【作者】 石卓；

【导师】 金旭；

【作者基本信息】 吉林大学 ， 固体地球物理学， 2010， 博士

【摘要】 地热是新能源家族中的重要种类,对于改善能源结构意义重大。与石油、煤炭和天然气相比,地热资源释放出的温室效应气体很少,具有廉价、清洁、易开采、可直接利用和可再生等优点。我国的地热资源总量仅次于美国,居世界第二位,约占全球地热资源的7.9%。我国利用地热的主要方式是高温地热发电和中低温地热直接利用。内蒙古自治区地热资源的勘查与开发起步较晚,发现的地热点不多,地下热水资源相对有限,赤峰市热水镇为一天然热水矿泉,在该热水矿泉进行了包括地质、重力和地温测量等项内容的地质、地球物理野外勘查,并结合对以往既有勘探资料的分析,对地热田的热结构模型进行了深入研究,为正确评价该地热田地热资源提供了科学依据。同时对开发利用该地热资源发展当地经济和提高当地人民生活水平有十分重要的现实意义。通过分析赤峰市热水镇地区地质构造特征,阴山断裂构造属于最古老的构造活动带,其活动一直延续到燕山造山活动时代,对本区的地质构造影响极大,与其斜交的八里罕断裂主要活动时期为燕山造山运动的末期。这一断裂在八里罕北部为北东—南西走向,以南变为南北走向。八里罕断裂在本区存在约100m宽破碎带,并发育有次级张性断层和裂隙。八里罕断裂现在还发生微小地震,说明其还在活动。本区除了南北走向的八里罕断裂之外,还存在北西—南东和北东—南西向的断裂系列。地热田正好在上述南北向、北西—南东向、北东—南西向及东西向断裂构造的交汇处,这些断裂构成了地热田热水上升的主要通道,与中生代燕山造山运动相伴的岩浆活动形成的花岗岩和古近纪岩浆活动相伴的玄武岩侵入体构成本区温泉的热源。研究区内地热田西临陡峻山区,东接平缓丘陵地带。两者的分界是南北走向的八里罕断裂,西部由前寒武纪结晶片岩、片麻岩和侵入岩等块状岩构成,东部凹陷上覆由侏罗纪火山岩和第四纪堆积岩所构成,下部为前寒武纪岩类。做为地热流体主体的水的起源,可通过对其氢、氧同位素组成的分析而得。研究中分别采集温泉水样,地热田附近井水样和周边地表水样,并对它们进行了化学成分和同位素成分的测试及分析,结合氚浓度分析可知在离地热田向西、北部约10～20km远处的高海拔地区向地下渗透的天水为地热田热水的起源,推测这些天水约经80年以上时间才流动、滞留在本地热田。渗透到地下的天水到达深部后,主要以热传导方式加热成热水。根据热水中的化学成份、同位素分析数据,用各种地球化学、同位素温度计,估算浅部热水层和深部储集层中的热水的温度分别为100～110℃和140～150℃,因此本地热田热水属于天水起源的中、低温裂隙水。为了探明地热田的基底构造和断层的位置,我们在该区进行了重力勘探。对所测重力数据进行了相应改正后得到了测区重力异常分布,该区重力异常具有西部高而向东方向逐渐变低的倾向。测区西北部还呈现局部的高异常。这正与该区西部为前寒武纪岩类,东部陷没,而上覆侏罗纪岩类的岩性分布特征相吻合。同时为了掌握地热田的热构造和范围,并选定开发有利地点的目的,在该区进行1m深和50cm深的地温测量。对测温数据进行各种改正后,绘制了50cm深、1m深地温分布图。由地温分布图可知地下的热水是向低高程方向流动的,并随着变浅逐渐朝南东向倾斜。从热构造背景分析可知,本地区热背景具有略厚的地壳、稍低的大地热流和壳内相对低温的特征。在这样的地温条件下,壳内很难发生热水对流的现象。又从该区火山活动的分析研究可知,在地壳浅部形成地热田热源的大规模岩浆囊或岩浆固结所成高温岩体的可能性也是非常小的。这样,我们只能想象该地热田热水的热源为伴随构造运动所侵入的侏罗纪花岗岩和第三纪玄武岩体。因此,该地热田的热水循环模型推断如下:从地热田西、北部山区渗透到地下深部的天水,流到地热田下部,受由花岗岩和玄武岩侵入体所构成热源以热传导方式加热变成高温热水,再经该区发育的断裂、裂隙上升到浅部,并与浅层地下水混合,形成了该地热田浅部的热水储集层。根据以上分析和研究,给出该地热田的热结构模型。通过放热量法、容积法和可采集热水量的方法评价地热储量。各种不同评价法给出的资源量大体都落在200～2000KW范围内。这些评价方法中,认为依放热量法所进行的评价最粗略的话,那么可信度较高的资源量应该是以容积法和可采集热水量来评价的190～900KW。这些资源的评价中已经考虑了具有最高温度150℃的储集层的存在,因此,又发生推算的资源量大幅上浮的可能性很小。根据已有资料记载地热田实际的热水总涌出量(总抽取量)为1400～2100m3/天,若按参考假设可采热水量为1200L/min(1730m3/天)及1500L/min(2160m3/天),则与其相应的发电量计算结果分别为252～720KW和315～900KW。更多还原

【Abstract】 Geothermal energy is one of the new energy.It is of great significance for improving energy structure.With oil,coal and natural gas,geothermal resource are cheap,clean and renewable.They can be used directly. China’s total geothermal resources are 7.9% around the world, ranking second, fewer than the United States’.High temperature geothermal resources are used for power generation, whereas low-medium geothermal resources mainly for non-electrical utilization. For the correct evaluation of the geothermal fields provide a scientific basis for geothermal resources. Meanwhile, development and utilization of geothermal resources in the development of local economy and improve the level of the living conditions of local people is very important practical significance.Through survering on geological structural of Reshuizhen of Chifeng, The Yinshan faulted structure belonging to one of the oldest tectonic activities with its activities has been extended to the era of the Yanshan orogenic activity, the geological structure of this enormous influence, Bias of Balihan fracture with its main activity period is broken end of the Yanshan orogeny. The fault in the northern part of Balihan is NE - SW direction, south into north and south. Balihan fracture in the area there is about 100m wide fracture zone, and development of a secondary tensile faults and fissures. Balihan occurrence of small earthquakes is still broken, indicating the still active. In addition to the area north-south fracture outside of Balihan fracture, there is also the north west - south east and north east–SW fracture series. Geothermal field is just in the junction of the above fracture structure of north-south direction, west north- east south direction, east north– west north direction, and east- west direction, and the main passageway of hot water in geothermal field consists of these fractures, which are made up of the heat source of local spring with granite formed together with magmatism of the Yanshan orogenic movement in Mesozoic Era and basalt formed together with orogenic movement in Paleocene. And the geothermal field in research faces high and precipitous mountainous area in the west and connects with flat hilly country in the east. The dividing line of the two landforms is Balihan fracture with south- north direction, in the west it is composed of massive rocks, such as crystalline schist, gneiss, and intrusive rock of Precambrian period; while the east sunk part is covered with volcanic rocks of the Jurassic Period and accumulative rocks of the Quaternary period, and in the under part they are Precambrian rocks.The origin of main water of geothermal fluid can be gained through the analysis of the composition of hydrogen and oxygen isotope. Hot spring water samples, water samples nearby geothermal field, and circumjacent earth’s surface samples are collected respectively in the research, which are tested and analyzed for chemical composition and isotopic composition, combining the analysis of tritium concentration, you can know that the meteoric water permeating to the underground in high-altitude areas 10～20 km away from geothermal field in the west and north, and we think that this meteoric water has flown to and stayed in this geothermal field through more than eighty years. After the meteoric water permeated to the underground reaches deep part, which is heated to hot water mainly in the way of heat conduction. According to the chemical composition in hot water and data of isotope analysis, the hot-water temperatures in superficial part hot-water layer and deep part reservoir stratum are respectively 100～110℃and 140～150℃, so the hot water in local geothermal field belongs to intermediate and low temperature crevice water originated from meteoric water.In order to detect clearly the basement structure of geothermal field and the location of fault, we should conduct gravitational prospecting in this area. After correcting relevantly the measured gravity data, we get the gravity anomaly distribution in measured area, and the gravity anomaly in this area has the tendency of western high and it becomes lower to the east direction gradually. In the northwest of this researched area also appears partial unusual height. And this is identical to the Precambrian rocks in the west, subsidence in the east, and lithological characters distribution characteristics of Jurassic Period rocks. And at the same time, in order to master the thermo-tectonics and scope of geothermal field and select vantage point, we measure the earth temperature in this area with the depth of 1m and 50cm. After the amendments of the temperature measurement data, the temperature distribution map with the depth of 1m and 50cm has been drawed.The underground hot water flows from the lower part to the higher part, which can be known through ground temperature distribution map, and it leans to the southeast direction.From thermo-tectonics backgrounds, the thermal background of this area has characteristics of thick earth’s crust, low terrestrial heat flow, and low temperature within the shell. Under this kind of ground temperature, convective phenomena in the shell are difficult to be seen. Through the analysis and research of volcanic activity in this area, we can know that it is nearly impossible to form large-scale magma pocket of heat source in the geothermal field or concrete to rock mass with high temperature. In this case, we only can imagine that the heat sources of this hot water in the geothermal field are granites of Jurassic Period and tortoise rocks of the Tertiary period. Therefore, the hot-water circulation of this geothermal field is inferred as follows: meteoric water permeating to the underground deep part from the west and north mountainous area of geothermal field, to the under part of geothermal field, and heat sources that consist of granite and basalt intrusive mass become high-temperature hot water in the way of heat conduction, and it rise to the superficial area through the fracture and fissuring of this area, combining with shallow ground water, in this way, the shallow hot-water reservoir stratum is formed. Through the above analysis and research, the thermal structural model of the local geothermal field is given.The terrestrial heat reserves are evaluated with the use of heat release method, volumetric method, and collectable hot water volume method. The given resource amount by different evaluation methods in mainly in the scope of 200～2000 KW. Among these evaluation methods, if the evaluation according to heat release amount method is roughest, then the resource amount with high credibility should be 190～900 KW that is evaluated with the use of volumetric method and collectable hot water volume method. In the evaluation of these resources, the existing reservoir stratum with the highest temperature of 150℃has been considered, therefore, it is nearly impossible to occur that the computative resources amount rise. According to the record of existing data, the actual hot water total gush amount of geothermal field (total extraction amount) is 1400～2100m3/day. If the collectable hot water amount is 1200L/min (1730m3/day) and 1500L/min (2160m3/day) according to reference, then the corresponding generated energy calculation results are 252～720 KW and 315～900 KW respectively.更多还原