金刚石钻进能量在风化花岗岩地层中的变化特征

利用钻进过程监测系统在风化花岗岩地层中的试验数据对钻进系统的动能、轴力功、黏滞能耗及钻进总能量进行了分析。研究表明,钻具系统的动能在钻进能量中占主导地位,轴力功与黏滞能耗所占的比重很低,钻具系统的动能以及钻进总能量与岩石的风化程度呈负相关,轴力功与岩石的风化程度呈正相关,说明钻进能量与岩石风化程度具有很好的响应关系。最后,从破碎单位体积能耗的观点出发,分析了钻进比功与岩石风化程度之间的关系。研究表明,在全风化及强风化花岗岩地层中,金刚石旋转钻进比功值明显低于冲击凿碎比功;在微风化的坚硬与极坚硬岩石中,金刚石旋转钻进比功则明显高于冲击凿碎比功。这为金刚石旋转钻进中岩石的实时分级与实时判层提供了新的方法。

Variation characteristics of penetrating energy for diamond drilling in weathered granite formation

Based on the test data from a drilling process monitoring system(DPM) instrumented with a hydraulic rotary drill rig in weathered granite formation,kinetic energy,energy from effective thrust force(ETF),energy for viscous frictional resistance(VFR) and total penetrating energy were analyzed for the diamond drilling system.It was shown that the kinetic energy of the drill string system was dominant and energy from EFT as well as VFR was very low in proportion of drilling energy.Besides,a negative correlation between the kinetic energy,the total penetrating energy and the weathered extent of granite existed and a positive correlation between the energy from ETF and the weathered extent was presented,indicating that there was a good response between the drilling energy and the weathered extent of rock.Finally,in a view of specific energy,the relationship between the specific energy of penetrating(SEP) and the weathered extent of rock was analyzed.It was shown that the SEP in diamond rotary drilling was apparently lower than the specific energy of fracture(SEF) in percussive drilling in very strongly weathered and strongly weathered granite formation.However,the SEP in diamond rotary drilling was higher than the SEF in percussive drilling in lightly weathered hard as well as in extremely hard rock.Then a theoretical foundation for classification of rock in the diamond rotary drilling and some new approaches for real-time-rock-classification and real-time-strata-decision were provided.