地质体形状对逐层优化正则化下延成像的影响研究
Affect of configuration parameters of geobody on regularization downward continuation imaging by successive layer optimization
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摘要: 重磁位场逐层截频优化正则化下延成像技术可用于研究地质体的形态和物性分布特征。由于不同形状地质体可能有相似的重磁异常,重磁位场下延存在多解性。通过对4种基本形体重磁位场波谱特征对比研究及对35组不同形体重力场下延成像参数优选,获得地质体的综合形态参数与波谱形状校正系数的回归方程,并构建了形态滤波因子。利用带形态滤波因子的逐层优化正则化下延成像可提高不同形状长方体中心深度的归位精度。结合地震构造特征和形态参数回归方程确定的形态滤波因子,对川西枫顺场地区重力资料进行逐层优化下延成像,与地震剖面及测井密度曲线整体特征基本一致,证实了带形态滤波因子逐层优化正则化下延方法技术的可行性和有效性。Abstract: Regularization downward continuation imaging by successive layer optimization (DCSLO) can be used to study the geometrical configuration and physical distribution of geological body(geobody). Due to possible similar features of potential fields for some bodies of different geometrical configurations, the downward continuation imaging is of no-uniqueness. From spectral study of 4 basic configurations of geological bodies and parameter selection for optimum downward continuation for the 35 gravity models of different configurations, a regressive formulas between configuration parameter and shape correction coefficient is obtained and consequently a configuration filter operator is proposed. With the configuration filter operator the DCSLO will enhance the imaging accuracy of geometrical center of complex geobody. A field example of DCSLO for gravity and magnetic data in FengSunChang area in Western Sichuan is given. With the configuration filter operator determined by the seismic structures and the regressive formulas, the DCSLO imaging is consistent with the main geometrical characteristics of the seismic deep structures and overall density logging data. This verified the applicability and effectiveness of the configuration filtering in DCSLO imaging.
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