歧口凹陷陡坡扇地震地质模型正演与应用

Steep Slope Fan Seismic Forward Modeling of Qikou Depression and Its Application

根据歧口凹陷典型陆相沉积为主的沉积模式,结合储层纵向砂泥薄互层、横向砂体变化大及砂泥岩速度接近造成的波阻抗差异小等特点,利用该区的实际井测井资料分别建立一维、二维、三维地质模型,进行正演模拟。通过实际井简化一维模型正演分析,建立歧口典型陡坡扇沉积特征的地质模型进行二维正演模拟,总结陡坡扇沉积的地震响应特征,再利用三维模型正演能很好的反映砂体纵横向变化引起地震属性变化的优势,对三维正演数据体的各种平面属性及时间切片等参数特征进行分析,优选出了适合该类储层的地震预测方法,为陡坡扇沉积砂体的地震资料剖面解释预测和地震相识别提供了理论依据。

According to the sedimentary pattern of Qikou hollow characterized by continen- tal deposit, we established 1D, 2D, and 3D geologic models from actual logging informa- tion for forward modeling, considering the significant variation in thin sand shale interbed vertically and in sand body horizontally, as well as the low wave impedance due to similar velocity among sand shales. Based on actual logging information, we simplified the 1D for- ward modeling, constructed geologic model for 2D forward modeling based on the typical slope fan sedimentation system in Qikou, and summarized its seismic response features. Then, as 3D forward modeling is a good indication of the change in seismic property due to vertical and horizontal variation of sand bodies, we analyzed the data volume of 3D forward modeling and analyzed the parameter characteristics of plane property and time slice, select- ed an optimized seismic prediction approach suitable for this type of reservoir, and provided evidence for the interpretation and prediction of seismic data and the identification of seismic facies for sedimentary sand bodies in steep slopes.