【作者】 杨帅；

【导师】 王山山；

【作者基本信息】 成都理工大学 ， 应用地球物理， 2010， 硕士

【摘要】 地震反演始终是地震勘探中的核心技术,特别是随着地质条件的日趋复杂和成本的急剧上升。目前地震技术的应用不再限于构造形态的描绘,而是己经深入到了储层描述阶段,直至含油气性检测等。近年来,地震油气检测技术在油气勘探中发挥着越来越重要的作用,有关油气检测的分析、参数提取、标定等技术得到了快速发展。地震反演的目的是根据地震资料,对地下岩石的波阻抗和其它储层参数进行估算,描述地下岩层的岩性和含流体的性质,为油气资源的勘探开发服务。传统的叠后地震反演只能得到波阻抗信息,使其解决地质问题的能力受到限制,也很难满足开发阶段对油藏精细描述的需要。叠前地震反演技术是勘探地球物理领域正在兴起的一项新技术,该技术在有些国家已经成为油气储层预测中不可缺少的手段,成为地震属性分析和反演研究的热点。叠前地震反演技术充分利用不同角度的叠前AVA地震道上丰富的振幅、频率等信息,可以得到除波阻抗之外的很多其它弹性参数的信息,大大丰富了描述储层的手段,增强了对复杂储层的描述和流体检测的能力,对储层预测和油藏描述具有重要意义。本文的研究目的是通过不同角度(近、中角度)叠加数据的反演,获取纵横波速度比、泊松比等重要的弹性参数,用于油气检测。在研究过程中,考虑到反演中构建低频信息首先要作好井资料本身的标准化问题,根据实践经验,提出了一种考虑深度影响的标准化方法。在进行叠前地震反演和叠前地震属性分析时,需要有准确的纵横波测井速度曲线,而在实际生产中往往缺乏横波速度信息,针对横波资料缺乏的问题,研究了目前常用的几种横波速度预测方法的基本原理,包括:经验公式法、模型正演估算法、基于Biot-Gassmann方程的约束反演法,并作了相应的分析。在应用实例中采用约束反演法对叠前反演所必须的横波速度进行了预测,该方法考虑了压实效应,计算每个深度点时只与当前点有关,有物理机理保证,提高了横波速度的预测精度。接下来,对弹性阻抗(EI)及广义弹性阻抗(GEI)的提出,进行了相应的研究。广义弹性阻抗(GEI)克服了弹性阻抗(EI)关于P波与S波速度比从浅到深保持某一常数不变的假设,随着入射角的变化,其量纲不会发生太大变化,所以不需要像弹性阻抗(EI)那样做归一化处理。在反演方法上,本文研究了有色反演技术,它是在有色滤波技术的基础上发展起来的一种新的反演方法。有色反演技术的优点是不需要初始模型约束,反演分辨率较高,反演过程中人为因素少。利用不同角度的叠前AVA角道集叠加数据,采用有色反演技术可以获得不同角度的广义弹性阻抗(GEI),通过不同角度的广义弹性阻抗(GEI)数据联合计算就可以提取纵横波速度比、泊松比等重要的弹性参数。最后通过应用实例,对同一工区的不同角度的角道集资料,采用有色反演技术进行广义弹性阻抗(GEI)反演,联合计算提取了纵横波速度比、泊松比等弹性参数,并用这些弹性参数对该地区进行油气检测,取得了良好的效果,证实了该方法在复杂储层描述以及流体检测方面具有明显的优势,表明这种多参数反演的油气检测方法具有广阔的应用前景。更多还原

【Abstract】 The seismic inversion is always the key technology in the seismic exploration, especially with more and more complex geological conditions and the steep rise of the exploration cost. At present, the application of seismic technology is no longer confined to describing the structure; it has entered into the field of reservoir characterization; even to oil-bearing test, etc. In recent years, seismic oil and gas testing technique is playing a more and more important role in the process of oil field prospecting and development. Analysis of the oil and gas detection, parameter extraction and calibration, etc. these techniques have been developed rapidly.The seismic inversion aimed at predicting the impedance and other parameters about reservoir property from seismic data. These estimations are then used for characterizing reservoir,determine the lithology of rock and finding out the existence and the type of fluid contained in the rock porosity and thus used for the exploration and development of oil and gas resource. The conventional post-stack seismic inversion can only obtain the impedance and this has limited its capability of solving geology problems and it can’t meet the demand of refined characterization of reservoir for the developing stage. The technology of pre-stack seismic inversion is a new technology that is emerging in geophysical exploration field.In some countries this technology has become an indispensable means of oil and gas reservoir prediction, and the hot spot of seismic attribute analysis and inversion study. The technology of pre-stack seismic inversion takes full advantage of abundant amplitude, frequency and other information in different angles pre-stack AVA seismic trace.It can obtain much more elastic parameters other than acoustic impedance,it can provide more way to characterizing reservoir and has enhanced the capability of describing complex reservoir and detection of fluid,which has important significance in reservoir prediction and reservoir characterization.Purpose of this paper is to obtain primary-shear wave velocity ratio, Poisson’s ratio and other important elastic parameters for hydrocarbon detection,by using inversion results of different angles (near, medium angle) stack data. In the course of the study,taking into account a problem that the construction of low-frequency information in the inversion first to make the standardization of the well data itself, according to practical experience, a standardized method to consider impact of the depth is proposed. When carrying out pre-stack seismic inversion and pre-stack seismic attribute analysis, it requires accurate logging velocity curve of primary and shear wave. In the actual production, we often lack the S-wave velocity information,this paper studys currently several methods of shear wave velocity prediction and their basic principles for the problem of lack shear wave data.including: empirical formula, the model forward estimation method, constrained inversion method based on Biot-Gassmann equation, and make relevant analysis. In the application example,we predict S-wave velocity that pre-stack inversion demands,using constrained inversion method.The method takes into account the compaction effect, as calculated each depth point is only related to the current point,it has a physical mechanism to ensure and improves shear velocity prediction accuracy. Next, making a study of the corresponding for origin of the elastic impedance (EI) and the generalized elastic impedance (GEI).Generalized elastic impedance (GEI) overcomes the problem that velocity ratio of P-wave and S-wave maintains a constant from shallow to deep on elastic impedance (EI).With the incidence angle changes, it will not be much change in the dimension, so you do not need make normalization as same as elastic impedance (EI).On the inversion method, this paper studys colored inversion technology, it is a new inversion method that is developed on the basis of the colored filter technology.Colored inversion technique has the advantage that it does not require constraint of the initial model,and has higher resolution of inversion, less human factors during inversion. Using stack data of different angles pre-stack AVA angle gather, to obtain generalized elastic impedance (GEI) of different angles by colored inversion technology.Through joint calculation of generalized elastic impedance (GEI) of different angles,we can extract primary-shear wave velocity ratio, Poisson’s ratio and the other important elastic parameters.Finally in an application example, using colored inversion technology makes generalized elastic impedance (GEI) inversion for angle gather data of the different angles on the same work area,then extract the primary-shear wave velocity ratio, Poisson’s ratio and the other important elastic parameters by joint calculation,and using these elastic parameters make oil and gas detection in the region that has achieved good results, which confirmed that the method has the obvious advantage in complex reservoir description and fluid testing,and showed that hydrocarbon detection method of this multi-parameter inversion has broad application prospect.更多还原