针对金刚石钻头的岩石研磨性测定方法

A modified determination method of rocks abrasiveness for well drilling using diamond bits

针对石油钻井地层岩石研磨性试验评价问题,根据金刚石钻头的磨损机制,改装试验装置,研制标准磨损件,优选试验规程,提出以标准磨损件研磨破碎单位体积岩石的磨损体积作为岩石研磨性指标,建立-套岩石研磨性测定方法.试验测定石油钻井地层代表性岩石的研磨性指标.通过研磨性试验,优选出标准磨损件的金刚石体积分数为25 %,粒度为0.3mm,胎体配方为酚醛树脂55% 、Cu 25 %、Cr2O3 8%、ZnO 6%、SiC 5 % 、空隙1% （体积分数）.优选出的试验钻压为500 N,转速为198r/min,排量为0.2L/s.试验中代表性岩石的研磨性指标数值为0.80 ~45. 78,取以2 为底的对数值作为研磨性级值,将中国石油钻井地层岩石的研磨性分为6 级.

In order to classify the rock＇s abrasiveness in oil well drilling using diamond or PDC bits, a conventional equipmentused for rock＇s abrasiveness testing w-as modified based on the wear mechanisms of diamond bits, and a new- kind of standardwear specimen made of diamond bit materials was manufactured. The volume worn of the standard wear specimen for breakingper unit volume of rocks was taken as the abrasiveness index, and a new- experimental method was proposed. An optimized diamondvolume fraction of the standard wear specimen was deter^nined as 25% with size of 0. 3 mm diamond grains, and the matrixwas formulated with phenolic resin 55% , Cu 2 5 %,Cr2〇3 38% , ZnO 6%, SiC 5% and with 1% volume of pores. For thestandard wear testing, the suggested weight on the wear specimen is of 500 N, and the rotation speed is 198 r/min with a circulationrate of drilling fluid of 0.2 L/s. The abrasiveness index of the representative rock samples from different for^mations encounteredin oil well drilling has been determined, which was found to be in the range of 0. 80 to 45. 78. The logarithm value ofthe abrasiveness index was used for the classification of the rock＇s abrasiveness, defined as the abrasiveness grade value. Therocks encountered in oil well drilling in China can be divided into six grades according to the abrasiveness grade values.