塔里木盆地西南坳陷山前带复杂地震资料“六分法”叠前去噪方法应用研究

塔里木盆地西南坳陷山前带勘探程度较低,是开展油气勘探的重要潜力区之一.受地表条件复杂、近地表激发条件差、目的层埋藏较深等地震地质条件的影响,研究区地震资料信噪比低、品质较差,严重地制约了地震资料解决地质问题的能力.本文在分析研究区新采集的深反射地震资料基础上,根据不同类型地区地震数据记录特点和噪声分布规律,采用"六分法"叠前去噪方法进行噪声压制,在实际资料处理中取得了较好的应用效果,中深层资料信噪比得到较大程度的改善.     

高精度组合式轻便小型可控震源的研究

由于自动控制、信号叠加等技术的不断发展,使得可控震源不断完善,成为我国地震勘探的重要手段之一.高精度组合式轻便小型可控震源是地震勘探中用于浅层地震勘探的一种高精度的激振设备,其组合安装模式适合于特殊复杂的野外环境,可以实现流动野外地震观测,能够产生高重复性,高精度的叠加信号,弥补了炸药震源在地表条件差及城市环保区无法施工的缺陷,在中浅层勘探中取得了较好的效果.发展适用于中浅层地震勘测的高精度轻便小型可控震源应用于地震野外勘探,也适应了当前技术及市场的需求.本文从工作原理、系统构成和结构特点等角度对高精度组合式轻便小型可控震源进行了初步的研究,并针对野外的数据验证其可靠性和实用性.     

发挥物探作用提高勘探效果

在煤田地质勘探中,钻探、地震、测井等多种勘查手段有机结合,提交综合研究成果,是山东省煤田地质局走出的综合勘探的成功道路.发挥物探的作用是取得最佳勘探效果的关键.本文系统总结了煤田综合勘探方法,分析了物探方法的应用.以中日合作勘探实例阐明了发挥物探作用,提高构造勘探精度,开拓岩性勘探领域,促进勘探方法改革,取得显著的经济效益和社会效益的新型勘探道路.     

多采样率地震勘探技术（MrSET）探讨

时间采样以及空间采样问题是地震勘探基本问题,空间采样方式包括规则采样、非均匀(非规则)采样、随机采样等.从地震波场的带限性、空间域非均匀性、地下构造多样性出发,提出多采样率地震勘探技术(MrSET),尝试组合不同空间采样方式.多采样率地震勘探观测系统设计一般应满足5项准则,探讨了多采样率数据处理基本方法,并以合成数据和实际数据的处理效果为基础,总结了多采样率地震勘探技术的7个方面优势.在相同道密度前提下,与规则采样相比,多采样率地震勘探技术更能满足复杂地震波场、弱能量绕射波与散射波充分采样的需要,是一项能提高反射地震数据成像精度的地震勘探技术,经过进一步研究将有巨大潜力成为(陆上、海洋)节点地震勘探时代常规技术.     

试论复杂地质体的油气地震勘探

论述了我国油气勘探工作中反射地震的发展历程,指出地震勘探中信噪比与分辨率之间的矛盾,针对中国前新生代海相残留盆地具有埋藏深、演化历史长、经受地质作用多,以致地表和地下条件都很复杂的特点,〖HT5”H〗提出了复杂地质体油气地震勘探的理念和方法途径〖HT5”K〗.我国油气资源多存储于复杂地质体如生物礁、鲕滩、风化壳、古潜山等储集体之中.不能完全搬用陆相油气勘探的经验.应在活动论大地构造理论指导下,根据“区域约束局部,深层制约浅层”的勘探经验,探索测区的时空演化规律,设计复杂地质体的观测系统,采取高密度连续采集技术,获取反射地震资料,再进行高分辨率与高信噪比的处理,从而使地震采集、处理与解释一体化,减轻山地采集困难,获取深部成像资料,在新的高度上寻找在复杂地质体中的油气资源.使地震勘探能在中国油气二次创业中发挥重要作用.     

叠前时间偏移技术在淮北某煤矿采区三维地震勘探中的应用与效果

淮北某煤矿采区三维地震勘探地质条件极为复杂,区内褶皱、断层构造发育,常规叠后时间偏移处理很难准确成像,给后期资料解释工作带来不利影响.针对这一问题,采用叠前时间偏移技术,结合煤田地震勘探特点,对影响叠前偏移处理质量的关键步骤（预处理、静校正、叠前去噪、时间域速度模型建立）进行了研究,取得了显著效果.利用叠前偏移数据体解释,最终圆满完成了地质任务.本文通过应用实例,说明了煤田地震勘探资料处理利用叠前时间偏移技术对复杂构造成像效果较好,信噪比提高,断点解释更可靠.     

地震采集技术在油田开发中的应用及相关问题探讨

随着老油区勘探开发的深入,勘探开发的难度越来越大.辽河油区的特点是储集体主要为陆相复杂小断块和复杂隐蔽岩性圈闭.目前开发面临的难点表现在四个方面：深、隐、低、小.“深”是指勘探目标埋深不断加大;“隐”是指勘探对象的隐蔽性不断增加;“低”是指低渗透、特低渗透油气藏所占的比例不断上升;“小”是指勘探对象的单元储量规模越来越小.从目前国内外地震技术的应用现状来看,要解决上述问题有以下两种有效途径：一是高密度地震勘探技术,二是开发地震技术,主要包括井间地震、多分量地震、VSP测井和四维地震技术.本文介绍了辽河探区近年来地震技术在油田开发中的应用,并对辽河探区下步针对油田开发的地震技术发展思路进行了分析^［1~5］.     

基于近地表多因素的频率响应特征分析及应用

随着勘探进程的不断深入,胜利探区勘探目标开始转向岩性隐蔽油气藏以及微幅构造等复杂地质目标.为寻找中小型、隐蔽性油气藏,对地震分辨率提出了更高的要求.在炸药震源施工区域,近地表速度、虚反射界面、激发岩性是影响激发频率的三种关键因素.本文针对黄河三角洲近地表复杂结构与多种岩性交互沉积等因素引起单炮品质差异明显的特点,通过综合应用地质学、岩土工程、测井工程等理论和方法,对近地表多种因素及其频率响应特征进行了研究,在此基础上形成了多因素激发井深约束设计方法,在胜利探区多个区块进行了应用,取得了较好的效果.     

在平原复杂地区煤田三维地震资料采集和处理的应用

本文介绍了在平原复杂地表及地质条件下开展三维地震勘探的资料采集和处理的过程,并提出了针对性的勘探方法和处理技术,以保证野外资料采集和数据处理的质量。通过对三维地震勘探的野外资料科学采集和高质量的数据处理,说明了三维地震勘探在水网区(河流、鱼塘、水库)、铁路、村庄及工厂、地下构造复杂等等的地区取得了成功,并为今后地表及地质复杂地区的煤田三维地震勘探工作提供了借鉴经验。     

海域岩石圈三维结构研究中地震方法的应用

岩石圈三维结构的研究,尤其是海域岩石圈三维结构的研究,需借助地球物理勘探手段.本文主要讨论南海海域岩石圈三维结构研究中所采用的几种地震勘探方法以及它们的应用效果,其中包括单船反射地震勘探、双船反射、折射地震勘探、海底地震接收以及地震层析成像等.     

云南腾冲地区三维地震定位

本文利用中国数字测震台网和流动台站的地震资料,基于参数优化的AICD自动拾取算法和质量评估方案得到了高质量的震相到时,并在此基础上使用一维、三维定位方法对腾冲地区的799次地震事件进行了重新定位。定位结果显示:水平方向上,一维、三维重定位结果相差较小;深度方向上,三维定位的震源成丛分布比一维定位结果更加密集,地震主要位于地壳内低速层之上。分别利用一维、三维定位方法对典型地震、人工震源进行定位,结果表明,三维定位的精度明显优于一维定位,其在水平、深度方向上的平均绝对定位误差分别为0.7 km和1.3 km。      

考虑视觉传达效果的震后区域三维图像虚拟重建

传统二维震害图像方法对震后区域进行研究时,由于其拍摄角度具有局限性,震后区域图像的视觉效果不理想。提出基于三维激光扫描技术的震后区域三维虚拟重建方法,采用三维激光扫描仪测量震后区域,获取该区域的点云数据,采用Cyclone软件合并点云数据后,得到震后区域拼接后的整体点云图,将该图点云数据进行去体外孤点、去噪声点以及点云取样等处理后实施封装,在封装的点云数据上采用Sketch模型实施贴图操作,实现视觉传达效果理想的震后区域三维图形的虚拟重建。实验证明,所提方法对震后区域的三维图像虚拟重建结果精度高、视觉效果好。     

Numerical estimation of site effects in the city of Arica due to natural soil variability using the spectral elements method

In recent years, because of a seismic gap of 136 years in the north of Chile, several studies have been carried out with the purpose of characterizing the dynamic properties of the soils of the most populated cities in this area. The purpose of this work is to estimate, by numerical modeling, the seismic amplification of a densely populated area of the city of Arica. Spatial distribution of main soil dynamic properties has been obtained from a detailed geophysical survey, including surface-wave based methods and gravimetry. To estimate the site effects, we solve the wave propagation equation in full heterogeneous media by the spectral element method. This method allows including the topography, the irregular contact between soils and bedrock and heterogeneities of main materials’ properties along the computational domain. The inelastic behavior of the soil has been considered, using stiffness degradation and damping curves. The computations were done using the high performance open-source numerical code SPEED. Results from the distribution of the peak ground acceleration are compared against standard 1D horizontally layered modeling using equivalent linear and nonlinear viscoelastic approximations of nonlinear soil behavior. Linear viscoelastic results indicate that the north area of the city of Arica is not especially prone to tridimensional site effects induced by soil’s natural variability and the apparent bedrock geometry. Nevertheless, non-conservative differences of about 20% between 1D v/s 3D analyses were found under inelastic material behavior. In general, the two 3D approaches followed to include soils’ nonlinearity provide similar site amplification estimates.     

徐闻地区综合地球物理勘探方法应用研究

徐闻地区位于北部湾盆地向雷州半岛的延伸部分,具有较好的油气勘探前景.2003年至今,江苏油田在徐闻地区先后开展了重力、大地电磁测深、二维地震和三维地震,以及钻探、VSP和试油测试等油气勘探工作.徐闻地区存在比较特殊的地表与地下地质条件.工区跨越半岛陆上和浅海水域,浅表层多套火成岩覆盖(出露),深层构造破碎、地震反射成像困难.因此,开展了具有针对性的综合地球物理方法(重力、大地电磁测深和地震)研究与勘探实践,克服了单一地球物理方法的局限性,获得了较好的数据资料,减少了多解性并为该地区的油气发现奠定基础.     

台湾地区地震的空间关联维特征与构造环境研究

采用关联维方法对台湾地区地震活动的空间特征进行了研究。先利用 10 0a来台湾的地震目录计算各个地震区、带的关联维数 ,将地震空间分布的分形特征定量表达出来 ,然后综合分析地震空间分布的关联维数和孕震构造环境之间的关系 ,得出了以下结论 :1)台湾东、西部地震区由于地震属于不同的大地构造单元 ,因此关联维数有较大的差异 ;2 )在各地震区内部的各个地震带由于板块构造、地壳结构、活断层分布上的差异 ,而具有与其构造特征相对应的关联维数 ;3)各地震带内部的各个不同的部位又由于不同的构造应力场 ,而导致地震分布上出现不同的丛集性 ,表现为不同的关联维数。这些结论充分说明通过关联维分析所得到的地震活动的空间图像与地震活动所代表的不同地质构造背景有着良好的对应关系     

Using geophysical methods to define the attitude and extension of water-bearing strata in the Miocene sediments of the Pannonian Basin

In the area near the village of Jazak (southern part of Fruška Gora mountain, Serbia), hydrogeological investigations were carried out for the purpose of finding a water supply source to provide an adequate volume of water for a mineral water bottling plant. The first exploratory borehole (IBJf-1) penetrated a water-bearing layer of Miocene organogenic limestones. This aquifer has a thickness of about 30 m and a yield of only 2.2 l/s, which falls short of the required water volume (5 l/s).The objective of further exploration was to define the attitude and extension of the aquifer and thus select a more favourable site for a new exploratory borehole that would secure the required volume of water. For this purpose, geophysical exploration was carried out in 2003 through vertical electrical sounding (VES) and high-resolution 3D reflection seismic methods. The VES measurements enabled determination of aquifer depth and indicated that the water-bearing strata extend over the entire area studied. However, because of the equivalence problem, it was not possible to determine the thickness of the water-bearing stratum based solely on the VES data. Thus, the 3D seismic method was used in the second stage of investigation. A low-cost 3D seismic survey was carried out with fixed receiver lines, using a vibrator as the source of the seismic waves.From the 3D seismic data it was possible to determine the aquifer thickness. The depth of the aquifer determined by interpretation of the 3D seismic data was in accordance with the depth determined by the VES method. Based on the assumption that the hydraulic conductivity of this formation is identical or similar over the entire area, as well as the fact that the first well showed the presence of a subartesian aquifer, we proposed drilling another borehole (IBJf-2) in the zone where the data indicated that the water-bearing stratum was much thicker. The data obtained by drilling and coring were in agreement with the predicted aquifer thickness. Pumping tests showed that the water discharge in borehole IBJf-2 was 6 l/s.The results show that the objective of delineating the groundwater body by combined application of two geophysical methods (VES and 3D seismic) was successfully performed.     

预测多次波的逆散射级数方法与SRME方法及比较

逆散射级数方法和SRME方法是典型的两类基于波动方程的无需地下结构信息的自由表面多次波预测方法,本文详细讨论了这两类方法的基本思想、方法原理和实现思路,并对2维逆散射级数方法进行了降维简化,推导给出了1.5维逆散射级数衰减自由表面多次波的方法,减少了计算量,并降低了对3维规则观测系统的要求.利用经典SMAART模型数据测试比较了2维逆散射级数方法、1.5维逆散射级数方法及2维SRME方法预测自由表面多次波的效果及优缺点,比较了三者在方法实现、并行计算效率及对数据要求上的异同,并结合分析比较结果,给出了实际应用中方法选择的建议.     

Three-dimensional boundary element reservoir model for seismic analysis of arch and gravity dams

The boundary element method has been successfully applied in the past to the analysis of hydrodynamic forces in two-dimensional infinite as well as two- and three-dimensional finite reservoirs subjected to seismic ground motions. This paper presents the results of more recent research on the application of the constant boundary element method to the 3D analysis of reservoir vibration. Special boundary conditions, previously used in the 2D case, to treat infinite radiation damping and damping from foundation soil and banks have been incorporated in this formulation. Numerical results for vibration of a 3D infinite rectangular reservoir as well as of a 3D infinite reservoir impounded by an arch dam are presented and compared with some existing results obtained by other researchers.     

中朝地台东北缘地区的地震层析成像

根据中朝地台东北缘地区 (东经 1 1 7°0 0′— 1 2 6°0 0′ ,北纬 36°0 0′— 44°0 0′) 1 980— 1 997年的 380 0 0余条P波走时数据 ,利用正交投影法重建了该区地壳和上地幔的三维速度结构 .通过分析及同人工地震测深剖面的详细对比 ,证明了成像结果的可靠性 .结果表明 :中朝地台东北缘地区地壳上地幔介质存在显著的横向不均匀性 ,直至 1 2 0km深度处依然明显 ;地壳上部的速度图像清楚地反映了不同岩石单元的分布与该区不同性质的基岩分布基本吻合 ;从上、中地壳的速度图像中发现了研究区存在海城、朝阳、义县、丹东南、唐山等几个低速异常区(即速度逆反层区 ) ,其中海城、唐山、朝阳等地区的壳内低速层已由深地震测深资料所证实 ;研究区陆地发生的几次强震均发生于壳内低速层上方的高速脆性介质内 ,而渤海发生的强震 ,此现象不明显 ,但都发生于横向介质速度显著突变的位置 ;在地壳不同深度上发现了普兰店至山海关横跨渤海的北西向低速异常带 ;地震层析二维速度图像与深地震测深资料的对比表明 ,研究区利用地震层析成像技术 ,在一定条件下可以获得与人工地震测深相似的效果     

The seismic microzonation of the city of Catania (Italy) for the maximum expected scenario earthquake of January 11, 1693

Safety against earthquake hazards presents two aspects: structural safety against potentially destructive dynamic forces and site safety related to geotechnical phenomena, such as amplification, landsliding and soil liquefaction. The correct evaluation of seismic hazard is, therefore, highly affected by risk factors due to geological nature and geotechnical properties of soils. In response to these new developments, several attempts have been made to identify and appraise geotechnical hazards and to represent them in the form of zoning maps, in which locations or zones with different levels of hazard potential are identified. The geotechnical zonation of the subsoil of the city of Catania (Italy) suggests a high vulnerability of the physical environment added to site amplification of the ground motion phenomena. The ground response analysis at the surface, in terms of time history and response spectra, has been obtained by some 1D equivalent linear models and by a 2D linear model, using a design scenario earthquake as input at the conventional bedrock. In particular, the study has regarded the evaluation of site effects in correspondence of the database of about 1200 boreholes and water-wells available in the data-bank of the Catania area. According to the response spectra obtained through the application of the 1D and 2D models, the city of Catania has been divided into some zones with different peak ground acceleration at the surface, to which corresponds a different value of the Seismic Geotechnical Hazard. A seismic microzoning map of the urban area of the city of Catania has been obtained. The map represents an important tool for the seismic improvement of the buildings, indispensable for the mitigation of the seismic risk.