Flow Properties and Drag-Reduction Characteristics of Surfactant-Based Fluids (SBF) in Large-Scale Coiled Tubing

2008 ◽  
Author(s):  
Ahmed Hosny Ahmed Kamel ◽  
Subhash Nandlal Shah
Author(s):  
Ahmed H. Kamel

This study involves experimental investigation of rheological and hydraulic characteristics of aqueous based polymeric and surfactant fluids in straight and coiled tubing. The fluids matrix includes guar, HPG, PHPA, welan, xanthan, and surfactant. Bohlin rheometer was used to evaluate rheological and viscoelastic characteristics. For hydraulic characteristics, small- and large-scale flow loops were used. It is observed that all fluids exhibit comparable non-Newtonian behavior and improved viscous and elastic properties. Among polymeric fluids, guar and welan provide better viscosity and suspension properties. Surfactant is significantly affected by the formation of rod-like micelles and other microstructures. Master curves for rheological and elastic properties are developed using the molecular theory approach. The foremost benefit of these curves is its dimensionless form that provides a unique technique to predict viscosity for all fluids. For hydraulic properties, friction losses in coiled tubing are significantly higher than in straight tubing due to centrifugal forces and secondary flows. Surfactant is more sensitive to shear field applied where different microstructures are induced and thus they exhibit better drag reduction characteristics than polymeric fluids especially in coiled tubing with larger sizes. However, in straight tubing, guar shows better drag reduction characteristics than surfactant and other polymers, which diminishes as tubing size increases. However, welan gum exhibits a comparable performance. Overall, all fluids are considered good candidates as fracturing fluids with specific features for each. Unique characteristics of each fluid is discussed and explained in more details within the context of the present paper.


2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Ahmed H. Kamel ◽  
Subhash N. Shah

Surfactants are superior to polymers in reducing drag and their advantages are very well established. As drag reducers, several factors, such as concentration, temperature, salinity, shear rate, etc., can affect their behavior. Other unique factors relevant to surfactants may include tubing diameter (scale-up effect), head group structure, counterion, charge, etc. Although, drag reduction envelope is customarily employed to investigate drag reduction phenomena, it is defined only for polymeric fluids in both straight and coiled tubing and for surfactant-based (SB) fluids in straight tubing. No such envelope is available for SB fluids in coiled tubing. The present research aims at experimentally investigating the drag reduction characteristics of the most widely used Aromox APA-T surfactant-based fluids. It is a highly active surfactant used as gelling agent in aqueous and brine base fluids. Flow data are gathered using small and large scale flow loops. Straight and coiled tubing with various sizes (1.27 cm to 7.30 cm o.d.) and curvature ratios (0.01 to 0.031) covering the field application range are utilized. The results show that SB fluids exhibit superior drag reduction characteristics. Their behavior is significantly affected by surfactant concentration, shear, tubing size, and geometry. Higher drag reduction is seen in straight tubing than in coiled tubing and increasing curvature ratio yields higher friction pressure losses. In coiled tubing, SB fluids exhibit better drag reduction characteristics than Shah and Zhou maximum drag reduction (MDR) asymptote for polymeric fluids. Therefore, a new maximum drag reduction asymptote is developed using data gathered in 1.27 cm o.d. tubing. The proposed correlation agrees with Zakin MDR asymptote for SB fluids in straight tubing where the curvature ratio is set to be zero. Employing the proposed correlation, a modified drag reduction envelope can be used to evaluate drag reduction characteristics of SB fluids.


2020 ◽  
Author(s):  
Philipp Eichheimer ◽  
Marcel Thielmann ◽  
Wakana Fujita ◽  
Gregor J. Golabek ◽  
Michihiko Nakamura ◽  
...  

Abstract. Fluid flow on different scales is of interest for several Earth science disciplines like petrophysics, hydrogeology and volcanology. To parameterize fluid flow in large-scale numerical simulations (e.g. groundwater and volcanic systems), flow properties on the microscale need to be considered. For this purpose experimental and numerical investigations of flow through porous media over a wide range of porosities are necessary. In the present study we sinter glass bead media with various porosities. The microstructure, namely effective porosity and effective specific surface, is investigated using image processing. We determine flow properties like hydraulic tortuosity and permeability using both experimental measurements and numerical simulations. By fitting microstructural and flow properties to porosity, we obtain a modified Kozeny-Carman equation for isotropic low-porosity media, that can be used to simulate permeability in large-scale numerical models. To verify the modified Kozeny-Carman equation we compare it to the computed and measured permeability values.


2004 ◽  
Vol 126 (2) ◽  
pp. 153-161 ◽  
Author(s):  
Yunxu Zhou ◽  
Subhash N. Shah

The rheological properties and friction pressure losses of several common well-drilling, completion, and stimulation fluids have been investigated experimentally. These fluids include polymeric fluids—Xanthan gum, partially hydrolyzed polyacrylamide (PHPA), guar gum, and hydroxyethyl cellulose (HEC), bentonite drilling mud, oil-based drilling mud, and guar-based fracturing slurries. Rheological measurements using a Bohlin CS 50 rheometer and a model 35 Fann viscometer showed that these fluids exhibit shear thinning and thermal thinning behavior except the bentonite drilling mud whose viscosity increased as the temperature was raised. Flow experiments using a full-scale coiled tubing test facility showed that the friction pressure loss in coiled tubing is significantly higher than in straight tubing. Since the polymeric fluids displayed drag reducing property, their drag reduction behavior in straight and coiled tubings was analyzed and compared. Plots of drag reduction vs. generalized Reynolds number indicate that the drag reduction in coiled tubing was not affected by polymer concentration as much as in straight tubing. The onsets of turbulence and drag reduction in coiled tubing were significantly delayed as compared with straight tubing. The effect of solids content on the friction pressure losses in coiled tubing is also briefly discussed.


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