本文選題：液氮溶浸 + 裂隙擴(kuò)展��； 參考：《河北科技大學(xué)》2015年碩士論文

【摘要】：隨著我國的經(jīng)濟(jì)持續(xù)快速發(fā)展,所需的各種能源也不斷增加。所以加大非常規(guī)能源如:煤層氣的開發(fā)及利用是非常必要的。但煤層氣儲(chǔ)層都是低孔低滲透,所以在開采時(shí)需要人工造縫或使用壓裂技術(shù)來改造儲(chǔ)層使其增大滲透性以便于開采。在國家自然科學(xué)基金項(xiàng)目(51574139,51274079)資助下,本文通過液氮溶浸不同飽水度煤樣的實(shí)驗(yàn),觀察記錄溶浸前后煤樣的微觀、表觀裂隙變化率?,波速變化率?等指標(biāo),分析不同飽水度對于液氮低溫凍卻作用下對煤樣致裂的影響。并對煤樣進(jìn)行二次凍融,再次比對煤樣1次溶浸與2次溶浸后各項(xiàng)指標(biāo)的變化。分析得出(1)在液氮溶浸后,原煤內(nèi)原生裂隙擴(kuò)展并有新生裂隙萌生。(2)煤樣的含水率對液氮溶浸的效果有很大影響,飽和試樣在溶浸前后的裂隙面積變化和波速變化比干燥和自然含水率兩組煤樣要明顯。(3)煤樣二次溶浸后比第一次溶浸的效果明顯,有些煤樣在進(jìn)行二次溶浸后碎裂。這表明經(jīng)反復(fù)凍融可以加劇煤樣內(nèi)部結(jié)構(gòu)改變。運(yùn)用斷裂力學(xué)方法,分析液氮凍卻下原生裂隙擴(kuò)展,結(jié)果表明在液氮冷卻作用下,煤裂隙中當(dāng)應(yīng)力強(qiáng)度因子與斷裂韌度相等時(shí),煤裂隙發(fā)生擴(kuò)展。若應(yīng)力強(qiáng)度因子達(dá)不到裂隙的斷裂韌度,煤裂隙不擴(kuò)展。應(yīng)用FLAC軟件構(gòu)建模型,分析鉆孔煤注入液氮后凍卻儲(chǔ)層的滲透率演化。模擬發(fā)現(xiàn)在煤層注入液氮后會(huì)在鉆孔附近出現(xiàn)0.16米的拉伸破壞帶。在拉伸破壞區(qū)域,裂紋萌生和擴(kuò)展,煤元的滲透性顯著增加。
[Abstract]:With the sustained and rapid development of China's economy, the amount of energy needed is increasing. Therefore, it is necessary to increase the development and utilization of unconventional energy such as CBM. But the coalbed methane reservoirs are all low porosity and low permeability, so artificial fracturing or fracturing technology is needed to improve the permeability of the reservoirs in order to facilitate exploitation. Supported by the project of National Natural Science Foundation of China 51574139 (51274079), this paper observed and recorded the microscopic, apparent fracture rate and wave velocity change rate of coal samples before and after leaching by liquid nitrogen leaching experiments with different saturated degree coal samples. The effects of different saturation degrees on the cracking of coal samples under the action of liquid nitrogen cryopreservation were analyzed. The coal samples were frozen and thawed again, and the changes of the indexes after 1 and 2 times leaching of coal samples were compared again. The results show that the water content of coal samples has a great influence on the effect of liquid nitrogen leaching after liquid nitrogen leaching, the primary cracks in the raw coal extend and the new fissures sprout. 2) the moisture content of the coal sample has a great influence on the effect of liquid nitrogen leaching. The change of fracture area and wave velocity of saturated samples before and after leaching is more obvious than that of two groups of coal samples: drying and natural moisture content.) the effect of secondary leaching of saturated samples is more obvious than that of the first. Some coal samples are cracked after secondary leaching. This indicates that repeated freezing and thawing can aggravate the internal structural changes of coal samples. By using the method of fracture mechanics, the primary crack propagation under liquid nitrogen freezing is analyzed. The results show that when the stress intensity factor and fracture toughness are equal to each other, the coal fissure expands under the action of liquid nitrogen cooling. If the stress intensity factor does not reach the fracture toughness of the fracture, the coal fracture does not extend. The permeability evolution of frozen reservoir after injection of liquid nitrogen from borehole coal was analyzed by using FLAC software. It is found that the tensile failure zone of 0.16 meters will appear near the borehole after injecting liquid nitrogen into the coal seam. In the tensile failure zone, the crack initiation and propagation increase the permeability of coal element significantly.
【學(xué)位授予單位】：河北科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TE37

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 張春會(huì);李偉龍;王錫朝;王來貴;李和萬;;液氮溶浸煤致裂的機(jī)理研究[J];河北科技大學(xué)學(xué)報(bào);2015年04期

2 張春會(huì);王來貴;趙全勝;李偉龍;;液氮冷卻煤變形-破壞-滲透率演化模型及數(shù)值分析[J];河北科技大學(xué)學(xué)報(bào);2015年01期

3 奚家米;楊更社;龐磊;呂曉濤;劉方路;;低溫凍結(jié)作用下砂質(zhì)泥巖基本力學(xué)特性試驗(yàn)研究[J];煤炭學(xué)報(bào);2014年07期

4 于永江;張春會(huì);趙全勝;王來貴;;承載圍巖滲透率演化模型及數(shù)值分析[J];煤炭學(xué)報(bào);2014年05期

5 蔡承政;李根生;黃中偉;沈忠厚;王海柱;田守]，

本文編號(hào)：1857012