Mathematical modeling of gravity and buoyancy effect on low IFT spontaneous imbibition in tight oil reservoirs

AIChE Journal ◽  
2021 ◽  
Author(s):  
Fuyong Wang ◽  
Jiuyu Zhao
Keyword(s):  
Mathematical Modeling ◽  
Spontaneous Imbibition ◽  
Oil Reservoirs ◽  
Tight Oil ◽  
Buoyancy Effect ◽  
Tight Oil Reservoirs

Investigations on spontaneous imbibition and the influencing factors in tight oil reservoirs

Fuel ◽  
2019 ◽  
Vol 236 ◽  
pp. 755-768 ◽  
Author(s):  
Wang Jing ◽  
Liu Huiqing ◽  
Qian Genbao ◽  
Peng Yongcan ◽  
Gao Yang
Keyword(s):  
Influencing Factors ◽  
Spontaneous Imbibition ◽  
Oil Reservoirs ◽  
Tight Oil ◽  
Tight Oil Reservoirs

Experimental Study on Spontaneous Imbibition of CO2-Rich Brine in Tight Oil Reservoirs

2019 ◽  
Vol 33 (8) ◽  
pp. 7604-7613
Author(s):  
Yongqiang Tang ◽  
Rui Wang ◽  
Zihao Li ◽  
Maolei Cui ◽  
Zengmin Lun ◽  
...  
Keyword(s):  
Experimental Study ◽  
Spontaneous Imbibition ◽  
Oil Reservoirs ◽  
Tight Oil ◽  
Tight Oil Reservoirs

scholarly journals Nuclear Magnetic Resonance Measurement of Oil and Water Distributions in Spontaneous Imbibition Process in Tight Oil Reservoirs

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3114 ◽  
Author(s):  
Xiangrong Nie ◽  
Junbin Chen
Keyword(s):  
Magnetic Resonance Imaging ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Spontaneous Imbibition ◽  
Oil Reservoirs ◽  
Tight Oil ◽  
Resonance Imaging ◽  
The Core ◽  
Tight Oil Reservoirs ◽  
Nuclear Magnetic

Spontaneous imbibition of water into tight oil reservoirs is considered an effective way to improve tight oil recovery. We have combined testing techniques such as nuclear magnetic resonance, mercury injection capillary pressure, and magnetic resonance imaging to reveal the distribution characteristics of oil and water during the spontaneous imbibition process of tight sandstone reservoir. The experimental results were used to describe the dynamic process of oil–water distribution at the microscopic scale. The water phase is absorbed into the core sample by micropores and mesopores under capillary forces that dry away the original oil phase into the hydraulically connected macropores. The oil phase entering the macropores will drive away the oil in place and expel the original oil from the macropores. The results of magnetic resonance imaging clearly show that the remaining oil accumulates in the central region of the core because a large amount of water is absorbed in the late stage of spontaneous imbibition, and the water in the pores gradually connects to form a “water shield” that blocks the flow of the oil phase. We propose the spontaneous imbibition pathway, which can effectively explain the internal mechanisms controlling the spontaneous imbibition rate. The surface of the core tends to form many spontaneous imbibition pathways, so the rate of spontaneous imbibition is fast. The deep core does not easily form many spontaneous imbibition pathways, so the rate of spontaneous imbibition is slow. This paper reveals the pore characteristics and distribution of oil and water during the spontaneous imbibition process, which is of significance for the efficient development of tight oil.

scholarly journals Experimental Study on the EOR Performance of Imbibition and Huff and Puff in Fractured Tight Oil Reservoirs

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 1) ◽  
Author(s):  
Zilin Zhang ◽  
Bo Huang ◽  
Liang Zhang ◽  
Guangqing Zhou ◽  
Yanhui Liu ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Oil Recovery ◽  
Mass Transfer Rate ◽  
Spontaneous Imbibition ◽  
Oil Reservoirs ◽  
Recovery Factor ◽  
Co2 Injection ◽  
Tight Oil ◽  
Core Flooding ◽  
Tight Oil Reservoirs

Abstract Injection of imbibition fluids or CO2 during hydraulic fracturing is an effective stimulation method for tight oil reservoirs. Selecting appropriate agents is significant to optimize the integrated scheme of fracturing and production in tight oil reservoirs. In this study, a series of lab experiments, including spontaneous imbibition, dynamic imbibition, and huff and puff, were carried out using real tight cores, water absorption apparatus, and core flooding equipment. The EOR performances of imbibition fluids and CO2 in fractured tight cores were compared. The mass transfer of imbibition fluids and CO2 in tight oil reservoirs and its influence on the sweeping volume and EOR mechanisms were discussed. The results show that (1) the spontaneous imbibition rate of imbibition fluids in tight cores is slow, and the oil recovery factor by spontaneous imbibition in cracked cores is relatively high, up to 13.42%. (2) In the dynamic imbibition experiments, the final oil recovery by CO2 injection was significantly higher than that by injecting imbibition liquids. Because of the excellent miscibility effect of CO2, oil production by CO2 injection mainly occurred in the primary displacement stage. Comparatively, the EOR effect of imbibition fluids mainly played its role during production after well shut-in, which can increase the oil recovery factor by 7.35%-11.64%. (3) The influence of the huff and puff mode of CO2 on EOR performance is greater than that of imbibition fluids due to its more sensitive compressibility and mass transfer rate. Generally, a high oil recovery factor can be obtained if the depletion production is conducted first, and a huff and puff operation is followed. (4) Comprehensively understanding the mass transfer characteristics of CO2 and imbibition fluids in tight oil reservoirs can guide the fracturing parameter design, such as the order of fracturing fluid slugs, the optimal soak time, and fracture spacing.

Facile Fabrication of Nanoemulsions through the Efficient Catanionic Surfactants for Spontaneous Imbibition in Tight Oil Reservoirs: Experimental and Numerical Simulation

2021 ◽  
Author(s):  
Bing Wei ◽  
Runxue Mao ◽  
Haoran Tang ◽  
Lele Wang ◽  
Dianlin Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Oil Recovery ◽  
Surfactant Solution ◽  
Spontaneous Imbibition ◽  
Oil Reservoirs ◽  
Wettability Alteration ◽  
Tight Oil ◽  
Catanionic Surfactants ◽  
The Matrix ◽  
Tight Oil Reservoirs

Abstract Spontaneous imbibition (SI) is an essential method for accelerating mass exchange between fracture and matrix in tight oil reservoirs. However, conventional systems such as brine and surfactant solution have limited imbibition effects, so there is still abundant remaining oil in the matrix. Nanoemulsion holds the most promising potential in improving tight oil recovery owing to the favorable surface activity and nanoscale droplets, but it still lacks economic and facile methods to fabricate nanoemulsions. Therefore, in this paper, we prepared a kind of O/W nanoemulsion of catanionic surfactants with a low dosage of surfactant and energy consumption, which was then used to assess spontaneous imbibition performance in Changqing outcrop cores by experimental and numerical simulation. We have fully considered the possible imbibition mechanisms of nanoemulsion including wettability alteration, IFT reduction, solubilization and emulsification, etc., and successfully applied to the nanoemulsion imbibition model. The model and experimental data were found to be in good agreement. The results showed that the imbibition rate and oil recovery factor of the nanoemulsion in the first 100 hours are lower than that of brine. In the late stage, we observed a longer equilibrium time and a faster and higher oil imbibition process in nanoemulsion with ultralow IFT. Finally, we confirmed that solubilization and emulsification is one of the domiant mechanisms for nanoemulsion imbibition by comparing with the modelling without considering solubilization and emulsification.

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