Abstract
Viscoelastic surfactant (VES) fluid and hydrolyzed polyacryamide (HPAM) solution are two of the most common fracturing fluids used in the hydraulic fracturing development of unconventional reservoirs. The filtration of fracturing fluids in porous media is mainly determined by the flow patterns in pore-throat structures. In this paper, three different microdevices analogue of porous media allow access to a large range of Deborah number (De) and concomitantly low Reynolds number (Re). Continuous pore-throat structures were applied to study the feedback effect of downstream structure on upstream flow of VES fluid and HPAM solution with Deborah (De) number from 1.11 to 146.4. In the infinite straight channel, flow patterns between VES fluids and HPAM solution were similar. However, as pore length shortened to 800 μm, flow field of VES fluid exhibited the triangle shape with double-peaks velocity patterns. The flow field of HPAM solution presented stable and centralized streamlines when Re was larger than 4.29 × 10−2. Additionally, when the pore length was further shortened to 400 μm, double-peaks velocity patterns were vanished for VES fluid and the stable convergent flow characteristic of HPAM solution was observed with all flow rates.
Highlights
Conventional oil and gas resources are steadily diminishing worldwide [1,2]
We present the flow patterns of the viscoelastic surfactant (VES) fluids and the and the hydrolyzed polyacryamide (HPAM)
Viscoelastic fluids underwent shear and extensional flow when flowing in porous media as characterized by pore-throat structures
Summary
Conventional oil and gas resources are steadily diminishing worldwide [1,2]. Most of the remaining oil and gas resources are unconventional oil and gas reservoirs, such as coalbed methane, shale gas, and tight oil and gas reservoirs. [3,4]. Hydraulic fracturing technology is one of the most effective techniques to increase the productivity of unconventional reservoirs [7,8,9]. In this technique, a particular viscoelastic fluid injected into the formation is referred as a fracturing fluid. Polymer fracturing fluid (HPAM solution) and viscoelastic surfactant (VES). It was found that the flow characteristics of the fracturing fluid in the porous media affect the amount of filtration loss. Research in this field is still insufficient.
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