An experimental and numerical analysis of water-alternating-gas and simultaneous-water-and-gas displacements for carbon dioxide enhanced oil recovery and storage

Kamali, Fatemeh, Hussain, Furqan and Cinar, Yildiray (2016) An experimental and numerical analysis of water-alternating-gas and simultaneous-water-and-gas displacements for carbon dioxide enhanced oil recovery and storage. SPE Journal, . doi:10.2118/183633-PA


Author Kamali, Fatemeh
Hussain, Furqan
Cinar, Yildiray
Title An experimental and numerical analysis of water-alternating-gas and simultaneous-water-and-gas displacements for carbon dioxide enhanced oil recovery and storage
Journal name SPE Journal   Check publisher's open access policy
ISSN 1086-055X
1930-0220
Publication date 2016-08-01
Sub-type Article (original research)
DOI 10.2118/183633-PA
Open Access Status Not yet assessed
Total pages 18
Place of publication Richardson, TX, United States
Publisher Society of Petroleum Engineers
Collection year 2017
Language eng
Formatted abstract
This paper presents an experimental and numerical study that delineates the co-optimization of carbon dioxide (CO2) storage and enhanced oil recovery (EOR) in water-alternating-gas (WAG) and simultaneous-water-and-gas (SWAG) injection schemes. Various miscibility conditions and injection schemes are investigated. Experiments are conducted on a homogeneous, outcrop Bentheimer sandstone sample. A mixture of hexane (C6) and decane (C10) is used for the oil phase. Experiments are run at 70°C and three different pressures (1,300, 1,700, and 2,100 psi) to represent immiscible, near-miscible, and miscible displacements, respectively. WAG displacements are performed at a WAG ratio of 1:1, and a fractional gas injection (FGI) of 0.5 is used for SWAG displacements. The effect of varying FGI is also examined for the near-miscible SWAG displacement. Oil recovery, differential pressure, and compositions are recorded during experiments. A co-optimization function for CO2 storage and incremental oil production is defined and calculated by use of the measured data for each experiment. The results of SWAG and WAG displacements are compared with the experimental data of continuous-gas-injection (CGI) displacements. A compositional commercial reservoir simulator is used to examine the recovery mechanisms and the effect of mobile water on gas mobility.

Experimental observations demonstrate that the WAG displacements generally yield higher co-optimization function than CGI and SWAG with FGI = 0.5 displacements. Numerical simulations show a remarkable reduction in gas relative permeability for the WAG and SWAG displacements compared with CGI displacements, as a result of which the vertical-sweep efficiency of CO2 is improved. More reduction of gas relative permeability is observed in the miscible and near-miscible displacements than in the immiscible displacement. The reduced gas relative permeability lowers the water-shielding effect, thereby enhancing oil recovery and CO2-storage efficiency. More water-shielding effect is observed in SWAG with FGI = 0.5 than in WAG. However, increasing FGI from 0.5 to 0.75 in the near-miscible SWAG displacement shows a significant increase in oil recovery, which is attributed to reduced water-shielding effect. So, an optimal FGI needs to be determined to minimize the water-shielding effect for efficient SWAG displacements.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Chemistry and Molecular Biosciences
 
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Created: Mon, 03 Apr 2017, 14:36:11 EST by Fatemeh Kamali on behalf of UQ Energy Initiative