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对井剖面地层岩石可钻性的确定直接影响到钻头选型和钻速预测，然而，现有的研究岩石可钻性的微可钻实验存在较多问题。现有的岩石微可钻性实验一般通过取心在室内常温常压下进行，脱离了地下高温高压环境后的岩心不仅不能代表地层的可钻性，而且这样的可钻性数据离散、随机、有限、成本高。但若能建立基于岩石物理参数的岩石可钻性预测模型，必将能缓解可钻性评价中存在的这些矛盾。尽管利用测井资料估算岩石可钻性时，由于岩石结构的复杂性以及不适当的参数化工作使测井估算的可钻性也存在不少问题，但利用测井资料获取岩石可钻性的方法能够提供逐点可钻性数值，既能反映出整个钻井剖面岩石可钻性变化的趋势，又能反映出不同地层间的变化规律，而且成本低。鉴于此，推导了利用声波测井资料预测岩石可钻性的计算模型，并结合 Ｓ油田实际资料开展了钻速预测方法研究。

FORECASTING ROCK DRILLABILITY AND PENETRATION RATE

Determining drillability of the rocks in a well bore is directly related to the selection of bit type and the forecast of penetration rate,but the existing microdrillability test for studying rock drillability has quite much troubles.Existing rocks microdrillability test is generally made through coring and at atmospheric temperature and ordinary pressure in room,thus,the core divorced from underground high temperature and high pressure circumstance not only can't represent the drillability of the formation,but also such drillability data are dispersive,random,limited and high cost.However,these contradictions in drillability evaluation can be certainly relaxed if a rock drillability forecast model can be set up based on rock's physical parameters.When rock drillability is calculated by well logging data,though the log calculated drillability has not a few problems due to the complexity of rock texture and improper parametrization,the method using logging data to obtain rock drillability can provide with drillability value point by point,which can reflect the drillability change trend of the rocks in wellbore profile as well as the change law of the drillability among different strata,and the cost is low.In view of this,a calculation model for forecasting rock drillability by use of acoustic logging data has been derived and the research on penetration rate forecasting method has been conducted based on the practical data from S oil field.