地热钻井牙轮钻头固齿强度研究

发布时间：2018-07-21 12:23

【摘要】：地热资源在全球储量丰富,分布广泛,随着原油资源的消耗,无污染可持续的高温地热资源逐渐受到人们重视。高温地热资源钻采与传统油气钻采不同,高温地热井常常处于地质环境恶劣的地区,岩层结构多为火成岩等耐磨岩层,地层中存在大量熔洞使钻井液漏失情况严重,井底温度能达到300℃以上,导致牙轮钻头在工作中掉齿失效现象非常普遍,极大程度影响了钻井成本和效率,而国内开展的高温条件下固齿技术研究成果发表较少,所以地热钻井牙轮钻头固齿强度研究显得尤为迫切和重要。本文主要研究内容如下：首先,对地热钻井牙轮钻头掉齿失效的相关文献进行调研和分析,并将地热钻井牙轮钻头与传统牙轮钻头进行对比,找出两者之间结构、材料、受载、工况上的区别,在传统牙轮钻头掉齿失效的基础上分析地热钻井掉齿失效的原因,并对其失效机理进行详细的论述。其次,针对地热钻井牙轮钻头掉齿失效的原因进行理论计算,运用弹塑性力学理论、固体力学理论和热力学理论,将常温下过盈配合的固齿力公式与材料性能受温度影响的变化规律结合,推导出适用于地热钻井牙轮钻头的固齿力公式,并用实例进行计算,得到高温下固齿力的变化规律与之前所阐述的理论掉齿原因相符。然后,建立地热钻井牙轮钻头的有限元仿真模型,构建牙轮钻头材料在不同温度下的本构关系,分析牙轮钻头在不同结构参数、不同温度情况下固齿力的变化规律,并参照同类型实验数据,证明仿真结果的正确性。最后,参考常温下牙轮钻头的载荷数据,在线性疲劳损伤累计理论的框架下,通过雨流计数法拟合出适用的载荷谱,建立地热钻井牙轮钻头交变冲击载荷疲劳分析模型,研究高温下牙轮钻头结构参数变化对齿孔的疲劳寿命影响规律。通过以上研究,最终得到了提高地热钻井牙轮钻头固齿力的可行性方案。
[Abstract]:Geothermal resources are abundant and widely distributed in the world. With the consumption of crude oil, the high temperature geothermal resources, which are not polluted and sustainable, are gradually paid attention to. The high temperature geothermal resources drilling is different from the traditional oil and gas drilling. The high temperature geothermal wells are often in the areas with bad geological environment, and the rock structure is mostly the fire resistant rock and other wear-resistant rock layers. The leakage of drilling fluid is serious and the bottom hole temperature can reach more than 300 degrees centigrade, which leads to the failure of tooth roller bit in work, which greatly affects the cost and efficiency of drilling. Research is particularly urgent and important. The main contents of this paper are as follows:
First, the relevant literature on the tooth loss failure of the geothermal drilling bit is investigated and analyzed, and the geothermal drilling bit is compared with the traditional roller bit to find out the structure, material, load, and the difference between the working conditions. On the basis of the failure of the traditional roller bits, the reasons for the failure of the geothermal drilling are analyzed, and the results are also analyzed. The failure mechanism is discussed in detail.
Secondly, according to the theoretical calculation of the cause of the tooth loss failure of the geothermal drilling bit, using the elastoplastic mechanics theory, the solid mechanics theory and the thermodynamics theory, the formula of the fixing force formula of the interference fit at normal temperature and the change law of the material properties under the influence of temperature is combined, and the formula of the tooth fixing force applicable to the drill bit of geothermal drilling is deduced. The results show that the variation law of solid tooth force is consistent with the theory of tooth dropping.
Then, the finite element simulation model of the geothermal drilling bit is set up, the constitutive relation of the roller bit material at different temperatures is constructed, and the change law of the tooth force is analyzed under the different structural parameters and different temperatures, and the correctness of the simulation results is proved by the same type of experimental data.
At last, referring to the load data of the roller bit at normal temperature, under the framework of linear fatigue damage accumulative theory, the applicable load spectrum is fitted through the rain flow counting method, and the fatigue analysis model of the alternating impact load of the geothermal drilling bit is established, and the influence of the structural parameters of the bit on the fatigue life of the toothed hole at high temperature is studied.
Through the above research, we finally get a feasible plan to improve the fixing force of the cone bit of geothermal drilling.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE921.1

【参考文献】