本文選題：頁(yè)巖氣　切入點(diǎn)：Ono-Kondo模型　出處：《地球科學(xué)》2017年08期

【摘要】：頁(yè)巖氣吸附機(jī)理的研究對(duì)于頁(yè)巖氣成藏和儲(chǔ)量評(píng)價(jià)具有重要意義.甲烷在地層溫度和壓力條件下處于超臨界狀態(tài),頁(yè)巖氣的吸附實(shí)際上為超臨界吸附,但其機(jī)理目前尚不明確.在建立Ono-Kondo格子模型的基礎(chǔ)上,結(jié)合低溫氮?dú)馕胶透邏杭淄榈葴匚綄?shí)驗(yàn),對(duì)龍馬溪組頁(yè)巖的微觀孔隙結(jié)構(gòu)和超臨界吸附曲線進(jìn)行了分析.結(jié)果表明,頁(yè)巖中發(fā)育的孔隙尺度較小,比表面積較大,吸附氣主要賦存于微孔和中孔中;頁(yè)巖的等溫吸附曲線在壓力較大時(shí),必然存在下降的趨勢(shì),這并非異常現(xiàn)象,而是超臨界甲烷過剩吸附量的本質(zhì)特征.Ono-Kondo格子模型對(duì)頁(yè)巖高壓等溫吸附曲線的擬合效果很好,相關(guān)系數(shù)均在0.99以上,說明該模型可以表征頁(yè)巖納米孔隙中超臨界甲烷的吸附特征.基于擬合得到的吸附相密度可將過剩吸附量轉(zhuǎn)換為絕對(duì)吸附量,并直接計(jì)算地層溫度和壓力下甲烷的吸附分子層數(shù),計(jì)算層數(shù)均小于1,表明甲烷分子并沒有鋪滿整個(gè)孔隙壁面.因此受流體性質(zhì)、吸附劑吸附能力和孔隙結(jié)構(gòu)3個(gè)方面的影響,頁(yè)巖氣的吸附機(jī)理為單層吸附,不可能為雙層甚至多層吸附.
[Abstract]:The study of shale gas adsorption mechanism is of great significance for shale gas reservoir formation and reserve evaluation. Methane is in supercritical state under formation temperature and pressure, and shale gas adsorption is actually supercritical adsorption. However, the mechanism is still unclear. Based on the Ono-Kondo lattice model, the micropore structure and supercritical adsorption curves of Longmaxi formation shale are analyzed by combining the experiments of nitrogen adsorption at low temperature and isothermal adsorption of methane at high pressure. The pore scale developed in shale is smaller, the specific surface area is larger, and the adsorption gas mainly occurs in micropores and mesoporous areas, and the isothermal adsorption curve of shale is bound to decrease when the pressure is high, which is not an abnormal phenomenon. But the essential characteristics of supercritical methane excess adsorption. The Ono-Kondo lattice model fits well the isothermal adsorption curve of shale at high pressure, and the correlation coefficient is above 0.99. This model can be used to characterize the adsorption characteristics of supercritical methane in shale nano-pores, and the excess adsorption capacity can be converted into absolute adsorption capacity based on the fitted adsorption phase density. The number of adsorbed molecular layers of methane under formation temperature and pressure is calculated directly, and the calculated layers are less than 1, which indicates that methane molecules are not covered with the whole pore wall. Therefore, it is affected by the fluid properties, adsorbent adsorption ability and pore structure. The adsorption mechanism of shale gas is monolayer adsorption, which can not be bilayer or even multilayer adsorption.
【作者單位】： 中國(guó)石油勘探開發(fā)研究院;國(guó)家能源頁(yè)巖氣研發(fā)(實(shí)驗(yàn))中心;中國(guó)石油非常規(guī)油氣重點(diǎn)實(shí)驗(yàn)室;
【基金】：國(guó)家重點(diǎn)基礎(chǔ)研究發(fā)展計(jì)劃(973計(jì)劃)項(xiàng)目(No.2013CB2281)
【分類號(hào)】：P618.13
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本文編號(hào)：1698271