【作者】 杨春；

【导师】 王成彪； 刘宝林；

【作者基本信息】 中国地质大学（北京） ， 地质工程， 2014， 博士

【摘要】 总结了国内外热熔钻进技术现状，借鉴前人研究成果，开展了电热熔套管护壁总体技术方案、热量传递与温度场分布规律、电热熔头研制、低熔点护壁材料选配、模拟实验装置研建和热熔套管护壁工艺的模拟实验等研究工作，验证了热熔套管护壁技术的可行性，在电热元件研制和低熔点护壁材料配方等关键技术上已经取得突破，该技术具有很好的潜在应用前景。设计了以电热熔头发热、电力调整器调压调功、低熔点护壁材料熔融-冷凝和半合模拟井筒模拟地层孔壁为核心技术的热熔套管护壁技术总体技术方案。在导热介质各向同性和热物性参数均为常数的假设条件下，建立了热熔护壁热传递物理模型，根据能量守恒定律与傅里叶定律，建立了热传导微分方程；利用解析和数值仿真方法得出了从热熔头外壁开始温度呈对数下降规律；利用实测方法得到了温度场符合自然指数规律（T=T0eξ）；热量主要集中在热熔头周围附近，利于护壁材料的熔融。上述研究结果为热熔头设计和低熔点护壁材料配方设计等提供了理论依据。研制了以高强石墨为电热元件、以GH742变形高温合金为壳体的热熔头。高强石墨电热元件在发热温度低于1200℃条件下能满足项目要求；研制的炭炭复合材料电热元件虽然具有强度高、电阻率大等优势，但高温抗氧化能力偏弱；GH742变形高温合金具有较强的抗氧化能力，高温热导率较大，高温机械强度高等优点，基本能满足本项目实验要求。以低熔点玻璃粉为基本组分，实验研究了添加石英砂、铝粉等添加剂对热熔材料物理力学性能的影响，得到的优选配方是同时添加20%-30%的铝粉和石英砂。研建了以可控硅三相电力调整器、变频调速、半合模拟井筒、红外测温仪及数显无线热电偶测温等为主要组成部分的热熔套管护壁模拟实验装置，为电热熔套管护壁工艺的研究提供了便利条件。开展了大量的热熔护壁模拟实验研究，验证了热熔护壁技术的可行性，验证了热熔头设计、低熔点材料配方和模拟实验装置的合理性，验证了热熔头外围径向温度场分布规律的理论计算结果和数值模拟计算结果的正确性。更多还原

【Abstract】 Based on rock melting technology, a novel method for mending Instable borehole wallis developed. It works through a manufactured wall that is built by meltingglass-ceramic casing under700℃. We have breakthroughs in developing an electricheat element and low melting point material. The results of laboratory experiments aresatisfying. It indicates that this technology has great market potential.First, we make a physical model to describe the law of heat transfer on twohypotheses: the heat transfer media are isotropic and the parameters ofthermo-physical properties are constant. On the basis of the law of conservation ofenergy and Fourier’s law of heat conduction, we deduce the differential equation ofheat conduction. The law of temperature drop outside the external surface of heathead agrees with Logarithm. In addition, the actual temperature field accords withEuler’s Number (T=T0eξ). The heat mainly concentrates near the head, which enablesthe mending material to reach its melting point more easily.Furthermore, the heat head consists of heat element of high strength graphite andexternal shell of GH742alloy. The high strength graphite can work under1200℃.Although carbon-carbon composite (C/C) is characterized by high strength and largethermal conductivity, it performs badly in resisting high temperature oxidation. Withhigh strength, large thermal conductivity and strong high temperature oxidation,GH742can basically meet the working requirements.The low melting point material mainly consists of glass. We research the influence ofquartz sand and aluminum (Al) on physical and mechanical properties. We selectglass-ceramic adding20%-30%quartz sand and Al as the final component.Finally, we develop a lab facility consisting of three-phase electric power regulator,frequency converter, split tubular simulator, infrared thermometer, and thermocouple.Using this facility, we conduct a series of experiments and validate the heat head, lowmelting point material, and device for simulation. Additionally, the result pertaining tothe radial temperature distribution basically agrees with the numerical simulation.更多还原