旋转钻井中岩石破碎能耗的分形分析

 通过旋转钻井中破碎岩石的能耗分析，应用分形岩石力学理论，从钻井过程中钻头破碎岩屑的粒度分布、能量耗散等角度，建立旋转钻井中钻头破碎岩石所需能量的分形描述模型，详细分析影响钻头破碎岩石能耗的因素。该模型显示出旋转钻井岩石破碎能耗不仅与钻压、转速等钻井参数关，还与地层岩石破碎体的尺度和粒度分布分形维数等因素有关。应用该模型不仅可以确定钻井过程中破碎岩石所需的能量，还可以反演计算，根据所需岩石的破碎能量优选钻进参数。将所建立的模型进行适当简化，可得到经典岩石破碎比功三大学说表达式，说明该模型具有一定的普遍性。

FRACTAL ANALYSIS OF ENERGY CONSUMPTION OF ROCK FRAGMENTATION IN ROTARY DRILLING

According to the fractal theory，a fractal model for consuming energy on rock fragmentation is provided through energy consumption analysis of rock fragmentation in rotary drilling. The factors，such as size distribution of rock cuttings and energy consumption in the process of drilling are taken into account and the factors affecting energy consumption of rock fragmentation on the bit are considered. The model shows that the energy consumption on rock fragmentation is not only related to the drilling parameters such as weight on bit and rotational speed，but also the size of rock cuttings and the fractal dimension of size distribution. The model can be used to determine the necessary energy consumed on rock fragmentation and it can also be inversely used to optimize drilling parameters with the energy consumption on the rock fragmentation. In addition，the three classical formulas of the crushing work ratio theory can be obtained by properly simplifying the model，hence，the general applycation of the model is proved.