本文關(guān)鍵詞：干熱巖裂隙滲流—傳熱試驗及儲層模擬評價研究　出處：《吉林大學》2016年博士論文　論文類型：學位論文

  更多相關(guān)文章： 干熱巖 增強型地熱系統(tǒng) 滲流傳熱 數(shù)值模擬 室內(nèi)試驗 儲層模擬

【摘要】：自工業(yè)革命以來,能源科學的不斷發(fā)展成為推動社會進步的強大動力,人類也因此享受到前所未有的便捷與舒適生活。然而伴隨著近一個世紀以來的人口膨脹及經(jīng)濟發(fā)展,以常規(guī)化石燃料為主的能源結(jié)構(gòu)所帶來的環(huán)境負面效應(yīng)逐漸凸顯。為應(yīng)對環(huán)境問題,改善能源結(jié)構(gòu),世界各國紛紛將目光投向潛力巨大且清潔無污染的干熱巖地熱資源。干熱巖(Hot Dry Rock, HDR)是指埋藏于深部地下的低孔、低滲的高溫巖體,儲存在其中的能量需要通過人工改造形成增強型地熱系統(tǒng)(Enhanced Geothermal System, EGS)才能得以開采。干熱巖資源的開發(fā)是一個復雜的系統(tǒng)工程,需要包括巖石力學、水文地質(zhì)、地球物理、工程熱物理、鉆探等在內(nèi)的多學科相互配合。熱能開采是干熱巖開發(fā)中一個重要的課題,其本質(zhì)是換熱工質(zhì)(水或超臨界CO2)在高溫裂隙巖體中的流動換熱過程。從科學問題的角度歸納來說,主要涉及以下兩個方面：一是裂隙巖體的滲流問題；二是流體掠過巖石裂隙表面的對流換熱問題。干熱巖儲層的模擬及場地的水熱產(chǎn)出能力預測與開采方案的優(yōu)化設(shè)計是干熱巖開發(fā)中的另一個重要問題,合理預測場地的產(chǎn)熱能力對于EGS工程的規(guī)劃、設(shè)計、施工均有重要的意義。想要準確的對場地的熱產(chǎn)出能力進行評價,需要對儲層的地質(zhì)情況有充分的認識,這需要先進的地球物理手段對儲層進行探測,同時借助數(shù)值模型的手段,建立合理的儲層模型,從而獲得合理的預測值。針對上述關(guān)鍵問題,本文首先對巖石單裂隙滲流及傳熱問題開展室內(nèi)試驗研究,結(jié)合松遼盆地鶯深井區(qū)地球物理資料,分析研究區(qū)儲層天然裂隙發(fā)育情況及地應(yīng)力狀態(tài),并針對松遼盆地裂隙型火山巖儲層建立多重介質(zhì)模型,分析了場地的產(chǎn)熱特征,開展了裂隙屬性對產(chǎn)熱能力的敏感性研究。針對松遼盆地致密砂巖儲層,基于現(xiàn)場水力壓裂試驗,借助擬三維水力壓裂程序,擬合地表壓力曲線,獲得裂縫的幾何形態(tài)與導流能力分布特征,并建立包含裂縫信息的三維水熱耦合模型,對場地的產(chǎn)熱能力、能源效率、環(huán)境效應(yīng)等做出評價。裂隙滲流方面,首先開展了巖心巴西劈裂,粗糙裂隙面三維激光掃描,及掃描電鏡等基礎(chǔ)性試驗研究,后重點研究了砂巖、花崗巖平直裂隙滲流性質(zhì)、花崗巖-支撐劑系統(tǒng)的滲流性質(zhì),以及應(yīng)力歷史與應(yīng)力過程對裂隙滲流性質(zhì)的影響等。(1)花崗巖與砂巖平直裂隙滲流試驗結(jié)果表明,各級圍壓下的流量與滲透壓力基本呈現(xiàn)線性正相關(guān)關(guān)系,在低圍壓條件下,裂隙的水力開度隨滲透壓力的增大而增大；當圍壓水平較高時,裂隙的水力開度不隨滲透壓力改變。(2)裂隙-支撐劑系統(tǒng)的滲流試驗結(jié)果表明,支撐劑對于改善裂隙的滲流能力具有顯著的效果。當圍壓水平較高時,支撐劑在應(yīng)力與滲流作用下發(fā)生破碎,產(chǎn)生的碎屑堆積堵塞滲流通道,導致裂隙滲流能力下降。同時支撐劑在裂隙面的不均勻分布使得裂隙面局部受到張力作用,導致裂隙面巖體產(chǎn)生新的裂紋。(3)加、卸載圍壓下的裂隙滲流試驗結(jié)果表明,對于平直裂隙而言,循環(huán)荷載對其總體滲透能力影響不大。但在每一級加載后卸載的過程中,裂隙滲流能力的恢復存在滯后現(xiàn)象。對于粗糙裂隙來說,加載與卸載階段,裂隙的滲流能力存在量級與規(guī)律性上的差異,經(jīng)歷過加載過程的粗糙裂隙往往難以恢復初始的滲流水平。裂隙滲流傳熱研究方面,開展了巖石單裂隙滲流傳熱特性試驗研究。試驗以蒸餾水為換熱工質(zhì),采用預制平直裂隙與粗糙裂隙的花崗巖與砂巖巖樣,在不同的溫度與水流條件下,研究了巖石裂隙的流動換熱特性。同一溫度水平下,對流換熱系數(shù)的量值與流量基本成線性正相關(guān)關(guān)系。裂隙面粗糙度的存在一定程度上增大了對流換熱過程的強度,但巖性的區(qū)別對于對流換熱過程無明顯影響。裂隙面不同位置處換熱強度存在差異,粗糙度對換熱過程的影響較為顯著。根據(jù)試驗結(jié)果,擬合了Nu與Re和Pr的冪指數(shù)關(guān)系式,其基本形式為Nu=CR en Rrm。擬合結(jié)果顯示,與流體掠過光滑平板的經(jīng)驗特征數(shù)方程相比,C值基本相同,而n值范圍較經(jīng)驗值偏大,這說明巖石裂隙滲流傳熱過程與光滑平板模型相比存在差異,主要考慮為粗糙度和裂隙面材料性質(zhì)的影響。討論了松遼盆地北部地區(qū)徐家圍子干熱巖靶區(qū)的天然裂隙發(fā)育特征及地應(yīng)力狀態(tài)。對該地區(qū)天然裂隙的定量研究表明,裂縫的水力開度在0.01-1.40 mm之間,裂隙發(fā)育密度在1.57-5.18/m之間,裂縫視孔隙率在0.002-0.138%之間。對地應(yīng)力場方向的研究表明,現(xiàn)今地應(yīng)力場的最大水平主應(yīng)力方向為近東西向。地應(yīng)力大小的研究主要依據(jù)現(xiàn)場水力壓裂測試,密度測井,震源機制解釋等手段,確定出的垂向應(yīng)力,最小水平主應(yīng)力分別為96.5MPa和82MPa。確定出最大水平地應(yīng)力的下限值為96.5MPa。針對松遼盆地鶯深井區(qū)裂隙型火山巖地熱儲層,建立了基于多重介質(zhì)模型思想的數(shù)值模型,主要分析熱能開采中儲層的溫度、壓力、流體密度等的演化規(guī)律,以及裂縫參數(shù)對于產(chǎn)熱特征的影響。研究表明,在系統(tǒng)運行的初期,注入井附近裂隙單元的溫度低于基質(zhì)的溫度,但這種差異隨著與注入井距離的增大及注采循環(huán)的不斷進行而趨于消失。儲層溫度的降低導致流體密度、粘度的增大,引起注入井井底壓力的升高。裂隙屬性對儲層產(chǎn)熱特征的影響研究表明,裂隙滲透率增大會加快生產(chǎn)井溫度的降低,加快熱突破(Thermal breakthrough)的發(fā)生。但另一方面會降低注入井井底壓力,減小系統(tǒng)的流動阻抗。裂隙間隔的增大會減小注入井與生產(chǎn)井之間滲流路徑的復雜程度,減小熱交換面積,加速熱突破過程,但裂隙間隔對注入井井底壓力的影響不明顯。松遼盆地致密砂巖地熱儲層地熱能開采分析評價研究中,從干熱巖供暖的實際問題出發(fā),基于松遼盆地達深井區(qū)實際地質(zhì)資料及現(xiàn)場水力壓裂試驗,建立了擬三維水力壓裂數(shù)值模型,通過擬合模型計算的井口壓力曲線與現(xiàn)場監(jiān)測曲線,校正了模型的準確性。進而獲得了現(xiàn)場壓裂所得水力裂縫的幾何尺寸及導流能力空間分布特征。后基于壓裂所得的裂縫信息,建立了預測熱儲產(chǎn)熱能力的三維數(shù)值模型,分析了場地最大生產(chǎn)流速,溫度、壓力時空分布和產(chǎn)熱功率等。研究結(jié)果表明,熱儲合理的生產(chǎn)流速為8 kg/s,系統(tǒng)運行三十年的過程中,儲層流動阻抗保持在經(jīng)濟標準的9.78-12.32倍。在系統(tǒng)的運行過程中,生產(chǎn)井溫度由初始的112.69℃降低至第三十年的89.01℃,對應(yīng)的產(chǎn)熱功率由初始的1.96 MW降低至第三十年的1.17 MW。熱突破發(fā)生在系統(tǒng)運行的第七年,此時生產(chǎn)井溫度降幅接近10%。人工熱儲30年內(nèi)的累積產(chǎn)能為1.36×1015J,三十年內(nèi)可節(jié)約用煤5.04×107kg,減少二氧化碳排放1.18×108kg,二氧化硫排放7.75×105kg。
[Abstract]:Since the industrial revolution, the development of energy science has become a powerful driving force to promote social progress, therefore the human enjoy the hitherto unknown convenience and comfort of life. However, with nearly a century of population expansion and the development of economy, the negative environmental effect of energy structure with conventional fossil fuel based brought to cope with the increasingly prominent. The environmental problems, improve the energy structure, the world will have eyes dry and clean the huge potential of rock geothermal resources. (Hot Dry Rock, hot dry rock HDR) refers to the low hole buried deep underground rock mass, high temperature and low permeability, in which the energy storage needs through artificial modification enhanced geothermal formation the system (Enhanced Geothermal System, EGS) in order to exploit the resource of hot dry rock is a complex system engineering, including rock mechanics, hydrogeology, geophysics Science and engineering thermal physics, multidisciplinary drilling, cooperate with each other. Energy exploitation is an important topic in the development of hot dry rock, its essence is the heat transfer medium (water or supercritical CO2) at high temperature in fractured rock flow and heat transfer process. From the perspective of inductive scientific problems, mainly involving the following two one is the seepage problem of fractured rock mass; two is the convection heat transfer across the rock fracture surface. The optimization design of hot dry rock reservoir simulation and ground water heat output capacity prediction and mining plan is the hot dry rock in the development of another important problem, reasonable prediction of heat production capacity site for the EGS project planning, design, construction has important significance to accurately. On the site of the heat output ability evaluation, the geological conditions of the reservoir need to have sufficient knowledge, which requires advanced geophysical methods for reservoir Detect at the same time with the numerical model, a reservoir model is reasonable, so as to obtain a reasonable forecast value. According to the above key issues, this paper carried out experimental study on indoor single rock fracture seepage and heat transfer problems, combined with the deep zone of Songliao Basin's geophysical data analysis, reservoir natural fracture and the stress state, and the establishment of multi medium model in Songliao Basin fractured volcano rock reservoir, analyzed the heat production of the site, the sensitivity of crack attributes on the heat production capacity. The tight sandstone reservoir in Songliao Basin, the hydraulic fracturing tests based on the three-dimensional hydraulic fracturing process, fitting the surface pressure curve. The distribution geometry and conductivity characteristics of cracks, and a three-dimensional water heat coupling model contains the crack information, to heat production capacity space, energy efficiency Rate of environmental effect was evaluated. The fracture seepage, firstly carried out the core of Brazil splitting, 3D rough fracture laser scanning, basic test and scanning electron microscope, after focusing on the properties of sandstone, granite straight fracture seepage, seepage properties of granite - supporting agent system, and stress history and stress the influence of process on seepage properties. (1) of granite and sandstone straight fracture seepage test results show that the flow rate and osmotic pressure at different confining pressures linearly correlated, under low confining pressure, the increase of hydraulic crack opening with the osmotic pressure increases when the confining pressure level; when high crack hydraulic aperture with osmotic pressure change. (2) fracture seepage test results supporting agent system show that the seepage ability of proppant to improve the crack has a significant effect when the confining pressure is higher, Support agent in the role of stress and seepage is broken, the debris flow channel blockage, resulting in a decline in the seepage ability. At the same time supporting agent in the fractured surfaces of the uneven distribution of the fracture surface by local tension, leading to new cracks of rock surface. (3), seepage test results of unloading confining pressure the results indicate that for the straight fracture, the cyclic load on the overall permeability little effect. But in the process of unloading each level after loading, the seepage ability recovery lags behind. For rough fracture, loading and unloading stage, differences in magnitude and regularity on the seepage capacity of fissure seepage the level of experienced rough fracture loading process is often difficult to recover. The initial research for flow and heat transfer in fissures, carried out experimental study on heat transfer characteristics of single fracture rock test with distilled water. As the heat transfer medium, the granite and sandstone samples with prefabricated straight fracture crack, temperature and flow in different conditions, the research of rock fracture flow and heat transfer characteristics. Under the same temperature level, the convective heat transfer coefficient values of a linear positive correlation with the surface roughness of fissure flow. There is a certain extent increase the intensity of convective heat transfer, but the difference of lithology on the heat transfer process has no obvious effect. Fracture surfaces at different positions of heat transfer intensity differences, the roughness effect on the heat transfer process is significant. According to the test results, the exponential relationship between Nu and Re and Pr were fitted. The basic form of Nu=CR en Rrm. fitting results show that compared with the past experience of the characteristics of flat smooth fluid equations, the C value is basically the same, but the n value range is the experience value is too large, the rock seepage heat transfer through Cheng Yuguang The sliding plate model compared with the differences, mainly consider the effect of crack surface roughness and material properties were discussed. The development characteristics and stress state of natural fracture in the North Songliao Basin Xujiaweizi dry rock target area. The quantitative research on the natural fractures in the area showed that the crack hydraulic aperture in 0.01-1.40 between mm, fracture the density between 1.57-5.18/m, fracture porosity in 0.002-0.138%. Research on the stress field direction shows that the maximum horizontal in-situ stress field and the principal stress direction is nearly east-west. Study on the basis of field test of hydraulic fracturing, the stress size density logging, focal mechanism explanation and other means to determine the vertical stress, minimum the horizontal principal stress are respectively 96.5MPa and 82MPa. determine the limit of maximum horizontal stress value is 96.5MPa. in Songliao Basin deep fractured zone warbler volcano rock heat Reservoir numerical model is established based on the idea of multi medium model, the main thermal analysis of mining reservoir temperature, pressure, evolution of fluid density, and fracture parameters influence the thermogenic characteristics. The results show that in the early stage of system operation, the injection wells near the fracture unit temperature is lower than the temperature of a substrate. But the difference with the increase of injection and injection well distance mining cycle continuously and tends to disappear. To reduce the temperature of the reservoir causes the fluid density, viscosity increases, increase the injection well bottom hole pressure. Fracture property indicates that the reservoir characteristics of heat production of fracture permeability increases will reduce the temperature and speed up the production wells the accelerated thermal breakthrough (Thermal breakthrough) occurred. But on the other hand will reduce the injection well bottom pressure, flow resistance decrease system. The increase will reduce the fracture interval and injection wells The complexity of the production well between the seepage path, reduce the heat exchange area, accelerate the heat breakthrough process, but the influence of crack spacing on injection well bottom pressure is not obvious. Mining analysis and evaluation research of tight sandstone geothermal geothermal reservoir in Songliao Basin, starting from the actual problem of heating hot dry rock, Songliao Basin of deep well hydraulic fracturing zone test the actual geological data and field based on a quasi three-dimensional numerical model of hydraulic fracturing, by fitting the model to calculate the wellhead pressure curve and field monitoring curve correction, the accuracy of the model. The spatial distribution characteristics of geometric dimensions of fracturing and hydraulic fracture conductivity and the fracture information. After fracturing is established based on the a three-dimensional numerical model for predicting the thermal storage heat production capacity, analysis of the maximum production rate, temperature field, pressure distribution and heat power. The research results The reservoir reasonable production rate was 8 kg/s, the process of system operation in thirty years, the reservoir flow impedance is maintained at 9.78-12.32 times of economic standard. In the process of running the system, the temperature of production well is reduced from the initial temperature of 112.69 to thirtieth years of 89.01 DEG C, corresponding to the production of thermal power from the initial 1.96 MW reduced to thirtieth years in 1.17 MW. thermal break occurred in the system for seventh years, the cumulative capacity of production wells temperature decline of nearly 10%. artificial reservoir in 30 years is 1.36 * 1015J, thirty years can save coal 5.04 * 107kg, to reduce carbon dioxide emissions of sulfur dioxide emissions of 1.18 * 108kg, 7.75 * 105kg.

【學位授予單位】：吉林大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：P314
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本文編號：1364454