中文摘要：

标准岩石可钻性是在室内常压下测定的,主要反映岩石固有的力学性质,没有考虑围压对于可钻性的影响。实际钻井条件下岩石受到井底各种应力的作用,其可钻性会发生变化。根据对可钻性测定原理的分析,牙齿吃入深度是影响可钻性的重要因素,基于摩尔-库仑准则,在考虑岩石本身的力学性质和岩石围压的基础上,建立了牙齿吃入深度计算公式。通过对某油田岩芯进行可钻性试验测定,并计算出试验条件下各岩芯的牙齿吃入深度,经过拟合发现,两者可以建立较为密切的关系。由于牙齿吃入深度的计算公式中包含围压以及岩石的力学性质两方面的影响,因此,可以利用计算吃入深度来预测实际钻井条件下的岩石可钻性。

英文摘要：

Standard drillability test is carried out at atmosphere pressure without considering the effect of confining pressures.The test results mainly reflect the intrinsic characters of rock.Downhole rock is under different stresses and these stresses influence the rock drillability a lot.Based on analysis of rock drillability test,the invasion depth of tooth is an important influential factor on rock drillability.A model for calculation invasion depth is presented considering both rock features and confining pressures,based on Mohr-Coulomb strength criterion.Through comparing rock drillability tested with invasion depth calculation,a close relationship can be built between invasion depth and drillability.Since the invasion depth formula includes the influences of rock features and confining pressures,the rock drillabilty under real drilling condition can be predicted by calculating invasion depth.