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Reservoir characterization needs the integration of various data through history matching, especially dynamic information
such as production or 4D seismic data. Although reservoir heterogeneities are commonly generated using geostatistical models,
random realizations cannot generally match observed dynamic data. To constrain model realizations to reproduce measured dynamic
data, an optimization procedure may be applied in an attempt to minimize an objective function, which quantifies the mismatch
between real and simulated data. Such assisted history matching methods require a parameterization of the geostatistical model
to allow the updating of an initial model realization. However, there are only a few parameterization methods available to
update geostatistical models in a way consistent with the underlying geostatistical properties. This paper presents a local
domain parameterization technique that updates geostatistical realizations using assisted history matching. This technique
allows us to locally change model realizations through the variation of geometrical domains whose geometry and size can be
easily controlled and parameterized. This approach provides a new way to parameterize geostatistical realizations in order
to improve history matching efficiency. 相似文献
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Local and regional minimum 1D models for earthquake location and data quality assessment in complex tectonic regions: application to Switzerland 总被引:1,自引:0,他引:1
One-dimensional (1D) velocity models are still widely used for computing earthquake locations at seismological centers or
in regions where three-dimensional (3D) velocity models are not available due to the lack of data of sufficiently high quality.
The concept of the minimum 1D model with appropriate station corrections provides a framework to compute initial hypocenter
locations and seismic velocities for local earthquake tomography. Since a minimum 1D model represents a solution to the coupled
hypocenter-velocity problem it also represents a suitable velocity model for earthquake location and data quality assessment,
such as evaluating the consistency in assigning pre-defined weighting classes and average picking error. Nevertheless, the
use of a simple 1D velocity structure in combination with station delays raises the question of how appropriate the minimum
1D model concept is when applied to complex tectonic regions with significant three-dimensional (3D) variations in seismic
velocities. In this study we compute one regional minimum 1D model and three local minimum 1D models for selected subregions
of the Swiss Alpine region, which exhibits a strongly varying Moho topography. We compare the regional and local minimum 1D
models in terms of earthquake locations and data quality assessment to measure their performance. Our results show that the
local minimum 1D models provide more realistic hypocenter locations and better data fits than a single model for the Alpine
region. We attribute this to the fact that in a local minimum 1D model local and regional effects of the velocity structure
can be better separated. Consequently, in tectonically complex regions, minimum 1D models should be computed in sub-regions
defined by similar structure, if they are used for earthquake location and data quality assessment. 相似文献
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While 3D seismic has been the basis for geological model building for a long time, time-lapse seismic has primarily been used
in a qualitative manner to assist in monitoring reservoir behavior. With the growing acceptance of assisted history matching
methods has come an equally rising interest in incorporating 3D or time-lapse seismic data into the history matching process
in a more quantitative manner. The common approach in recent studies has been to invert the seismic data to elastic or to
dynamic reservoir properties, typically acoustic impedance or saturation changes. Here we consider the use of both 3D and
time-lapse seismic amplitude data based on a forward modeling approach that does not require any inversion in the traditional
sense. Advantages of such an approach may be better estimation and treatment of model and measurement errors, the combination
of two inversion steps into one by removing the explicit inversion to state space variables, and more consistent dependence
on the validity of assumptions underlying the inversion process. In this paper, we introduce this approach with the use of
an assisted history matching method in mind. Two ensemble-based methods, the ensemble Kalman filter and the ensemble randomized
maximum likelihood method, are used to investigate issues arising from the use of seismic amplitude data, and possible solutions
are presented. Experiments with a 3D synthetic reservoir model show that additional information on the distribution of reservoir
fluids, and on rock properties such as porosity and permeability, can be extracted from the seismic data. The role for localization
and iterative methods are discussed in detail. 相似文献
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Oleg Volkov Vladislav Bukshtynov Louis J. Durlofsky Khalid Aziz 《Computational Geosciences》2018,22(6):1465-1485
The advantages of the simultaneous integration of production and time-lapse seismic data for history matching have been demonstrated in a number of previous studies. Production data provide accurate observations at particular spatial locations (wells), while seismic data enable global, though filtered/noisy, estimates of state variables. In this work, we present an efficient computational tool for bi-objective history matching, in which data misfits for both production and seismic measurements are minimized using an adjoint-gradient approach. This enables us to obtain a set of Pareto optimal solutions defining the optimal trade-off between production and seismic data misfits (which are, to some extent, conflicting). The impact of noise structure and noise level on Pareto optimal solutions is investigated in detail. We discuss the existence of the “best” trade-off solution, or least-conflicting posterior model, which corresponds to the history-matched model that is expected to provide the least-conflicting forecast of future reservoir performance. The overall framework is successfully applied in 2D and 3D compositional simulation problems to provide a single least-conflicting posterior model and, for the 2D case, multiple samples from the posterior distribution using the randomized maximum likelihood method. 相似文献
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《Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy》1999,24(3):261-268
Visualisation of seismic and tomographic results is a crucial point to properly understand the models provided by seismic methods. We consider several geostatistical methods (inverse distance weighting, point kriging and mathematical wavelets) to map surface wave tomography in a sparsely sampled study area, and to compare their accuracy and efficiency with proper raypath methodologies (inversion and projection onto convex sets). A large set of synthetic data is used to estimate seismic velocities before application to real data. The contour maps of prediction errors indicate that spatial prediction and inversion perform similarly. 相似文献
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时移地震油藏监测技术是直接确定剩余油分布的关键技术之一。针对时移地震油藏监测在国内的需求及推广应用难点,研究了时移地震数据空间偏差校正处理方法。由于在观测系统、采集方向的处理参数等方面的差异,导致地下同一反射点在不同时移地震数据偏移后空间位置存在差异,产生与油藏变化无关的地震差异,增加数据解释的难度和风险。通过对参考数据与监测数据三维空间内的局部数据体的三维相关计算,确定监测数据体在x方向、y方向和时间方向上最佳移动量,从而实现两次地震数据空间位置差异校正。实际时移地震数据处理试验结果分析表明,空间偏差校正处理方法在消除时移地震数据三维空间非线性空间偏差方面是有效的。 相似文献
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Pilot Block Method Methodology to Calibrate Stochastic Permeability Fields to Dynamic Data 总被引:1,自引:1,他引:0
Mickaele Le Ravalec-Dupin 《Mathematical Geosciences》2010,42(2):165-185
In the present paper, a new geostatistical parameterization technique is introduced for solving inverse problems, either in
groundwater hydrology or petroleum engineering. The purpose of this is to characterize permeability at the field scale from
the available dynamic data, that is, data depending on fluid displacements. Thus, a permeability model is built, which yields
numerical flow answers similar to the data collected. This problem is often defined as an objective function to be minimized.
We are especially focused on the possibility to locally change the permeability model, so as to further reduce the objective
function. This concern is of interest when dealing with 4D-seismic data. The calibration phase consists of selecting sub-domains
or pilot blocks and of varying their log-permeability averages. The permeability model is then constrained to these fictitious
block-data through simple cokriging. In addition, we estimate the prior probability density function relative to the pilot
block values and incorporate this prior information into the objective function. Therefore, variations in block values are
governed by the optimizer while accounting for nearby point and block-data. Pilot block based optimizations provide permeability
models respecting point-data at their locations, spatial variability models inferred from point-data and dynamic data in a
least squares sense. A synthetic example is presented to demonstrate the applicability of the proposed matching methodology. 相似文献
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In this paper we have described the proceduresused, input data applied and results achieved in ourefforts to develop seismic hazard maps of Honduras.The probabilistic methodology of Cornell is employed.Numerical calculations were carried out by making useof the computer code SEISRISK III. To examine theimpact of uncertainties in seismic and structuralcharacteristics, the logic tree formalism has beenused. We compiled a de-clustered earthquake cataloguefor the region comprising 1919 earthquakes occurringduring the period from 1963 to 1997. Unified momentmagnitudes were introduced. Definition of aseismotectonic model of the whole region under review,based on geologic, tectonic and seismic information,led to the definition of seven seismogenetic zones forwhich seismic characteristics were determined. Fourdifferent attenuation models were considered. Resultsare expressed in a series of maps of expected PGA for60% and 90% probabilities of nonexceedence in a50-year interval which corresponds to return periodsof 100 and 475 years, respectively. The highest PGAvalues of about 0.4g (90% probability ofnon-exceedence) are expected along the borders withGuatemala and El Salvador. 相似文献
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针对地震信号多子波分解与重构技术中匹配追踪算法能够根据地震信号自身特点进行自适应分解、但其计算量庞大的问题,笔者提出一种粒子群快速优化算法,用于快速搜索地震信号稀疏分解的最优匹配原子。即在迭代过程中,将搜索区域确定在高斯函数能量集中的部分,避免了搜索过程的"贪婪性",能有效降低稀疏分解复杂度。同时,在粒子群算法中引入了一种多项式变异算子,可以有效避免搜索最优解的过度集中。实验结果证明,此算法将匹配追踪的分解精度提高了67倍,更使计算效率提高了153倍。 相似文献
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A global seismic hazard assessment was conducted using the probabilistic approach in conjunction with a modified means of evaluating the seismicity parameters. The earthquake occurrence rate function was formulated for area source cells from recent instrumental earthquake catalogs. For the statistical application of the G–R relation of each source cell, the upper- and lower-bound magnitudes were determined from, respectively, historical earthquake data using a Kernel smoothing operator and detection thresholds of recent catalogs. The seismic hazard at a particular site was obtained by integrating the hazard contribution from influencing cells, and the results were combined with the Poisson distribution to obtain the seismic hazard in terms of the intensity at 10% probability of exceedance for the next 50 years. The seismic hazard maps for three countries, constructed using the same method, agree well with the existing maps obtained by different methods. The method is applicable to both oceanic and continental regions, and for any specific duration of time. It can be used for those regions without detailed geological information or where the relation between existing faults and earthquake occurrence is not clear. 相似文献
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通过分析常规煤矿采区三维地震勘探存在的问题及技术瓶颈,提出了全数字高密度煤矿采区三维地震勘探的主要技术框架,即:数字检波器、单点接收、更小的接收道距与线距、更小的激发点距与线距、单炮超多道数、小面元、全方位、高覆盖次数观测,真实记录全波场海量数据的采集技术,及其与之相配套的高精度地震成像处理和精细综合地震解释技术。与以往的常规三维地震勘探相比,全数字高密度煤矿采区三维地震勘探技术在断层方位、小断层识别、陷落柱探测、下组煤层探测、高陡构造勘探等多个方面都有明显优势。 相似文献
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《Journal of African Earth Sciences》2000,30(1):63-78
Gravity data were integrated with seismic refraction/reflection data, well data and geological investigations to determine a general crustal structure of Tunisia. The gravity data analysis included the construction of a complete Bouguer gravity anomaly map, residual gravity anomaly maps, horizontal gravity gradient maps and a 2.5-D gravity model. Residual gravity anomaly maps illustrate crustal anomalies associated with various structural domains within Tunisia including the Sahel Block, Saharian Flexure, Erg Oriental Basin, Algerian Anticlinorium, Gafsa Trough, Tunisian Trough, Kasserine Platform and the Tell Mountains. Gravity anomalies associated with these features are interpreted to be caused either by thickening or thinning of Palæozoic and younger sediments or by crustal thinning. Analysis of the residual gravity anomaly and horizontal gravity gradient maps also determined a number of anomalies that may be associated with previously unknown structures. A north-south trending gravity model in general indicated similar subsurface bodies as a coincident seismic model. However, thinner Mesozoic sediments within the Tunisian Trough, thinner Palæozoic sediments in the Gafsa Trough, and a greater offset on the Saharian Flexure were required by the gravity data. Additionally, basement uplifts under the Kasserine Platform and Gafsa Trough, not imaged by seismic data, were required by the gravity data. The gravity model revealed two previously unknown basins north and south of the Algerian Anticlinorium (5 km), while the Erg Oriental Basin is composed of at least two sub-basins, each with a depth of 5 km. 相似文献
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Ramdhane Benassi 《Arabian Journal of Geosciences》2013,6(4):1173-1182
Understanding the formation and the development of salt structures is very important especially because they are of significant economical interest. Detailed understanding of this process will help reservoir prediction and hydrocarbon recovery. In this work, we use a combination of geological observations along with the interpretation of geophysical data (seismic and Bouguer anomaly data) to better constrain the geology of the Jbel Cheid structure. The shape of Triassic body of Jbel Cheid (Northern Tunisian Atlas) structure and its geodynamic evolution have been determined by gravity analyses and 2.5D modeling, correlated with others geophysical data (seismic) and geological observations. Semi-automatic structural analysis was performed before modeling, to identify lateral gravity discontinuities. The complete Bouguer and residual gravity anomaly maps indicate a positive amplitude gravity anomaly over the Triassic evaporitic outcrop (Jbel Cheid) and prominent NE–SW-trending features associated with the boundary of the Triassic rocks and surrounded layers. The seismic profile shows a thickness variation of post-salt layers. Taking into account the 2.5D gravity model, seismic profile and surface data, geodynamic evolution of Jbel Cheid can be subdivided on three stages (reactive, active, and passive) which well correlated to the model proposed by Vendeville (2002). 相似文献
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Seyed Naser Hashemi 《Mathematical Geosciences》2013,45(6):705-725
This paper presents the results of two multivariate analysis techniques—principal component and cluster analysis—as they are applied to the seismicity characterization of Iran. The seismic data used in this study covers a period of 50 years, from the beginning of 1957 to the end of 2006. The values of eight seismic variables were calculated on a grid of equally spaced points at one geographic degree spacing in both latitude and longitude. The data matrix was analyzed using principal component and cluster analysis. Principal component analysis identified two significant components, introduced in this study as the Seismic Frequency Index (SFI) and the Seismic Severity Index (SSI), responsible for the data structure. The SFI and SSI explain 34.34 % and 32.33 % of the total variance of the data set, respectively, and allowed grouping of the selected variables according to their common features. The standardized data matrix was analyzed using Ward’s clustering method. The resulting seismicity pattern recognition maps of the region at three levels of similarity are presented. From these maps, differentiated seismic zones are outlined in detail and compared quantitatively. Comparison between the seismic zoning maps obtained in this analysis and the general tectonic map of the region indicates that the seismic zones are consistent with the tectonic zones of the region. This study presents the necessity and usefulness of multivariate analysis in evaluating and interpreting seismic data catalogues with the goal of obtaining more objective information about the seismicity pattern of regions. 相似文献
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本文针对煤田地震勘探的特点,就如何应用偏移时间剖面直接作构造图问题进行了论述,提出了一套完整的交点闭合方法和空间校正方法。并结合实际使用PC-1500微机进行空间校正作构造图,实践证明效果良好。 相似文献