Abstract
With the growing demand for oil energy and a decrease in the recoverable reserves of conventional oil, the development of viscous oil, bitumen, and shale oil is playing an important role in the oil industry. Bohai Bay in China is an offshore oilfield that was developed through polymer flooding process. This study investigated the pore-scale displacement of medium viscosity oil by hydrophobically associating water-soluble polymers and purely viscous glycerin solutions. The role and contribution of elasticity on medium oil recovery were revealed and determined. Comparing the residual oil distribution after polymer flooding with that after glycerin flooding at a dead end, the results showed that the residual oil interface exhibited an asymmetrical “U” shape owing to the elasticity behavior of the polymer. This phenomenon revealed the key of elasticity enhancing oil recovery. Comparing the results of polymer flooding with that of glycerin flooding at different water flooding sweep efficiency levels, it was shown that the ratio of elastic contribution on the oil displacement efficiency increased as the water flooding sweep efficiency decreased. Additionally, the experiments on polymers, glycerin solutions, and brines displacement medium viscosity oil based on a constant pressure gradient at the core scale were carried out. The results indicated that the elasticity of the polymer can further reduce the saturation of medium viscosity oil with the same number of capillaries. In this study, the elasticity effect on the medium viscosity oil interface and the elasticity contribution on the medium viscosity oil were specified and clarified. The results of this study are promising with regard to the design and optimum polymers applied in an oilfield and to an improvement in the recovery of medium viscosity oil.
Highlights
According to BP’s “Statistical Review of World Energy” data, oil prices have decreased from 2014 [1,2,3]
Based on many different experiments, some researchers have come to believe that viscous oil with a viscosity of below 100 mPa·s and an oil saturation of above 30% is suitable for polymer flooding technique to enhance oil recovery (EOR); the permeability of the reservoir is above 20 × 10−3 μm2, the thickness of the oil layers is above 3 m, and the temperature of the reservoir is under 90°C [16,17,18,19,20]
The purpose of this study is to reveal the mechanism of elastic polymer enhancing medium viscosity oil recovery and identify the quantitative contribution of elasticity on the oil recovery
Summary
According to BP’s “Statistical Review of World Energy” data, oil prices have decreased from 2014 [1,2,3]. The viscous oil is mainly distributed in many basins, especially in the region of Middle East, North America, and South America [7, 8]. The popular development technique of heavy oil is thermal process; it is limited by many factors. The polymer flooding is the other main technique for exploiting heavy oil. Amirian et al reviewed the half-century heavy oil polymer flooding application, including the universal country distribution, polymer types, development effects, onshore or offshore projects, and well types [11]. In China, viscous oil is a rich resource, mainly distributed in the Liaohe oilfield, Shengli oilfield, and Bohai offshore oilfield [12,13,14,15]. Sheng et al presented that there are nine oilfields in the world that have
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
