【作者】 于磊；

【导师】 赵大军；

【作者基本信息】 吉林大学 ， 地质工程， 2012， 硕士

【摘要】 油页岩（油母页岩）为固体可燃有机沉积岩，世界油页岩资源丰富，全世界已有36个国家发现油页岩矿床共100多个，页岩油资源量达4100亿吨，是目前世界天然原油探明可采储量的3倍。中国石油开采年限至多为40年，而在我国东北、新疆、内蒙古等地区，冬季漫长，温度较低，自然能源非常丰富。在油页岩原位高温开采中，需要用到地下冷冻法，俗称冷冻墙，国内相关研究报告较少，国外较成熟的是壳牌公司的ICP技术，主要是为了防止地下水的流动和地下油气的散失。冷冻墙工艺主要是将低温冷冻液泵入冷冻井中，在孔内与土体发生热交换，实现冻结。在冻结过程中，快速冻结靠近冻结孔的区域，随着冻结的深入，范围将不断扩大，最后冻结区域相互连接起来，形成冷冻墙屏障。地下冷冻墙的制冷系统以前主要是采用压缩机制冷机组，而在我国东北地区，冬季漫长而且寒冷，可以利用东北的自然冷源，制冷循环液，从而减少设备的功率和整个项目的投资。实验中研究利用自然冷源制冷达到的效果，周围温度场的变化规律。利用有限元分析软件ANSYS建立了利用自然冷源冻结的传热模型，模拟分析了冻结过程中的地下温度场的温度变化规律，其中桩中心、桩边缘平均温度变化为0.13℃/h、0.12℃/h，分析比较了不同冻结时间、不同流速、不同初始温度下的温度场的变化规律和其热物性参数对地下温度场的影响。由地下冷冻墙制冷系统模拟实验可知，由于自然冷源随着昼夜温度的变化而变化，1.5m处桩中心、桩边缘温度平均下降0.11℃/h、0.10℃/h，略低于模拟分析的结果，但地下温度场的变化过程与模拟分析的结果吻合。东北自然冷源资源丰富，结合利用自然冷源进行冻结的模拟实验平台，分析了使用该方法制冷形成冷冻墙，与常规压缩机组制冷系统相比，制冷设备投入减小36.6%，运行成本减小43.7%，地下冷冻墙的总投入减小42.3%。从以上可知，若能充分利用自然低温，并将该方法应用到油页岩高温原位开采当中，能降低能耗，减少建造冷冻墙的初始投资和维护费用，且减少氨等制冷剂的使用，保护环境，从而推动油页岩的进一步开发。更多还原

【Abstract】 Oil shale (oil forming shale) is a kind of solid combustible organic sedimentaryrock and oil shale resources are plentiful in the world. Around the world there aremore than100oil shale deposits are found in36countries. The shale oil resourcesamount to410billion tons, which is3times of the proven recoverable reserves atpresent of the world’s natural crude oil. The age limit of oil exploitation in China is atmost40years. The per capita recoverable reserves of natural in China is only4.33percent of the world average, and according to the current level of exploitation, theage limit of extraction is less than60years. In northeast, Xinjiang, Inner Mongoliaand other regions of China, the winter is long, the temperature is low, and naturalenergy is very rich.During Oil shale in high-temperature situ exploitation, underground freezingmethod is needed, which is commonly known as frozen wall. Domestic is lack ofrelated research reports, and foreign relatively mature technology is Shell’s ICP. Inorder to prevent the flow of groundwater and the loss of underground oil and gas,Shell has used underground freezing technology, namely frozen wall technology, toestablish frozen wall and prevent the flow of groundwater and the loss of oil and gasof in situ exploitation, then ensure the success of in situ exploitation.The frozen wall technology is mainly to pump low-temperature freezing liquidinto the frozen well. In the well heat exchange happens between the soil and thefreezing liquid to realize the soil freeze. In the freezing process, the soil near the wellis rapidly frozen. With the depth of the freeze, the range of freezing will continue toexpand. Finally, frozen region is connected together to form the frozen wall.The frozen wall technology is mainly used refrigeration units, but in NortheastChina, winter is long and cold. Heat exchanger can directly use the condition ofnatural low temperature in Northeast, to refrigerate the circulation fluid in frozen well,thereby reducing equipment power and the whole project investment. And throughoutthe trial, the main problem is observing the natural low temperature conditionswhether can reduce the temperature of circulate fluid low enough to meet theconditions for further trials under natural conditions. At the same time the experimentresearch the change law of the temperature field around in such experimentalconditions.The finite element analysis software——ANSYS is used to establish thesimulation model of natural freezing cold source’s heat transfer. The temperaturechange rule of the underground freezing process is analyzed. From the analysis, theaverage temperature changes of pile center, pile edge are respectively0.13℃/h,and0.12℃/h. Then the analyses of the temperature change rule and the thermalphysical parameters is made under different freezing time, different velocity, differentinitial temperature to determine the influence on the underground temperature field.From the simulation experiment of ground freezing wall refrigeration system, itis known that the natural cold source changes with the climate temperature.Theaverage declining temperature of1.5m away from pile center, pile ridge is respectively0.11℃/h and0.10℃/h, slightly lower than the results of thesimulation analysis, but the change process of underground temperature field is thesame with the simulation results of analysis.The natural cold source in northeast of China is very rich. The simulationexperiment platform uses this natural cold source to simulate the frozen wall.Comparing with the conventional method of refrigeration to form freezing wall, theinvestment of refrigeration equipments is reduced by36.6%, the operation cost isreduced by43.7%, and the total investment underground freezing wall is reduced by42.3%.From the above analysis, if the natural low temperature can be made full use andthe method is used to exploit oil shale in high-temperature situ exploitation, it willreduce the energy consumption, the initial investment of the frozen wall built andmaintenance costs. And the use of ammonia will be also reduced. It is benefit forprotecting the environment and promoting the further development of the oil shale.更多还原