共查询到20条相似文献，搜索用时 31 毫秒
1.
天然气在开发过程中,储层有效压力和含气饱和度均会发生变化,研究有效压力和含气饱和度的变化对地震响应特征的影响,在基于时移地震的剩余气分布预测研究中具有重要意义。天然气和石油的声学性质有着明显的差异,油藏时移地震的研究成果不能直接应用于气藏,因此需要开展气藏的时移地震研究。利用Shapiro模型表征干岩石弹性模量随有效压力的变化,借助Batzle-Wang方程描述流体速度随压力的变化关系,联合Gassmann理论进行流体替代,表征饱和流体岩石速度随含气饱和度的变化,建立了饱和流体岩石速度随有效压力和饱和度变化的岩石物理模型。基于该模型,对不同含气饱和度和不同有效压力下的气藏储层模型进行了多波时移地震叠前振幅变化（AVO）模拟。结果表明多波时移地震AVO技术可以有效地区分有效压力变化和含气饱和度变化,为进一步开展气藏多波时移地震流体监测提供了理论参考依据。 相似文献
2.
Although previous seismic monitoring studies have revealed several relationships between seismic responses and changes in reservoir rock properties, the quantitative evaluation of time‐lapse seismic data remains a challenge. In most cases of time‐lapse seismic analysis, fluid and/or pressure changes are detected qualitatively by changes in amplitude strength, traveltime and/or Poisson's ratio. We present the steps for time‐lapse seismic analysis, considering the pressure effect and the saturation scale of fluids. We then demonstrate a deterministic workflow for computing the fluid saturation in a reservoir in order to evaluate time‐lapse seismic data. In this approach, we derive the physical properties of the water‐saturated sandstone reservoir, based on the following inputs: VP, VS, ρ and the shale volume from seismic analysis, the average properties of sand grains, and formation‐water properties. Next, by comparing the in‐situ fluid‐saturated properties with the 100% formation‐water‐saturated reservoir properties, we determine the bulk modulus and density of the in‐situ fluid. Solving three simultaneous equations (relating the saturations of water, oil and gas in terms of the bulk modulus, density and the total saturation), we compute the saturation of each fluid. We use a real time‐lapse seismic data set from an oilfield in the North Sea for a case study. 相似文献
3.
The propagation of seismic waves through a saturated reservoir compresses the fluid in the pore spaces. During this transition, parts of seismic energy would be attenuated because of intrinsic absorption. Rock physics models make the bridge between the seismic properties and petrophysical reality in the earth. Attenuation is one of the significant seismic attributes used to describe the fluid behaviour in the reservoirs. We examined the core samples using ultrasonic experiments at the reservoir conditions. Given the rock properties of the carbonate reservoir and experiment results, the patchy saturation mechanism was solved for substituted fluid using the theory of modulus frequency. The extracted relationship between the seismic attenuation and water saturation was used in time–frequency analysis. We performed the peak frequency method to estimate the Q factor in the Gabor domain and determined the water saturation based on the computed rock physics model. The results showed how the probable fault in the reservoir has stopped the fluid movement in the reservoir and caused touching the water‐bearing zone through drilling. 相似文献
4.
Uncertainties in quantitative time-lapse seismic analysis 总被引：1，自引：0，他引：1
Martin Landrø 《Geophysical Prospecting》2002,50(5):527-538
Most seismic time-lapse studies so far have been of a qualitative nature. Identification of areas with minor or no seismic changes has been used to plan new infill drilling targets. Increased accuracy in seismic acquisition methods, in both conventional streamer surveys and newer methods such as multicomponent sea-bed seismic and permanent sensors, opens possibilities for the next step: quantitative time-lapse analysis. Quantitative methods here mean the estimation of, for instance, a change in fluid saturation from 20% water to 90% water or the estimation of a pore pressure change of 5 MPa. Explicit expressions for the uncertainties associated with estimated changes in, for instance, reservoir pressure and fluid saturation are derived. These formulae can be used to compare relative uncertainties between estimated parameters as well as to identify the critical factors in various estimation techniques. The importance of accurate rock physics input, as well as that of highly repeatable time-lapse seismic data, is emphasized. Furthermore, uncertainty analysis can be used to find optimal weight factors when the same parameter (e.g. saturation change) is estimated by two or three different techniques. 相似文献
5.
Numerous examples of reservoir fields from continental and marine environments involve thin‐bedded geology, yet, the inter‐relationship between thin‐bedded geology, fluid flow and seismic wave propagation is poorly understood. In this paper, we explore the 4D seismic signature due to saturation changes of gas within thin layers, and address the challenge of identifying the relevant scales and properties, which correctly define the geology, fluid flow and seismic wave propagation in the field. Based on the study of an outcrop analogue for a thin‐bedded turbidite, we model the time‐lapse seismic response to fluid saturation changes for different levels of model scale, and explore discrepancies in quantitative seismic attributes caused by upscaling. Our model reflects the geological complexity associated with thin‐bedded turbidites, and its coupling to fluid flow, which in turn affects the gas saturation distribution in space, and its time‐lapse seismic imprint. Rock matrix and fluid properties are modelled after selected fields to reproduce representative field models with realistic impedance contrasts. In addition, seismic modelling includes multiples, in order to assess their contribution in seismic propagation through thin gas layers. Our results show that multiples could contribute significantly to the measured amplitudes in the case of thin‐bedded geology. This suggests that forward/inverse modelling involving the flow simulation and seismic domains used in time‐lapse seismic interpretation should account for thin layers, when these are present in the geological setting. 相似文献
6.
在双相介质理论指导下构建的流体因子Gassmann流体项f可以实现对油水层的有效判识。本文基于包含流体因子f的反射系数近似公式推导,得到相应的流体弹性阻抗方程,将流体因子纳入地震反演过程并直接参与目标储层的流体识别,实现了从弹性阻抗数据体中直接反演流体因子f的方法技术流程。流体因子f的直接反演有效减少间接计算所带来的累计误差,提高了地震流体识别的精度。在实际资料应用中,结合研究区地质背景与地球物理特征开展的岩石物理分析表明,Gassmann流体因子f对含油和含水特征有较好的区分作用。反演结果表明,流体因子f能为有效地识别目的层的油水特征,为下一步的钻井开发提供可靠的技术支持。 相似文献
7.
为了研究孔隙流体对不同渗透率岩石地震波速度的影响,在实验室利用跨频带岩石弹性参数测试系统得到了应变幅值10-6的2~2000Hz频段下的地震波速度和1 MHz频率下的超声波速度,利用差分共振声谱法得到了频率600Hz岩石干燥和完全饱水情况下岩石声学参数.实验表明,在低饱和度下,致密砂岩在地震和超声频段下没有明显的频散;在高饱和度下纵波速度的频散变得明显.从干燥到完全水饱和条件,不同频率测量的致密砂岩的体积模量随岩石孔隙度增高而降低,且体积模量的变化量受岩石微观孔隙结构的影响较大.高孔、高渗砂岩无论在低含水度下还是在高含水饱和度下频散微弱,并且在地震频段下围压对于岩石纵横波速度的影响要大于频率的影响.高孔、高渗砂岩和致密砂岩不同含水饱和度下的频散差异可应用于储层预测,油气检测等方面,同时该研究可以更好地帮助理解岩石的黏弹性行为,促进岩石物理频散理论的发展,提高地震解释的精度. 相似文献
8.
基于岩石物理和地震反演理论,提出了一种同步反演储层孔隙度和含水饱和度的方法.以岩石物理为基础,建立了砂泥岩储层物性和弹性参数之间定量的关系-Simon模型,以贝叶斯理论为手段,结合不同类型的砂泥岩储层,建立了多信息联合约束的物性参数反演目标函数,并通过蒙特卡罗和遗传算法相结合的思路求解该目标函数,最终得到孔隙度和含水饱和度的同步反演结果.将该方法应用于河道砂和砂砾岩两种不同的砂泥岩储层中,孔隙度和含水饱和度数据的联合应用,进一步减少了储层预测的多解性,为石油地质综合研究提供了更加丰富准确的基础数据. 相似文献
9.
孙林洁 《CT理论与应用研究》2020,29(5):566-575
优质气层与低含气饱和度的差气层、气水同层均呈现"亮点"强振幅的地震响应特征,利用振幅类属性或者常规弹性参数难以进行有效判识。考虑到密度参数随含气饱和度的高敏感性,本文在贝叶斯叠前反演框架下,以三变量柯西分布为先验正则约束进行叠前地震反演,减小了纵波速度、横波速度与密度三参数统计相关性造成的参数估算误差,进一步提高了弹性参数的可靠性,模型测试表明新方法反演的密度精度及稳定性更高。将方法应用于马达班湾盆地X区块,在流体替代及岩石物理统计分析的指导下,利用基于三变量柯西分布的叠前地震反演方法提取密度参数,预测优质气层富集区,实钻结果与预测结果吻合度高,表明该方法具有较高的实用性。 相似文献
10.
We present a new petro-elastical and numerical-simulation methodology to compute synthetic seismograms for reservoirs subject
to CO2 sequestration. The petro-elastical equations model the seismic properties of reservoir rocks saturated with CO2, methane, oil and brine. The gas properties are obtained from the van der Waals equation and we take into account the absorption
of gas by oil and brine, as a function of the in situ pore pressure and temperature. The dry-rock bulk and shear moduli can be obtained either by calibration from real data or
by using rock-physics models based on the Hertz-Mindlin and Hashin-Shtrikman theories. Mesoscopic attenuation due to fluids
effects is quantified by using White's model of patchy saturation, and the wet-rock velocities are calculated with Gassmann
equations by using an effective fluid modulus to describe the velocities predicted by White's model. The simulations are performed
with a poro-viscoelastic modeling code based on Biot's theory, where viscoelasticity is described by generalizing the solid/fluid
coupling modulus to a relaxation function. Using the pseudo-spectral method, which allows general material variability, a
complete and accurate characterization of the reservoir can be obtained. A simulation, that considers the Utsira sand of the
North Sea, illustrates the methodology. 相似文献
11.
储层物性参数作为描述储层特性、储层建模和流体模式的重要指标,其准确估算可以为储层预测提供有力参考依据,但传统储层物性参数反演方法无法兼顾反演精度及空间连续性。针对上述问题,本文引入地震属性作为深度学习算法输入,针对地震属性之间存在的信息冗余特征,利用随机森林-递归消除法对地震属性进行约简预处理,最终建立一种基于地震属性约简的储层物性参数预测方法。实际数据测试结果表明,地震属性约简的深度学习储层物性参数预测结果具有良好的精度及横向分辨率,证实本文方法的有效性。 相似文献
12.
地震波本征衰减反映了地层及其所含流体的一些特性,对油气勘探开发有重要意义.已有的理论研究与实验发现,地震频带内的衰减主要与中观尺度(波长与颗粒尺度之间)的斑状部分饱和、完全饱和岩石弹性非均匀性情况下波诱导的局部流体流有关.这种衰减与岩石骨架、孔隙度及充填流体的性质密切相关.本文着重讨论均匀流体分布、斑状或非均匀流体分布两种情况下部分饱和岩石的纵波模量差异.以经典岩石物理理论和衰减机制认识为基础,通过分析低频松弛状态、高频非松弛状态岩石的弹性模量,讨论储层参数(如孔隙度、泥质含量以及含水饱和度等)与纵波衰减之间的确定性关系.上述方法与模型在陆相砂泥岩地层与海相碳酸盐岩地层中的适用性通过常规测井资料得到了初步验证. 相似文献
13.
叠前反演和地震吸收技术在复杂天然气藏地震预测中的应用 总被引：1，自引：0，他引：1
针对某复杂断块天然气目标储层,在岩石物理分析的指导下,综合利用地质、地震、测井等资料,提出了一套面向复杂天然气藏的叠前地震预测技术.首先基于地震岩石物理分析得到的初始横波信息,采用叠前贝叶斯非线性三参数反演得到了井旁控制点处精确纵横波速度和密度信息,然后通过叠前/叠后联合反演技术实现了面向目标的弹性阻抗体反演及含气储层敏感参数直接提取,最后结合小波变换时频谱分析的方法从叠前地震资料中估算地层吸收参数值,提高天然气藏识别精度.实际应用表明,综合各种叠前地震预测技术,可以大大提高对复杂天然气藏的识别精度,降低勘探风险. 相似文献
14.
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. 相似文献
15.
Partially saturated reservoirs are one of the major sources of seismic wave attenuation, modulus defect and velocity dispersion in real seismic data. The main attenuation and dispersion phenomenon is wave induced fluid flow due to the heterogeneity in pore fluids or porous rock. The identification of pore fluid type, saturation and distribution pattern within the pore space is of great significance as several seismic and petrophysical properties of porous rocks are largely affected by fluid type, saturation and fluid distribution pattern. Based on Gassmann-Wood and Gassmann- Hill rock physics models modulus defect, velocity dispersion and attenuation in Jurassic siliclastic partially-saturated rocks are studied. For this purpose two saturation patterns - uniform and patchy - are considered within the pore spaces in two frequency regimes i.e., lower frequency and higher frequency. The results reveal that at low enough frequency where saturation of liquid and gas is uniform, the seismic velocity and bulk modulus are lower than at higher frequency where saturation of fluid mixture is in the form of patches. The velocity dispersion and attenuation is also modeled at different levels of gas saturation. It is found that the maximum attenuation and velocity dispersion is at low gas saturation. Therefore, the dispersion and attenuation can provide a potential way to predict gas saturation and can be used as a property to differentiate low from high gas saturation. 相似文献
16.
裂缝型储层表现出较强的各向异性特征.缝隙中充填不同流体时,裂缝储层的地震响应特征也不相同.本文从各向异性岩石物理模型出发,引入可有效识别缝隙流体的指示因子,并研究缝隙充填流体类型、饱和度以及缝隙纵横比与流体因子的相互关系,进而分析不同流体充填时介质的地震响应特征,并基于AVAZ反演方法估测缝隙流体指示因子.首先对缝隙流体因子的敏感性进行了分析,讨论当缝隙充填不同流体时,缝隙流体因子值的变化特征,同时研究了不同流体类型充填时裂缝储层反射系数随方位角和入射角的变化特征.某工区测井数据和复杂裂缝模型应用表明,基于各向异性岩石物理的缝隙流体因子AVAZ反演方法合理、可靠,且具有良好的抗噪性,即当对合成地震记录添加信噪比不小于1/2的随机噪声时,利用AVAZ反演方法估测所得流体因子值与真实值仍然吻合较好. 相似文献
17.
CT技术具有无损、三维并可与计算机应用模拟相结合等特点,使其在储层地质研究中作用独特。本文从CT技术特点入手,总结分析其在储层地质研究中的应用发展历程:储层岩石组构识别、储层表征、微观流体输运过程的在线监测及剩余油分布研究等。随着高分辨率工业CT及数字岩心技术的发展,CT扫描三维数据体与数字岩心相结合,不仅可以提取岩石物理属性参数,如储层岩石的孔渗、地层因子、弹性模量、横纵波分析等,建立三维孔喉网络模型,还可以直接对复杂的孔喉系统进行定量化的结构表征和微渗流数值模拟。最后,本文作出展望,随着计算机技术的提高和油气勘探需求的增长,其应用会越来精细,越来越广泛。 相似文献
18.
油藏开发过程的有效监测是合理开采油藏和提高采收率的关键之一.本文根据水驱油藏流体变化的基本规律以及其他实验和统计结果,讨论了长期注水开采油藏储层物性变化及其引起的弹性参数变化和地震响应变化特征,明确了水驱前沿的概念,提出了基于差异振幅和奇异值分析的时移地震监测水驱前沿方法.理论模型研究表明该方法是可行的.通过对东部地区某油田的两次三维地震数据处理、分析,确定了水驱前沿的位置,后钻的两口井证实了预测结果的准确性和方法的有效性.研究结果还表明,通过水驱前沿的监测并结合初期油藏描述的结果,时移地震可以很好地预测长期水驱油藏剩余油的分布. 相似文献
19.
复杂孔隙储层往往同时发育孔缝洞等多种孔隙类型,这种孔隙结构的复杂性使得岩石的速度与孔隙度之间的相关性很差.经典的二维岩石物理模版只研究弹性参数与孔隙度和饱和度之间的定量关系,而不考虑孔隙结构的影响,用这样的模版来预测复杂孔隙储层的物性参数时带来很大偏差.本文首先证明多重孔隙岩石的干骨架弹性参数可以用一个等效孔隙纵横比的单重孔隙岩石物理模型来模拟;进而基于等效介质岩石物理理论和Gassmann方程,建立一个全新的三维岩石物理模版,用它来建立复杂孔隙岩石的弹性性质与孔隙扁度及孔隙度和饱和度之间的定量关系;在此基础上,预测复杂储层的孔隙扁度、孔隙度以及孔隙中所包含的流体饱和度.实际测井和地震反演数据试验表明,三维岩石物理模版可有效提高复杂孔隙储层参数的预测精度. 相似文献
20.
Alistair R. Brown 《Geophysical Prospecting》2001,49(6):729-733
Stratigraphic, reservoir and fluid interpretation demands a thorough understanding of the seismic-to-well tie. Data phase, polarity and tuning effects significantly influence this tie and are often poorly understood. By relating seismic character to known subsurface geology, the interpreter should gain better understanding and be able to calibrate himself to his data. This is an important preliminary stage in any seismic interpretation beyond structure. 相似文献