ISSN: 2375-3846
American Journal of Science and Technology  
Manuscript Information
The Effect of WAG Ratio and Oil Density on Oil Recovery by Immiscible Water Alternating Gas Flooding
American Journal of Science and Technology
Vol.4 , No. 5, Publication Date: Oct. 30, 2017, Page: 80-90
598 Views Since October 30, 2017, 510 Downloads Since Oct. 30, 2017

Nur Ain Binti Mohd Anuar, Department of Petroleum Engineering and Renewable Energy, Universiti Teknologi Malaysia (UTM), Johor, Malaysia.


Mat Hussin Yunan, Department of Petroleum Engineering and Renewable Energy, Universiti Teknologi Malaysia (UTM), Johor, Malaysia.


Farad Sagala, Department of Chemical and Petroleum Engineering, University of Calgary, Alberta, Canada.


Allan Katende, Department of Geoscience and Petroleum, Norwegian University of Science and Technology, Trondheim, Norway.


An Enhanced Oil Recovery (EOR) method named Immiscible Water-Alternating-Gas (IWAG) is one of the well-established methods for improving oil recovery in reservoirs. IWAG injection combines both improved displacement efficiency of the gas flooding with an improved macroscopic sweep by water injection. The objective of this study is to investigate the effect of Water-Alternating-Gas (WAG) ratio and oil density on residual oil recovery during IWAG flooding process using dimensions of a real reservoir. A series of six injections were conducted at WAG ratio of 1:1, 1:2, 1:3 and oil densities of 0.72 g/cc, 0.81 g/cc, 0.88 g/cc with flow rate of 1 cc/min for every injection. In this study, a secondary recovery method, which is water-flooding, had been conducted first and continued with immiscible gas-flooding before the start of IWAG to determine the overall recovery factor that can be increased with the utilization of IWAG as an EOR tertiary method. Water flooding had resulted in good oil recovery, which was about 36%–50% Oil Initially In Place (OIIP). Meanwhile immiscible gas-flooding had resulted in only 1% –3% OIIP. The results showed that a WAG ratio of 1:1 was the optimal ratio since the tertiary oil recovery using IWAG was 8% and total 45% of OIIP whereas oil density of 0.72 g/cc was the optimal density which gave 9% of oil recovery using IWAG and total 64% of OIIP. The experimental outcome additionally demonstrated that the IWAG method becomes more efficient in equal water and gas slug ratio which is favourable for low oil density. This is because water and gas help in both microscopic and macroscopic sweep efficiency whereas the mobility of low oil density is higher and flows with low resistance.


Enhanced Oil Recovery, Water Alternating Gas, Oil Initial in Place, Viscous Gravity Ratio, Displacement Efficiency, Mobility Ratio


Kjell Aleklett, Mikael Hk, Kristofer Jakobsson, Michael Lardelli, Simon Snowden and Bengt Soderbergh. The peak of the Oil Age. Analysing the world oil production Reference Scenario in World Energy Outlook 2008, Energy Policy, Volume 38, Issue 3, Mar 2010. Pages 1398-1414.


J. R. Christensen (Elf Exploration UK plc) M, Larsen (Technical University of Denmark), H. Nicolaisen (Elf Petroleum Norge A/S). Compositional Simulation of Water-Alternatin-Gas Processes, 2000. Pages 1-11.


S. B. Gorell (Shell Development Co.) Implications of Water-Alternate-Gas-Injection, for Profile Control and Injectivity, 1990. Pages 1-8 SPE-202210-MS


H. S. Al-Shuraiqi (Imperial College), A. H. Muggeridge (Imperial College), C. A. Grattoni (Imperial College). Laboratory Investigations of First Contact Miscible WAG Displacement: The Effects of WAG ratio and Flow Rate, 2003. Pages 1-10. SPE-84894-MS


John Alex Lasen and Arne Skauge. Computing Hysterisis for Relative Permeability in WAG Studies, 1995. Pages 1-10. SPE-84894-MS.


R. J. Blackwell (Humble Oil & Refining Co.), W. M. Terry (Humble Oil & Refining Co), D. C. Lindley (Humble Oil & Refining Co.), J. R. Henderson (Douglas Aircraft). Recovery of Oil by Displacements With Water-Solvent Mixtures, 1960. Pages 1-8


Herbert L. Stone (Exxon Production Research Company), Vertical Conformance in An Alternating Water-Miscible Gas Flood. 1982. Pages 1-15.


Raheleh Farokpoor, Erik Lindeberg, Ole Torsaeter, Mai Britt Mørk and Alte Mørk. Permeability and Relative Measurements for C=2-brine System at Reservoir Conditions in Low Permeable Sandstones in Svalbard, October 2013. Society of Chemical Industry and John Wiley & Sons.


L. A. Rapoport (The Carter Oil Co.) and W. J. Leas (The Carter Oil Co.) Properties of Linear Waterfloods, 1953. Pages 1-10. SPE-213-G.


Jigar Chandrakantbhai Bhatia (PD Petroleum University), J. P. Srivastava (Oil and Natural Gas Corporation), Jitendra Shia Sangwai (Indian Institute of Technology Madras, Chennai) and Abhay Sharma (Indian Institute of Technology Hyderabad). Investigations on Gas Trapping Phenomena for Different EOR-Water Alternate Gas Injection Methodologies, 2011.


Richard Baker (Epic Consulting Services). Reservoir Management for Waterfloods-Part II, January 1998. Pages 12-17. PETSOC-98-01-DA, Journal of Canadian Petroleum Technology.


I. Lazar, I. G. Petrisor & T. F. Yen. Microbial Enhanced Oil Recovery (MEOR), Nov 2007. Journal of Petroleum Science and Technology.


S. Chen (University of Regina), H. Li (University of Regina), D. Yang (University of Regina). Optimal Parametric Design foe Water-Alternating-Gas (WAG) Process in a CO2-Miscible Flooding Reservoir, October 2010. SPE-141650-PA. Journal of Canadian Petroleum Technology


Corey, A T. 1954 (The Interrelation between Gas and Oil Relative Permeabilities. November 1954, PRODUCERS MONTHLY, Pages 38–41.


Steve B. Dyer *Pan Canadian Petroleum Ltd) and S. M. Farouq Ali (U. of Alberta). Linear Model Studies of the Immiscible CO2 WAG Process for Heavy-Oil Recovery. May 1994, SPE-21162-PA, SPE Reservoir Engineering, Pages 1-5


Tianguang Fan (New Mexico Tech) and Jill S. Buckley (New Mexico Tech). Acid Number Measurements Revisited. December 2007, SPE-99884-PA, SPE Reservoir Engineering, Pages 1-5.


E. M. freer, T. Svitova and C. J. Radke. The role of interfacial rheology in reservoir mixed wettability. Journal of Petroleum Science and Engineering. Volume 39, Issues 1-2, August 2003, Pages 137-158.


R. E. Guzman (Stanfdord U.), Giordano Domenico (AGIP SPA), F. J. Fayers (Stanford U.), Khalid Aziz (Stanford U.) and Antonella Godi (AGIP SPA). Three-Phase Flow in Field-Sacale Simulations of Gas and WAG Injections 1994, SPE-28897-MS, Society of Petroleum Engineers, Pages 1-14.


Joost Clemens Heeremans (Delft University of Technology), Talal Ebraheem Esmael (Delft University of Technology) and Cor P. J. W. Van Kruijsdijk (Shell Canada Ltd.) Feasibility Study of WAG Injection in Naturally Fractured Reservoirs. 2006, SPE-100034-MS, Society of Petroleum Engineers, Pages 1-10.


D. D. Jackson (Exxon Co.), G. L. Andrews (Shell Oil Co.) and E. L. Claridge (U. of Houston). Optimum WAG Ratio vs Rock Wettability in CO2 Flooding. 985, SPE-14303-MS, Society of Petroleum Engineers, Pages 1-11.


Gary R. Jerauld (ARCO Technology and Operations Services). Timing of Miscible Hydrocarbon Gas Injection after Waterflooding. 2000, SPE -59341-MS, Society of Petroleum Engineers, Pages 1-13.


L. W. Holm (Unocal Corp.) Miscibility and Miscible Displacement. August 1986, SPE-15794-PA Society of Petroleum Engineers, Pages 1-2


Binayak P. Mohanty and Jianing Zhu. Effective Hydraulic Parameters in Horizontally and Vertically Heterogeneous Soils for Steady State Land Atmosphere Interaction. 2006, American Meteorological Society.


Mustafa Cobanoglu (Turkish Petroleum Corp., TPAO). A Numerical Study TO Evaluate The Use of WAG As An EOR Method For Oil Production Improvement At B. Kozluca Field, Turkey 2001, SPE-72127-MS. Society of Petroleum Engineers.


D. W. L. Pritchard (Esso Resources Canada Ltd.) and R. E. Nieman (Esso Resources Canada Ltd.) Improving Oil Recovery Through WAG Cycle Optimization in a Gravity Overide-Dominated Miscible Flood. 1992, SPE-2481-MS, Society of Petroleum Engineers.


Vishnu Simlote (Cities Services Co.) and Eric M. With-jack (Cities Services Co.) Estimation of Tertiary Recovery by CO2 Injection-Springer. A Sand Northeast Purdy Unit. May 1981, SPE-9431-PA. Society of Petroleum Engineers.


Nestor L. Sanchez (PDVSA Exploration and Production). Management of Water Alternating Gas (WAG). Injection Projects. 1999, SPE-53714-MS, Society of Petroleum Engineers.


Arne Skauge (Ctr for Integrated Petr Research) and Elisabeth Iren Dale (Statoil ASA). Progress in Immiscible WAG Modelling, 2007, SPE-11435-MS, Society of Petroleum Engineers.

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