岩石可钻性井底卸载效应研究与实践

STUDY AND PRACTICE OF THE BOTTOM-HOLE UNLOADING EFFECT ON ROCK DRILLABILITY

尹宏锦 石林

Yin Hongjin Shi Lin

石油大学, 华东 塔里木石油勘探开发指挥部

本文用试验方法研究了石油钻井过程中井底岩石零孔隙压力条件下的岩石可钻性。试验结果表明,随着井深的增加,井底岩石卸载量亦增加,岩石可钻性级值存在一个由增加变为减少的趋势。变化的全过程是级值开始呈缓慢上升趋势,继之趋于平缓,往后呈下降趋势,最后急剧下降,直至井底岩石失去稳定性。该过程反映了井底岩石的卸载效应,是深井岩石可钻性的一个新概念。塔里木钻井界运用这一规律优选钻头类型.成效显著。

Rock drillability of rock samples was studied by means of experiment under zero pore pressure and simulated down hole conditions. The results of drillability grade shows a bow-shaped curve the unloading force rising as increasing the well depth. The magnitude of drillability grade experence four stages which are increasing lightly, keeping constant, decrease slightly and decreasing rapidly until the samples are unstable at the bottom of hole finally. This is a response of the bottom-hole unloading effect on rock drillability which is a new concept of deep well drillability. The significant benefit have been gotten by using this ideal mentioned above in bit selecting in Tarim oil field.

10.3969/j.issn.1000-7393.1995.05.001