为了提高基于欠压实成因机制的地层孔隙流体压力预测的准确性, 这里从提高地震层速度场的计算精度的角度出发, 提出了一种高精度地层孔隙流体压力预测技术.①该技术针对浅部地层 (无测井曲线的地层段) 采用三维约束DIX反演方法和叠加速度体、层位数据计算浅部地层的地震层速度体;②针对中深层地层 (有测井曲线的地层段) 采用叠后波阻抗反演方法和叠后三维地震数据体、测井数据、层位数据计算中深层地层的地震层速度;③沿着研究区的某一浅部地层分界面将浅部地层与中深层地层的地震层速度体进行拼接处理, 得到一个完整的地震层速度体;④采用"Fillippone方法+Eaton方法"的组合方法进行三维地层孔隙流体压力预测.某区页岩气地层的实际计算结果验证了该技术的正确性与可靠性, 其预测的地层孔隙流体压力与实钻井一致, 且目的层的地层孔隙压力平面分布特征与地质认识一致, 有助于指导研究区后续的勘探与开发.%In order to improve calculation precision of pore pressure prediction for uncompacted formation, this paper proposes a high precision pore pressure prediction method based on high precision seismic interval velocity. The first step of the method is to calculate seismic interval velocity of shallow layers by using 3 D constrained DIX inversion method with stack velocity data and seismic horizon data, and the shallow layers have no logging data. The second step of the method is to calculate seismic interval velocity of middle-deep layers by using post-stack impedance inversion method with 3 D seismic data, logging data and seismic horizon data. The third step is to splice the two different kinds of seismic interval velocity along a special shallow layer, and obtain a complete seismic interval velocity field. The fourth step is to calculate pore pressure by using a combined method of "Fillippone method + Eaton's method". The results show that the proposed method can obtain accurate values of pore pressure which is consistent with the measured values, and the calculated plane distribution characteristics of pore pressure is consistent with geological results.
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