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1.
垦71开发区块的主要产油层系为新近系的馆陶组河流相和古近系的东营组三角洲相地层,具有被断层复杂化的多油水系统。该区井网密集,储层厚度薄,横向关系复杂,储层与非储层速度差异小,后续开发方案调整所要求的精细储层描述难度较大。本文展示了以精细储层描述为目标的地震约束反演实例,利用多井地震、地质标定,结合三维构造解释成果,建立三维多断层精细约束地质模型。在此基础上,采用随机地震反演方法,进行了波阻抗、岩性等多种地层参数反演,较好地解决了该区薄互层储层精细描述问题,证实了精细储层反演技术在油田开发中的重要作用。 相似文献
2.
面向油藏开发地质问题的精细储层反演研究 总被引：1，自引：0，他引：1
垦71开发区块的主要产油层系为新近系的馆陶组河流相和古近系的东营组三角洲相地层,具有被断层复杂化的多油水系统。该区井网密集,储层厚度薄,横向关系复杂,储层与非储层速度差异小,后续开发方案调整所要求的精细储层描述难度较大。本文展示了以精细储层描述为目标的地震约束反演实例,利用多井地震、地质标定,结合三维构造解释成果,建立三维多断层精细约束地质模型。在此基础上,采用随机地震反演方法,进行了波阻抗、岩性等多种地层参数反演,较好地解决了该区薄互层储层精细描述问题,证实了精细储层反演技术在油田开发中的重要作用。 相似文献
3.
针对随机地震反演中存在的两个主要问题,随机实现含有噪声和难以从大量随机实现中挖掘有效信息,提出了一种基于神经网络的随机地震反演方法.通过对多组随机实现及其正演地震数据的计算,构建了基于序贯高斯模拟的训练集.这也为应用神经网络求解地球物理反问题,提供了一种有效建立训练集的方法.较之传统的神经网络反演,这种训练集不仅保证了学习样本具有多样性,同时还引入了空间相关性.数值模拟结果表明,该方法只需要通过单层前馈神经网络,就可以比较有效的解决一个500个阻抗参数的反演问题. 相似文献
4.
提出了各向异性页岩储层统计岩石物理反演方法.通过统计岩石物理模型建立储层物性参数与弹性参数的定量关系,使用测井数据及井中岩石物理反演结果作为先验信息,将地震阻抗数据定量解释为储层物性参数、各向异性参数的空间分布.反演过程在贝叶斯框架下求得储层参数的后验概率密度函数,并从中得到参数的最优估计值及其不确定性的定量描述.在此过程中综合考虑了岩石物理模型对复杂地下介质的描述偏差和地震数据中噪声对反演不确定性的影响.在求取最大后验概率过程中使用模拟退火优化粒子群算法以提高收敛速度和计算准确性.将统计岩石物理技术应用于龙马溪组页岩气储层,得到储层泥质含量、压实指数、孔隙度、裂缝密度等物性,以及各向异性参数的空间分布及相应的不确定性估计,为页岩气储层的定量描述提供依据. 相似文献
5.
储层弹性与物性参数可直接应用于储层岩性预测和流体识别,是储层综合评价和油气藏精细描述的基本要素之一.现有的储层弹性与物性参数地震同步反演方法大都基于Gassmann方程,使用地震叠前数据,通过随机优化方法反演储层弹性与物性参数;或基于Wyllie方程,使用地震叠后数据,通过确定性优化方法反演储层弹性与物性参数.本文提出一种基于Gassmann方程、通过确定性优化方法开展储层弹性和物性参数地震叠前反演的方法,该方法利用Gassmann方程建立储层物性参数与叠前地震观测数据之间的联系,在贝叶斯反演框架下以储层弹性与物性参数的联合后验概率为目标函数,通过将目标函数的梯度用泰勒公式展开得到储层弹性与物性参数联合的方程组,其中储层弹性参数对物性参数的梯度用差分形式表示,最后通过共轭梯度算法迭代求解得到储层弹性与物性参数的最优解.理论试算与实际资料反演结果证明了方法的可行性. 相似文献
6.
鄂尔多斯盆地北部上古生界陆相致密碎屑岩隐蔽气藏具有低孔、低渗、致密、薄互层、多层叠置和非均质性强的特点.其勘探开发一直是世界性难题.针对该区储层特点,展开了以三维地震为核心的储层综合地球物理预测技术研究,开发应用了储层岩石物理分析、地震属性优化、随机模拟反演、地震吸收衰减、地震频谱分析、地震波正演模拟、地震相划分和AVO等多项技术,形成了一整套适合该地区油气地质特征的方法技术系列,有效提高了储层预测的精度,提高了勘探开发井位部署的成功率. 相似文献
7.
储层岩相分布信息是油藏表征的重要参数,基于地震资料开展储层岩相识别通常具有较强的不确定性.传统方法仅获取唯一确定的岩相分布信息,无法解析反演结果的不确定性,增加了油藏评价的风险.本文引入基于概率统计的多步骤反演方法开展地震岩相识别,通过在其各个环节建立输入与输出参量的统计关系,然后融合各环节概率统计信息构建地震数据与储层岩相的条件概率关系以反演岩相分布概率信息.与传统方法相比,文中方法通过概率统计关系表征了地震岩相识别各个环节中地球物理响应关系的不确定性,并通过融合各环节概率信息实现了不确定性传递的数值模拟,最终反演的岩相概率信息能够客观准确地反映地震岩相识别结果的不确定性,为油藏评价及储层建模提供了重要参考信息.模型数据和实际资料应用验证了方法的有效性. 相似文献
8.
SLG地区天然气资源量丰富,是我国油气增储上产的重要区域,利用叠后地震描述进行储层预测时多解性很强.本文针对SLG地区盒8段储层,充分利用了叠前地震资料信息丰富的特点,以AVO模型正演技术为基础,研究含气砂岩的地球物理响应特征.利用弹性波阻抗反演和叠前同步反演等技术,开展了叠前储层预测和含气性检测,形成了叠前地震描述技术系列.实际钻探结果表明,预测结果的精度较高,表明利用叠前地震描述技术进行SLG地区盒8段储层预测是可行的. 相似文献
9.
地层密度直接与孔隙度、孔隙流体类型、饱和度和骨架矿物成分有关.本文通过理论分析和计算,讨论了油气藏储层物性参数变化引起的密度变化及密度变化对地震波速度、阻抗和振幅的影响,提出了基于完全纵波方程的全波形地震密度反演和孔隙度估计方法,克服了常规地震密度反演对地震数据更多处理引起的信号畸变,提高了地震密度反演和地层孔隙度估计的精度.该方法采用波场导数的时间积分和多炮求和,对地震数据中的噪声具有比较强的压制作用.理论模型研究表明该方法是可行的.通过对我国西部某气田实际数据处理、分析和反演,获得了地层密度和孔隙度,结果与测井基本吻合,证明了预测结果的准确性和方法的有效性,从而为后续的有效储层预测和储量计算提供了可靠的数据. 相似文献
10.
本文研究了一种基于随机地震反演的Russell流体因子直接估算方法,该方法是一种基于蒙特卡罗的非线性反演,能够有效地融合测井资料中的高频信息,提高反演结果的分辨率.本文应用贝叶斯理论框架,首先通过测井数据计算井位置处的Russell流体因子,利用序贯高斯模拟方法(sequential Gaussian simulation,SGS)得到流体因子的先验信息;然后构建似然函数;最后利用Metropolis抽样算法对后验概率密度进行抽样,得到反演的Russell流体因子.其中对每道数据进行序贯高斯模拟时,采用一种新的逐点模拟方式,具有较高的计算速度.数值试验表明:反演结果与理论模型和实际测井数据吻合较好,具有较高的分辨率,对于判识储层含流体特征具有较好的指示作用. 相似文献
11.
Characterization of a reservoir model requires determination of its petrophysical parameters, such as porosity and saturation.
We propose a new method to determine these parameters directly from seismic data. The method consists of the computation and
inversion of seismic waveforms. A high frequency method is presented to model wave propagation through an attenuative and
dispersive poroelastic medium. The high frequency approximation makes it possible to efficiently compute sensitivity functions.
This enables the inversion of seismic waveforms for porosity and saturation. The waveform inversion algorithm is applied to
two laboratory crosswell datasets of a water saturated sand. The starting models were obtained using travel time tomography.
The first dataset is inverted for porosity. The misfit reduction for this dataset is approximately 50%. The second dataset
was obtained after injection of a nonaqueous-phase liquid (NAPL), possibly with some air, which made the medium more heterogeneous.
This dataset was inverted for NAPL and air saturation using the porosity model obtained from the first inversion. The misfit
reduction of the second experiment was 70%. Regions of high NAPL and high air saturation were found at the same location.
These areas correlate well with the position of one of the injection points as well as regions of higher NAPL concentrations
found after excavation of the sand. It is therefore possible to directly invert waveforms for pore fluid saturation by taking
into account the attenuation and dispersion caused by the poroelasticity. 相似文献
12.
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
13.
One of the major aspects of rock-physics forward modelling is to predict seismic behaviour at an undrilled location using drilled well data. It is important to model the rock and fluid properties away from drilled wells to characterize the reservoir and investigate the root causes of different seismic responses. Using the forward modelling technique, it is possible to explain the amplitude responses of present seismic data in terms of probable rock and reservoir properties. In this context, rock-physics modelling adds significant values in the prospect maturation process by reducing the risk of reservoir presence in exploration and appraisal phases. The synthetic amplitude variation with offset gathers from the forward model is compared with real seismic gathers to ensure the fidelity of the existing geological model. ‘Prospect A’ in the study area has been identified from seismic interpretation, which was deposited as slope fan sediments in Mahanadi basin, East Coast of India. The mapped prospect has shown class-I amplitude variation with offset response in seismic without any direct hydrocarbon indicator support. The existing geological model suggests the presence of an excellent gas reservoir with proven charge access from the fetch area, moderate porosity and type of lithology within this fan prospect. But, whether the seismic response from this geological model will exhibit a class-I amplitude variation with offset behaviour or ‘dim spot’ will be visible; the objective of the present study is to investigate these queries. A rock-physics depth trend analysis has been done to envisage the possibilities of class-I reservoir in ‘Prospect A’. Forward modelling, using a combination of mechanical and chemical compaction, shows the synthetic gas gathers at ‘Prospect A’, which are class I in nature. The study has also depicted 2D forward modelling using lithology and fluid properties of discovery well within similar stratigraphy to predict whether ‘dim spot’ will be seen in seismic. The estimated change in synthetic amplitude response has been observed as ∼5% at contact, which suggests that the changes will not be visible in seismic. The study connects the existing geological model with a top-down seismic interpretation using rock-physics forward modelling technique to mature a deep-water exploratory prospect. 相似文献
14.
秦皇岛32-6油田明化镇组储层为河流相沉积,单砂体规模小,砂体间接触关系复杂,受到地震分辨率限制,对叠置砂体储层地震响应规律认识不明确,导致基于地震信息的储层砂体解释错误.通过数值正演模拟,可以正确认识砂体储层的地震响应规律,提高砂体储层预测的准确率.所以,在进行地震响应正演模拟前,非常有必要对该区储层地球物理参数影响因素展开研究,通过分析研究区14口测井资料,建立了岩石物理参数(孔隙度、泥质含量、合流体性)与地球物理参数(速度、密度、波阻抗等)之间的相关关系,分析了不同沉积微相对地球物理参数的控制作用,并给出了相应的数学表达式,为正确认识河流相储层砂体地震响应规律奠定了准确的地球物理参数基础. 相似文献
15.
Seismic Rock physics plays a bridge role between the rock moduli and physical properties of the hydrocarbon reservoirs. Prestack seismic inversion is an important method for the quantitative characterization of elasticity, physical properties, lithology and fluid properties of subsurface reservoirs. In this paper, a high order approximation of rock physics model for clastic rocks is established and one seismic AVO reflection equation characterized by the high order approximation(Jacobian and Hessian matrix) of rock moduli is derived. Besides, the contribution of porosity, shale content and fluid saturation to AVO reflectivity is analyzed. The feasibility of the proposed AVO equation is discussed in the direct estimation of rock physical properties. On the basis of this, one probabilistic AVO inversion based on differential evolution-Markov chain Monte Carlo stochastic model is proposed on the premise that the model parameters obey Gaussian mixture probability prior model. The stochastic model has both the global optimization characteristics of the differential evolution algorithm and the uncertainty analysis ability of Markov chain Monte Carlo model. Through the cross parallel of multiple Markov chains, multiple stochastic solutions of the model parameters can be obtained simultaneously, and the posterior probability density distribution of the model parameters can be simulated effectively. The posterior mean is treated as the optimal solution of the model to be inverted.Besides, the variance and confidence interval are utilized to evaluate the uncertainties of the estimated results, so as to realize the simultaneous estimation of reservoir elasticity, physical properties, discrete lithofacies and dry rock skeleton. The validity of the proposed approach is verified by theoretical tests and one real application case in eastern China. 相似文献
16.
Time‐lapse seismic modelling of CO2 fluid substitution in the Devonian Redwater Reef,Alberta, Canada
Common shot ray tracing and finite difference seismic modelling experiments were undertaken to evaluate variations in the seismic response of the Devonian Redwater reef in the Alberta Basin, Canada after replacement of native pore waters in the upper rim of the reef with CO2. This part of the reef is being evaluated for a CO2 storage project. The input geological model was based on well data and the interpretation of depth‐converted, reprocessed 2D seismic data in the area. Pre‐stack depth migration of the ray traced and finite difference synthetic data demonstrate similar seismic attributes for the Mannville, Nisku, Ireton, Cooking Lake, and Beaverhill Lake formations and clear terminations of the Upper Leduc and Middle Leduc events at the reef margin. Higher amplitudes at the base of Upper‐Leduc member are evident near the reef margin due to the higher porosity of the foreslope facies in the reef rim compared to the tidal flat lagoonal facies within the central region of the reef. Time‐lapse seismic analysis exhibits an amplitude difference of about 14% for Leduc reflections before and after CO2 saturation and a travel‐time delay through the reservoir of 1.6 ms. Both the ray tracing and finite difference approaches yielded similar results but, for this particular model, the latter provided more precise imaging of the reef margin. From the numerical study we conclude that time‐lapse surface seismic surveys should be effective in monitoring the location of the CO2 plume in the Upper Leduc Formation of the Redwater reef, although the differences in the results between the two modelling approaches are of similar order to the effects of the CO2 fluid replacement itself. 相似文献
17.
基于流体替换技术的地震AVO属性气藏识别(英文) 总被引：2，自引：1，他引：1
传统上,油藏地球物理工程师是基于测井数据进行流体替换,计算油藏饱和不同流体时的弹性参数,并通过地震正演模拟分析油藏饱和不同流体时的地震响应,从而进行油气藏识别研究。该研究方案为油藏研究提供了重要的弹性参数和地震响应信息,但这些信息仅限于井眼位置。对于实际油藏条件,地下储层参数都是随位置变化而变化的,如孔隙度、泥质含量和油藏厚度等,因此基于传统流体替换方案得到的流体变化地震响应信息对于油气藏识别具有很大的局限性。研究通过设定联系油藏弹性参数与孔隙度、矿物组分等参数的岩石物理模型,并基于三层地质模型,进行地震正演模拟与AVO属性计算。得到油藏孔隙度、泥质含量和储层厚度变化时地震AVO属性,并建立了饱和水储层和含气储层对应AVO属性(包括梯度与截距)之间的定量关系。建立的AVO属性之间的线性关系可以实现基于地震AVO属性直接进行流体替换。最后,应用建立的流体替换前后AVO属性之间线性方程,对模拟地震数据直接进行流体替换,并通过流体替换前后AVO属性交汇图分析实现了气藏识别。 相似文献
18.
We investigate the interactions between the elastic parameters, VP, VS and density, estimated by non-linear inversion of AVA data, and the petrophysical parameters, depth (pressure), porosity, clay content and fluid saturation, of an actual gas-bearing reservoir. In particular, we study how the ambiguous solutions derived from the non-uniqueness of the seismic inversion affect the estimates of relevant rock properties. It results that the physically admissible values of the rock properties greatly reduce the range of possible seismic solutions and this range contains the actual values given by the well. By means of a statistical inversion, we analyse how approximate a priori knowledge of the petrophysical properties and of their relationships with the seismic parameters can be of help in reducing the ambiguity of the inversion solutions and eventually in estimating the petrophysical properties of the specific target reservoir. This statistical inversion allows the determination of the most likely values of the sought rock properties along with their uncertainty ranges. The results show that the porosity is the best-resolved rock property, with its most likely value closely approaching the actual value found by the well, even when we insert somewhat erroneous a priori information. The hydrocarbon saturation is the second best-resolved parameter, but its most likely value does not match the well data. The depth of the target interface is the least-resolved parameter and its most likely value is strongly dependent on a priori information. Although no general conclusions can be drawn from the results of this exercise, we envisage that the proposed AVA–petrophysical inversion and its possible extensions may be of use in reservoir characterization. 相似文献
19.
传统基于单相介质理论的储层参数反演方法将孔隙流体与固体骨架等效为单一固体,弱化了孔隙流体的影响,反演结果精度不高.本文提出根据双相介质理论反演储层参数的方法.首先,在前人研究的基础上,利用岩石物理模型建立弹性参数与孔隙度、饱和度、泥质含量等储层参数间的关系,进而将双相介质反射系数推导为储层参数的函数;其次,根据贝叶斯反演理论,在高斯噪声假设的基础上,采用更加符合实际情况的修正柯西分布函数描述反射系数的稀疏性,推导出储层物性参数目标反演函数;最后,应用差分进化非线性全局寻优算法来求解目标反演函数,使得反演结果与实际资料间误差最小.新方法旨在突出流体对介质反射系数的影响,以期得到较高的储层参数反演精度.模型与实际资料测试均表明该方法可行、有效且反演精度较高. 相似文献
20.
By substituting rock skeleton modulus expressions into Gassmann approximate fluid equation, we obtain a seismic porosity inversion equation. However, conventional rock skeleton models and their expressions are quite different from each other, resuling in different seismic porosity inversion equations, potentially leading to difficulties in correctly applying them and evaluating their results. In response to this, a uniform relation with two adjusting parameters suitable for all rock skeleton models is established from an analysis and comparison of various conventional rock skeleton models and their expressions including the Eshelby-Walsh, Pride, Geertsma, Nur, Keys-Xu, and Krief models. By giving the two adjusting parameters specific values, different rock skeleton models with specific physical characteristics can be generated. This allows us to select the most appropriate rock skeleton model based on geological and geophysical conditions, and to develop more wise seismic porosity inversion. As an example of using this method for hydrocarbon prediction and fluid identification, we apply this improved porosity inversion, associated with rock physical data and well log data, to the ZJ basin. Research shows that the existence of an abundant hydrocarbon reservoir is dependent on a moderate porosity range, which means we can use the results of seismic porosity inversion to identify oil reservoirs and dry or water-saturated reservoirs. The seismic inversion results are closely correspond to well log porosity curves in the ZJ area, indicating that the uniform relations and inversion methods proposed in this paper are reliable and effective. 相似文献