本文關(guān)鍵詞：超臨界流體萃取致密介質(zhì)中原油的可行性研究　出處：《西南石油大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 致密油 孔隙介質(zhì) 超臨界CO_2萃取 萃取率 傳質(zhì)

【摘要】：致密油是指夾在或緊鄰優(yōu)質(zhì)生油層系的致密碎屑巖或者碳酸鹽巖儲(chǔ)層中,沒有經(jīng)過長距離運(yùn)移而形成的石油聚集,在中國陸相沉積盆地分布廣泛,已在鄂爾多斯、松遼、準(zhǔn)噶爾等盆地獲得一些重要發(fā)現(xiàn)。它的自然能量一般很小,原油性質(zhì)比較好,主要以輕質(zhì)原油為主,地下流動(dòng)狀況比較好。致密油的賦存狀態(tài)主要表現(xiàn)在三個(gè)方面：一是原油以薄膜狀涂抹在顆粒的表面；二是原油以短柱狀集合體發(fā)育于顆粒間微孔內(nèi),相互粘連；三是原油黏結(jié)于裂縫兩壁。致密油藏,由于其儲(chǔ)層巖性致密、滲流阻力大、壓力傳導(dǎo)能力差,導(dǎo)致油藏有效驅(qū)替系統(tǒng)難以建立。 超臨界CO2具有強(qiáng)滲透性和對(duì)有機(jī)物的高溶解能力,它可滲透到致密基質(zhì)中溶解原油,在不能建立有效驅(qū)替情況下,利用其對(duì)原油的抽提(萃取)作用開采原油。首先,超臨界流體溶解原油分子依靠分子的擴(kuò)散作用進(jìn)入到儲(chǔ)層的基質(zhì)中,和基質(zhì)里面的原油發(fā)生傳質(zhì)作用,使原油溶解于超臨界流體中；溶解后的原油,通過超臨界流體很強(qiáng)的滲透力,使其通過孔道擴(kuò)散出來,在這個(gè)過程中,實(shí)現(xiàn)了超臨界流體與原油兩者之間的交換。超臨界CO2兼有氣液兩相的雙重特點(diǎn),既具有與氣體相當(dāng)?shù)母邤U(kuò)散系數(shù)和低粘度,又具有與液體相近的密度和對(duì)物質(zhì)良好的溶解能力,表現(xiàn)出極好的溶解性、傳遞性和流動(dòng)性。把在其他領(lǐng)域應(yīng)用成熟的超臨界流體萃取技術(shù)運(yùn)用到致密介質(zhì)中原油的萃取,為建立此類原油的開采技術(shù)的可行性提供指導(dǎo)。 論文分析了常規(guī)流體萃取固體物料的機(jī)理,在溶劑化締合觀點(diǎn)的基礎(chǔ)之上,提出了超臨界流體締合萃取機(jī)理,建立了超臨界締合萃取固態(tài)物料的數(shù)學(xué)模型。通過對(duì)建立的萃取數(shù)學(xué)模型進(jìn)行分析求解,得到了宏觀萃取速率的數(shù)學(xué)方程；并對(duì)所建立的數(shù)學(xué)模型進(jìn)行了實(shí)驗(yàn)驗(yàn)證。發(fā)現(xiàn)在30min-120min時(shí)間范圍內(nèi),宏觀萃取速率逐漸減小；在120min-180min的時(shí)間段內(nèi),宏觀萃取速率基本保持不變。 在了解致密油儲(chǔ)層物性的基礎(chǔ)之上,通過實(shí)驗(yàn)對(duì)超臨界CO2萃取飽和油巖心的規(guī)律進(jìn)行了深入研究,并分析了各個(gè)參數(shù)對(duì)萃取率的影響規(guī)律。研究表明：萃取飽和油巖心時(shí),萃取率隨著壓力的增加而增大,并且在臨界點(diǎn)附近增大得最快；溫度對(duì)萃取率的影響比較復(fù)雜,會(huì)出現(xiàn)萃取率減小的情況；萃取率會(huì)隨著浸泡時(shí)間和循環(huán)時(shí)間的延長而增大,120min達(dá)到最好,最后基本都不再增加。實(shí)驗(yàn)條件下得到的最優(yōu)參數(shù)方案為：壓力20MPa、溫度50℃、浸泡時(shí)間120min、循環(huán)時(shí)間150min,此時(shí)萃取率將會(huì)達(dá)到最大。和普通溶劑的洗油率相比,超臨界C02萃取的效率具有很大優(yōu)勢(shì)。
[Abstract]:Dense oil is a kind of petroleum accumulation which is not formed by long distance migration and is widely distributed in continental sedimentary basins of China because of the tight clastic rock or carbonate reservoir which is sandwiched in or adjacent to the high quality oil source system. Some important discoveries have been made in Ordos, Songliao and Junggar basins. Its natural energy is generally very small, and its crude oil properties are relatively good, mainly light crude oil. The occurrence of dense oil is mainly shown in three aspects: first, the crude oil is smeared on the surface of particles in the form of thin film; Second, the crude oil develops in the micropore between the particles with short columnar aggregates and adheres to each other; The third is that the crude oil is bonded to the fractured two walls. Because of its tight lithology, large seepage resistance and poor pressure conductivity, it is difficult to establish an effective displacement system in a tight reservoir. Supercritical CO2 has strong permeability and high solubility to organic matter, it can permeate into dense matrix to dissolve crude oil, without establishing effective displacement. Firstly, the molecules of supercritical fluid dissolved crude oil enter into the reservoir matrix by molecular diffusion, and the crude oil in the matrix has mass transfer. Dissolving crude oil in supercritical fluids; The dissolved crude oil diffuses through the pores through the strong permeability of the supercritical fluid, and in the process. The exchange between supercritical fluid and crude oil has been realized. Supercritical CO2 has the dual characteristics of gas-liquid two-phase, which has high diffusion coefficient and low viscosity. It also has similar density to liquid and good solubility to substance, showing excellent solubility. The application of mature supercritical fluid extraction technology in other fields to the extraction of crude oil in dense medium provides guidance for the feasibility of establishing the extraction technology of this kind of crude oil. In this paper, the mechanism of conventional fluid extraction of solid materials is analyzed, and the supercritical fluid association extraction mechanism is proposed on the basis of solvation association theory. The mathematical model of supercritical association extraction of solid material was established, and the mathematical equation of macro extraction rate was obtained by analyzing and solving the mathematical model of extraction. The experimental results show that the macroscopic extraction rate decreases gradually in the range of 30min-120min. In the period of 120 min-180 min, the macro extraction rate remained basically unchanged. On the basis of understanding the physical properties of tight oil reservoir, the rule of supercritical CO2 extraction of saturated core is studied through experiments. The influence of various parameters on extraction rate is analyzed. The results show that the extraction rate increases with the increase of pressure and increases fastest near the critical point. The influence of temperature on the extraction rate is complex and the extraction rate will decrease. With the increase of immersion time and cycle time, the extraction rate will reach the best value for 120min, and no increase will be achieved in the end. The optimum parameters under the experimental conditions are as follows: pressure 20MPa. When the temperature is 50 鈩，

本文編號(hào)：1416541