层窜流通道平面分布规律研究

国内大部分高含水油田,注入水窜流现象较为严重,已成为影响油田高效开发的主要矛盾,对窜流通道形成后渗透率场的计算与描述显得尤为迫切和重要。目前窜流通道参数计算方法,只能计算得到注采井点的渗透率数值,不能计算得到注采井间的渗透率分布状况,并且目前窜流通道渗透率计算方法没有将室内实验结果、数值模拟结果和油藏工程方法结果有效结合起来。以国内某高含水油田为例,通过长期注水冲刷实验,模拟了窜流通道的动态形成过程,归纳出了储层岩石注水冲刷倍数与渗透率之间的关系式。在常规数值模拟计算方法的基础上,将渗透率变化规律模型引入到数值模拟计算中,建立了计算窜流通道平面分布的新方法。以海上某油田的地质模型为基础,计算得到了该油田目前状态的窜流通道渗透率平面二维分布规律。综合对比动态数据法、概率密度模型法、经验公式法和示踪剂测试结果,证明本方法得到的结果真实可靠。     

塔南凹陷下白垩统南屯组砂体展布特征及分散机制

通过对研究区下白垩统南屯组沉积时期重矿物组合、砂岩组合和地震反射特征资料的综合研究,确定了沉积物的物源方向和砂体展布特征。研究发现同生断裂组合对砂体起到了分散及阻挡的作用,根据同生断裂的组合以及与砂体的制约关系,划分出掀斜型阶梯状、未掀斜型阶梯状和极性3种类型的控砂断裂组合。并根据物源特征和砂体展布特征,将控砂断裂组合分为"横向砂体"和"纵向砂体"2种砂体展布类型;综合各类断裂组合对砂体的控制作用,总结出"诱导型"和"遏制型"两种控砂机制模式。本次研究对在断陷湖盆开展构造对沉积控制作用及分散机制研究提供一个实例。     

致密砂岩储层中钙质夹层特征及与天然裂缝分布的关系

鄂尔多斯盆地镇泾区块长8致密砂岩储层普遍发育钙质夹层,本文利用露头、岩芯、薄片及测井等资料,对钙质夹层的岩性特征、电性特征、分布规律以及与天然裂缝分布的关系进行了研究。研究表明,钙质夹层具有明显的低伽马、低声波时差、高密度、高感应的特点,电成像测井表现为明显的亮色条带。钙质夹层主要分布在部分水下分流河道砂体的中部或下部及河口坝砂体的中部或上部,同时也发育在一些分选较好、颗粒支撑的薄层细砂岩中以及砂泥岩的接触地带。钙质夹层内主要发育高角度构造裂缝,不发育近水平成岩裂缝;与非钙质胶结致密砂岩储层相比,钙质夹层脆性较大,天然裂缝更为发育,且大部分裂缝被方解石充填,为无效裂缝;钙质夹层层厚及岩性界面控制着裂缝纵向延伸高度。论文成果对进一步研究致密储层天然裂缝的分布模式,弄清裂缝对注水开发的影响具有重要意义。     

深圳断裂带构造活动性分析

深圳断裂带的活动性关系到深圳发展的前景,从构造地质学、遥感图像、地震学、地貌学和地球动力学的角度出发,论述了深圳及其邻近地区的地质构造背景,阐述了深圳断裂带的构造活动性。通过对断裂带地层剖面和断层物质研究发现,断裂带晚更新世以来没有明显活动迹象;地震活动方面,断裂带所在区域地震活动以微震为主,且震源分布与断裂带产状一致,反映断裂具有一定的活动性;根据地应力监测资料,最大主应力量值小且应力方向北西向,与断裂近乎垂直,不利于断裂活动。综合各方面因素,认为深圳断裂带晚更新世至今活动已经明显减弱;现代微震活动是其构造能量缓慢释放的表现,现今深圳断裂带构造稳定,不会发生较大规模的活动。     

An Experimental Study of the Fracture Coalescence Behaviour of Brittle Sandstone Specimens Containing Three Fissures

To analyse the fracture coalescence behaviour of rock, rectangular prismatic sandstone specimens (80?×?160?×?30?mm in size) containing three fissures were tested under uniaxial compression. The strength and deformation behaviours of the specimens are first analysed by investigating the effects of the ligament angle β₂ on the peak strength, peak strain and crack initiation stress of the specimens. To confirm the sequence of crack coalescence, a photographic monitoring technique is used throughout the entire period of deformation. Based on the results, the relationship between the real-time crack coalescence process and the axial stress–strain curve of brittle sandstone specimens is also developed, and this relationship can be used to evaluate the macroscopic deformation characteristics of pre-cracked rock. The equivalent strain evolution fields of the specimen, with α?=?β₁?=?45° and β₂?=?90°, are obtained using the digital image correlation technique and show good agreement with the experimental results of pre-cracked brittle sandstone. These experimental results are expected to improve the understanding of fracture mechanisms and be used in rock engineering with intermittent structures, such as deep underground excavated tunnels.     

Correlation Study on the Geochemical Characteristics and Brittleness of Tight Sandstone in the Longmenshan Foreland Basin

<正>Through the research of Index of Compositional Variability(ICV)and Chemical Index of Alteration(CIA)about Xujiahe Formation sandstone in the Longmenshan foreland basin.To show the brittle characteristics of the sandstone.Make an analysis of pore development and fracking potential in the tight sandstone gas reservoir.In order to ensure reducing the effect of modern weathering,     

基于砂岩型铀矿原状岩心的渗流特性试验研究

为研究不同围压、不同组合形式下疏松砂岩的渗透率变化规律,以砂岩铀矿原状岩心为试验对象,采用自行研制的HKY-1型长岩心渗流试验仪进行了应力-渗流耦合试验。笔者分别从围压、排列次序和长度占比三个方面开展试验研究,结果表明:1)梯度围压条件下,两段岩心组合后的整体渗透率与围压呈负相关,符合二次多项式函数衰减规律;2)围压梯度递增,多段岩心组合中不同岩性试样孔隙尺寸的差异逐渐减小,细砂岩的排列次序对整体渗透率的影响也随之减弱;3)5 MPa围压作用下,当两种试样长度占比为1∶1时,组合试样的整体渗透率与目标试样长度占比之间的变化规律符合幂指数分布,粗砂岩组递增,细砂岩组递减,中砂岩组为近似水平分布。     

The Constitute of Thick Tight Sandstone Belt and the Main Controlling Factors of Effective Reservoir

<正>1 Introduction The western 3D region of the Sulige gas field is located in the Yi-shan slope north of northern Su47 and south of Su48 medium sand belt of the Ordos Basin,the area of it is about 431 km2.The average thickness of He8 is 69.1m,the thickness of it is 83.9m;The effective sand thickness is14.4 m,the thickness of it is 21.5m.     

黄骅坳陷北部马头营凸起馆陶组砂体成因及展布特征

综合运用钻井岩心、测井、三维高分辨率地震等资料,对渤海湾盆地黄骅坳陷北部马头营凸起馆陶组砂体成因及展布特征进行了系统的研究。结果表明:馆陶组沉积前期发育2条规模大、延伸较远,呈近NS、NNW—SSE展布的沟槽,指示物源主要来源于北部燕山褶皱带。馆陶组为冲积扇-辫状河-曲流河沉积序列;馆三下段为冲积扇扇中辫状河道和河道间漫流相,发育扇中辫状河道成因砂体;馆三上段为辫状河道和泛滥平原相,发育河床滞留沉积和心滩成因砂体;馆二段和馆一段为曲流河沉积,河床滞留沉积、边滩、决口扇和天然堤是主要的砂体成因类型。馆陶组可划分为3个长期旋回,7个中期旋回,16~19个短期旋回;以短期旋回为单元,建立了馆二段等时地层对比的高分辨层序地层格架;层序格架控制着砂体的分布模式,馆二段短期旋回的下部砂岩发育,是主要的储集层。层控测井约束反演提高了馆二段薄互层河道砂体预测的精度,馆二段各砂层组反演预测平面砂地比反映河道砂体呈NE—SW向的展布特征。     

软硬互层金刚石复合片钻头在地浸砂岩型铀矿中的研究及应用

针对近年在巴音戈壁盆地及鄂尔多斯盆地钻探所遇到的复杂地质情况,研究试验了PDC钻头,在地浸砂岩铀矿钻探生产中取得了良好的效果,并制定总结了相应的钻进参数.     

伊犁盆地南缘可地浸砂岩型铀矿化特征及空间展布规律研究

本文从盆地矿岩型铀矿产出层位，岩相及岩性序列组合特征，含矿砂体特征，铀矿化时代等方面总结了盆地砂岩型铀矿化的形成特征，提出了盆地卷状砂央型铀矿化是早期板状沉积一地预富集矿化基础上发展而来的成因观点。文中还对盆地铀矿化的空间展布规律进行了研究，指出了含矿性序列组合差异是导致盆地南缘东西矿化类型差异的原因，盆地后期抬升剥蚀程度差异是决定了主矿化层位高低差异的原因，并对盆地的找矿方向提出三条重要的参考意     

岩石受热后的强度,变形破坏特性的微观研究

本文对砂岩、灰岩、大理岩在不同温度条件下的单轴抗压强度进行了实验研究,并对岩石在各种温度下结构变化进行了镜下分析,探讨了岩石受热后的破裂机理,定性定量地分析了岩石裂纹随温度变化而发展的规律。研究和分析结果表明:在热应力和外应力的作用下,随着温度增加,砂岩单轴抗压强度有增加的趋势,而灰岩、大理石的强度则有所降低。温度对这几种岩石的变形和破坏特性也有很大影响。     

Fracture flow modelling based on satellite images of the Wajid Sandstone, Saudi Arabia

Large-scale geological features have been identified by satellite imagery and global positioning system data in the Wajid Sandstone in Saudi Arabia. The main objective is to evaluate the importance of fractures for the overall flow behaviour in this fractured rock aquifer and to estimate in-situ hydraulic apertures. Data on fractures and lineaments were available for three outcrops. By applying a “cut-out” routine on the fracture endpoint data of these fracture trace windows, three deterministic discrete fracture networks (DFN), with an area of 100 m?×?100 m, could be generated. These were used to simulate the fracture flow and to determine the hydraulic conductivity tensors. Using additional data on hydraulic pumping tests and matrix conductivities, in-situ hydraulic apertures could be determined. Average in-situ hydraulic apertures range from 1,300 to 1,700 µm. Observations from the field support these results. In addition, a hydraulic conductivity ratio between the matrix and fracture system was used to identify the contribution of the DFN to the overall fluid transport. A ratio of 10.4 was determined, which indicates that the effective flow behaviour in the Wajid Sandstone aquifer is not entirely dominated by the fracture system, though evidently strongly controlled by it.     

Research on Roof Fracture Characteristics of Gob-Side Entry Retaining with Roof Cutting and Non-pillar Mining in Thick Coal Seam,China

Geotechnical and Geological Engineering - Based on the S1201-2 large height mining in the 2–2 coal seam of Ningtiaota colliery with on-site microseismic measurement, physical simulation and...     

鄂尔多斯盆地上古生界两大气田不同石英砂岩储层 特征对比研究

通过对鄂尔多斯盆地上古生界榆林气田和苏里格气田石英砂岩储层特征的对比,指出榆林气田山2段石英砂岩储层属于相对低孔高渗型储层,苏里格气田盒8段石英砂岩储层属于相对高孔低渗型储层;通过分析两类石英砂岩的物源、沉积条件和成岩作用等因素,认为沉积期海水改造及后期成岩作用形成了榆林气田山2段储层的低孔高渗,而沉积时的高杂基含量与后期成岩共同作用形成了苏里格气田盒8段储层的高孔低渗。     

漳州地热田基岩裂隙水系统温度分布特征

为研究漳州地热田基岩裂隙水系统温度分布特征,建立了新的三维基岩裂隙水系统概念模型,并利用Fluent软件求解模型。结果表明:基岩裂隙热水温度场受到断裂区的强烈控制,在北东—南西向断裂中,强烈对流形成的高温热柱刺穿了基岩顶部形成热田高温中心;基岩热流在断裂区中部高温区达到最大,在北东—南西方向上最大值为343.02mW/m2,在北西—南东方向最大值为368.72mW/m2,并向边缘逐渐降低;第四系孔隙水的存在和运动使得地表热流的最大值和局部值降低。未来漳州热田应加强深部温度的测量研究。