The application of well logging and seismic modeling to assess the degree of gas saturation in Miocene strata (Carpathian Foredeep, Poland)

The presence of natural gas in the pore space of reservoir rocks results in a significant decrease in P-wave velocity. Even low gas saturation can generate seismic anomalies (DHI) and false image of gas accumulation of economic importance. This article presents an attempt to evaluate gas saturation from 2D seismic section in the Miocene sandstone strata in the south-eastern part of the Carpathian Foredeep. The ESTYMACJA program and the Biot-Gassmann model were used to study the dependence between elastic parameters and saturating fluids (water and gas) recorded in wells. Series of calculations was carried out using a method of fluid substitution for various gas saturation. The applicability of seismic data for evaluating gas saturation of reservoir beds was assessed with the use of 1D modelling (synthetic seismograms) and 2D modelling (theoretical seismic section) calculated for different gas saturation. The proposed methodology can be used to identify low and high gas-saturated zones and contour the reservoir.     

Identification method of seismic phase in three-component seismograms on the basis of wavelet transform

IntroductionThe three-component seismograms represents ground motion. Seismic signal contains various types of phase arrivals. Some of the most significant are the P, S, LQ and LR arrivals. Accurately determining the time of these arrivals 'is importal to determine the location of an event.Although a lot of work in determining the location have been done, researchers have not carriedout the target in trying to determine this information more accurately from single-station seismogram due to …     

利用背景噪声研究紫坪铺水库水位加卸载对库区地下介质波速的影响

基于2005年1月1日~2008年1月1日紫坪铺台网及YZP台连续波形资料,利用噪声互相关技术研究了紫坪铺水库区域在蓄水、泄水过程中库区介质的变化特征,同时对可能的渗透过程进行了讨论。使用移动窗口互谱方法计算了库区台站对之间的相对波速变化。结果表明,在紫坪铺水库的3次大规模蓄水及2次泄水过程中,地下介质相对波速变化与水位变化之间存在较为明显的相关性,且在时间上有一定延迟,其可能与水的渗透有关。分析认为蓄水对浅层介质产生的作用最快,影响最大,波速的变化是蓄水产生的压力及渗透共同作用的结果。在第1次蓄水时,压力起主要作用,后2次蓄水时,渗透起主要作用,且渗透作用已影响至深达8km左右的断层。     

松辽盆地徐深气田火山岩气藏地质约束-测井地震建模方法探讨

本文在借鉴徐深气田以往地质建模成功经验基础上,针对徐深气田B区块火山体规模小、横向变化快、开发井少、认识程度较低的实际,密切结合火山岩成因特点,探索性地提出体控地质建模的新思路,即以地震反射特征和地震属性特征为依据,结合钻井、测井资料,井震结合从三维空间上精细识别和刻画火山岩体,通过利用神经网络算法建立多种地震属性与测井参数的定量关系,实现了火山岩体内部多种地质属性的定量表征,建立的三维可视化地质模型比较真实地反映了火山机构及其内部属性空间发育和分布特征.     

中深层天然气藏地震预测技术研究

济阳坳陷天然气资源丰富,已在多个层系发现了不同类型的中深层天然气藏,由于气藏地质条件、地震反射复杂,针对不同的气藏需采用不同的地震预测技术。本文在中深层天然气藏地质特点分析的基础上进行了岩石物理、地震反演、地震属性等预测技术研究,结果表明：中层气藏储层物性较好,储层与围岩的岩石物理参数差异明显,应用亮点、AVO、叠前弹性阻抗反演技术可较好地识别预测三角洲砂岩气藏;针对深层低孔低渗砂岩气藏,地震属性及多属性反演是有效的储层预测技术,并预测了孤北地区二叠系有利储集相带分布,结合构造分析,指出了孤北地区深层气勘探方向。     

青藏高原东南缘中-下地壳地震波各向异性成因——来自云南六合深源包体组构学的约束

本文通过对出露于青藏高原东南缘云南六合地区的新生代深源岩石包体（斜长角闪岩、角闪石岩和石榴石透辉岩）的显微组构和地震波各向异性的研究来约束新生代青藏高原东南缘的地壳各向异性.通过角闪石地质压力计计算得知斜长角闪岩、角闪石岩和石榴石透辉岩包体来源于地壳28~36 km,为中-下地壳岩石包体.EBSD测量结果显示包体中角闪石的CPO（晶格优选定向）为Type-Ⅳ型和（100）[001]滑移,单斜辉石的CPO为SL型和（100）[001]滑移,暗示中-下地壳为高温强变形的特征.通过CPO数据计算获得斜长角闪岩、角闪石岩和石榴石透辉岩包体全岩V_P各向异性为1.9%~13.3%,最大分裂的剪切波各向异性（AV_S）为1.17%~8.01%.结合前人的研究结果,该地区的地壳岩石能够解释利用Pms震相测量获得的分裂延迟时间,表明云南西北地区的壳内各向异性源于中-下地壳矿物的定向排列.云南西北地区的Pms快波方向近NW-SE向分布并与SKS的快波方向相近,暗示岩石圈变形是耦合的,受控于青藏高原向东南挤出的构造背景.

     

基于频率域峰值属性的河道砂体定量预测及应用(英文)

河道砂体是陆相含油气盆地最重要的储集类型之一,其边界识别和厚度定量预测是储层预测的热点难题。本文在总结现有方法技术的基础上,提出一种利用频率域峰值属性进行河道砂体边界识别和厚度定量预测的新方法。对典型河道薄砂体地震反射进行了正演模拟,构造了一种新的地震属性——峰值频率-振幅比,研究表明:峰值频率属性对地层厚度变化敏感,振幅属性对地层岩性变化敏感,两者比值突出河道砂体的边界,同时,借助峰值频率与薄层厚度间存在的定量关系进行薄砂体厚度计算。实际数据应用表明,地震峰值频率属性可以较好的刻画河道的平面展布特征;峰值频率-振幅比属性可以提高对河道砂体边界的识别能力;利用频率域地震属性进行砂体边界识别及厚度定量预测是可行的。     

全直径岩心分析Archie参数在DQ油田XX区块的非均质火成岩气层评价中的应用

指出了全直径岩心分析的Archie参数(m、n)对非均质储层含油(气)性评价的重要性.使用新疆测井公司开发的全直径岩心多参数分析实验装置及实验方法,以DQ油田XX区块的非均质火成岩气层评价为例,由7块全直径岩样该获得了储层的物性和Archie参数.当应用于该储层含气饱和度估算后,与密闭取心饱和度分析的含气饱和度结果比较,含气饱和度估算误差大致在5%以内,较按Archie参数的确省值(m=n=2)估算的含气饱和度的精度高 10%左右.考虑到非均质储层在岩性、物性、孔隙结构的特殊性,推荐“真正”使用全直径岩心分析方法应用于非均质储层的物性、含油(气)性的评价,并重视模拟油藏条件的全直径岩心分析装置的开发.     

A centrifuge study of the influence of site response,relative stiffness,and kinematic constraints on the seismic performance of buried reservoir structures

The seismic performance of underground reservoir structures depends on the properties of the structure, soil, and ground motion as well as the kinematic constraints imposed on the structure. A series of four centrifuge experiments were performed to evaluate the influence of site response, structural stiffness, base fixity, and excitation frequency on the performance of relatively stiff reservoir structures buried in dry, medium-dense sand. The magnitude of seismic thrust increased and the distribution of seismic earth pressures changed from approximately triangular to parabolic with increasing structural stiffness. Heavier and stiffer structures also experienced increased rocking and reduced flexural deflection. Fixing the base of the structure amplified the magnitude of acceleration, seismic earth pressure, and bending strain compared to tests where the structure was free to translate laterally, settle, or rotate atop a soil layer. The frequency content of transient tilt, acceleration, dynamic thrust, and bending strain measured on the structure was strongly influenced by that of the base motion and site response, but was unaffected by the fundamental frequency of the buried structure (f_structure). None of the available simplified procedures could capture the distribution and magnitude of seismic earth pressures experienced by this class of underground structures. The insight from this experimental study is aimed to help validate analytical and numerical methods used in the seismic design of reservoir structures.     

井震联合分析预测神狐海域天然气水合物可能的垂向分布

已有的地质与地球物理信息表明南中国海北部陆坡神狐海域存在天然气水合物,2007年钻井和取样结果证实其以细颗粒均匀存在于水合物稳定带内,但区域分布范围极不规则.由于测井记录长度和取样深度的范围有限,天然气水合物垂向分布特征难以确定.为了深入了解此区域天然气水合物深度上的分布规律,对SH7井的多种测井数据进行综合分析并与地震反射特征建立联系,得到三个主要的沉积物性变化层位并以此为基础进行叠后数据的伪井约束反演,结果表明在已证实的含水合物层之下还存在高速层.而AVO叠前正演模拟分析结果与实际地震数据对比表明,研究区的天然气水合物稳定带可能由含水合物沉积物与饱水沉积物的薄互层组成,这就意味着在取样获得天然气水合物样品的深度之下,很可能存在另一个含水合物层.     

Detection of gas reservoirs by the joint use of P- and PS-waves: A case study on the Ordos basin, China

We present an example of using converted-waves for characterizing onshore gas reservoirs in the Ordos basin in Northwest China. The Ordos basin is the largest gas province in China. The main gas reservoirs (about 3 300 m in depth) are in upper Paleozoic sandstone that has low or reversed P-wave impedance and is immediately above a coal seam. This makes it very difficult to image the gas reservoirs using conventional P-wave data. Analysis of core, log and VSP data shows a weak PP reflection but a relatively ...     

基于数据挖掘的甘肃武都殿沟泉氡异常与地震活动统计关系研究

殿沟泉气氡浓度在汶川地震后经常出现成簇高频震荡异常.应用数据挖掘方法,采用正规化、聚类、特征值计算等方法对氡观测数据和地震目录进行预处理,提取气氡异常、震级、震源深度和地震分区等参数,在此基础上采用贝叶斯网络模型开展殿沟泉氡异常与周边区域地震活动统计关系研究.利用聚类开展的地震分区结果显示与构造分区基本吻合,反映出不同...     

2008年新疆于田MS7.3地震前区域地震活动和应力状态特征初步研究

从区域地震活动和中等地震震源机制特征的角度,初步研究了2008年新疆于田7.3级地震前区域地震活动和应力场的应力状态特征．结果表明,于田7.3级地震前区域地震活动存在中短期异常特征．一方面,该地震前1年其震区500km范围内中强震以及西昆仑地震带和阿尔金地震带3.5级以上地震出现了增强活动;另一方面,该地震前出现了4级地震孕震空区和近乎共扼分布的3.5级地震密集条带异常图象．于田7.3级地震前新疆区域应力场和震源区及其附近局部应力场的应力状态发生了一定程度的改变,拉张作用力相对挤压作用力有所加强．这可能是于田7.3级地震前新疆和于田震区及其附近具有正断层性质的中等地震增多的原因．     

新西兰2010年M7.1地震与2011年M6.3地震活动和灾害分析

本文对新西兰.2010年9月4日M7.1地震(国际标准时间)与2011年2月22日(国际标准时间)M6.3地震活动和灾害情况进行了分析,用同震位移方法计算了两次地震的地震烈度,结果表明尽管两次地震震级相差较大,但由于M6.3地震震源深度较浅,两次地震在地表的烈度相同.本文用主余震序列方法计算了两次地震的断层滑动参数,结...     

基于重磁震资料的南海新生代盆地分布综合研究

作为西太平洋最大的边缘海,南海分布有30多个新生代沉积盆地,其蕴含着丰富的油气资源.但由于资料的限制,南海存在不同区域盆地研究程度不同,不同区域盆地面积差别较大,部分盆地只是坳陷而没有达到盆地的级别以及盆地外围可能存在凹陷等问题.南海新生代盆地分布问题制约了其油气分布规律、储量等基础地质问题的研究.本文以地震剖面数据为约束,以重力资料为主、辅以磁力资料,研究了南海新生代盆地分布及构造区划.通过提取新生代盆地及其构造单元引起的重力异常,结合地震剖面等资料反演了新生界底界面深度及新生界厚度.在充分调研已有盆地和构造单元划分方案的基础上,根据南海的地质及地球物理特征,确定了盆地及构造单元划分标准.以新生界厚度为基础并结合重、磁、震、地质等资料,进行地质-重磁震联合解释,将南海原有的36个盆地重新划分为24个盆地,盆地总面积扩大了约15万km2.研究表明,南海新生代盆地沉积层厚度在1.5~16 km之间,有6个北东东/北东向沉积坳陷带、2个近南北向沉积坳陷带以及1个三角沉积坳陷区;盆地展布方向主要为北东和北东东向,其次为北西和近南北向,呈现"南三北三"的分布特征.     

晋冀蒙交界地区地壳三维P波速度结构及地震活动性研究

2014年9月晋冀蒙临时地震台网正式运行,为晋冀蒙交界地区的地震研究提供了丰富的资料。结合临时台与固定台记录的P波走时资料,采用双差层析成像方法对该区进行地震重定位和三维P波速度结构联合反演,分析该区3个典型盆地的速度扰动结果,结果表明,地震重定位残差显著降低,震源深度分布更加合理;P波速度浅层基本符合平原地区低速、山区高速的特点,深层则有相反表现,典型盆地P波速度在浅层较为复杂,高低速相间,深层表现为低速;研究时段内忻定盆地和延怀盆地地震活动密集,大同盆地地震活动较弱,低速体及边缘地震活动强度高于高速体及边缘。     

Dynamic properties of the Quaternary sedimentary rocks and their influence on seismic site effects. Case study in Bucharest City,Romania

Bucharest is one of the cities most affected by earthquakes in Europe. Situated at 150–170 km distance from Vrancea epicentral zone, Bucharest had suffered many damages due to high energy Vrancea intermediate-depth earthquakes. For example, the 4 March 1977 event produced the collapse of 32 buildings with 8–12 levels, while more than 150 old buildings with 6–9 levels were seriously damaged. The studies done after this earthquake had shown the importance of the surface geological structure upon ground motion parameters. New seismic measurements are performed in Bucharest area aiming at defining better elastic and dynamic properties of the shallow sedimentary rocks. Down-hole seismic measurements were performed in a number of 10 cased boreholes drilled in the Bucharest City area. Processing and interpretation of the data lead to the conclusion that shallow sedimentary rocks can be considered weak in the area, down to 150–200 m depth. Seismic wave velocity values and bulk density values presented in the paper associated with local geology are useful primary data in the seismic microzonation of Bucharest City. They are used as 1D models to derive transfer functions and response spectra for the stack of sedimentary rocks in several parts of Bucharest area, leading to a better knowledge of the local site amplification and associated frequency spectra. In a recent study the H/V spectral ratio using Nakamura’s method was applied on the seismic noise measurements in 22 sites in Bucharest City in order to derive the fundamental period associated with these sites. The values confirm the previous results, showing a dominant resonance in the period range of 1.25–1.75 s. The fundamental periods obtained with Nakamura’s method are in good agreement with those computed on the basis of geological and geotechnical data in boreholes, which show an increase of the fundamental period in the Bucharest area from south to north, in the same direction as the increase of the thickness of the Quaternary deposits above the Fratesti layer which is considered the bedrock in the area.     

柴达木盆地三湖地区北斜坡岩性地层气藏形成的地质条件与预测技术研究

三湖地区北斜坡褶皱发育,相变快,生储盖组合优越,具备形成岩性地层气藏的构造背景和地质务件.由于本区储层厚度薄(1～3m),缺乏三维地震资料,砂体分布难以准确追踪,导致岩性地层气藏勘探难以取得突破.已知气藏解剖和理论研究表明地层含气后会产生特殊的地震响应,通过地震异常信息研究,结合构造、沉积和成藏条件分析,发现驼西地区是岩性圈闭发育带,Tzh2井获得工业气流证明该区带具备形成岩性气区的潜力.     

滇西地区GPS时间序列中陆地水载荷形变干扰的GRACE分辨与剔除

利用“中国大陆构造环境监测网络”在云南西部地区的13个连续GPS观测站和法国空间大地测量研究组Space Geodesy Research Group）的GRACE时变重力场资料,定量分析了该区域陆地水载荷所产生的非构造形变的量值和变化特点,探讨了利用GRACE分辨和剔除GPS观测中陆地水负荷所引起的非构造形变干扰的依据和模型.结果表明：滇西地区GPS坐标变化时间序列的垂向分量中,普遍包含有明显的年周期非构造形变波动,高值可达12mm,其中约42%源于陆地水迁徙变化所引起的负荷形变;通过主成份分析方法所获取的区域GPS共模误差与GRACE陆地水载荷形变序列的相关性高达0.87,若以GRACE扣除陆地水负荷形变,则滇西地区GPS网共模误差可消除约64%,且物理机制明确.然而,由于目前的GRACE只能有效分辨大约400km范围内陆地水载荷的整体变化,所以对于各GPS站点更加局部化的陆地水负荷非构造形变干扰,尚无法进行有效分辨.