提高大位移井环空携岩效率的方法研究

发布时间：2018-07-25 21:16

【摘要】：岩屑床的清除是大位移井钻井技术领域关注的热点之一,大位移井钻井过程中容易形成岩屑床,岩屑床的存在给钻井施工带来诸多安全问题。因此本文对如何提高大位移井携岩效率展开研究。本文以岩屑颗粒为研究对象,对不同井段的岩屑颗粒进行受力分析,建立了岩屑颗粒的力学模型,计算岩屑临界滚动返速和临界举升返速,得到了岩屑运移规律。结果表明,井斜角50°的井段容易形成岩屑床。在此基础上,运用拉格朗日方法和欧拉方法对岩屑床的形成过程进行了详细研究,结果表明:粒径大的颗粒容易沉积到下井壁,井壁摩擦力越大岩屑越容易沉积。同时,分别从井斜角、环空返速、钻具转速、钻具偏心度四个方面对携岩效率进行分析,所得结果与实际作业规律一致。为了提高岩屑床的清除效率,本文设计了利用机械作用和水力作用清除了岩屑床的清除器。并运用fluent软件模拟岩屑床清除器对环空流场的影响,获得了新型岩屑床清除器在不同井段的最佳间隔距离。结果表明该岩屑床清除器效果良好。
[Abstract]:The removal of cuttings bed is one of the hotspots in the field of drilling technology for extended reach wells. It is easy to form cuttings bed in the drilling process of extended reach wells, and the existence of cuttings bed brings many safety problems to drilling construction. Therefore, this paper studies how to improve the rock carrying efficiency of long-reach wells. Taking cuttings as the research object, the mechanical model of cuttings is established by analyzing the stress of cuttings in different well sections, and the critical rolling velocity and lifting velocity of cuttings are calculated, and the rule of cuttings migration is obtained. The results show that cuttings bed is easy to be formed in the section with a slope angle of 50 掳. On this basis, the formation process of cuttings bed is studied in detail by using Lagrangian method and Euler method. The results show that the larger the particle size is, the easier it is to deposit the debris into the lower shaft wall, and the greater the friction of the shaft wall is, the easier it is for the cuttings to deposit. At the same time, the rock carrying efficiency is analyzed from four aspects: well inclination angle, annulus return velocity, drilling tool rotation speed and drilling tool eccentricity. The results are consistent with the actual operation rule. In order to improve the removal efficiency of cuttings bed, this paper designs a scavenger for removing cuttings bed by mechanical action and hydraulic action. The influence of cuttings bed scavenger on annular flow field was simulated by fluent software, and the optimum spacing distance of new type cuttings bed scavenger in different well segments was obtained. The results show that the chip bed remover is effective.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE242

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