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莫索湾凸起井下侏罗系下部普遍表现为超压特征,但井底以下地层压力特征不清楚。莫深1井是莫索湾凸起上以深层石炭—三叠系大型背斜圈闭为勘探目标的一口重点科学探索井,钻前开展压力预测,对莫深1井钻井工程的合理设计具有十分重要的意义。采用地震层速度法预测地层压力在正常压力段比较准确,但在超压段,地震层速度与真实地层速度之间的系统误差较大,预测压力明显小于实测压力值。VSP测井速度较地震层速度对超压段更为敏感,利用VSP速度对地震速度进行校正,可以大大降低这种系统误差。采用校正后的地震层速度进行地层压力预测,其预测精度有较大提高。
The lower part of the Lower Jurassic in the prominence of the Mosuo Bay is characterized by overpressure, but the pressure characteristics of the formation below the bottom of the well are not clear. Mo 1 deep well is a key scientific exploration well on the Mosoowou uplift with deep Carboniferous-Triassic large-scale anticline trap as the exploration target. Before drilling, the pressure prediction is carried out. The rational design of drilling for Mo Shen 1 well has Very important meaning. The prediction of formation pressure by the seismic velocity method is more accurate in the normal pressure range. However, the system error between the velocity of the seismic layer and the actual formation velocity is larger in the overpressure section, and the predicted pressure is obviously smaller than the measured pressure. The VSP logging speed is more sensitive to overpressure than the seismic velocity, and the use of VSP velocities to correct for seismic velocities can greatly reduce this systematic error. The stratigraphic pressure prediction using the corrected seismic velocity shows a great improvement in prediction accuracy.