About role of capillary impregnation in oil recovery from carbonate reservoirs from the example of subsalt oil deposits in the Pripyatskiy trough

A factor influencing the effectiveness of CO2 injection is miscibility. Besides the miscible injection, CO2 may also contribute to oil recovery improvement by immiscible injection through modifying several properties such as oil swelling, viscosity reduction, and the lowering of interfacial tension (IFT). Moreover, CO2 immiscible injection performance is also expected to be improved by adding some solvent. However, there are a lack of studies identifying the roles of solvent in assisting CO2 injection through observing those properties simultaneously. This paper explains the effects of CO2–carbonyl and CO2–hydroxyl compounds mixture injection on those properties, and also the minimum miscibility pressure (MMP) experimentally by using VIPS (refers to viscosity, interfacial tension, pressure–volume, and swelling) apparatus, which has a capability of measuring those properties simultaneously within a closed system. Higher swelling factor, lower viscosity, IFT and MMP are observed from a CO2–propanone/acetone mixture injection. The role of propanone and ethanol is more significant in Sample A1, which has higher molecular weight (MW) of C7+ and lower composition of C1–C4, than that in the other Sample A9. The solvents accelerate the ways in which CO2 dissolves and extracts oil, especially the extraction of the heavier component left in the swelling cell.

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Controlling factors of remaining oil distribution after water flooding and enhanced oil recovery methods for fracture-cavity carbonate reservoirs in Tahe Oilfield

Petroleum Exploration and Development ◽

10.1016/s1876-3804(19)60236-3 ◽

2019 ◽

Vol 46 (4) ◽

pp. 786-795 ◽

Cited By ~ 6

Author(s):

Songqing ZHENG ◽

Min YANG ◽

Zhijiang KANG ◽

Zhongchun LIU ◽

Xibin LONG ◽

...

Keyword(s):

Enhanced Oil Recovery ◽

Oil Recovery ◽

Controlling Factors ◽

Carbonate Reservoirs ◽

Water Flooding ◽

Tahe Oilfield ◽

Oil Distribution ◽

Remaining Oil ◽

Remaining Oil Distribution ◽

Recovery Methods

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Assessing the Role of Temperature and Morphology on the Performance of Anionic and Cationic Surfactants for Enhanced Heavy Oil Recovery

Journal of Molecular Liquids ◽

10.1016/j.molliq.2021.116051 ◽

2021 ◽

pp. 116051

Author(s):

Seyed Mohammad Amin Hoseini Moghadam ◽

Baharan Ghiasimehr ◽

Mohammad Torkaman ◽

Peyman Mirmarghabi

Keyword(s):

Oil Recovery ◽

Heavy Oil ◽

Cationic Surfactants ◽

Heavy Oil Recovery ◽

Anionic And Cationic Surfactants

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Can unmixed complex forming polymer surfactant formulations be injected into oil reservoirs or aquifers without clogging them?

Soft Matter ◽

10.1039/d1sm00252j ◽

2021 ◽

Author(s):

Massinissa Hamouna ◽

Aline Delbos ◽

Christine Dalmazonne ◽

Annie Colin

Keyword(s):

Enhanced Oil Recovery ◽

Soil Remediation ◽

Oil Recovery ◽

Oil Reservoirs ◽

Polymer Surfactant

In the context of enhanced oil recovery or soil remediation, we study the role of interactions between polymers and surfactants on the injectivity of formulations containing mixtures of polymers and...

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Saturated carbon dioxide nanofluids enhanced oil recovery in carbonate reservoir cores using nuclear magnetic resonance

10.5194/egusphere-egu21-6762 ◽

2021 ◽

Author(s):

Yongsheng Tan ◽

Qi Li ◽

Liang Xu ◽

Xiaoyan Zhang ◽

Tao Yu

Keyword(s):

Carbon Dioxide ◽

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Enhanced Oil Recovery ◽

Oil Recovery ◽

Carbonate Reservoir ◽

Carbonate Reservoirs ◽

Residual Oil ◽

Core Flooding ◽

Nuclear Magnetic

The wettability, fingering effect and strong heterogeneity of carbonate reservoirs lead to low oil recovery. However, carbon dioxide (CO2) displacement is an effective method to improve oil recovery for carbonate reservoirs. Saturated CO2 nanofluids combines the advantages of CO2 and nanofluids, which can change the reservoir wettability and improve the sweep area to achieve the purpose of enhanced oil recovery (EOR), so it is a promising technique in petroleum industry. In this study, comparative experiments of CO2 flooding and saturated CO2 nanofluids flooding were carried out in carbonate reservoir cores. The nuclear magnetic resonance (NMR) instrument was used to clarify oil distribution during core flooding processes. For the CO2 displacement experiment, the results show that viscous fingering and channeling are obvious during CO2 flooding, the oil is mainly produced from the big pores, and the residual oil is trapped in the small pores. For the saturated CO2 nanofluids displacement experiment, the results show that saturated CO2 nanofluids inhibit CO2 channeling and fingering, the oil is produced from the big pores and small pores, the residual oil is still trapped in the small pores, but the NMR signal intensity of the residual oil is significantly reduced. The final oil recovery of saturated CO2 nanofluids displacement is higher than that of CO2 displacement. This study provides a significant reference for EOR in carbonate reservoirs. Meanwhile, it promotes the application of nanofluids in energy exploitation and CO2 utilization.

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A Novel Coreflood Test to Evaluate EOR Potential of Wettability-Altering Surfactants in Oil-Wet Heterogeneous Carbonate Reservoirs

10.2118/206151-ms ◽

2021 ◽

Author(s):

Yue Shi ◽

Kishore Mohanty ◽

Manmath Panda

Keyword(s):

Oil Recovery ◽

Carbonate Reservoirs ◽

Wettability Alteration ◽

Low Permeability ◽

High Permeability ◽

Matrix Permeability ◽

Rock Heterogeneity ◽

The Matrix ◽

Flow Through ◽

Main Factors

Abstract Oil-wetness and heterogeneity (i.e., existence of low and high permeability regions) are two main factors that result in low oil recovery by waterflood in carbonate reservoirs. The injected water is likely to flow through high permeability regions and bypass the oil in low permeability matrix. In this study, systematic coreflood tests were carried out in both "homogeneous" cores and "heterogeneous" cores. The heterogeneous coreflood test was proposed to model the heterogeneity of carbonate reservoirs, bypassing in low-permeability matrix during waterfloods, and dynamic imbibition of surfactant into the low-permeability matrix. The results of homogeneous coreflood tests showed that both secondary-waterflood and secondary-surfactant flood can achieve high oil recovery (>50%) from relatively homogenous cores. A shut-in phase after the surfactant injection resulted in an additional oil recovery, which suggests enough time should be allowed while using surfactants for wettability alteration. The core with a higher extent of heterogeneity produced lower oil recovery to waterflood in the coreflood tests. Final oil recovery from the matrix depends on matrix permeability as well as the rock heterogeneity. The results of heterogeneous coreflood tests showed that a slow surfactant injection (dynamic imbibition) can significantly improve the oil recovery if the oil-wet reservoir is not well-swept.

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