钻头工作效率实时评估新方法

为了实时评估钻头的工作效率，增加钻井施工的可控性，对钻头工作效率实时评估方法进行了研究。基于前人提出的机械比能理论，对钻头扭矩进行简化处理并提出了岩石有侧限抗压强度理论，给出了相关计算公式，利用各参数间的相关性，反推出钻速方程，达到了通过邻井钻井数据预测钻速的目的。根据以上理论模型，开发研制了相关软件，实现综合利用测井数据、岩石力学参数、机械比能和机械效率等多类连续剖面科学评估钻头性能，并采用现场数据进行了验证。结果表明:该模型计算出的钻头扭矩、岩石有侧限抗压强度和机械效率等参数很好地反映了现场钻头运行情况和磨损程度，基本满足了钻井施工的要求。所研究的评估方法对钻头优选、钻井实时模拟决策和钻后分析具有指导性意义。

Novel approach for assessing real-time bit working efficiency

A novel approach is studied for assessing real-time bit working efficiency and increasing controllability of drilling. Based on the previous mechanical specific energy theory, bit torque calculation is simplified and the confined compressive strength and related formula is proposed. In addition, the rate of penetration equation is deduced based on the correlation between parameters. The software of assessing real-time bit working efficiency is developed on the basis of the theoretical models above and is tested through field data. It can estimate bit performance by making use of log data, rock mechanical parameters, MSE, and mechanical efficiency. The results show that the predicted bit torque, CCS, EFF and bit performance are consistent with drilling field conditions and basically meet the requirement of drilling engineering. The method is instructive and meaningful to bit optimization, real-time drilling decision and analysis after drilling.