Intraplate Strike-Slip Reactivation of the Sinnyeong Fault in the Cretaceous Gyeongsang Basin, Korea, Due to the Concentration of Later Compressional Stress

This study focuses on the geometry and kinematics of the Sinnyeong Fault which is the most conspicuous fault among the WNW-trending Gaeum Fault System in the Gyeongsang Basin,SE Korea. The fault is traced for over ca.70 kmand has a consistent WNW-trending strike with a nearly vertical dip. It has an asymmetric fault damage zone of several meters to several tens of meters in width and a several meter-thick fault core. Its main movement is interpreted as sinistral-reverse oblique-slip or sinistral strike-slip under NE-SW compressional stress regime, although it could have experienced other faultings with different senses before/after this movement. Cylindrical folds, having the NW-trending fold axes of low angle plunge, are only observed along the southern damage zone of the fault with a continuous narrow width of several tens of meters. It is thus interpreted that the formation of the folds and sinistral movement of the fault were almost contemporaneously generated due to the concentration of the regional NE-SW compressional stress along pre-existing WNW-trending faults or densely populated fracture zone in a relatively stable intraplate region.

基于叠前地震纵横波模量直接反演的流体检测方法

流体因子是储层流体识别的重要方法,而叠前地震反演是获得流体因子的有效途径之一.本文从流体因子的构建出发,基于多孔弹性介质岩石物理模型,建立了流体因子与纵横波模量之间的直接关系,避免了流体因子计算所需的密度参数无法准确求取的问题,通过推导基于纵横波模量的Zeoppritz近似方程及弹性阻抗方程,探讨了基于弹性阻抗的纵横波模量直接反演方法,模型与实际应用表明,基于弹性阻抗的纵横波模量直接反演方法合理、可靠,减少了常规方法间接计算纵横波模量带来的累积误差,基于纵横波模量的流体因子计算方法有较好的实际应用效果.

基于Zoeppritz方程的纵横波模量反演

叠前地震反演的主要目的是根据地震数据精确地求取地下介质的弹性参数,进而进行流体识别和油藏描述。常规叠前反演方法使用Zoeppritz方程近似式计算反射系数,但是含有丰富信息的大偏移距地震数据无法被有效利用,针对这个问题,将纵横波模量引入Zoeppritz方程,建立了基于Zoeppritz方程的纵横波模量广义线性反演方法,适用于大角度地震数据。模型测试和实际地震资料应用表明,此方法能够可靠的得到地下介质的纵横波模量,相对于间接反演减小了间接反演带来的累积误差,为后续流体识别和含油气检测提供了很好的数据基础。