| SUNYSB-AMS-08-01: | Understanding the Rate of Clean Up for Oil Zones after a Gel Treatment | |
| SUNYSB-AMS-08-02: | Dominance Hierarchies as a Model of Network Formation in Small Groups |
| SUNYSB-AMS-08-01 | Understanding the Rate of Clean Up for Oil Zones after a Gel Treatment | R.S. Seright, W.B. Lindquist and R. Cai |
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The dependence of oil permeability on oil throughput determines how long it takes for a production well to "clean up" or restore productivity after a gel treatment. Consequently, we were interested in how the gel dehydration process progresses as a function of oil throughput. This paper describes a new study where pore-scale XMT images were obtained at a variety of oil (hexadecane) throughput values after gel placement (involving a pore-filling Cr(III)-acetate- HPAM gel). For each pore in our image volume, we followed oil and water saturations as a function of oil throughput. These studies were performed both in water-wet Berea sandstone and in hydrophobic porous polyethylene. In hydrophobic porous polyethylene, oil saturations increased and gel was destroyed (presumably dehydrated) quite quickly in the smallest pores (10-6 mm3). Also, oil saturations increased and gel was destroyed quickly in the largest pores (<0.005 mm3). In contrast, oil saturations rose much more gradually for the most common or intermediate-sized pores (around 5x10-5 mm3, the peak in the pore size distribution). The minimum in oil saturation versus pore size may result from a balance between gel dehydration by oil film growth versus gel extrusion. Presumably, during oil injection after gel placement, an oil film forms with a thickness that is about the same on all polyethylene surfaces. However, because the ratio of film thickness to pore or throat size increases with decreased pore size, gel dehydration occurs faster and more effectively in the smallest polyethylene pores, causing oil saturation to increase with decreased pore size. This effect may lose its signicance for pore sizes above 10-4 mm3. As pore size increases above 10-4 mm3, gel extrusion from the pore becomes more lIKELY - explaining why oil saturation increased with increased pore size for the largest pores.
In contrast in water-wet Berea sandstone, increases in oil saturation occurred evenly over all pore sizes (10-6 to 0.02 mm3) for all oil throughput values. Consistent with imbibition and drainage studies performed before gel placement, oil apparently had equal access to Berea pores of all sizes, and thus uniformly dehydrated gel in pores of all sizes. Gel extrusion did not appear to be significant in the Berea pores.
To be presented at the 2008 SPE Improved Oil Recovery Symposium, Tulsa, OK, Apr. 19-23, 2008.
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| SUNYSB-AMS-08-02 | Dominance Hierarchies as a Model of Network Formation in Small Groups | I.D. Chase and W.B. Lindquist |
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We explore these questions in an unusual way for sociology: we first look at theoretical models for the explanation of dominance hierarchies ("pecking orders") in small groups of animals before considering hierarchies in small groups of humans. We describe dominance relationships and dominance hierarchies in animal groups, evaluate the various theoretical models that biologists have proposed to explain the structural forms of these hierarchies, outline a new type of model for animal hierarchies that avoids some of the problems inherent in the earlier models, and then compare current models for human small group hierarchies with those of animal hierarchies. We conclude that both our new model and current experimental work on animals indicate, ironically, that animals generate their hierarchies through richer and more sociologically sophisticated dynamics than those proposed in the current models for humans.
To appear in The Oxfold Handbook of Analytic Sociology, P. Hedstrom and P. Bearman (Eds.) Oxford University Press
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