3D seismic structure description method is relatively perfect at present,especially the method of coherent data volume could be used to identify fault visually and quickly.But complex faults could not be identified accurately,especially their combination in plane by conventional fault description method when faults intersect in small angle,as a result the structure evaluation be affected greatly.Geometry characteristics of fault interfaces are analyzed by using analytic geometry method combining with relationships of lines resulting from faults intersecting horizon and seismic section with their projection.The results show that the relationships among faults can be identified easily through crossing obliquely seismic section when faults intersect each other in small angle.The geometry of fault is similar to its projection in the plane,so the faults' strike,geometry and their composites could be determined effectively combining with tomographic image of section closure.The method is applied to solve complex structure description in Qingdong area successfully.%目前基于三维地震的构造描述方法已经相对成熟,特别是利用相干数据体进行断层识别具有方法直观、效率高的特点.但当断层面小角度相交时,断层形态和组合就变得复杂,利用上述常规方法很难准确识别,从而影响构造圈闭评价.本文从断层面的几何形态入手,结合断面与地层面、剖面交线及投影的关系,运用解析几何方法分析其几何特征,明确在断层面小角度相交时,斜交断层的剖面容易识别断层间的关系,断层的形态与其平面投影相似,结合断面闭合的断层影像法,可有效判定断层走向、形态及断层间的组合关系.在青东地区,利用研究的方法解决了复杂构造描述问题.
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