渤南洼陷钻前地层压力地震预测

沾化凹陷渤南洼陷沙三段和沙四段普遍存在着异常高压。为全面了解该区纵、横向压力分布特征，采用叠前时间偏移速度谱资料，利用VSP速度，应用Fillippone公式压力预测模型，成功地预测了渤南洼陷的孔隙压力体。采用VSP测井优化校正地震层速度，可以使速度误差小于8%，从源头上降低地层孔隙压力的不确定性。在确定研究区相对应的模型参数前提下，依照每个速度谱点分别求取最大、最小压实速度，为压力预测模型提供了良好的速度处理方法。利用经校正的速度资料和预测模型，获得了流体压力的三维数据体，可以从任意方向切片观察凹陷内压力的空间展布。由于地震垂向分辨率影响着地震速度精度，再加上多种地质因素影响地震速度，从而导致地震预测压力值与实测值存在误差。经速度校正系数和实测值的校正，82%的统计数据误差在±10%的允许范围内，基本能满足勘探、开发的需要。

Formation pressure prediction in Bonan Sag

Overpressures are commonly observed in the third and fourth member of Shahejie (Es3 and Es4) formations in Bonan Sag, Zhanhua Depression. The optimized and calibrated velocity data along with the Fillippone formula pressure prediction model have been used to predict formation pressure in Bonan Sag. VSP and logging information is used to calibrate seismic velocity, which reduces greatly velocity error and the uncertainty of pore pressure prediction. After determining the model parameters of the study area, we obtain each maximum and minimum velocity of seismic velocity spectrum. Using corrected seismic data and predictive models, we get the pore pressure 3D modeling. It offers a comprehensive picture by showing the overall variation in 3D view and reveals a comprehensive understanding of the pressure distribution at any direction slice. The pressure prediction may cause errors due to inaccurate seismic velocity and low seismic resolution. For our applications, 82 percent of the predictions are within an error less than 10 percent, which can meet the requirements of the exploration in the area.