Development of low permeability carbonate reservoirs presents challenges associated with the original structure of such reservoirs and complex molecular and mass processes, which take place in their porous & fractured structure during reservoir and injected fluids flow. With available commercial technologies (in PJSC TATNEFT) based on hot water injection and surfactant flooding oil recovery factors in such reservoirs do not exceed 0.25. One of the key factors responsible for efficiency of oil recovery from carbonate rocks is surface wettability of capillary porous rock space. It has been demonstrated previously, that application of ion-modified water enables efficient adjustment of surface wettability in carbonate rocks [1 - 4]. This can be attributed primarily to high affinity of Ca2+, Mg2+ and SO4 2- to carbonate rock surface. In addition to that, the temperature of flowing fluids has a significant impact on changes of surface wettability in fractured and porous rocks and increase in displaced oil mobility (due to oil viscosity reduction). The paper describes fluid flow experiments with ion-amended fresh process water conducted at high temperatures (75оС) on Bashkirian core samples from Akanskoye field. The results suggest high efficiency of ionamended fresh water for enhancing oil recovery from low-permeability carbonate rocks.
hot waterflooding, hot smart water, wettability, oil recovery, oil recovery factor
1. The Adverse Effect of Monovalent Ions on Wettability Alteration Rate. A Case Study on Akanskoe Reservoir in Russia –Tatarstan. M. Rezaei Koochi. A. Shakirov. 2018 Saint Petersburg, EAGE.
2. Water‐based EOR by "Smart Water": Optimal ionic composition for enhanced oil recovery in carbonates. S.J. Fathi, T. Austad, and S. Strand. (2011). Energy & Fuels (in press).
3. "Smart Water" as wettability modifier in chalk: The effect of salinity and ionic composition.
4. "Smart water" for oil recovery from fractured limestone ‐ A preliminary study. S. Strand, T. Austad, T. Puntervold, E.J. Hognesen, M. Olsen, and S.M.F. Barstad. (2008). Energy & Fuels, 22.
Rezaei Koochi Mojtaba, PhD candidate, Kazan (Volga Region) Federal University, Kazan, republic of Tatarstan, Russia E-mail:
Gubaidullin F.A., PhD, Associate Professor, Department for Development and Operation of Hard-to-Recovery Oil and Gas Fields, Institute of Geology and Petroleum Technologies, Kazan (Volga Region) Federal University, Kazan, republic of Tatarstan, Russia E-mail:
M. Rezaei Koochi, F.A. Gubaydullin Primenenie ionno-modificirovannoj vody dlja uvelichenija nefteotdachi iz nizkopronicaemyh karbonatnyh kollektorov [Application of ion-modified water to enhance oil recovery from low-permeability carbonate reservoirs]. Neftyanaya Provintsiya, No. 1(13), 2018. pp. 100-109. https://doi.org/10.25689/NP.2018.2.100-109 (in Russian)