本文選題：構(gòu)造煤 + 分形維數(shù)　； 參考：《河南理工大學(xué)》2016年博士論文

【摘要】：擴(kuò)散在瓦斯運(yùn)移產(chǎn)出過(guò)程中發(fā)揮著重要作用,針對(duì)以往構(gòu)造煤瓦斯擴(kuò)散特性研究多采用顆粒煤樣和解吸擴(kuò)散法進(jìn)行,實(shí)驗(yàn)煤樣和方法不能客觀(guān)反映原始煤層物性特征和儲(chǔ)層條件,控制機(jī)理缺乏結(jié)合煤的微觀(guān)結(jié)構(gòu)分析內(nèi)外因素的耦合作用,現(xiàn)有擴(kuò)散模型存在理想化程度高、準(zhǔn)確性低、適用條件不明確等問(wèn)題,從煤層在井下的實(shí)際賦存狀態(tài)出發(fā),采用氣相色譜擴(kuò)散法和解吸擴(kuò)散法兩種擴(kuò)散系數(shù)測(cè)定方法,開(kāi)展了模擬地層條件下構(gòu)造煤瓦斯擴(kuò)散規(guī)律實(shí)驗(yàn),分析了兩種方法反映構(gòu)造煤瓦斯擴(kuò)散規(guī)律的差異性和適用性,探討了圍壓、氣壓、溫度、煤質(zhì)、煤體結(jié)構(gòu)、微觀(guān)結(jié)構(gòu)等因素對(duì)瓦斯擴(kuò)散規(guī)律影響及耦合控制機(jī)理,構(gòu)建了反映不同地層條件下的構(gòu)造煤瓦斯擴(kuò)散模型,并對(duì)新模型進(jìn)行了驗(yàn)證和應(yīng)用,論文取得了以下主要研究成果:(1)探討了四類(lèi)煤體結(jié)構(gòu)原煤柱狀煤樣制作方法,針對(duì)碎粒-糜棱煤柱狀煤樣制作困難這一難題,提出了構(gòu)造煤等靜壓制作柱狀煤樣方法。(2)采用壓汞、液氮吸附、小角X射線(xiàn)散射、掃描電鏡等方法獲取了構(gòu)造煤微觀(guān)孔裂隙的特性,提出了構(gòu)造煤全孔徑分形維數(shù)定量表征方法,為揭示構(gòu)造煤瓦斯擴(kuò)散控制機(jī)理奠定了基礎(chǔ)。①無(wú)煙煤、貧煤孔容主要集中在微孔和過(guò)渡孔,肥煤孔容主要集中在過(guò)渡孔和中孔,而孔比表面積均集中在微孔;無(wú)煙煤、貧煤、肥煤的總孔容、總比表面積、退汞效率隨破壞程度增大而增大,中值孔徑、排驅(qū)壓力隨破壞程度的增大而減小,但在不同的破壞階段,增加或減小的速率不同。②相同孔徑段,小角X射線(xiàn)散射測(cè)定的孔比表面積明顯大于液氮吸附所測(cè)結(jié)果,高出1.7~8.8倍左右,以無(wú)煙煤增幅最大,可能由封閉孔隙含量增多導(dǎo)致。③定義并提出了構(gòu)造煤全孔徑分形維數(shù)計(jì)算方法,實(shí)現(xiàn)了不同有效測(cè)試范圍內(nèi)壓汞和液氮吸附分形維數(shù)的有效統(tǒng)一,便于對(duì)構(gòu)造煤非均質(zhì)性進(jìn)行定量表征。④無(wú)煙煤、貧煤、肥煤顯微裂隙發(fā)育總數(shù)隨破壞程度的增大呈現(xiàn)先增大后減小的變化規(guī)律,以碎裂煤最為發(fā)育。(3)采用氣相色譜法對(duì)柱狀煤樣和解吸法對(duì)顆粒煤樣進(jìn)行了擴(kuò)散系數(shù)測(cè)定,研究了兩種方法反映構(gòu)造煤瓦斯擴(kuò)散規(guī)律的差異性和適用性,探討了圍壓、氣壓、溫度、破壞程度等不同地層條件下構(gòu)造煤瓦斯擴(kuò)散規(guī)律。①搭建了氣相色譜法模擬原始地層條件瓦斯擴(kuò)散系數(shù)測(cè)定試驗(yàn)平臺(tái)。②氣相色譜法采用原煤柱狀煤樣進(jìn)行測(cè)試,可同時(shí)施加有圍壓、氣壓、溫度影響,解吸法采用顆粒煤樣進(jìn)行測(cè)試,僅施加有氣壓、溫度,未考慮圍壓影響,兩種擴(kuò)散系數(shù)測(cè)定方法都反映了構(gòu)造煤的瓦斯擴(kuò)散規(guī)律,但屬于不同的地層賦存狀態(tài),兩者不能簡(jiǎn)單替代;前者主要應(yīng)用于原始煤層擴(kuò)散速率預(yù)測(cè)與評(píng)價(jià),后者主要應(yīng)用于瓦斯含量測(cè)定過(guò)程中損失量計(jì)算。③氣相色譜法測(cè)定的無(wú)煙煤、貧煤、肥煤四類(lèi)煤擴(kuò)散系數(shù)隨圍壓的增大呈現(xiàn)指數(shù)關(guān)系減小;隨氣壓的增大呈現(xiàn)指數(shù)關(guān)系增大;隨溫度的升高呈現(xiàn)指數(shù)關(guān)系增大;在相同圍壓、氣壓、溫度條件下,無(wú)煙煤、貧煤、肥煤四類(lèi)煤擴(kuò)散系數(shù)隨著破壞程度的增加呈現(xiàn)先增大后減小的變化規(guī)律;相同破壞程度煤樣隨著變質(zhì)程度增大呈現(xiàn)出先增大后減小的變化規(guī)律。④解吸法測(cè)定的無(wú)煙煤、貧煤、肥煤四類(lèi)煤擴(kuò)散系數(shù)隨氣壓的增大呈現(xiàn)指數(shù)增大;隨溫度的升高呈線(xiàn)性關(guān)系增大;在相同的氣壓和溫度條件下,無(wú)煙煤、貧煤、肥煤四類(lèi)煤擴(kuò)散系數(shù)隨著破壞程度的增加而增大;相同破壞程度煤樣隨著變質(zhì)程度增大而增大。這與氣相色譜擴(kuò)散法測(cè)定的構(gòu)造煤擴(kuò)散規(guī)律顯著不同,反映了構(gòu)造煤在不同地層條件下的瓦斯擴(kuò)散規(guī)律。(4)分析了圍壓、溫度、氣壓、煤質(zhì)、煤體結(jié)構(gòu)、微觀(guān)孔裂隙結(jié)構(gòu)等內(nèi)外因素對(duì)瓦斯擴(kuò)散規(guī)律的耦合影響及控制機(jī)理,構(gòu)建了反映不同地層條件下的構(gòu)造煤瓦斯擴(kuò)散模型,并對(duì)新模型進(jìn)行了驗(yàn)證和應(yīng)用。①溫度對(duì)不同地層狀態(tài)下構(gòu)造煤瓦斯擴(kuò)散的影響基本一致,擴(kuò)散系數(shù)均隨著溫度升高而增大,作用機(jī)理主要通過(guò)改變氣體分子的均方根速度和平均自由程。②氣壓對(duì)構(gòu)造煤擴(kuò)散規(guī)律影響,宏觀(guān)上均呈現(xiàn)擴(kuò)散系數(shù)隨氣壓升高而增大,但控制機(jī)理不同,分兩種情況,一是當(dāng)擴(kuò)散煤樣施加有圍壓影響時(shí),受力學(xué)作用、吸附作用綜合控制,其主控因素為有效應(yīng)力作用;圍壓條件下構(gòu)造煤擴(kuò)散系數(shù)具有效應(yīng)力負(fù)效應(yīng)。二是當(dāng)擴(kuò)散煤樣未施加圍壓影響,相當(dāng)于卸壓狀態(tài),氣壓主要改變吸附氣體內(nèi)外濃度差和氣體分子均方根速度和平均自由程;卸壓作用對(duì)煤樣本身的微觀(guān)孔隙結(jié)構(gòu)也會(huì)產(chǎn)生重要影響,可能導(dǎo)致部分封閉、半封閉孔隙打開(kāi)。③相同溫壓條件下,氣相色譜法測(cè)定的擴(kuò)散系數(shù)隨著變質(zhì)程度和破壞程度的增高呈現(xiàn)先增大后減小的變化規(guī)律,主要受微觀(guān)孔隙結(jié)構(gòu)和顯微裂隙共同耦合控制。解吸法測(cè)定的構(gòu)造煤擴(kuò)散系數(shù)隨著變質(zhì)程度和破壞程度的增高而增大,主要受原始孔隙結(jié)構(gòu)特征和原始微觀(guān)結(jié)構(gòu)受外界環(huán)境變化影響后再分布特征控制,其中微孔、細(xì)頸瓶孔、部分封閉孔起主導(dǎo)作用。由此可見(jiàn),兩種方法測(cè)定的擴(kuò)散系數(shù)雖然都反映了構(gòu)造煤的瓦斯擴(kuò)散特性,但關(guān)鍵控制因素不同,各有特定的適用條件,兩種方法測(cè)定的擴(kuò)散系數(shù)不能簡(jiǎn)單替代使用。④依據(jù)影響構(gòu)造煤瓦斯擴(kuò)散規(guī)律的主控因素,選擇不同的建模工具和原理,構(gòu)建了反映不同地層條件下的構(gòu)造煤瓦斯擴(kuò)散模型:基于氣相色譜法建立的構(gòu)造煤瓦斯擴(kuò)散耦合數(shù)學(xué)模型,可以實(shí)現(xiàn)對(duì)原始煤層條件下構(gòu)造煤的瓦斯擴(kuò)散系數(shù)預(yù)測(cè)與評(píng)價(jià);基于解吸法的建立的構(gòu)造煤分形-時(shí)效-Fick擴(kuò)散模型,主要應(yīng)用于瓦斯含量測(cè)定過(guò)程中損失量計(jì)算;新模型經(jīng)理論和實(shí)踐檢驗(yàn)精度較高,滿(mǎn)足生產(chǎn)要求。
[Abstract]:Diffusion is playing an important role in the process of gas migration and output. According to the previous research on the characteristics of coal gas diffusion, the particle coal sample and the desorption diffusion method are mostly used. The experimental coal samples and methods can not objectively reflect the physical characteristics and reservoir conditions of the original coal seam, and the control mechanism lacks the coupling of the microstructure analysis of the coalseam. The existing diffusion model has many problems, such as high degree of idealization, low accuracy and unclear application conditions. Starting from the actual condition of coal seam in the underground, two kinds of diffusion coefficient determination methods of gas chromatography diffusion method and desorption diffusion method are used to carry out the experiment of gas diffusion law under simulated formation conditions and analyze two kinds of methods. The method reflects the difference and applicability of the law of gas diffusion in structural coal, and discusses the influence of confining pressure, air pressure, temperature, coal quality, coal structure, microstructure and other factors on the law of gas diffusion and the mechanism of coupling control, and constructs a model of gas diffusion under different stratum conditions, which is verified and applied to the new model. The following main research results are obtained: (1) the method of producing column like coal samples for coal structure of four types of coal is discussed. In view of the difficult problem of making the clastic chype coal columnar coal, the method of making column like coal with isostatic pressure of tectonic coal is put forward. (2) using mercury pressure, liquid nitrogen adsorption, small angle X ray scattering and scanning electron microscopy to obtain the microstructure of coal. The characteristics of pore fissure, the quantitative characterization method of fractal dimension of total pore size of structural coal is put forward, which lays the foundation for revealing the mechanism of controlling the gas diffusion of structural coal. (1) anthracite coal, the pore volume of poor coal mainly concentrated in micropores and transition pores, and the pore volume of the fat coal mainly concentrated in the transition and middle holes, and the pore surface area is concentrated in the micropores; anthracite, lean coal and fertilizer The total pore volume of coal, the total specific surface area, the efficiency of mercury removal increases with the extent of damage, and the median pore size, displacement pressure decreases with the increase of damage degree, but the rate of increase or decrease is different at different stage of destruction. 2. The pore area of small angle X ray scattering measurement is obviously greater than that measured by liquid nitrogen adsorption, up to 1 About.7~8.8 times, the increase in the increase of anthracite coal is the biggest, which may be caused by the increase of closed pore content. (3) a method for calculating the fractal dimension of total pore size of structural coal is defined and proposed. The effective unification of the fractal dimension of pressure mercury and liquid nitrogen adsorption in different effective testing ranges is realized, and the quantitative characterization of the heterogeneity of structural coal is convenient. 4. Anthracite and lean coal, The total number of microfracture development of the fat coal increases first and then decreases with the increase of the damage degree. (3) the gas chromatography method is used to determine the diffusion coefficient of the cylindrical coal samples and desorption methods, and the differences and applicability of the two methods to reflect the law of gas diffusion in the tectonic coal are studied. A test platform for gas diffusion coefficient determination was built by gas chromatography to simulate the gas diffusion coefficient of original formation conditions. (2) gas chromatography was used to test the coal samples with coal column like coal, and the influence of confining pressure, air pressure, temperature, and desorption were applied at the same time. Coal samples are tested with only air pressure, temperature and no consideration of the influence of confining pressure. The two methods of determination of diffusion coefficient reflect the law of gas diffusion of the tectonic coal, but they belong to different strata, and the two can not be replaced simply. The former is mainly applied to the prediction and evaluation of the diffusion rate of the original coal seams, and the latter is mainly applied to the gas content measurement. The four types of coal diffusion coefficient of coal, poor coal and fat coal decreased exponentially with the increase of confining pressure, and increased exponentially with the increase of pressure; under the same confining pressure, pressure and temperature, the four types of coal, anthracite, lean coal and fat coal The diffusion coefficient increases first and then decreases with the increase of damage degree; the coal sample with the same damage degree increases first and then decreases with the increase of metamorphism. (4) the four types of coal diffusion coefficient of anthracite, lean coal and fat coal determined by the method of desorption increase exponentially with the increase of pressure; linear with the increase of temperature Under the same air pressure and temperature conditions, the four kinds of coal diffusion coefficient of anthracite, lean coal and fat coal increases with the increase of damage degree, and the same destruction degree increases with the degree of metamorphism. This is significantly different from the gas chromatography diffusion method for structural coal diffusion rules, which reflects the conditions of different formation coal in different formation conditions. The law of gas diffusion below. (4) the coupling influence and control mechanism of internal and external factors such as confining pressure, temperature, pressure, coal quality, coal structure, micro pore fracture structure and other internal and external factors on the law of gas diffusion are analyzed, and a model of gas diffusion in different formation conditions is constructed, and the new model is verified and applied. (1) temperature to different strata The influence of the diffusion coefficient of coal gas diffusion is basically the same, the diffusion coefficient increases with the increase of temperature. The mechanism of action is mainly by changing the root mean square velocity and the average free path of the gas molecules. 2. The influence of gas pressure on the diffusion law of the tectonic coal shows that the diffusion coefficient increases with the increase of air pressure on macro, but the control mechanism is different, two The first is that when the diffusion coal is affected by confining pressure, it is subjected to mechanical action and the adsorption is controlled synthetically. The main controlling factor is effective stress, and the structural coal diffusion coefficient has effect negative effect under confining pressure. Two is when the diffusion coal samples are not affected by confining pressure, and the pressure mainly changes the internal and external concentration of the adsorbed gas. Degree difference and the mean square root velocity and average free range of the gas molecules; the pressure relief effect also has an important effect on the micro pore structure of the coal sample itself, which may lead to partially closed and semi closed pores open. 3. The diffusion coefficient of gas chromatography is first increased and then decreased with the increase of quality and the degree of destruction under the same temperature and pressure conditions. The small change law is mainly controlled by micropore structure and microscopic fissure. The diffusion coefficient of structural coal measured by desorption increases with the increase of metamorphism degree and degree of destruction, and is mainly controlled by the redistribution characteristics of the original pore structure and the original microstructure after the changes of the external environment. It can be seen that the diffusion coefficients measured by the two methods reflect the gas diffusion characteristics of the tectonic coal, but the key control factors are different, each has the specific applicable conditions. The diffusion coefficient measured by the two methods can not be replaced simply. By choosing different modeling tools and principles, the gas diffusion model of structural coal is constructed under different stratum conditions: a mathematical model of gas diffusion coupling based on gas chromatography is established, which can be used to pre test and evaluate the gas diffusion coefficient of structural coal under the condition of original coal seam. The shape time -Fick diffusion model is mainly applied to the calculation of the loss of gas in the process of gas content determination. The new model has high accuracy in theory and practice to meet the production requirements.
【學(xué)位授予單位】：河南理工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：TD712
，

本文編號(hào)：1907632