高温超压地层随钻声波速度预测方法研究

Sonic Velocity Prediction While Drilling at High Temperature and Overpressure Formation

受高温超压条件的限制,莺歌海盆地深层探井钻探过程中往往缺少声波测井曲线,而随钻过程中声波速度预测对于高温超压井的顺利钻探非常关键。因此,研发一套适用于莺歌海盆地高温超压地层的随钻声波速度预测方法,首先分析了莺歌海盆地高温超压区地层岩石物理特征;随后,利用体积加权模型计算地层声波速度,并通过区分不同岩性拟合得到该区不同岩性的声波速度预测关系;最后将这两种方法应用于实际随钻深度预测中。结果显示,此文方法预测的声波速度精度高,能够准确预测钻头位置及后续储层深度,解决了莺歌海盆地高温超压带声波缺失的难题,同时保障了高温超压井的安全钻探及顺利完钻。

Due to the limitation of high temperature and overpressure conditions, the sonic logging curve is often lacking in the deep exploration well drilling process in Yinggehai Basin. However, the sonic velocity is very important for the successful exploration of high temperature and overpressure well while drilling. Thus, it is necessary to develop a sonic velocity prediction method that is suitable for this district. Firstly, the rock physics of this layer was analyzed.Then the volume weighting method was used to calculate the sonic velocity, and the fitting function of sonic velocity by differentiate the sand and shale was obtained by distinguishing different lithology fittings. Finally, the two methods are applied to predict the depth while drilling.It can accurately predict the broach location and the subsequent reservoir depth, and solve the problem of lacking of sonic log while drilling process in Yinggehai Basin. The method is to ensure the safe drilling and smooth drilling of high temperature and overpressure wells.