热氮气地下原位裂解油页岩温度场数值模拟及野外试验

发布时间：2018-05-07 11:08

本文选题：油页岩 + 原位裂解　；参考：《吉林大学》2017年硕士论文

【摘要】：截至2015年底,世界石油探明资源量为1.6976万亿桶,仅满足全球50.7年的生产需要。中国是世界第一能源消费大国,且石油对外依存度高,这些因素将直接威胁到我国的经济发展甚至是国家安全。因此我国有必要对非常规能源进行开发利用,以寻找新的替代能源。油页岩是一种富含有机质的沉积岩,作为一种非常规能源,因其资源量大而具有极好的开发潜力。中国油页岩资源量丰富,将其折算成页岩油可达476.44亿吨,高居世界第二位。目前油页岩的开发利用方式有地上干馏和地下原位裂解,后者因产品质量好和环保等优点而具有更好的前景。本文基于国家油页岩原位开采先导试验工程进行研究。本文首先用热重分析仪(STA-449F3)研究农安油页岩的热解特性,发现其裂解温度范围为300℃~540℃(N2气氛);用Hot Disk热常数分析仪测试油页岩的热物理性质,发现该性质具有各向异性,并分析了热物理性质系数随温度的变化规律,最后拟合出导热系数随温度变化的公式。然后对油页岩原位裂解的温度场进行了数值模拟。农安油页岩层厚7.2m,注热井和开采井间距5m,假定通过压裂的方式建立了三种裂缝,即模型1(两条裂缝、缝高4mm)、模型2(三条裂缝、缝高4mm)和模型3(四条裂缝、缝高4mm)。用ICEM CFD划分网格,Fluent模拟在注气温度450℃或420℃、不同注气流量下油页岩层的温度场。模拟结果表明:在裂解区域建立3条裂缝、缝高4mm(模型2)的注气通道,且N2注入流量为140Nm3/h时,其能量利用率可达58.3%,加热47.3天即可完全裂解该区域的油页岩。接着选取适用于注热管柱的保温材料;采用理论计算的方式,计算出保温层的临界厚度;进行注热管柱的保温结构设计并在地面进行测试,最后用Fluent软件模拟一定初始条件下不同气体流量流过注热管柱后的温度。结果发现:长70米,外径?32mm的注热管柱,缠绕4层纳米SiO2气凝胶GR10,当N2注入温度为500℃的情况下,注热管柱的出口温度在一定注气时间后可达400℃以上。最后依托于农安油页岩原位裂解先导试验工程,通过射孔—压裂的方式建立裂缝,对注热管柱进行了保温处理,最后进行了注热试验。试验发现N2在注热井井口温度450~500℃、注入流量120~140Nm3/h的情况下,其孔底温度可达400~420℃。在加热10d左右后,可监测到产物中HC含量大于10%,说明油页岩层开始裂解。
[Abstract]:By the end of 2015, the world's proven resources are 1 trillion and 697 billion 600 million barrels, which only meet the production needs of 50.7 years in the world. China is the world's largest consumer of energy, and the dependence of oil on foreign countries is high. These factors will directly threaten our country's economic development and even national security. Therefore, it is necessary for us to develop and utilize unconventional energy. In order to find new alternative energy sources, oil shale is a kind of rich organic sedimentary rock. As a kind of non conventional energy, it has great potential for development because of its large amount of resources. China's oil shale is rich in resources, and it is converted into shale oil up to 476.44 million tons and ranks second in the world. At present, the exploitation and utilization of oil shale has the land on the dry distillation. In situ cracking in the underground, the latter has a better prospect because of the advantages of good quality and environmental protection. This paper is based on the pilot test project of the national oil shale in situ mining. Firstly, the pyrolysis characteristics of Nongan oil shale were studied by thermogravimetric analyzer (STA-449F3), and the pyrolysis temperature range was 300 C ~540 C (N2 atmosphere), and Hot D was used. Isk thermal constant analyzer tests the thermal physical properties of oil shale. It is found that the property is anisotropic, and the change law of thermal physical property coefficient with temperature is analyzed. Finally, the formula of thermal conductivity change with temperature is fitted. Then the temperature field of the in-situ pyrolysis of oil shale is simulated. The thickness of the oil shale is thick 7.2m, heat injection well. The distance between the mining well is 5m, and it is assumed that three kinds of fractures are established by fracturing, namely, model 1 (two cracks, high 4mm), model 2 (three cracks, seam height 4mm) and model 3 (four cracks, high 4mm). The grid is divided by ICEM CFD, and the temperature field of the oil shale is simulated at the gas injection temperature 450 or 420, and the temperature field of the oil page rock under different gas injection flow. Simulation results table Ming: 3 cracks were established in the cracking area, the gas injection channel of 4mm (model 2) was sewn up, and when the flow rate of N2 was 140Nm3/h, the energy utilization rate could reach 58.3%, and the oil shale in this area could be completely cracked for 47.3 days. Then, the thermal insulation material suitable for heat injection pipe column was selected, and the critical thickness of the insulation layer was calculated by the method of mining theory. The thermal insulation structure of the pipe column is designed and tested on the ground. Finally, Fluent software is used to simulate the temperature after the flow of different gas flow through the heat pipe column under certain initial conditions. The results show that the heat pipe column is 70 meters long, the outer diameter 32mm tube column, winding 4 layers of nano SiO2 aerogel, when the N2 injection temperature is 500 C, the heat pipe column is out. The mouth temperature is up to 400 degrees centigrade after a certain gas injection time. Finally, relying on the pilot project of the in-situ pyrolysis of Nongan oil shale, the cracks are established through perforation fracturing, and heat preservation treatment is carried out for the heat injection pipe column. Finally, the heat injection test is carried out. The test results show that N2 is 450~500 C at the wellhead temperature of the injection well and the flow rate of 120~140Nm3/h. In the case, the temperature of the bottom hole can reach 400~420 degrees Celsius. After heating about 10d, the HC content in the product can be monitored to be greater than 10%, which indicates that the oil shale formation is cracking.

【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD83

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