@Article{fdmp.2025.060393,
AUTHOR = {Zhengyang Zhang, Jing Sun, Xin Shi, Dehua Liu},
TITLE = {Water Huff-n-Puff Optimization in High Saturation Tight Oil Reservoirs},
JOURNAL = {Fluid Dynamics \& Materials Processing},
VOLUME = {21},
YEAR = {2025},
NUMBER = {3},
PAGES = {509--527},
URL = {http://www.techscience.com/fdmp/v21n3/60158},
ISSN = {1555-2578},
ABSTRACT = {High saturation pressure reservoirs experience rapid pressure decline during exploitation, leading to significant changes in crude oil phase behavior and a continuous increase in viscosity after degassing, which adversely affects oil recovery. This challenge is particularly acute in tight sandstone reservoirs. To optimize the development strategy for such reservoirs, a series of experiments were conducted using core samples from a high saturation tight sandstone reservoir in the JS oilfield. Gas-dissolved crude oil was prepared by mixing wellhead oil and gas samples, enabling the identification of the critical point where viscosity changes as pressure decreases. Oil-water relative permeability experiments under varying viscosities revealed crude oil mobility trends with declining production pressure. Additionally, physical and numerical simulations of water huff-n-puff processes were performed, while nuclear magnetic resonance methods explored the effects of soaking time on oil-water imbibition. Key findings include the following optimal parameters for water huff-n-puff: (1) initiating the process when formation pressure is 75% of its original level, (2) a soaking time of 48 h, (3) an injection volume of 0.6 pore volumes per cycle, and (4) a 5 MPa pressure reduction per production stage. Numerical simulations further recommend initiating water injection after one year of depletion, with an optimal cumulative injection volume of 18,000 cubic meters, a soaking time of 10 days, and a producing pressure difference of 5 MPa.},
DOI = {10.32604/fdmp.2025.060393}
}