岩相骨架的地质统计模拟

储集层非均质性是碎屑岩储集层描述中的重要问题。与流体性质分布的不确定性相比，岩相骨架的不确定性对流体预测影响更大。近十年来，地质统计方法大量地应用于岩相骨架的模拟中，其模拟方法主要有离散及连续两类。用数学语言对４个主要的离散模拟方法（序贯指示模拟、截断高斯模拟、模拟退火及示性点过程模拟）进行概述，展示其工作过程，讨论各自的优缺点，特别强调如何合并次生数据以及在现场应用的可能性。此外，还提出了该领域未来的研究方向。表１参２９（邹冬平摘     

Ensemble Kalman filter for automatic history matching of geologic facies

In this paper we address two fairly difficult problems. The first is the problem of matching production data (in this case, production and injection rates) by adjustment of the locations of the geologic facies boundaries. The second is the use of a Kalman filter for updating the facies locations in the reservoir model.Traditional automatic history matching tools are not widely available for reservoirs with unknown facies boundaries, largely because of the complexity of developing software for computing the sensitivity of the data to model parameters, the lack of differentiability of facies type, and the high computational cost in generating multiple reservoir models that are conditional to given data. With careful definition of variables, the use of the ensemble Kalman filter (EnKF) minimizes those difficulties. First, the gradient does not need to be computed explicitly, the coding for the EnKF algorithm is easy and adaptable to any reservoir simulator on a plug-in basis. Second, an approximation to differentiability results from the correlation of variables. Third, the ensemble Kalman filter (EnKF) method takes one simulation run per reservoir model realization, and the simulations of the reservoir models in the ensemble are ideal for multiple-processor parallel computation.We use the truncated pluri-Gaussian model to generate random facies realizations. The geostatistical model is fully specified by the threshold truncation map and the covariance models for the two Gaussian random fields. The pluri-Gaussian model is well known but not widely used, partly because of the difficulty of generating conditional realizations. In the first example, we demonstrate the application of the EnKF to the problem of generating facies realizations conditional to observations at 18 wells on a 128 × 128 grid. In the second example, realizations of facies on a 50 × 50 grid, conditional to facies observations at the wells and to production and injection rates, are generated using the EnKF. In general, we found that application of the EnKF to the problem of adjusting facies boundaries to match production data was relatively straightforward and efficient.     

十万大山盆地晚二叠世、早三叠世烃源岩中铁元素丰度与有机碳丰度相关关系

海相烃源岩中铁的来源受气候、时代、海水中生物量、海水性质、海洋基底等多因素影响。在稳定的浅海陆棚环境发育的泥岩中，铁元素丰度主要受控于沉积物颗粒大小和有机质丰度，铁元素丰度与有机碳丰度呈正相关关系。十万大山盆地的三化、大寺、旧城、油隘4个研究区域晚二叠世早三叠世的陆棚泥岩沉积环境相对稳定，烃源岩中的铁元素丰度与有机碳丰度存在正相关性。深入研究铁元素丰度与有机碳丰度的相关性，可为地层对比以及判识沉积环境提供一定信息。图2参24     

我国不同沉积类型储集层中的储量和可动剩余油分布规律

研究中国不同沉积类型储集层中的储量和可动剩余油分布规律，了解储集层非均质性对剩余油的控制作用，是储集层精细描述和不同类型储集层剩余油挖潜的基础。按河流相、三角洲相、扇三角洲相、滩坝相、湖底扇（浊积）相、冲积扇相和基岩（包括变质岩、火山岩和岩浆岩）七大类储集层，研究了中国１５个主要油区７１个油田的原始地质储量、水驱标定采收率、水驱油效率和可动剩余油储量等油藏参数在各类储集层中的分布规律。统计结果表明，中国已探明和投入开发储量的９２％赋存于陆源碎屑岩储集层中；各类陆源碎屑岩储集层中的原始地质储量分布情况是：河流相４２．６％，三角洲相３０％，扇三角洲相５．４％，滩坝相１．４％，湖底扇（浊积）相６．３％，冲积扇（冲积—河流）相６．４％，基岩８％。各类碎屑岩储集层中可动剩余油储量的分布情况是：河流相４８．６％，三角洲相２７．６％，扇三角洲相５．５％，滩坝相１．８％，湖底扇（浊积）相９．６％，冲积扇（冲积—河流）相６．９％。此外还分析对比了各类碎屑岩储集层的平均水驱标定采收率、平均水驱油效率。结果表明，三角洲相、扇三角洲相和湖底扇相三大类储集层是中国今后储集层研究的重点及调整挖潜的主要对象。图１表３参４（邹冬平摘）     

我国油田河流相与三角洲相储层参数统计研究

中国油田河流相与三角洲相储层的地质储量占碎屑岩相总储量的近８０％，是主要的沉积相类型。统计研究了中国油田河流相与三角洲相的典型油水相对渗透率曲线、典型毛管压力曲线、典型ＰＶＴ关系，以及多种储层参数的平均值。比较了它们之间的差异。     

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储层的空间连通性对于油气田的开发有很大程度的影响，但如何正确地描述出储层的空间连通模式是地质学家所面临的难题之一。文章引入连通性的定义后，将储层连通性的模拟问题转化为在模拟区域G中模拟一满足条件连通约束条件的平稳随机集A，利用随机模拟理论中的截断高斯模拟技术，建立了在给定的连通约束条件下模拟储层岩相的空间展布的方法和具体的模拟步骤，分析了影响连通性的因素。实例模拟结果表明：模拟结果能很好地符合于连通约束条件；由于不同的初始图像代表对模拟区域连通性的不同估计，初始图像的不同，会导致模拟结果上的差异，这种差异性反映出模拟具有一定的多解性，但它能为地质学家提供多种可供选择的连通模型。     

碳酸盐岩古岩溶相的发育模式,演化特点及储层类型

碳酸盐岩古岩溶有着良好的油气储集性能,世界上许多高产油气田均与其有关。本文介绍了近年来石油地质界对古岩溶相的发育模式、古岩溶相的演化和保存条件以及古岩溶相的储层类型的研究成果。     

应用卷积神经网络识别测井相

选用东海F气田的砂质辫状河三角洲的自然伽马数据作为训练数据构建深度卷积神经网络,并首次用于测井相识别。选用四种自然伽马曲线形态作为特征,将数值转变为图像形式,首先对图像做标准化、添加噪声、旋转和转灰度等处理,再对数据增强与扩充,建立训练和测试数据集;然后,训练卷积神经网络建立测井相识别模型,并在训练过程中加入了Dropout、局部响应归一化和L₂正则化等策略限制了模型的复杂程度,提高了模型泛化能力;针对测井信息中不同级次沉积单元响应叠加带来的自动识别难题,使用不同尺度的小波基函数及极值分割处理和切分测井数据,最终有效划分了不同尺度沉积单元。通过与其他分类算法对比,验证了所提方法具有较好的测井相识别效果。     

平面岩相解释法在河流相储层研究中的应用

与常规的剖面解释和传统的平面划相不同,平面岩相解释法是利用三维地震资料横向密集连续性好的特点,将地震属性信息与储层层序和地质过程相结合,运用地层切片技术、多属性融合成像技术、平面岩相自动追踪解释技术,结合地震资料、测井资料和钻井资料相,最终在平面上再现地下地层的岩相图像。在松辽盆地南部QD工区河流相储层研究中的应用结果表明,该方法具有解释精度高、速度快、微相解释和构造细节清楚等特点,在岩性油气藏勘探开发中具有广阔的应用前景。     

熵分析在单井相划分中的应用

熵作为随机过程中一种不确定性程度的量度,广泛应用在地质学领域。本文应用马尔柯夫链的熵分析方法,分析了邓1-邓5井不同层位地层的系统熵及其各种岩性的前熵、后熵,并推测了各层位可能的沉积相。      

准噶尔盆地腹部陆西地区石炭系火山岩储层的物性特征及其与电性的关系

通过对准噶尔盆地腹部陆西地区石炭系火山岩的研究,提出了该区的火山岩岩相模式,即火山通道相、爆发相、喷溢相、侵出相、火山-沉积相等5个相。对156个实测孔隙度和104个实测渗透率数据分析后发现：不同岩相火山岩的物性不同,且以爆发相和喷溢相为好;不同岩性火山岩的物性也有较大的差别,并以熔渣状玄武岩、杏仁状安山岩、火山角砾岩为好;在合适的条件下,加上岩相与岩性的有利组合,可以形成良好的储层;不同岩性火山岩的孔隙度和渗透率与不同,与电性之间的线性相关性亦有较大的差别,但总体上来说相关性都不大。     

Geochemical Characterization of Offshore Western Niger Delta Source Rock

Abstract

A geochemical characterization of rock samples obtained from three offshore fields, MJ, MF, and ML, was carried out. Offshore oil and onshore oil samples were also studied for correlation. The gas chromatographic data showed that the three offshore fields studied exhibited different and unique geochemical signatures. Most rock samples from the MJ field have moderate thermal maturity; n-alkane and their isoprenoid hydrocarbon distribution indicated predominant mixed organic matter with some terrestrial organic matter. The organic matters were deposited in alternating oxic and anoxic environments. In the MF field, sedimentation of the organic matter in the shallow depths was under reducing environments, whereas that of the deeper depth horizons was under oxidizing environments. The rock samples in the field had predominant input from marine organic matter with moderate thermal maturity. In the ML field, the geochemical data indicated that oxic conditions prevailed during sedimentation of the organic matter. About half of the rock samples from this field are thermally mature, with almost equal distribution of marine and terrestrial organic facies. Marine organic matter was prevalent in the shallow depth horizons, whereas terrestrial organic matter was prevalent in deeper depth horizons. The offshore oil samples and offshore rock extracts are also correlative. This study indicates that there are two petroleum systems in the offshore western Niger Delta—marine and terrigenous petroleum systems—though the terrigeonous system is more pervasive.     

3D seismic and formation micro-imager (FMI) integrated study to delineate depositional pattern of Abu Madi (Upper Miocene) clastic reservoir rocks in El-Wastani gas field,onshore Nile Delta,Egypt

Ten wells (EW-4, EW-5, EW-6, EW-7, EW-8, EW-9, EW-10, EW-12, EW-13 and EW-15) were interpreted using the composite well logs, data of core analysis, gamma-ray logs, formation micro-imager logs (FMI), and 3D seismic data in SEGY format to understand the stratigraphy of the onshore, Nile Delta, Egypt.The amplitude analysis of 3-D seismic horizon slice of Lower Abu Madi rock unit together with the lithostratigraphic correlation through the study area depending on the gamma-ray log “HSGR” (left to right increasing), and the identification of type of bed geometry, nature of bed contacts, type of the sedimentary structures and the dominant formative paleocurrents by using some available borehole micro-resistivity images (FMI) and core photos. All of these techniques are used together to define the different depositional facies and depositional environment of the Messinian clastics (Lower Abu Madi rock unit), which is considered to be the main reservoir in the El-Wastani gas field, onshore Nile Delta, Egypt.The present study of depositional pattern of the Upper Miocene clastics reservoir (Lower Abu Madi rock unit) revealed that it is represented by high sinuous meandering channels or paleo-valley and three types of fluvial facies were defined; channel fill, channel margin, and floodplain basin.     

王府断陷火石岭组火山岩岩性及岩相识别

王府断陷火山岩岩性及岩相复杂,利用常规方法识别难度较大。为了提高王府断陷火石岭组火山岩岩性及岩相识别的可靠性,文中从火石岭组不同类型火山岩储层的岩心观察出发,对岩石薄片、测井资料等进行详细分析,总结了火山岩储层的测井响应特征,提出了适应本区的火山岩岩性及岩相识别方法。研究中充分利用常规测井及特殊测井资料识别火山岩岩性的结构构造,并通过测井相、地震相综合标定,建立该区典型的火山岩岩相、测井相和地震相模式,从而进一步识别火山岩岩石结构构造特征。该方法对王府断陷火山岩研究具有较好的指导意义。     

FACIES HETEROGENEITIES IN A RAMP CARBONATE RESERVOIR ANALOGUE: A NEW HIGH‐RESOLUTION APPROACH FOR 3D FACIES MODELLING

In contrast to the conventional view that facies distribution patterns on carbonate ramps are relatively simple, outcrop analogue studies point to a high degree of internal facies complexity. Depending on the diagenetic overprint, this complex pattern may result in reservoir compartmentalization due to the presence of interflow baffles. The often subseismic scale heterogeneities may not be included in conventional reservoir modelling. In order to evaluate how facies heterogeneities in shoal reservoirs can be modelled realistically, this paper presents a facies modelling workflow which includes a new approach to the design of training images for multiple‐point statistics (MPS). The workflow was developed in the course of a reservoir outcrop analogue study of a Ladinian (Middle Triassic) coquinadominated shoal complex in SW Germany which was deposited on an epicontinental, gently inclined carbonate ramp. The data set was based on an intensive field study and includes 3D facies and sequence stratigraphic analyses of the largest shoal complex in the Quaderkalk Formation (Upper Muschelkalk). This several metre thick shoal complex represents a subseismic scale, bioclast‐rich reservoir analogue and has a very heterogeneous facies pattern. Integrating 1D facies logs and sequence stratigraphic trends from tens of outcrop sections and cores, two nested 3D geocellular facies models were produced: (i) a large‐scale (30 × 30 km) model based on truncated Gaussian simulation (TGS); this formed the basis for (ii) a smaller‐scale (10 × 10 km), more detailed model based on multiple point statistics. In addition, a new approach for training image design was developed to honour small‐scale sequence stratigraphic trends and lateral facies patterns observed in modern analogues. Compared to facies patterns in modern analogues, the large‐scale model presents geologically‐feasible facies distribution patterns and geometries, and in addition shows a vertical facies distribution which is similar to the observed sequence stratigraphic architecture of the outcrop data‐set used. Due to the new training image design, the final small‐scale model has a distribution pattern of facies heterogeneities which looks similar to modern facies distributions in the offshore UAE and thus represents a valuable method of producing realistic reservoir facies models. The modelling workflow and the new approach for training image design presented will help to reduce uncertainties in the understanding and modelling of subsurface reservoirs by using a systematic combination of outcrop data and modern analogues, with the consistent application of sequence stratigraphic principles. In addition, this study emphasises the importance of careful training image design, derived from modern analogues, which can be used as realistic inputs in order to optimize multiple point simulations, and which may be applied to producing bioclastic reservoirs such as those located on the Arabian Plate or offshore Brazil.     

珠三坳陷文昌组中深湖相烃源岩新的生物标志化合物组合模式与油源对比

原油样品和不同相带烃源岩样品的地球化学分析结果表明,珠三坳陷文昌组中深湖相烃源岩具有低丰度C304-甲基甾烷,并在C29甾烷上有强共逸出峰(X峰),这种新的生物标志化合物组合模式在南海北部盆地尚属首次提出。依据这一新的生物标志化合物组合模式对珠三坳陷油源重新进行了对比分析,认为文昌B凹陷主力烃源岩是文昌组中深湖相烃源岩,文昌A凹陷主力烃源岩是恩平组河沼相烃源岩;文昌B凹陷区原油的主要贡献者是文昌组中深湖相烃源岩,文昌A凹陷区原油的主要贡献者是恩平组河沼相烃源岩,而琼海凸起西区原油主要源自文昌B凹陷文昌组中深湖相烃源岩,琼海凸起东区原油则主要源于文昌A凹陷恩平组河沼相烃源岩。     

裂缝对致密碎屑岩储层弹性影响的数值分析

有效预测裂缝发育区是寻找致密气甜点区的关键,但目前海陆过渡相致密碎屑岩储层裂缝预测的效果较差。利用DEM理论模型获得岩石孔隙纵横比α及干岩石体积模量,探讨裂缝对致密碎屑岩地层岩石弹性的影响及不同尺度裂缝间的关联性。利用模型确定的α可以较好地识别出裂纹发育段,随着孔隙纵横比由1.0转变为0.01,地层岩石体积模量和剪切模量也逐渐降低,表明裂纹相比孔隙而言更容易引起岩石弹性发生改变。地层岩石由干岩石到饱和地层流体过程中,裂缝不发育地层的体积模量增加幅度为3.1%;对于裂缝发育地层段,孔隙度小于4.7%时其体积模量的增加幅度平均为7.0%,孔隙度大于4.7%时其体积模量增加幅度平均为23.0%,拐点处所对应岩石孔隙度可作为岩石内部裂纹发育程度的评价指标。对于裂缝不发育段地层,干岩石体积模量与剪切模量的比值和孔隙度具有较好的正相关性;对于裂缝发育段地层,干岩石体积模量与剪切模量的比值和孔隙度具有较好的负相关性。研究结果表明,利用岩石弹性性质可以定量表征碎屑岩地层裂缝的发育特征。      

成岩相的形成、分类与定量评价方法

根据成岩作用和成岩相对储集层发育的控制作用及与储集层分布的关系,探讨成岩相的形成机理、划分方案与评价方法及其在油气勘探中的应用和意义。针对碎屑岩、碳酸盐岩和火山岩等扩容性成岩相,提出了有机酸性水溶解作用、白云石化等8种主要成岩作用机理。划分出9类扩容性成岩相和7类致密化成岩相,提出了反映岩性、成岩作用和孔渗性3个层次内容的“孔渗级别＋岩石类型＋成岩作用类型”的成岩相命名方案。在成岩相勘探评价中,强调根据沉积相、测井相、地震相和岩心薄片等综合定量预测,提出了“四个步骤”、“三图叠合”的评价方法和成图方式,根据不同成岩相类型的分布预测有利储集体、“甜点”、成岩圈闭及油气成藏。指出了成岩相的发展方向及成岩学的设想和思考。图16表6参31     

准噶尔盆地东部地区地表火山口类型及特征

准噶尔盆地东部地区基底主要是中石炭统的安山岩和玄武岩,近年来在该区发现了多个火山岩油气藏,该区现已成为重要的油气产区。2008 年在准噶尔盆地东部地区进行了野外地质踏勘,共实测地质剖面4 条,分别为白碱沟、双井子、金山沟、沙尔布拉克,并确定了火山口的准确位置,文章论述了这些火山口的类型及地表特征。该区火山口划分为放射状火山口、环状火山口和半环状火山口3 种类型。对不同类型的火山口分析后,归纳出5 种火山口的识别标志：①侵出相珍珠岩;②火山岩岩性、岩相的环带状分布;③ 硫磺矿沉积;④大面积热液侵染;⑤大规模隐爆角砾岩和堆砌结构。最后讨论了火山口存在的重要意义。     

基于小波变换和中值滤波的FMI信号去噪方法

介绍了二维离散小波变换下的图像分解与重构算法。在图像分解与重构的基础上,提出应用中值滤波和二雏离散小波变换相结合的方法对舍噪的FMI图像进行去噪处理,通过实例验证,采用新方法对一口溶蚀孔洞储层井的FMI图像进行去噪分析,并与单一的中值滤波或小波变换法的结果进行比较。实验结果表明,应用二维小波分析结合传统方法对FMI图像进行去噪,能够有效地去除图像中的随机噪声,其结果优于单一的中值滤波或小渡分析法,对提高油、气层裂缝和孔洞的自动识别具有重要的指导意义。