Experimental Investigation of the Effects of Temperature and Oil Composition on CO2-Crude Oil Swelling, Extraction Mechanisms, and Displacement Performance
DOI:
https://doi.org/10.17794/rgn.2026.3.4Keywords:
CO2 flooding, Swelling-extraction mechanisms, Miscibility, Asphaltene precipitation, Oil Recovery, SARA fractionsAbstract
CO₂ flooding has several advantages for enhancing oil recovery, including a reduction in crude oil viscosity, a decrease in interfacial tension, and an increase in oil volume through swelling. Although the mechanisms of oil swelling and extraction in CO₂–crude oil systems have been widely studied, the combined effects of temperature and oil composition on these mechanisms—and their influence on CO₂ displacement efficiency in porous media—remain insufficiently understood, especially under high reservoir temperatures. Therefore, this study investigates how temperature and crude oil composition affect swelling-extraction behaviour and CO₂ displacement efficiency. High-pressure and high-temperature (HPHT) PVT tests were conducted to evaluate swelling and extraction phenomena, while slim tube experiments were used to assess oil recovery performance. Tests were carried out at 70°C and 90°C using two light dead oils from an Indonesian field under varying injection pressures. Compositional analysis of produced oils was performed using Gas Chromatography (GC) and further interpreted through SARA fractions (saturates, aromatics, resins, and asphaltenes). Results show that lower temperatures enhance CO₂ extraction efficiency due to higher CO₂ density, leading to more pronounced swelling and miscibility effects. The miscibility was observed within the extraction region, emphasizing the role of hydrocarbon extraction in the miscibility mechanism. Higher temperatures were found to improve oil recovery, primarily due to viscosity reduction. Additionally, increasing CO₂ injection pressure reduced resin and asphaltene content, with evidence of asphaltene precipitation in the porous medium—particularly at lower temperatures. These findings provide valuable insight into how temperature and oil composition influence CO₂–oil interactions and support more effective implementation of CO₂ flooding at elevated reservoir temperatures.
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Copyright (c) 2026 Kartika Hartono, Asep K Permadi, Ucok W. R. Siagia, Andri L Hakim, Sumadi Paryoto, Ahlul H. Resha, Syaeful A. Satya, Reno Pratiwi, Maman Djumantara, Dina A. Chusniah
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