一种基于破碎比功的岩石破碎效率评价新方法

A new evaluation method for rock-crushing efficiency based on crushing work ratio

在石油钻井工程中,评价钻进效率差别的方法是利用钻速方程来计算各单因素对钻速的影响,计算工作量大,缺乏综合性。根据岩石破碎的基本理论,对牙轮钻头破碎岩石所消耗的能量进行分析,建立了岩石破碎比功的计算模型,并提出一种基于破碎比功的岩石破碎效率评价方法。应用所建立的模型和方法,可以有效地分析和确定不同条件下的岩石破碎效率,分析评价不同钻头、不同钻进措施条件下所产生的钻井效果,为钻井工程设计中优选钻头类型、优化钻进参数以及钻井事后效果分析提供了依据。应用该方法所得的计算结果,很好地解释了过平衡钻井和欠平衡钻井条件下同种地层而钻速差异较大的根本原因。

In the evaluation of drilling efficiency in drilling engineering, the conventional drilling rate models were often used to analyze the effect of a single factor contribution on drilling efficiency. This method has the shortages of large calculation work and low comprehensive function. According to the basic rock-crushing theory, a computation model and an evaluation method for rock-crushing efficiency based on the crushing work ratio were provided by analyzing the energy consumption of rock crushing with roller bit. By using the new model and method, the rock-crushing efficiency could be analyzed in different conditions and the drilling efficiency with different bits could also be evaluated in different conditions. This model can provide the base for selection of bits, optimization of drilling parameters and analysis of drilling efficiency. The calculation result of this method also explained the basic reason for the difference of drilling speeds in the same formation between excessive balanced drilling and under-balanced drilling.