排序方式： 共有67条查询结果，搜索用时 187 毫秒
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含气饱和度预测是天然气储层地震解释工作的重要目标.本文将岩石物理分析与地震物理模拟技术相结合,构建了部分;饱和砂岩储层物理模型并进行含气饱和度预测分析.物理模型中设置了高孔渗常规砂岩和低孑孔渗致密砂岩两种模拟储层,每种储层都是由具有不同含水饱和度的气-水双相饱和砂体组成.岩石物理分析结果显示在低孔渗致密砂岩中气-水混合流体更加倾向于非均匀的斑块分布,而结合了Brie等效流体公式的Gassmann流体替换理论可以更准确地描述纵波速度随含水饱和度的变化趋势.对物理模型进行地震资料采集处理后,对比了AVO特征和叠前同步反演结果对两种砂岩储层含气饱和度预测能力的差异.AVO特征结果显示,对于混合流体均匀分布的高孔渗砂岩储层,AVO响应曲线和属性变化很难对含气饱和度进行估算;对于混合流体斑块分布的致密砂岩储层,AVO特征可以定性地分辨出储层是否为高、中、低含气情况.反演结果显示,密度及纵横波速度比分别对高孔渗及致密砂岩储层的含气饱和度有着较好的指示能力. 相似文献
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基于地震波反射系数近似公式的叠前反演是油气勘探的重要工具.本文在已有研究的基础上,推导了一个改进的射线参数域地震纵波反射系数近似方程.该方程建立了地震纵波反射系数与纵波阻抗和横波阻抗的非线性关系,在中、小角度的范围内较现有的反射系数线性近似公式精度更高.另外,由于该方程仅包含纵波和横波阻抗反射系数项,因此基于新方程的反演能够有效地降低同步反演纵波速度、横波速度、密度三个参数的不适定性.在此基础上,结合广义线性反演法(GLI)理论和贝叶斯理论,相应地发展了一种叠前地震同步反演方法.模型测试和实际资料的应用表明,基于新方程的反演方法能够利用有限角度(偏移距)的数据稳定地反演纵波和横波阻抗,由于在反演过程中,不需要假设纵横波速度为常数,因此该方法还能有效地提高反演结果的精度. 相似文献
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研究与实践表明,对于长偏移距、宽方位地震数据,忽略各向异性会明显降低成像质量,影响储层预测与描述的精度.针对典型的横向各向同性(TI)介质,本文面向深度域构造成像与偏移速度分析的需要,研究基于射线理论的局部角度域叠前深度偏移成像方法.它除了像传统Kirchhoff叠前深度偏移那样输出成像剖面和炮检距域的共成像点道集,还遵循地震波在成像点处的局部方向特征、基于扩展的脉冲响应叠加原理获得入射角度域和照明角度域的成像结果.为了方便快捷地实现TI介质射线走时与局部角度信息的计算,文中讨论和对比了两种改进的射线追踪方法:一种采用从经典各向异性介质射线方程演变而来的由相速度表征的简便形式;另一种采用由对称轴垂直的TI(即VTI)介质声学近似qP波波动方程推导出来的射线方程.文中通过坐标旋转将其扩展到了对称轴倾斜的TI(即TTI)介质.国际上通用的理论模型合成数据偏移试验表明,本文方法既适用于复杂构造成像,又可为TI介质深度域偏移速度分析与模型建立提供高效的偏移引擎. 相似文献
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纵横波弹性阻抗联立反演在GD地区的应用 总被引：2，自引：0，他引：2
在GD油田复杂油藏描述中应用叠前纵横波弹性阻抗反演,精确地进行了油藏岩性的划分。利用三个或三个以上部分叠加数据,进行纵横波弹性阻抗联立反演,既克服了因叠后地震反演结果单一而不能满足复杂储层描述的需求,又避免了由于叠前道集信噪比低造成反演结果不稳定的缺陷。本文论述了叠前弹性波阻抗反演的基本原理,结合GD地区实际资料,对反演过程中涉及的角道集子波提取、层位标定、横波速度预测、弹性参数提取与解释等关键步骤进行了详细研究,指出基于测井资料分析的多种弹性参数综合解释是提高叠前地震反演应用效果的关键。 相似文献
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Xu Zhaotao Wang Huazhong 《应用地球物理》2006,3(4):226-233
Based on perturbation theory, the wave equation extrapolation operator with mixed domains has the ability to deal with lateral velocity variations. It is the image method that has undergone much research in seismology. All extrapolation operators face the problem of choosing the reference velocity due to continuation in depth. The wavefield extrapolation operator with a single reference velocity is suitable for media with weak lateral variation. The multi-reference velocity extrapolation operator can cope with severe lateral velocity variations and improve image accuracy. However, the calculation cost is large. We present a self-adaptive approach to automatically determine the number of selected reference velocities according to the complexity of structure and the given velocity threshold value. The approach can be used to construct the SSF, FFD, WXFD, and GSP multi-reference velocity wavefield extrapolation image algorithms. The result of a salt-dome model data test demonstrates that the self-adoptive multi-reference wavefield extrapolation algorithm has the ability to deal with severe lateral velocity variations and can also be used for structure edge detection. The method is flexible and computationally cost-effective. 相似文献
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M. Malinowski M. Grad A. Guterch E. Takcs Z.
liwi&#x;ski L. Antonowicz E. Iwanowska G.R. Keller E. Heged&#x;s 《Tectonophysics》2007,439(1-4):89-106
The extent of the Variscan deformation front is one of the key problems of the regional geology of the Central European Permian Basin system, particularly in its Polish part. Conventional reflection seismics usually fails to produce a satisfactory image of the pre-Permian strata due to the shielding effect of Zechstein (Upper Permian) evaporites. Thus we used a novel seismic acquisition technique to study the base of the Permian complex and its Variscan basement. In the GRUNDY 2003 experiment we combined wide-angle reflection–refraction measurements with the near-vertical reflection seismics by the use of the constant geophone array with dense (100 m) receiver spacing occupying 50-km long profile. 3D design of the experiment, covering 50 × 10 km area, helped in eliminating the effect of out-of-plane propagations and local inhomogeneities. An effective integration of traveltime tomography, CDP reflection processing and prestack depth migration of wide-angle reflections applied to our data, allowed us to present the model in which we deduced the contact zone of the Variscan overthrust structure (Variscan front) with its molasse-filled foredeep. The latter might be a gas-generation zone, which is of a great importance for hydrocarbons prospecting in this area. 相似文献
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