Experimental Investigation of Asphaltene Content Effect on Crude Oil/CO2 Minimum Miscibility Pressure

Mehdi Ghorbani,Amin Azdarpour,Asghar Gandomkar,Mohammad Rezaee,Gholamhosein Montazeri,Bizhan Honarvar

doi:10.3311/ppch.15980

Abstract

Minimum Miscibility Pressure (MMP) is regarded as one of the foremost parameters required to be measured in a CO2 injection process. Therefore, a reasonable approximation of the MMP can be useful for better development of injection conditions as well as planning surface facilities. In this study, the impact of asphaltene content ranging from 3.84 % to 16 % on CO2/heavy oil MMP is evaluated. In this respect, slim tube miscibility and Vanishing Interfacial Tension (VIT) tests are used. Regarding the VIT test, the Interfacial Tension (IFT) is measured by means of two methods including pendant drop and capillary apparatuses, and thereafter the MMP measurement error between slim tube and VIT methods are calculated. Based on the results, by increasing the asphaltene content, the measured MMP by slim tube method increases linearly while that by VIT follows no clear trend. The results also indicate that there is an asphaltene content range within which the MMP error between slim tube and VIT tests is minimized. IFT measurement by pendant drop and Capillary Glass Tube (CGT) methods show that by increasing asphaltene content up to 10.15 %, IFT declines, whereas for further increase in content, IFT increases because of the irregular dispersion of asphaltene in oil droplets.

Highlights

Carbon dioxide injection processes can improve oil recovery and reduce greenhouse gas emissions simultaneously via sequestration of CO2 in oil reservoirs [1]
3 Results and discussion After running slim tube experiments and Vanishing Interfacial Tension (VIT) for seven synthesized oil samples with different asphaltene contents, the corresponding results regarding Minimum Miscibility Pressure (MMP) measurement are summarized in Figs. 6 to 8
The VIT approach using pendant drop method, which is based on static condition, is not an appropriate way to determine the sensitivity of the MMP to asphaltene concentration, while Capillary Glass Tube (CGT) can be more trustworthy for such evaluations

Summary

Introduction

Carbon dioxide injection processes can improve oil recovery and reduce greenhouse gas emissions simultaneously via sequestration of CO2 in oil reservoirs [1]. The effect of asphaltene content on the MMP during CO2 injection process is examined for samples with asphaltene content between 3.84 % and 16 % by slim tube and VIT (Pendant drop method) tests.

Results

Conclusion