Joint inversion of travel times and waveforms by means of annealing algorithms. Application to a seismic refraction experiment

An algorithm of annealing is applied to a joint inversion of travel times and waveforms belonging to a synthetically generated seismic refraction experiment. The medium (crust and upper mantle) is modelled by a set of plane stratified layers and a halfspace. The obtained structure (elastic parameters and depth of layers) shows that, in spite of contaminating seismic noise and poor knowledge of the seismic source, annealing methods are a good tool in these kinds of inversion problems. We think that many characteristics of the annealing process described here could be used with real data and more sophisticated media for the crust and upper mantle of the earth than the present example.     

测井、井间地震与地面地震数据联合约束下的地质统计学随机建模方法研究

利用能够整合测井信息与井间地震信息的地质统计学随机模拟方法,结合传统的地质统计学反演思路,得到了一种能够同时整合测井、井间地震与地面地震三种先验信息的地质统计学反演与储层建模方法.由于井间射线信息、测井信息与地面地震数据在随机反演与建模过程当中都得到了尊重,因此与传统地质统计学反演仅利用了测井与地面地震数据相比,本文的地质统计学反演与建模方法更充分地利用了先验信息,有效提高了反演的精度,降低了随机建模中的多解性.基于理论数据的测试证实了上述观点.     

测井、井间地震与地面地震数据联合约束下的地质统计学随机建模方法研究

利用能够整合测井信息与井间地震信息的地质统计学随机模拟方法,结合传统的地质统计学反演思路,得到了一种能够同时整合测井、井间地震与地面地震三种先验信息的地质统计学反演与储层建模方法.由于井间射线信息、测井信息与地面地震数据在随机反演与建模过程当中都得到了尊重,因此与传统地质统计学反演仅利用了测井与地面地震数据相比,本文的地质统计学反演与建模方法更充分地利用了先验信息,有效提高了反演的精度,降低了随机建模中的多解性.基于理论数据的测试证实了上述观点.     

地震走时与重力数据的联合反演

对目前的地震走时与重力数据联合反演发展进行了简要的概述。首先,从两类数据单独反演的基本原理出发,对两者进行了分析比较,并由两者参数间存在的相互关系,可将两类数据归并、统一到一个系统,合理地进行联合反演。其次,根据目前国内外的相关研究,介绍了当前联合反演的两种算法:依次反演和同时反演。最后,对联合反演中存在的问题进行了讨论。     

地震-重力联合反演及效果——以天津-北京-赤城地震探测剖面为例

充分运用地震与重力场不同方法的优点,以天津-北京-赤城高精度、高分辨率人工地震探测剖面(DSS)为例,采用地震解释模型结果为约束,通过正反演拟合,获得剖面上密度结构,再对剖面两侧地震解释的模型结果重新进行拟合修正.实践表明,用重力-地震相互约束开展联合反演,可以克服单一方法存在的缺陷和不足,使获得的结果更接近研究区的实...     

The use of low frequencies in a full‐waveform inversion and impedance inversion land seismic case study

Velocity model building and impedance inversion generally suffer from a lack of intermediate wavenumber content in seismic data. Intermediate wavenumbers may be retrieved directly from seismic data sets if enough low frequencies are recorded. Over the past years, improvements in acquisition have allowed us to obtain seismic data with a broader frequency spectrum. To illustrate the benefits of broadband acquisition, notably the recording of low frequencies, we discuss the inversion of land seismic data acquired in Inner Mongolia, China. This data set contains frequencies from 1.5–80 Hz. We show that the velocity estimate based on an acoustic full‐waveform inversion approach is superior to one obtained from reflection traveltime inversion because after full‐waveform inversion the background velocity conforms to geology. We also illustrate the added value of low frequencies in an impedance estimate.     

复杂盆地地球物理-地质结构模型的构建——重磁电震综合解释在楚雄盆地勘探中的应用

楚雄盆地由于其复杂的地质构造,基底深度及内部构造隆拗深度一直不明了.本文以楚雄盆地区域重力及航磁数据为基础,依据横贯东西的两条重磁电震剖面定量反演解释结果,并以云参1及楚参1钻井作为约束,分西区、中区及东区三个区块反演得到了楚雄盆地三叠系顶底界面深度,进而得到三叠系厚度分布特征.本次取得的成果为研究楚雄地区深部地质构造和主要沉积盆地厚度以及盆地基底深度提供了较为可靠的资料,可作为楚雄盆地油气评价的重要依据;同时也为复杂盆地地球物理-地质结构模型的构建提供了一条可行的思路.

     

基于密集台阵地震背景噪声成像预测煤矿瓦斯分布

瓦斯突出是一种常见的煤矿动力灾害现象,随着煤矿矿井开采深度的增加,煤层瓦斯含量、压力都呈上升趋势,发生煤与瓦斯突出的危险性加大.传统的瓦斯测量方法只能测量局部离散点瓦斯含量,难以从矿井及采区尺度对瓦斯含量进行预测.因此需要寻求一种能够在采区及工作面布设前预测煤层瓦斯富集程度的高效地球物理方法.背景噪声成像方法已经在城市地下空间、矿产资源等近地表成像中得到广泛的运用.本文将该方法首次应用到阳泉寺家庄煤矿井田区域,采用96个台站记录的连续背景噪声数据,通过互相关方法获得了台站对之间的瑞利面波经验格林函数,并进一步提取了5 Hz~1.4 s的基阶瑞利面波的群速度和相速度频散曲线.本研究首先通过区域的平均频散曲线获得该区域的平均一维横波速度结构作为三维反演的初始模型;其次,利用基于射线追踪的面波频散直接成像方法获得研究区1.0 km以浅的三维横波速度结构;最后,结合获得的三维速度结构,以及岩石物理实验获得的瓦斯含量与地震波速度的经验关系,预测了寺家庄井田15号煤的瓦斯含量,预测的瓦斯含量与实际巷道揭露的瓦斯含量具有较好的一致性.本研究成果表明,对于煤矿瓦斯分布预测来说,背景噪声成像方法是一种潜在有效的全新的技术形式.

     

3D inversion of gravity data by separation of sources and the method of local corrections: Kolarovo gravity high case study

We present a novel methodology for 3D gravity/magnetic data inversion. It combines two algorithms for preliminary separation of sources and an original approach to 3D inverse problem solution. The first algorithm is designed to separate sources in depth and to remove the shallow ones. It is based on subsequent upward and downward data continuation. For separation in the lateral sense, we approximate the given observed data by the field of several 3D line segments. For potential field data inversion we apply a new method of local corrections. The method is efficient and does not require trial-and-error forward modeling. It allows retrieving unknown 3D geometry of anomalous objects in terms of restricted bodies of arbitrary shape and contact surfaces. For restricted objects, we apply new integral equations of gravity and magnetic inverse problems. All steps of our methodology are demonstrated on the Kolarovo gravity anomaly in the Danube Basin of Slovakia.     

双层界面重磁联合反演方法研究

Based on the synchronous joint gravity and magnetic inversion of single interface by Pilkington and the need of revealing Cenozoic and crystalline basement thickness in the new round of oil-gas exploration, we propose a joint gravity and magnetic inversion methodfor two-layer models by concentrating on the relationship between the change of thicknessI and position of the middle layer and anomaly and discuss the effects of the key parameters. Model tests and application to field data show the validity of this method.