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Experimental study of miscible displacement with hydrocarbon solvent in shaly heavy oil reservoirs using five-spot micromodels: The role of shale geometrical characteristics

Mohammadi, S ; Sharif University of Technology

2007 Viewed
  1. Type of Document: Article
  2. DOI: 10.1615/JPorMedia.v15.i5.20
  3. Abstract:
  4. Most of the heavy oil reservoirs contain discontinuous shale which affects fluid flow through porous media as well as recovery efficiency during enhanced oil recovery processes. However, the role of shale geometrical characteristics (including orientation, length, discontinuity, and spacing of the shale) on oil recovery remains a topic of debate in the literature, especially during miscible injection of heavy oils and five-spot systems. Here, a series of hydrocarbon solvent injection tests have been performed on various five-spot glass micromodels containing barriers which are initially saturated with heavy oil under fixed flow rate conditions. Oil recoveries as a function of pore volumes of injected fluids were determined from analysis of continuously recorded pictures during the experiments. It was observed that oil recovery decreased in the presence of shale in the models, and also these barriers cause bypassing of displacing fluids and consequently early breakthrough of injected fluids. The oil recovery efficiency depends strongly on the orientation of the shale. For the range of experiments performed here, by increasing the shale orientation angle from 0? to 90?, the oil recovery factor decreased; when displacing fluid flows perpendicular to shale orientation, the volume of bypassed oil behind the shale streak is maximized. It has been found that by increasing the length of the shales perpendicular to flow, the sweep efficiency decreases, while for the case of discontinuous structures it increased. Also, the oil recovery factor decreases with the increase of the shale spacing. Microscopic observations confirmed that addition of an antiasphaltene precipitant agent to the solvent reduced the volume of bypassed oil behind the shale. Besides, the presence of connate water in the solvent injection scheme in shaly systems can improve the recovery efficiency specifically at higher water saturations. Results of this work reveal the effect of shales on oil recovery efficiency in five-spot models, which might be helpful for successful mapping design of injection/production wells in miscible injection operations of shaly oil reservoirs
  5. Keywords:
  6. Discontinuous shale ; Five-spot glass micromodel ; Bypassed oil ; Enhanced oil recovery ; Experimental ; Experimental studies ; Five-spot ; Fixed flow ; Flowthrough ; Geometrical characteristics ; Glass micromodels ; Heavy oil reservoirs ; Hydrocarbon solvents ; Injected fluid ; Mapping design ; Micromodels ; Microscopic observations ; Miscible displacement ; Oil recoveries ; Oil recovery efficiency ; Oil reservoirs ; Orientation angles ; Pore volume ; Precipitant agent ; Recovery efficiency ; Solvent injection ; Sweep efficiency ; Water saturations ; Efficiency ; Enhanced recovery ; Experiments ; Flow of fluids ; Heavy oil production ; Hydrocarbons ; Petroleum reservoirs ; Recovery ; Shale ; Solvent ; Water injection ; Shale oil
  7. Source: Journal of Porous Media ; Vol. 15, issue. 5 , 2012 , p. 415-427 ; ISSN: 1091028X
  8. URL: http://www.dl.begellhouse.com/journals/49dcde6d4c0809db,752da0d1454264c6,4246710342c6d123.html