CO₂-EOR in Shale-Oil Reservoirs based on a Laboratory Database


In this chapter, CO2-EOR mechanisms in unconventional reservoirs are introduced, and the early lab and simulation studies, which investigated the fundamentals of CO2-EOR in unconventional reservoirs, are presented. Data are analyzed to determine the feasibility of CO2-EOR in 95 cases of natural preserved cores collected from different formations, including 44 cases from the Middle Bakken, 26 cases from the Lower Bakken, 17 cases from the Upper Bakken, 4 cases from Three Forks, and 4 cases from an unknown formation/formations. The relationship between the improved oil recovery achieved by the CO2 injection and six rock properties, including porosity, permeability, mean pore throat radius, total organic carbon content (TOC), water saturation, and oil saturation, has been separately determined and is discussed here. Furthermore, the relationships between the improved oil recovery achieved by the injected CO2 and four operating parameters, including pressure, temperature, core sample bulk volume, and exposure time, have also been separately investigated. A proxy model to associate the functionality of the improved oil recovery by CO2 injection and these 10 parameters has been constructed. Moreover, statistical methods for the design of experiments (DOEs) have been used to rank the most important parameters affecting CO2-EOR performance in the microscale level (lab scale) of these unconventional reservoirs. This chapter provides an important set of lab-based data obtained from natural preserved cores to determine the applicability of CO2-EOR in these unconventional reservoirs. Also, this research demonstrates some key points which could help in understanding CO2-EOR mechanisms in shale plays because they are very complex and much different from conventional formations.


Geosciences and Geological and Petroleum Engineering


Chapter 2

Keywords and Phrases

CO -EOR data analysis 2; CO -EOR huff-n-puff 2; CO -EOR lab database 2; CO -EOR mechanisms in shale and tight oil reservoirs 2

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Book - Chapter

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© 2020 Elsevier B.V., All rights reserved.

Publication Date

01 Jan 2020