综合地震勘探方法在陕北煤田采空区探测中的应用

基于陕北黄土塬煤层采空区地震勘探方法研究项目,在该类复杂地质背景和地震地质条件下进行了煤层采空区多种地震探测方法的应用。探测中依据不同的地震勘探方法原理,针对同一目标地质体,提取了识别其地震波场的响应特征:①在地震反射时间剖面上呈现反射波组中断缺失、不连续特征;②在折射层析速度剖面上反射为低速异常;③面波记录出现强能量基阶面波传播中止(波散),面波速度剖面呈现为低速异常,频散曲线发生畸变(呈"之"字型回折);④煤层采空区边界显现出散射波特征。这些地震波场特征在鄂尔多斯等地的煤层采空区探测中也已得到验证。陕北煤田采空区探测实例表明,采用综合地震勘探方法探测可有效解决单一方法的多解性问题,提高其成果的准确性和可靠性。     

用地震反射波定量解释煤层厚度的方法

煤层变薄模型地震反射特征的研究发现:对层厚小于λ/4(λ为地震主波长)的煤层来说,煤层顶、底板的反射波迭加形成复合反射波,几乎不能拾取顶底板反射波的初至时间;地震波的动力学特征(振幅等)与煤厚不是一一对应的,而是出现多个极值点,在层厚为λ/4、λ/2等处出现极值,但在区间〔0,λ/4〕及〔λ/4,λ/2〕内振幅是层厚的单调函数。因此,利用地震波的运动学及动力学特征就可以进行煤层厚度的定量解释。山西朔县地震资料的定量解释结果与钻探资料对比最大误差不超过0.6m,证明了该解释方法的可靠性。     

利用地震时间剖面反射波特征解释煤矿采空区的方法

为排除安全隐患,对山西省某煤矿周边的小煤窑采空区进行探测。在资料处理中,通过对比性研究,发现采空区的时间剖面会出现,反射波同相轴下凹时间发生延迟、反射波同相轴中断、不连续或间断连续等现象。利用地震时间剖面反射波的特征对采空区进行解释,查出了勘探区内3号煤层采空区7处,,共计面积约0.808 km2,其中3个采空区现已揭露,采空区的解释范围和所揭露的基本相符,解释成果得到很好验证。     

地震超前探测技术在老窑采空区探测中的模拟与应用

巷道前方的地质异常与巷道内地震测线存在角度关系,依据地震超前探测原理,其反射波时距曲线为一直线且呈现负视速度特征。据此建立一采空区地震超前探测模型,以研究采空区条件下检波器后置观测系统的地震波场传播特征。通过对全空间地震波场的分析发现,距离震源越远的检波器越先接收到迎头前方异常界面的PP波与S-S波,为此采用τ-p域滤波或F-K域滤波对地震波场进行分离解释。以山西临汾某矿井2号煤层老窑采空区超前探测为例,通过反射波提取、绕射扫描及叠加偏移对巷道前方进行成像,解释迎头前方35m处存在异常,经钻探验证其为老窑采空区,取得了较好的应用效果。     

河南省煤系地层地震反射波发育特征

对河南省不同区域的煤系地层反射波发育特点进行分析研究、归类总结和正反演对比,建立了地震波-地质层位的对应关系,有利于解释人员从时间剖面上准确分辨出新生界、煤系地层和煤系基底反射波组,确定煤层反射波及煤层赋存状况,为类似地区的地震资料解释工作提供科学的指导。     

三维地震技术在探测煤矿腔状采空区中的应用

采用三维地震勘探方法对采空区进行勘探,虽积累了大量的经验,但在实际应用中,解释误差依然存在,尤其是煤层顶板悬空,并在一定范围内呈"腔状"类型的采空区,会出现较高的"漏检率"。为此根据实际地层序列设计了地质模型,对采空区的地震反射波场特征进行了研究。将腔状采空区充气、充水时的正演地震剖面,与煤层开采前正常地层波场响应特征进行对比发现,煤层开采后将会产生比正常波场能量更强的反射波组。另外根据腔状采空区充水和充气反射波最大振幅及反射波频谱对比结果,还发现充气时产生的反射波能量比充水时产生的反射波能量强;充气时产生的反射波频率比充水时产生的反射波频率要低。山西左权佳瑞煤业有限公司的应用实例佐证了三维地震勘探技术探测腔状采空区的有效性。     

不同年限采空区下地震勘探效果实例研究

随着煤炭资源的持续开发,部分煤矿上组煤已经开采殆尽,亟需开展下组煤的探测工作。受上组煤采空影响,下组煤地震波能量吸收和散射衰减严重,资料信噪比低,三维地震对采空区下组煤的探测尚属于探索阶段。以冀中能源东庞矿采空区下组煤三维地震勘探项目为例,采用“两宽一高”采集、高精度资料处理和属性体解释等技术,对不同年限采空区下组煤的探测效果进行了对比分析。结果表明:采用“两宽一高”采集技术能够获取采空区下组煤的地震信息;振幅补偿、地震拓频技术使得9号煤反射波波组丰富、连续性好;采空区年限大于10年时,破碎岩层压实,相对稳定,下组煤反射波利于追踪,而小于10年时,岩层破碎未压实,导致下组煤反射波能量弱、杂乱无章。这一认识对于类似煤矿采空区下组煤探测具有一定的指导意义。      

砾石层覆盖区煤田高精度三维地震勘探技术在张家口蔚县单侯井田的应用

以张家口蔚县单侯井田三维地震勘探为例,在松散厚砾石层覆盖区使用可控震源组合激发进行三维地震勘探,获得了较高质量的原始资料.地震资料经精细处理及三维多属性地质解释,断层的断点清晰、自然,煤层缺失区反射波特征明显,褶曲(向斜、背斜)显示明显.在使用炸药震源难以取得较好地质成果的厚砾石层覆盖区,使用可控震源组合激发取得了较满...     

三维地震勘探解释煤层地质异常体的应用

三维地震勘探在控制煤层赋存形态方面已取得了令人满意的效果，但矿井高产高效地质保障系统需要准确圈定“无煤带”、陷落柱、老窑采空区、煤层露头等地质异常体。通过河北、辽宁、河南等地煤矿采区三维地震勘探实例，介绍了确定煤层地质异常体采用的方法：结合钻孔资料进行正演地震模型试验，掌握地质异常体地震剖面特征，进行三瞬处理，研究振幅异常与地质现象的对应关系，更重要的是在地震资料解释方面，要充分利用已知地质资料，依据各种地质现象在地震时间切片（垂直切片和等时切片）、顺层切片、方差体切片上的识别特征解释各种地质异常体。     

基于地震属性分析的红柳林煤矿采空区解释

以红柳林煤矿采空区的三维地震勘探为例,对房柱式采煤形成的采空区的地震波场进行了正演模拟,分析了不同采空区地震波振幅特征、频谱特征及绕射波对采空区地震响应的影响;利用均方根振幅(RMS)属性圈定了小煤窑采空区范围。钻探验证结果表明,利用地震属性解释采空区的应用效果良好。      

Unity of the national and the international in the socio-cultural development of the peoples of the USSR

International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen.     

Report of the restudy of the defined global stratotype of the base of the Silurian System

The Global Stratotype Section and Point （GSSP） for the base of the Silurian System was defined in 1985. Since that time, a number of researchers have suggested that this section has serious deficiencies for use as a GSSP. As a result, in 2000, the Subcommission on Silurian Stratigraphy （SSS） proposed undertaking a formal restu@ of this GSSP, which was subsequently approved by the International Commission of Stratigraphy （ICS）. The result of this restudy was the formal proposal that the current GSSP, at 1.6 m above the base of the Birkhill Shale, at Dob＇s Linn, Scotland, should be maintained as the same locality and stratigraphic level, but the bios- tratigraphical definition of the boundary should be revised. The previously defined, basal Silurian grapto- lite zone, the Parakidograptus acuminatus Zone, should be subdivided into a lower Akidograptus ascensus Zone and a higher E acuminatus Zone. The base of the A. ascensus Zone, marked by the first appearance of A. ascensus, should be regarded as the biostratigraphic mark for the base of the Silurian. This proposal has now been formally approved by the SSS and ICS, and ratified by International Union of Geological Sciences. This is the first GSSP to undergo formal restudy and redefini- tion, and the proposal also included a recommended procedure for restudy of GSSPs.     

Deviation of the major axis of the inertia ellipsoid of the Moon from the direction toward the Earth

It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T ₃ = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″.     

The Tendencies of the Development of the Mineral-Resources Sector at the Turn of the Century

Important tendencies in development of the world mineral-resources sector at the beginning of the 21st century were an increase in production and consumption of mineral materials differentiated by types of metals and nonmetallic mineral raw materials, by countries and regions, as well as the concentration of the production of mineral raw materials in a small number of countries, and a reduction in industrial reserves of minerals in the world economy, even at the current stage of their extraction. These tendencies should be taken into account in working out a strategy for development of the Russian mineral raw-material base.     

Causes of the famine among the rural population of the Sahelian zone of the Sudan

Taking the example of W Sudan, an analysis of the climatic incidents leading to the two recent famine disasters is made. On this natural background, the human side is investigated. Focus is directed towards the fragile economic structure of the famine-prone population groups. An early-warning system for famine in the Sahelian Zone is proposed taking grain production and storage, livestock development and the relationship between the prices of livestock and grain as major indicators.     

东濮凹陷北部沙河街组三段中亚段沉积环境分析

东濮凹陷北部沙三中亚段广泛发育盐岩和烃源岩,这两个看似不能共存的物质却在这里互层共生。该时期研究区沉积特征为多盐韵律与多层烃源岩互层共生、连续沉积,单个盐韵律厚度从几米到十几米,烃源岩有机质丰度高、类型好。平面上,两者在湖盆沉积沉降中心共生;垂向上,高有机质丰度、好干酪根类型与高盐度地层具有较好的对应关系。因而成为恢复古气候和古环境的重要研究对象。通过岩石学、古生物学以及Sr/Ba、B/Ga、(V+Ni+Mn)、Fe/Mn、Sr/Cu、Mg/Ca、V/(V+Ni)、稀土元素含量和氯同位素等方法对凹陷北部沙三中亚段的沉积环境进行研究。结果表明,凹陷北部沙三中亚段为深水沉积的还原环境,古盐度较高,达到半咸水-咸水沉积;微量元素和孢粉化石特征表明研究区沙三中亚段为温暖潮湿的环境。     

郯庐断裂南段研究进展与断裂性质讨论

据1：5万区域地质调查和专题研究资料，就郯庐断裂带是否南延与消失的原因，其与大别—苏鲁造山带交截形成的假位错效应，以及与中新生代沉积盆地形成演化的关系等作了新的阐述。在此基础上，讨论了郯庐断裂带是否为巨大的左行平移断层或转换断层。认为郯庐断裂带可能是在“古郯庐带”的基础上于早侏罗世重新活动、白垩纪强烈活动的地堑型枢纽断裂带。     

The Importance of the Precipitation and the Susceptibility of the Slopes for the Triggering of Landslides Along the Roads

In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning.