Feasibility of miscible CO2 flooding in hydrocarbon reservoirs with different crude oil compositions

Mudassir Khan,Arshad Raza,Muhammad Khurram Zahoor,Raoof Gholami

doi:10.1007/s13202-020-00899-0

Abstract

Miscible CO2-based enhanced oil recovery (CO2-EOR) flooding has been used, on many occasions, to maximize the recovery by mobilizing the residual oil. The success of this method, however, depends highly on the minimum miscibility pressure (MMP), the compatibility of CO2 with the reservoir rock and fluids. Although there have been several studies on the application of CO2-EOR, the impact of oil compositions associated with MMP on the feasibility of this technique has not been addressed elsewhere. In this study, a simulation study was carried out to investigate the effect of three different oil compositions on the miscibility and ultimate oil recovery of miscible CO2-EOR method. The results obtained indicated the oil type does not pose a significant impact on the success of miscible CO2-EOR. It was also found that the ultimate recovery of oil increases in a short period of time by injecting CO2 at the miscible conditions at the early stage of natural production. Comparatively, the reservoir with the fluid sample S2 seems to be a suitable choice for the miscible CO2 flooding once the recovery factor was considered together with the total amount of the fluid injected and produced.

Highlights

Natural depletion of hydrocarbon reservoirs often does exceed 20% to 40% in the primary recovery phase (Orr et al 1982; Muggeridge et al 2014; Raza et al 2019)
The results presented as part of this study help to understand the importance of minimum miscibility pressure (MMP) in the selection of oil reservoirs and the injection strategy
It was revealed that miscible CO2 injection is a suitable technique for the reservoir under consideration, but the main objective of the study was to select the most suitable injection scheme that could increase the recovery in a short time period

Summary

Introduction

Natural depletion of hydrocarbon reservoirs often does exceed 20% to 40% in the primary recovery phase (Orr et al 1982; Muggeridge et al 2014; Raza et al 2019). CO2 injection is done under the miscible or immiscible phases depending on the minimum miscibility pressure (MMP) (Gao et al 2013). This MMP depends on a variety of different parameters including the purity of C O2, reservoir pressure, and temperature as well as the composition of the reservoir oil. Some other factors such as the pressure, residence time, slug size, and fluid properties (i.e., Department of Petroleum & Gas Engineering, University of Engineering and Technology (UET), Lahore, Pakistan

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Conclusion