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在石油钻探过程中,地层压力预测对钻井液密度的选择和合理井身结构设计起着非常重要的作用，也是钻井安全技术中的一个重要问题。传统的地层压力预测是通过对钻前的地震资料进行处理而获得预测结果，而在钻井过程中，则是利用随钻录井数据来监视正钻地层的地层压力变化。由于钻前地震预测的地层压力精度一般较低，因此，预测钻头下部未钻开地层的孔隙压力，只靠钻前的地震预测，其精度不能满足钻井施工的需要。文章基于灰色理论，提出了钻头下部未钻开地层的孔隙压力预测新方法，建立了地层孔隙压力随钻预测灰色模型。该模型根据上部已钻井段的随钻监测结果，对钻头下部未钻开地层的孔隙压力进行随钻预测。应用大量的随钻录井数据对上述模型进行了验证，并成功应用于某油田几口探井。应用结果表明：该模型是合理的，其预测精度较高，能够满足现场施工的安全和技术要求，是一种值得推广的地层孔隙压力随钻预测方法。

PORE PRESSURE PREDICTION WHILE DRILLING FOR UNDRILLED FORMATION BENEATH THE BIT

Because the accuracy of predicting the formation pressure by seismic data before drilling was relatively low in general, it is necessary to develop a new method for predicting the pore pressure of undrilled formation beneath the bit. According to the grey theory, a grey model of formation pore pressure prediction while drilling was established by the authors. In light of the results of monitor while drilling of the upper drilled intervals, the pore pressure prediction while drilling for undrilled formation beneath the bit was carried out by use of the model. This model was verified by a great number of data on mud-logging while drilling and successfully applied to several exploration wells in one oil field. Through application on the spot, it was indicated that this model is a good method of formation pore pressure prediction while drilling and it is worth popularizing, because it can meet the needs of the safety and technology for field operation, being high prediction accuracy.