岩石抗钻能力界定新方法——五参数法

A new method for defining the rock drilling resistance: five-parameter method

准确评价地层岩石力学特征参数是钻头优选的基础。对现场岩心进行室内实验,利用回归分析法建立岩石抗钻特性参数计算模型,考虑岩石物理性质、力学性质及孔隙特征对岩石抗钻特性参数的影响,兼顾钻头攻击性和耐磨性,根据不同声波时差与地层岩石硬度、内摩擦角、单轴抗压强度、研磨性级值及岩石可钻性级值之间的关系,应用归一化处理方法,建立了地层抗钻特性五参数雷达图,绘制并应用雷达图对X油田渔洋组层段进行了钻头选型。结果表明:应用雷达图选出的钻头,平均进尺提高188%,平均机械钻速提高7%,平均纯钻时间提高160%,应用该方法进行钻头优选能够指导现场施工。

The accurate evaluation on the characteristic parameters of rock mechanics of strata is the base of bit selection. Field cores were tested in the laboratory, and a model to calculate the parameters of rock drilling resistances was established by means of regression analysis method. Then, the five-parameter radar map of formation drilling resistance was plotted by means of normalization processing method according to the relationships of interval transit time vs. rock hardness, internal friction angle, uniaxial compressive strength, abrasiveness grade and rock drillability grade. In this map, the effects of rock’s petrophysical property, mechanical property and pore characteristics on its drilling resistance parameters, as well as the aggression and abrasiveness of bit are taken into consideration. Finally, the radar map was plotted and applied to the bit type selection for the Yuyang Formation in X Oilfield. It is indicated that when the bit selected on the basis of the radar map is applied, average drilling footage, average rate of penetration （ROP） and average net drilling time are increased by 188%, 7% and 160%, respectively. In conclusion, this bit selection method can be used to instruct the field construction.