本文選題：多孔介質(zhì) + CO_2驅(qū)油　； 參考：《大連理工大學》2015年碩士論文

【摘要】：大氣中CO2濃度升高引發(fā)的溫室效應對全球生態(tài)環(huán)境系統(tǒng)造成了極大的影響。CO2驅(qū)油(CO2-EOR)是目前有效的CO2減排方案之一。為了確保CO2驅(qū)油的經(jīng)濟性以及封存的安全性,測量油氣的最小混相壓力(MMP)是十分必要的。CO2在注入過程中以分子擴散形式進入原油中,擴散系數(shù)對驅(qū)油工程安全性評估以及整體性能預測等方面都是必要的數(shù)據(jù)。本文應用了X射線CT可視化技術(shù),研究了油氣兩相相態(tài)隨壓力的變化特性以及恒溫恒壓條件下CO2在油相中的擴散過程。提出了基于X射線CT可視化技術(shù)觀察油氣相態(tài)變化及測量最小混相壓力的方法,獲得了油氣系統(tǒng)的最小混相壓力值,并與文獻中傳統(tǒng)實驗方法測量值進行比較,驗證了CT可視化方法的可靠性。實現(xiàn)油氣相態(tài)變化過程中油相體積及接觸角的實時測量。結(jié)果表明,油相體積隨壓力的增高成指數(shù)形式增大,兩相接觸角也隨壓力增高而增大。建立了基于CT可視化技術(shù)研究多孔介質(zhì)中油氣相態(tài)變化及混相的實驗系統(tǒng),開展了多孔介質(zhì)中油氣混相過程實驗研究。分析了孔喉半徑對混相的影響。結(jié)果表明,隨著孔喉尺寸的減小,孔隙中流體受到的毛細管力增大,導致流體在多孔介質(zhì)中的界面張力增大,最終增大了多孔介質(zhì)內(nèi)油氣混相壓力。提出了一種恒溫恒壓條件下測量CO2在油中擴散系數(shù)的實驗方法。基于CT可視化技術(shù)和非迭代有限體積法,計算了CO2向油溶液中擴散過程的局部擴散系數(shù)。結(jié)果表明,CO2擴散系數(shù)沿著擴散方向逐漸降低,擴散系數(shù)隨時間減小,并且實驗中的整體擴散系數(shù)呈現(xiàn)隨時間減小、隨壓力增大趨勢。通過測量CO2在油飽和多孔介質(zhì)中的擴散系數(shù),分析了多孔介質(zhì)對CO2擴散進程的影響。結(jié)果表明,多孔介質(zhì)阻礙了CO2向油中的擴散,相比于CO2直接向純油溶液擴散,CO2在多孔介質(zhì)中的有效擴散系數(shù)明顯偏小。
[Abstract]:Greenhouse Effect caused by the increase of CO _ 2 concentration in the atmosphere has a great impact on the global ecological system. Co _ 2-EOR is one of the effective CO2 emission reduction schemes. In order to ensure the economy of CO2 flooding and the safety of oil storage, it is necessary to measure the minimum miscible pressure (MMP) of oil and gas. Diffusion coefficient is necessary for safety evaluation and overall performance prediction of oil displacement engineering. In this paper, X-ray CT visualization technique is used to study the variation characteristics of oil and gas two-phase state with pressure and the diffusion process of CO _ 2 in oil phase under constant temperature and constant pressure. Based on the X-ray CT visualization technique, a method for observing the change of oil and gas phase behavior and measuring the minimum miscible pressure is proposed. The minimum miscible pressure of oil and gas system is obtained and compared with the traditional experimental method in literature. The reliability of CT visualization method is verified. The oil phase volume and contact angle can be measured in real time. The results show that the volume of oil phase increases exponentially with the increase of pressure, and the contact angle of two phases increases with the increase of pressure. An experimental system based on CT visualization was established to study the phase change and miscibility of oil and gas in porous media and the experimental study on the process of oil and gas miscibility in porous media was carried out. The influence of pore throat radius on the misphase is analyzed. The results show that the capillary force on the pore fluid increases with the decrease of the pore throat size, which leads to the increase of the interfacial tension of the fluid in the porous medium, and finally increases the oil / gas miscible pressure in the porous medium. An experimental method for measuring the diffusion coefficient of CO _ 2 in oil under constant temperature and constant pressure is presented. Based on CT visualization technique and non-iterative finite volume method, the local diffusion coefficient of CO _ 2 diffusion to oil solution is calculated. The results show that the diffusion coefficient of CO _ 2 decreases gradually along the direction of diffusion, and the diffusion coefficient decreases with time, and the overall diffusion coefficient decreases with time and increases with pressure. By measuring the diffusion coefficient of CO _ 2 in oil-saturated porous media, the influence of porous medium on the diffusion process of CO _ 2 was analyzed. The results show that the effective diffusion coefficient of CO _ 2 in porous medium is smaller than that in pure oil solution.
【學位授予單位】：大連理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TE357.7

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本文編號：2034528