Liu Dongdong, Wang Yefei, Liang Hao, Li Gang
National Key Laboratory of Deep Oil and Gas, China University of Petroleum (East China), Qingdao 266580, China.
Key Laboratory of Unconventional Oil and Gas Development (China University of Petroleum (East China)), Ministry of Education, Qingdao 266580, China.
ACS Omega. 2024 Jul 16;9(30):33044-33054. doi: 10.1021/acsomega.4c04144. eCollection 2024 Jul 30.
Due to the fact that more conventional heavy oil recovery methods (heating, emulsification, dilution, and other methods) have many shortcomings, they cannot meet the demand of heavy oil exploitation. Therefore, there is a need for new recovery methods. In this paper, the surface of nano SiO was modified with a silane coupling agent, KH-560, to prepare a nanoviscosity reducer (NRV), which has high-temperature resistance (300 °C), calcium and magnesium resistance (Ca + Mg > 900 mg/L) and high viscosity reduction rate (>99%). FTIR and SEM measurements showed that KH560 has been successfully connected to the surface of SiO. The particle size distribution of NRV is mainly distributed in 50-80 nm, which matches the results of SEM. The experimental results showed that the viscosity reduction rates of 1 wt % NRV on M-1 heavy oil before and after aging were 99.73% and 99.71%, respectively. The viscosity reduction effect of 1% NRV on M-1 heavy oil and the bleeding rate of emulsion formation were investigated when the oil-water ratio ranged from 9:1 to 1:9. The results showed that when the oil-water ratio was between 7:3 and 1:9, the viscosity reduction rate was greater than 99%. Besides, the bleeding rate of emulsion increases with the decrease of the oil-water ratio. What's more, static and dynamic adsorption experiments showed that the adsorption capacity of 1 wt % NRV was 1.746 mg/g and 1.668 mg/g sand, respectively. The interfacial tension experiment showed that the interfacial tension (IFT) between 1 wt % NRV and M-1 heavy oil was 0.052 mN/m, and low interfacial tension was beneficial to displace the oil in the formation pores. At the same time, the displacement effect of NRV on M-1 heavy oil at different concentrations (0.5, 1.0, and 1.5 wt %) and temperatures (200, 250, and 300 °C) was investigated by core flooding experiments. The results showed that the recovery rate increases with the increase of NRV concentration, and 1 wt % NRV at 300 °C will improve the recovery rate of M-1 heavy oil by 27.3% compared to steam flooding. NRV could reduce the viscosity of crude oil, which provides technical guidelines for the exploitation of heavy oil and extra heavy oil.
由于较为传统的稠油开采方法（加热、乳化、稀释等方法）存在诸多缺点，无法满足稠油开采的需求。因此，需要新的开采方法。本文采用硅烷偶联剂KH-560对纳米SiO表面进行改性，制备了一种具有耐高温（300℃）、耐钙镁（Ca+Mg>900mg/L）和高降粘率（>99%）的纳米降粘剂（NRV）。傅里叶变换红外光谱（FTIR）和扫描电子显微镜（SEM）测量结果表明，KH560已成功连接到SiO表面。NRV粒径分布主要集中在50-80nm，与SEM结果相符。实验结果表明，1wt%NRV对老化前后M-1稠油的降粘率分别为99.73%和99.71%。研究了油水比在9:1至1:9范围内时，1%NRV对M-1稠油的降粘效果及乳液形成的析水率。结果表明，当油水比在7:3至1:9之间时，降粘率大于99%。此外，析水率随油水比的降低而增加。而且，静态和动态吸附实验表明，1wt%NRV的吸附量分别为1.746mg/g和1.668mg/g砂。界面张力实验表明，1wt%NRV与M-1稠油之间的界面张力（IFT）为0.052mN/m，低界面张力有利于驱替地层孔隙中的原油。同时，通过岩心驱替实验研究了不同浓度（0.5、1.0和1.5wt%）和温度（200、250和300℃）下NRV对M-1稠油的驱替效果。结果表明，采收率随NRV浓度的增加而提高，300℃下1wt%NRV相比蒸汽驱可将M-1稠油采收率提高27.3%。NRV能够降低原油粘度，为稠油和超稠油的开采提供了技术指导。
