【作者】 刘国华；

【导师】 李庆春；

【作者基本信息】 长安大学 ， 地质工程， 2009， 博士

【摘要】 德国Karlsurhe大学Hubral教授于二十世纪九十年代提出的共反射面叠加方法属于宏速度模型无关的完全数据驱动模拟零偏移距剖面地震成像方法,是对动校正/叠加与倾角时差校正/叠加等常规模拟零偏移距剖面方法的扩展。该方法通过合并相邻的共中心点道集直接对叠前时间域反射同相轴进行处理,收集并更好地利用了叠前数据中属于深度域内共反射面的冗余信息,可大幅度提高地震叠加剖面信噪比和分辨率,是复杂地区地震资料处理技术的重要发展方向。本文对二维零偏移距共反射面叠加与共偏移距共反射面叠加方法进行了仔细研究与分析,主要进行了以下几方面的工作：1)从面到面传播矩阵和共反射点轨迹出发,分别采用旁轴射线理论及几何方法,推导了复杂非均匀介质条件下适用于任意弯曲反射段的二维零偏移距共反射面抛物线与双曲线走时近似公式。共反射面叠加通过两种假想特征波(法向入射点波与法向波)建立了深度域与时间域的联系。相对于常规叠加方法来说,零偏移距共反射面叠加使用全部叠前多次覆盖数据体,并不局限于特定的道集,因此有更多数量的地震道对叠加结果产生贡献。2)对二维零偏移距共反射面叠加属性参数实用搜索策略进行了研究分析及改进,通过将黎曼球半径引入共反射面叠加参数搜索策略中,避免了出现数值问题；将相干阀值引入相干分析过程,大大提高了共反射面叠加属性参数搜索效率；对部分灵活多面体参数搜索优化算法进行了改进,在确保其精度的前提下,使得共反射面叠加优化算法计算效率更高。形成了一套面向对象的共反射面叠加属性实用搜索策略实现方法,能够对实际数据进行处理并更强有力、更灵活地控制叠加参数扫描范围。3)针对实用搜索策略中法向入射点波曲率半径RNIP的计算容易导致不确定性问题的缺陷,建立一种面向对象的扩展零偏移距共反射面叠加参数搜索策略来克服这种局限性,并且尽可能保留了实用搜索策略的效率,从而使得共反射面叠加提供一个更完全及更具有物理意义上的零偏移距模拟剖面。4)分别对共反射面叠加中的共中心点叠加孔径、零偏移距叠加孔径及共反射面超道集孔径问题进行了详细探讨,并给出了计算办法,为共反射面叠加的正确高效执行提供了保障。在共反射面叠加每个步骤中合理地应用合适的叠加孔径可以得到比较理想的共反射面叠加剖面。5)将共反射面叠加理论引入共偏移距叠加中,根据旁轴射线理论推导了复杂非均匀介质条件下的五参数二维共偏移距共反射面抛物线与双曲线走时二阶近似公式。所推导的走时近似公式与实际反射响应比较结果证明共偏移距共反射面叠加算子在较大范围内与反射响应拟合得非常好,能够产生非常好的拥有高信噪比的叠加结果。6)借鉴零偏移距共反射面叠加实现过程建立了共偏移距共反射面叠加处理流程,对同时进行的五参数搜索进行分解,在保证正确性的同时大量地节约了计算时间。共偏移距共反射面叠加可得到质量明显改善的共偏移距叠加剖面及五个运动学波场属性剖面,并能够处理大偏移距情况及具有处理转换波的潜力,这扩展了地震资料处理的思路,为将来复杂地区转换波地震资料处理开辟了一条新途径。理论模型与实际资料试算表明,零偏移距与共偏移距共反射面叠加方法都是完全数据驱动且与宏速度模型无关的方法,零偏移距共反射面叠加能够适用于海洋及陆地地震资料数据处理,可提高数据覆盖次数与信噪比,显著改善模拟零偏移距剖面的成像质量,是一种非常有发展前景的地震成像方法；共偏移距共反射面叠加能够改善共偏移距叠加剖面质量,得到的角度值及波前曲率等波场属性参数为将来转换波处理提供了可能。更多还原

【Abstract】 The common-reflection-surface(CRS) stack method developed in the end of 1990’s by professor Hubral of Karlsurhe university in Germany is an entirely data-oriented seismic reflection imaging approach of zero-offset section simulation in a macro-velocity model independent way. The idea of the CRS stack method is to provide an extension of conventional zero-offset section simulateion approaches such as normal moveout (NMO)/stack and dip moveout/stack. The CRS stack method parameterizes the reflection events in the pre-stack time domain by incorporating neighboring common-mid-point (CMP) gathers directly, and the inherent redundancy of the pre-stack data is used to collect information that pertains to common reflection surfaces in depth, which can improve the signal-to-noise ratio and resolutions of seismic stacked sections. The CRS stack approach has become an important development trend of seismic data processing in difficult terrians.Two-dimensional (2D) zero-offset CRS stack and common-offset CRS stack method have been studied respectively in this paper.Firstly,2D zero-offset CRS parabolic and hyperbolic traveltime approximation for arbitrarily curved reflector segment in complex inhomogeneous media have been derived by means of paraxial ray method and geometrical approach by starting with the surface-to-surface progagator matrix and common-reflection-point trajectory. Two hypothetical eigenwaves (the normal- incidence-point and nomal wave) establish a relationship between the depth and the time domain. In contrast to conventional stacking methods, the zero-offset CRS stack uses the full multi-coverage data volume in the stacking procedure as the CRS operator is not restricted to specific gathers. Consequently, many more traces compared to conventional stacking methods contribute to the stack.Secondly, the pragmatic search strategy for 2D zero-offset CRS attributes was studied. A Riemann sphere radius was introduced into the CRS stacking attributes search to avoid causing numerical problems and some improvement was made that the efficiency of the pragmatic search strategy is enhanced by giving a threshold in coherence analysis. The flexible polyhedron search algorithm used by the implementation of the CRS stack was studied and analized, and some adaptation was made to enhance the efficency of the CRS stacking operator optimization algorithm. Consequently, an object-oriented implementation of CRS search strategy implementation has been presented to allow a generalized handling of real data and provide more powerfull and flexible features to control the range of tested CRS stacking attributes.Thirdly, an object-oriented implementation of extended zero-offset CRS atttibutes search strategy implementation has been presented to overcome some of limitations in pragmatic search strategy caused by the ambiguity in the determineation of the radii of curvature RNIP, and the efficiency of the pragmatic search strategy is preserved as far as possible so that a more complete and more physical zero-offset simulateion section is provided by the CRS stack approach.Fourthly, the calculation of CMP stacking aperture, zero-offset stacking aperture and the CRS super gather aperture was discussed respetively, and which ensures the high efficency of the implementation of CRS stack. Consequently, the ideal CRS stacked section was acheieved by means of reasonable application of suitable stacking aperture to respective steps of the CRS stacking implementation.Fifthly,2D five-parameter CO CRS parabolic and hypobolic traveltime second-order approximation equation in complex inhomogeneous media was derived by means of paraxial ray theory by introducing the CRS stack approach into common-offset (CO) stack. Compared to the real reflection response show that the CO CRS stacking operator derived fits well to the relection response over a large range and could yield stack sections of better quality with high signal-to-noise ratio.Finally, CO CRS stack processing sequence was established by referring to the implementation of ZO CRS stack. The simultaneously five-parameter search was correctly split to save enormous computation time. The CO CRS stack can yield noteworthy CO stacked section and five kinematic wave-field attributes sections, and it also has the potential to simulate sections for converted waves. This extends the idea of seismic data processing and provides a new approach for seismic coverted wave processing in difficult terrians.Applications of the CRS stack method to several synthetic and real data sets have proved that the CRS stack approach is an entirely data-oriented macro-velocity model independent seismic reflection imaging approach, and the ZO CRS stack method can handle marine and land seismic data sets, increase fold and signal-to-noise ratio of data sets and improve the imaging quality of simulated ZO sections, so the ZO CRS stack has greate developing prospects. The CO CRS stack approach can improve the quality of CO stacked sections, and the wave field attributes determined by this approach can serve for converted waves processing.更多还原