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1.
Scales of Reservoir Heterogeneities and Impact of Seismic Resolution on Geostatistical Integration 总被引：1，自引：0，他引：1
Seismic measurements may be used in geostatistical techniques for estimation and simulation of petrophysical properties such as porosity. The good correlation between seismic and rock properties provides a basis for these techniques. Seismic data have a wide spatial coverage not available in log or core data. However, each seismic measurement has a characteristic response function determined by the source-receiver geometry and signal bandwidth. The image response of the seismic measurement gives a filtered version of the true velocity image. Therefore the seismic image cannot reflect exactly the true seismic velocity at all scales of spatial heterogeneities present in the Earth. The seismic response function can be approximated conveniently in the spatial spectral domain using the Born approximation. How the seismic image response affects the estimation of variogram. and spatial scales and its impact on geostatistical results is the focus of this paper. Limitations of view angles and signal bandwidth not only smooth the seismic image, increasing the variogram range, but also can introduce anisotropic spatial structures into the image. The seismic data are enhanced by better characterizing and quantifying these attributes. As an exercise, examples of seismically assisted cokriging and cosimulation of porosity between wells are presented. 相似文献
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本文在特殊地质填图的过程中研究了哈密地区砂岩的地震波速,利用ZBL-U520非金属超声检测仪和Autolab2000多功能岩石物性设备,在0~200 MPa(约0~7000 m地下深度)下研究了密度、孔隙度和压力三个因素对砂岩地震波速的影响。研究发现:砂岩的波速与密度呈正相关关系,但与孔隙度呈负相关关系;纵波与密度和孔隙度的线性关系好于横波;波速与压力呈对数关系。此外,本文还分析了ZBL-U520与Autolab2000两种仪器测试方法的适用性。最后针对地质填图的特点给出建议:在特殊地质填图中,不仅要按照规范采集标本,测试其在常温常压下的岩石波速,还应该适当考察不同地层压力状态下的速度特征,才能更全面地认识填图区地震波的性质。 相似文献
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弹性模量、波速与应力的关系及其应用 总被引：1，自引：0，他引：1
为充分了解不同尺度地质系统的岩石动力学特征,更好利用不同规模勘探资料有效解释地质系统的特征,在岩石物理实验对岩石弹性模量、波速与应力的关系进行研究总结的基础上,探讨野外实际地震勘探中地震波速与地应力的关系。研究表明,岩石、岩体或地质系统是多相(固液气)、多种矿物、各种构造的综合体,不论尺度如何均可以用多重介质孔隙裂隙地质模型描述,而波速是一定尺度不均匀地质体的等效波速,在一定地质条件下,各种尺度介质波速、岩石弹性模量与有效应力存在依存关系。坚硬的岩石通常很脆,如果岩石处于很大的应力之下,应力的释放将在岩石中产生微裂隙,微裂隙会降低地震速度。只要把岩石恢复到原来的应力状态就可能消除所引发的微裂隙。在岩体未达到破坏时,应力越大,波速愈高。压力释放引发的微裂隙有助于现场确定最大/最小水平应力方向,波速的椭圆长轴即为主应力方向。而上覆地层压力不变(或变化很小),净储层压力的影响正好与储层压力对地震特性的影响相反。随着净储层压力的增加,所有岩石的地震特性都增高。这种增高的量级取决于若干其它的因素(孔隙形状、孔隙度、孔隙流体、岩性等等)。不论野外地震勘探还是实验研究,地震波速与地应力的一致性为地质系统的正反演解释提供了宏观控制依据:通过测量弄清 相似文献
4.
与孔隙几何相对简单的高孔隙度、高渗透率砂岩不同,致密砂岩的岩石骨架和孔隙结构通常表现出不同尺度上的非均质性。为了研究这种非均质性和饱和流体对致密砂岩性质的影响,测量了具有9块不同孔隙度的致密砂岩在不同围压、干燥和水饱和条件下的超声波速度。利用速度随有效压力的变化曲线估计软孔隙的纵横比分布,进而利用喷射流模型进行流体替换效应解释。基于超声测试数据和局部流机制,建立了考虑软孔隙随纵横比分布的喷射流模型,实现了致密砂岩跨频段岩石物理建模,利用此模型分析了超声频段和地震频段内饱和致密砂岩的流体敏感性。基于超声频段测量的流体敏感度被高估,实际上地震频段的流体敏感度可能与超声分析结果存在较大差异,因此实现实验室低频直接测量对于准确的岩石物理建模和应用具有关键性的意义。 相似文献
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辽河油田某地区孔隙度的预测 总被引：1，自引：0，他引：1
储层分析和油气预测中,孔隙度的预测是至关重要的,本文用Ｇ－ＬＯＧ方法计算层速度;并与分辨率高的测井,岩芯资料建立关系模式,然后利用地震层速度计算机隙度,文章还介绍了该方法在该区的实际应用。 相似文献
8.
综合三维地震、钻井岩心、测录井、物性分析、薄片鉴定资料,通过宏观描述与微观镜下分析相结合的方法,系统分析了东营凹陷永北地区古近系顶部不整合结构体岩石学特征、测井曲线特征、物性响应特征及其与圈闭的关系。研究表明,不整合可划分为3层结构:水进砂层、风化粘土层和半风化淋滤层。每个结构层具有不同的岩石学和测井响应特征。水进砂层孔隙度高;风化粘土层风化作用最强,泥质含量高,孔隙度低;半风化淋滤层溶蚀作用强,次生溶孔发育,孔隙度较高;未风化层未受风化作用改造,孔隙发育差。永北地区沙三上段发育断块掀斜型和盆缘型两种地层不整合圈闭模式:断块掀斜型模式受到不整合与二级或二级以下序级断层的共同控制,圈团发育规模较小;盆缘模式多出现在抬升强烈的湖盆边缘,主要受控盆断层的控制,圈闭发育规模较大。 相似文献
9.
Estimating spatial distributions of heterogeneous subsurface characteristics by regionalized classification of electrofacies 总被引：1，自引：0，他引：1
Regionalized classification of electrofacies utilizes the statistical relationships between laboratory determined hydrologic properties and field-measured geophysical properties to estimate spatial distributions of porosity, permeability, and diagenetic characteristics. The method, illustrated with an application to the St. Peter Sandstone in the Michigan basin, combines techniques for multivariate analysis and spatial estimation. Core plug and borehole geophysical data are clustered into electrofacies that reflect the hydrologic properties and diagenetic characteristics of the formation. Electrofacies characteristics then are used to assign a class membership probability at locations where only geophysical data are available. Three-dimensional estimation of electrofacies occurrence is done by kriging datasets containing the probability of electrofacies membership at borehole locations. The discretization and kriging geometry allow three-dimensional estimation of hydrologic parameters for a large region that incorporates meter-scale heterogeneity. Finally, permeability and porosity are estimated at each grid location by probability-weighting. Because the electrofacies carry information about both the hydrologic and lithologic properties, the resulting spatial distributions provide an understanding of both the present-day flow characteristics and the extent of processes that control them.Managed by Martin Marietta Energy Systems. Inc., under contract DE-AC05-84OR21400 with the U.S. Department of Energy); Publication No. 4371, Environmental Sciences Division, ORNL. 相似文献
10.
Application of EM algorithms for seismic facices classification 总被引：1，自引：0，他引：1
Identification of the geological facies and their distribution from seismic and other available geological information is
important during the early stage of reservoir development (e.g. decision on initial well locations). Traditionally, this is
done by manually inspecting the signatures of the seismic attribute maps, which is very time-consuming. This paper proposes
an application of the Expectation-Maximization (EM) algorithm to automatically identify geological facies from seismic data.
While the properties within a certain geological facies are relatively homogeneous, the properties between geological facies
can be rather different. Assuming that noisy seismic data of a geological facies, which reflect rock properties, can be approximated
with a Gaussian distribution, the seismic data of a reservoir composed of several geological facies are samples from a Gaussian
mixture model. The mean of each Gaussian model represents the average value of the seismic data within each facies while the
variance gives the variation of the seismic data within a facies. The proportions in the Gaussian mixture model represent
the relative volumes of different facies in the reservoir. In this setting, the facies classification problem becomes a problem
of estimating the parameters defining the Gaussian mixture model. The EM algorithm has long been used to estimate Gaussian
mixture model parameters. As the standard EM algorithm does not consider spatial relationship among data, it can generate
spatially scattered seismic facies which is physically unrealistic. We improve the standard EM algorithm by adding a spatial
constraint to enhance spatial continuity of the estimated geological facies. By applying the EM algorithms to acoustic impedance
and Poisson’s ratio data for two synthetic examples, we are able to identify the facies distribution. 相似文献
11.
Seismic characterization of switching platform geometries and dominant carbonate producers (Miocene,Las Negras,Spain) 
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下载免费PDF全文 Lucas M. Kleipool Koos de Jong Eveline L. de Vaal John J. G. Reijmer 《Sedimentology》2017,64(6):1676-1707
The primary goals of seismic interpretation and quantification are to understand and define reservoir architecture and the distribution of petrophysical properties. Since seismic interpretation is associated with major uncertainties, outcrop analogues are used to support and improve the resulting conceptual models. In this study, the Miocene carbonates of Cerro de la Molata (Las Negras, south‐east Spain) have been selected as an outcrop analogue. The heterogeneous carbonate rocks of the Cerro de la Molata Platform were formed by a variety of carbonate‐producing factories, resulting in various platform morphologies and a wide range of physical properties. Based on textural (thin sections) and petrophysical (porosity, density, carbonate content and acoustic properties) analyses of the sediments, eleven individual facies types were determined. The data were used to produce synthetic seismic profiles of the outcrop. The profiles demonstrate that the spatial distribution of the facies and the linked petrophysical properties are of key importance in the appearance of the synthetic seismic sections. They reveal that carbonate factory and facies‐specific reflection patterns are determined by porosity contrasts, diagenetic modifications and the input of non‐carbonate sediment. The reflectors of the seismograms created with high‐frequency wavelets are coherent with the spatial distribution of the predefined facies within the depositional sequences. The synthetic seismograms resulting from convolution with lower frequency wavelets do not show these details – the major reflectors coincide with: (i) the boundary between the volcanic basement and the overlying carbonates; (ii) the platform geometries related to changes in carbonate factories, thus sequence boundaries; and (iii) diagenetic zones. Changes in seismic response related to diagenesis, switching carbonate producers and linked platform geometries are important findings that need to be considered when interpreting seismic data sets. 相似文献
12.
Fracture-cavity reservoirs can be described in terms of storage space, filling materials and distribution, however, characterizing these variables remains a challenge. In this study, a method was developed to characterize complex reservoirs by integrating outcrop, core, well log, and seismic data from the Tahe oilfield. Outcrop analogs were used to identify and qualitatively analyze the genesis of different reservoir spaces. Cores, well logs, and seismic data were used to identify different types of reservoir space in the subsurface, to describe the spatial distribution, and to establish the distribution pattern of fracture-cavity reservoirs. Clastic sediments, collapse breccia, and chemical fillings were described from the cores and used to assess porosity and permeability. On the basis of the results, a three-dimensional geological model was constructed incorporating a structural model, a reservoir space model, and a property model. Caves and fractures were the main storage spaces and seepage passages. The cave model was built using multi-point geostatistical simulation, while the fracture model was established using deterministic modeling combined with manual interpretations and ant-tracking technology. 相似文献
13.
Retention of surface-modified nanoscale zero-valent iron (NZVI) particles in the porous media near the point of injection has been reported in the recent studies. Retention of excess particles in porous media can alter the media properties. The main objectives of this study are, therefore, to evaluate the effect of particle retention on the porous media properties and its implication on further NZVI particle transport under different flow conditions. To achieve the objectives, a one-dimensional transport model is developed by considering particle deposition, detachment, and straining mechanisms along with the effect of changes in porosity resulting from retention of NZVI particles. Two different flow conditions are considered for simulations. The first is a constant Darcy’s flow rate condition, which assumes a change in porosity, causes a change in pore water velocity and the second, is a constant head condition, which assumes the change in porosity, influence the permeability and hydraulic conductivity (thus Darcy’s flow rate). Overall a rapid decrease in porosity was observed as a result of high particle retention near the injection points resulting in a spatial distribution of deposition rate coefficient. In the case of constant head condition, the spatial distribution of Darcy’s velocities is predicted due to variation in porosity and hydraulic conductivity. The simulation results are compared with the data reported from the field studies; which suggests straining is likely to happen in the real field condition. 相似文献
14.
Tofig Ahmadov Aleksandr V. Dozorov Vladimir N. Zapevalov 《Journal of the Geological Society of India》2018,91(3):380-382
This paper is devoted to the study of a cross-borehole section based on seismic and well-logging data using the “AZERI” software package to determine the well-placement. The main objective was verification of the algorithm and the software on the currently active wells. Overall, the study was conducted on two wells, one of them is reference and the other is the projected well which enabled us to compare the two results.There are several approaches to determine the pay zone heterogeneity in cross-borehole section using the seismic data. Despite various applications, currently there is no application of the filtration properties determination methodology of pay zones in cross-borehole section based on seismic data. Completely different approach to the solution of this problem is considered in this paper. Especially the study of reservoir porosity and permeability of pay zone, as well as the prediction of the producibility of cross-borehole section based on seismic and welllogging data. Thus, the necessary knowledge about porosity and permeability of pay intervals and their producibility is obtained, i.e. the quantitative estimation of the parameters mentioned above is derived.As a result, the accuracy of the achieved results is closely linked to the exploration field’s seismic-geological conditions, depth and the level of seismic data processing as well as the level of similarity of two seismic traces that are picked near the reference and projected wells, not to mention the accuracy of the interpretation of log data.In conclusion, the production well placement determination was carried out by PANGEA Company of Moscow. The selected position of well No.1867 is matching well with the geological results of PANGEA. Therefore, “AZERI” software, constructed based on the algorithms developed by authors, shows that the future well placement risks for the deep drilling are significantly reduced. 相似文献
15.
Textural and mineralogical properties of the sediment, facies characteristics (both derived from well data), stacking patterns (derived from well and seismic data) and plan‐view shapes (derived from seismic data) are all essential components when reconstructing reservoir geometries from subsurface data sets. Without the availability of all these sources of information, reservoir predictions can potentially deviate significantly from the true geometries. In particular, inferences about internal sandbody geometry from plan‐view considerations (isopach maps and seismic attribute maps) may lead to erroneous conclusions without knowledge of facies and textural properties of the sediment. Analysis of well‐exposed sedimentary systems has the potential to establish links between internal facies characteristics and large‐scale geometry and to improve models coupling information at these variable scales. The Palaeogene Battfjellet Formation, Svalbard, has been studied with the aim to unravel internal characteristics and external form by investigating sediment properties, facies and stacking patterns. The formation shows a combination of texturally and mineralogically very immature sediments, a predominance of wave‐generated or wave‐induced sedimentary structures and a stacking pattern of highly variable numbers of parasequences at localities few kilometres apart that best can be explained in terms of small shifting deltaic lobes that produced a complex pattern of overlapping sandbodies. The strong evidence of wave action in the receiving basin could in itself indicate strike‐extensive sandstone bodies; however, the complex sandbody arrangement and the immaturity of the sediments preclude such an interpretation. Traditional facies models coupling plan‐view geometries with internal facies characteristics (such as the coupling of strike extensive barrier systems with wave‐dominated sedimentary structures or the coupling of elongated fluvial‐dominated deltas with offshore‐directed current‐generated structures) are much too simple and may lead to erroneous interpretations if the complexity revealed by all sources of data is not appreciated. 相似文献
16.
深地震测深是探测壳幔岩石圈精细速度结构、探讨岩石圈变形和演化过程的一种有效方法,在青藏高原隆升、克拉通裂解等大陆动力学研究中已发挥了重要的作用。然而,地震测深方法与深部动力学研究的结合尚处于现象描述为主的状态。因此,本文对前人利用深地震测深资料进行深部动力学研究的相关方法进行了回顾与总结:宽角反射/折射地震震相特征具有明显的动力学响应,是进行动力学研究的基础;通过速度结构对比可以确定不同地壳速度结构模型所对应的构造单元及其演化过程,地壳厚度和泊松比等参数可以用于地壳变形模式的讨论,壳内高速和低速异常体反映了不同动力学过程对地壳的改造;人工地震S波资料与Pn波速度可以用于壳幔各向异性的研究,为动力学演化过程研究提供独立的观测证据;运用现代构造解析方法可以构建不同的地壳结构—动力型式,进而通过壳幔结构的解构恢复岩石圈演化过程;此外,地震测深资料可以约束地壳成分结构,为动力学数值模拟提供岩石流变参数等资料。本文对于充分挖掘深地震测深资料在动力学研究中的应用价值至关重要,对于加强地震测深同其他学科的交叉研究也具有重要意义。 相似文献
17.
R. C. Neagu U. Tinivella V. Volpi M. Rebesco A. Camerlenghi 《International Journal of Earth Sciences》2009,98(4):839-848
Petrophysical properties (wet bulk density, porosity, P-wave velocity) are used to predict biogenic silica contents along
a seismic reflection profile that ties two well sites, 1095 and 1096, drilled by Ocean Drilling Program (ODP) Leg 178 on sediment
drifts on the Pacific continental margin of the Antarctic Peninsula. The biogenic silica contents along the seismic reflection
profile were estimated on the basis of three hypotheses about petrophysical properties distributions in the two boreholes
and statistical relationships between biogenic silica and other petrophysical properties, which were established on various
sediment layers within the boreholes. Our study demonstrates the possibility to reliably predict the distribution of biogenic
silica in the sub-seabed sediments if seismic data processed with amplitude preservation are used and statistical relations
are considered. We conclude that the statistical extrapolation of biogenic silica content along seismic reflection profiles
tied to borehole data is an efficient tool to quantify the amounts of silica undergoing crystalline transformation, which
may have strong implications for submarine slope destabilisation. 相似文献
18.
The offset-domain prestack depth migration with optimal separable approximation, based on the double square root equation, is used to image complex media with large and rapid velocity variations. The method downward continues the source and the receiver wavefields simultaneously. The mixed domain algorithm with forward Fourier and inverse Fourier transform is used to construct the double square root equation wavefield extrapolation operator. This operator separates variables in the wave number domain and variables in the space domain. The phase operation is implemented in the wave number domain, whereas the time delay for lateral velocity variation is corrected in the space domain. The migration algorithm is efficient since the seismic data are not computed shot by shot. The data set test of the Marmousi model indicates that the offset-domain migration provides a satisfied seismic migration section on which complex geologic structures are imaged in media with large and rapid lateral velocity variations. 相似文献
19.
《Journal of Structural Geology》2004,26(6-7):1067-1086
Structural controls on the distribution of gold in the Witwatersrand Basin can be seen at scales ranging from that of thin sections up to regional seismic data sets. At the thin section scale, gold occurs largely in fractures with hydrocarbons. These fractures are associated with pulses of thrusting deformation that occurred in the latter stages of the basin's development. The distribution of thrust–fracture networks (and therefore gold) is controlled by the mechanical attributes of the host stratigraphy. Thrust displacements are generally very low, with structures exploiting depositional contacts and mesoscale sedimentary bedforms. Many of the small faults are isolated from each other with bimodal vergence between larger-scale thrusts of the same age. Early-formed faults and fractures become folded and faulted by subsequent propagation of larger-scale thrusts. These characteristics are consistent with formation of the mineralised thrust–fracture networks in the frontal, low-displacement parts of a thrust system. In the Carletonville goldfield, the prospectivity of the Ventersdorp Contact Reef (VCR) has been evaluated by using underground observations to pinpoint the structural habitat of gold, and therefore characterise the size of prospective zones around structures intersecting the VCR, mapped within 3D seismic data. In the Welkom goldfield, the controls on gold distribution at the Tshepong mine have been characterised from 3D seismic data, drilling and underground observations, and used to develop an ore-body model that aids reserve estimation and production planning. 相似文献
20.
Simultaneous Integration of Pressure, Water Cut,1 and 4-D Seismic Data In Geostatistical Reservoir Modeling 总被引：1，自引：0，他引：1
A geostatistically-based inverse technique, the sequential-self calibration (SSC) method, is used to update reservoir models so that they match observed pressure, water cut and time-lapse water saturation derived from 4-D seismic. Within the SSC, a steady-state genetic algorithm (GA) is applied to search the optimal master point locations, as well as the associated optimal permeability perturbations at the master locations. GA provides significant flexibility for SSC to parameterize master point locations, as well as to integrate different types of dynamic data because it does not require sensitivity coefficients. We show that the coupled SSC/GA method is very robust. Integrating dynamic data can significantly improve the characterization of reservoir heterogeneity with reduced uncertainty. Particularly, it can efficiently identify important large-scale spatial variation patterns (e.g., well connectivity, near well averages, high flow channels and low flow barriers) embedded in the reservoir heterogeneity. Using dynamic data, however, could be difficult to reproduce the permeability values on the cell-by-cell basis for the entire model. This reveals the important evidence that dynamic data carry information about large-scale spatial variation features, while they may be not sufficient to resolve the individual local values for the entire model. Through multiple realization analysis, the large-scale spatial features carried by the dynamic data can be extracted and represented by the ensemble mean model. Furthermore, the region informed by the dynamic data can be identified as the area with significant reduced variances in the ensemble variance model. Within this region, the cell-by-cell correlation between the true and updated permeability values can be significantly improved by integrating the dynamic data. 相似文献