Petroleum Science - Investigation of feasibility of alkaliecosolvent flooding in heavy oil reservoirs

Aug 24, 2026

Cold production remains challenging for heavy oil due to high viscosity and poor fluidity under reservoir conditions. Alkaliecosolvent flooding is investigated as a low-cost microemulsion flooding approach, while polymer-related injection difficulties in highly viscous systems motivate studying alkali ecosolvent (AC) without polymer. Interfacial tension screening, phase behavior testing, and sandpack displacement experiments identify a Type III microemulsion, optimize salinity across multiple cosolvent concentrations, and show AC slug injection can lower injection pressure and enhance displacement efficiency versus waterflooding.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages12

Reading Time30 min

AccessFree to download

Introduction

Cold production challenges for heavy oil

Limitations of thermal recovery

CO2 flooding considerations

Role of chemical flooding

Petroleum Science 20 (2023) 1608e1619 Contents lists available at ScienceDirect Petroleum Science journal [homepage:](homepage: www. keaipublishing. com/en/journals/petroleum-science)[ www. keaipublishing. com/en/journals/petroleum-science](homepage: www. keaipublishing. com/en/journals/petroleum-science) | Original Paper
Investigation of feasibility of alkaliecosolvent ﬂooding in heavy oil reservoirs
Yi-Bo Li a, *, He-Fei Jia a, Wan-Fen Pu a, Bing Wei a, **, Shuo-Shi Wang a, b, Na Yuan b
a State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, 610500, Sichuan, China b Mewbourne School of Petroleum and Geological Engineering, University of Oklahoma, Norman, OK, 73019, USA | | | | | --- | --- | --- | --- | | a r t i c l e i n f o | | a b s t r a c t | | | Article history:
Received 31 August 2022
Received in revised form
1 December 2022
Accepted 1 December 2022
Available online 5 December 2022
Edited by Yan-Hua Sun | | Cold production is a challenge in the case of heavy oil because of its high viscosity and poor ﬂuidity in reservoir conditions. Alkaliecosolventepolymer ﬂooding is a type of microemulsion ﬂooding with low costs and possible potential for heavy oil reservoirs. However, the addition of polymer may cause problems with injection in the case of highly viscous oil. Hence, in this study the feasibility of alkali ecosolvent (AC) ﬂooding in heavy oil reservoirs was investigated via several groups of experiments. The interfacial tension between various AC formulations and heavy crude oil was measured to select appropriate formulations. Phase behavior tests were performed to determine the most appropriate formulation and conditions for the generation of a microemulsion. Sandpack ﬂooding experiments were carried out to investigate the displacement efﬁciency of the selected AC formulation. The results showed that the interfacial tension between an AC formulation and heavy oil could be reduced to below 10􀀁3 mN/m but differed greatly between different types of cosolvent. A butanol random polyether series displayed good performance in reducing the watereoil interfacial tension, which made it possible to form a Type III microemulsion in reservoir conditions. According to the results of the phase behavior tests, the optimal salinity for different formulations with four cosolvent concentrations (0.5 wt%, 1 wt%, 2 wt%, and 3 wt%) was 4000, 8000, 14000, and 20000 ppm, respectively. The results of rheological measurements showed that Type III microemulsion had a viscosity that was ten times that of water. The results of sandpack ﬂooding experiments showed that, in comparison with waterﬂooding, the injection of a certain AC formulation slug could reduce the injection pressure. The pressure gradient during waterﬂooding and AC ﬂooding was around 870 and 30e57 kPa/m, respectively. With the addition of an AC slug, the displacement efﬁciency was 30%e50% higher than in the case of waterﬂooding.
© 2022 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license ([http://creativecommons.org/licenses/by-nc-nd/](http://creativecommons.org/licenses/by-nc-nd/)[ ](http://creativecommons.org/licenses/by-nc-nd/)4.0/). | | | Keywords:
Heavy oil Microemulsion
Cold production Chemical ﬂooding Displacement efﬁciency | | | | 1. Introduction Heavy oil resources are abundant throughout the world. According to statistics, the total reserves of crude oil worldwide are about 9e11 trillion barrels, of which heavy oil and bitumen resources comprise about two-thirds. Canada and Venezuela possess 40% of the world's heavy oil and bitumen resources (Dong et al., 2019 ; Li et al., 2021). In contrast to light oil, heavy oil has high viscosity and low ﬂuidity as a result of its high contents of resin and asphaltene. Therefore, reducing viscosity and improving ﬂuidity

FAQs

Why is cold production difficult for heavy oil reservoirs?

Heavy oil exhibits high viscosity and poor fluidity under reservoir conditions, making it hard to mobilize and produce efficiently.

How was the feasibility of alkali ecosolvent (AC) flooding evaluated in the study?

The study used interfacial tension measurements to select formulations, phase behavior tests to generate microemulsions under relevant conditions, and sandpack flooding experiments to assess displacement efficiency.

What performance benefits were observed compared with waterflooding?

AC slug injection reduced injection pressure and increased displacement efficiency by roughly 30%–50% relative to waterflooding.

Aug 24, 2026

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