Enhanced Heavy Oil Recovery by Intermittent CO2 Injection

Author(s):  
S. Mehdi Seyyedsar ◽  
S. Amir Farzaneh ◽  
Mehran Sohrabi
Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 1) ◽  
Author(s):  
Shuo Zhang ◽  
Yanyu Zhang ◽  
Xiaofei Sun

Abstract CO2 injection enhanced oil recovery has become one of the most important approaches to develop heavy oil from reservoirs. However, the microscopic displacement behavior of heavy oil in the nanochannel is still not fully understood. In this paper, we use CO2 as the displacing agent to investigate the displacement of heavy oil molecules confined between the hydroxylated silica nanochannel by nonequilibrium molecular dynamics simulations. We find that for heavy oil molecules, it requires more much higher displacing speed to fully dissipate the residual oil which is found related to the decreased CO2 adsorption on the silica nanochannel. A faster CO2 gas injection rate will lower the CO2 adsorption inside the nanochannel, and more CO2 will participate in the displacement of the heavy oil. The results from this work will enhance our understanding of the CO2 gas displacing heavy oil recovery and design guidelines for heavy oil recovery applications.


2014 ◽  
Vol 17 (02) ◽  
pp. 286-301 ◽  
Author(s):  
K.. Naderi ◽  
T.. Babadagli

Summary Because of low efficiencies and the high cost of the individual injection of steam and solvent for heavy-oil recovery, their hybrid applications have gained significant attention recently. Although numerous laboratory studies exist and there are a considerable number of field projects for sandstone environments, fractured carbonates lack technologies to drain matrix oil efficiently. An alternative-method injection of solvent and steam was proposed and tested earlier (Babadagli and Al-Bahlani 2008). This process applies steam initially to condition the matrix oil for succeeding solvent injection and steam reinjection to retrieve solvent in the matrix and to recover additional upgraded oil. The present study uses carbon dioxide (CO2) as a solvent and compares it with hydrocarbon solvents in this type of application. To clarify the physics of the process and to test the applicability of the method for different reservoir and injection conditions, we conducted a series of experiments by first injecting steam, followed by CO2 injection. In the third cycle, steam was injected again to produce upgraded oil in the matrix. The experiments were performed under static conditions (soaking sand and carbonate samples in steam or CO2 chambers) at different temperatures and pressures. CO2 is shown to be a reasonable alternative for hydrocarbon solvents in such a process in terms of cost and benefits by reducing the solvent expenses, keeping the oil-production levels, and disposing of a greenhouse gas.


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