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Investigating the effect of co-solvents on heavy oil recovery in different pore geometries using five-spot micromodels

Dehghan, A. A ; Sharif University of Technology

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  1. Type of Document: Article
  2. Abstract:
  3. The main issue in heavy oils enhanced recovery methods is to reduce their viscosity in order to get a better mobility. This is commonly obtained by blending the oil with light hydrocarbons. Co-solvents are good candidates to improve the hydrocarbon recovery efficiency especially in miscible processes. However, the effect of co-solvents on miscible flooding of heavy oil reservoirs at different pore geometries is not well understood. In this work different one-quarter five-spot network patterns along with those generated from reservoir rocks' thin sections were etches on glass surfaces. The models that had been initially saturated with the heavy crude oil were used to perform a series of solvent injection experiments. Four different groups of chemicals and their mixtures have been used to investigate the effects of co-solvents with different proportions when they were added to light liquid hydrocarbons. Macroscopic displacement efficiency of solvent mixtures floods in strongly water wet media by considering the effect of connate water has been studied. Viscosity lowering effect of the solvent mixtures was measured by static tests. Influence of effective pore geometry parameters on oil recovery and microscopic displacements was investigated during miscible floods. Precise analyses of the high quality pictures provided continuously during injection processes were used to explore the solvents' displacement behavior. The results showed that the displacement efficiencies of solvent mixtures greatly depend on the chemical properties of added co-solvents. An optimum mixture of co-solvents with greatest sweep efficiency was found. The experiments performed on network patterns demonstrated that higher coordination number along with lower pore to throat ratio of the flow paths could improve the displacement efficiency. The microscopic observations confirmed that the presence of connate water in strongly water-wet medium could improve the final recovery, while its extent greatly depends on the type of co-solvents used in the injection process
  4. Keywords:
  5. Coordination number ; Different proportions ; Displacement efficiency ; Heavy oil reservoirs ; Hydrocarbon recovery ; Liquid hydrocarbons ; Microscopic displacement ; Microscopic observations ; Blending ; Chemical properties ; Computer system recovery ; Crude oil ; Efficiency ; Enhanced recovery ; Experiments ; Floods ; Heavy oil production ; Hydrocarbons ; Mixtures ; Petroleum reservoirs ; Viscosity ; Water injection ; Solvents
  6. Source: 15th European Symposium on Improved Oil Recovery 2009, 27 April 2009 through 29 April 2009, Paris ; 2009 , Pages 669-682 ; 9781622768912 (ISBN)
  7. URL: http://www.earthdoc.org/publication/publicationdetails/?publication=20845