基于地震的地层压力预测在渤中凹陷西南地区的应用

The Application of Seismic Formation Pressure Prediction to Southwest Area of Bozhong Depression

渤中凹陷西南地区钻遇多段地层超压段,直接影响到钻前地层深度预测及钻井工程安全。首先以基于叠加速度的约束反演获得背景层速度,再以叠后波阻抗反演获得目的层精确的层速度,然后采用Fillippone公式直接由地震速度计算得到地层压力,最后通过等时切片成图,可以有效预测异常地层压力的纵向深度和平面分布范围。根据该方法指导钻探的3井,在对应深度段实测地层压力高于1.4,与预测值基本吻合,有效地确保了钻井安全。

The drilling of the southwest area in Bozhong depression has several strata with overpressure sections. This situation directly affects the safety of drilling. In this study, Fillippone formula is applied to calculate strata pressure from seismic velocity which is extracted from stacking velocity constraint inversion and post stack inversion. Then the feature of time slice group is able to represent the overpressure sections distribution. According to the application of this method to the drilling of the 3rd well, the measured formation pressure of corresponding depth section is higher than 1.4 meter, which agrees with the prediction and effectively ensures the drilling safety.