Effects of Coiled Tubing Curvature on Drag Reduction of Polymeric Fluids

2006 ◽  
Vol 21 (01) ◽  
pp. 134-141 ◽  
Author(s):  
Yunxu Zhou ◽  
Subhash N. Shah ◽  
Parag V. Gujar
Keyword(s):  
Drag Reduction ◽  
Polymeric Fluids ◽  
Coiled Tubing

Rheological Properties and Frictional Pressure Loss of Drilling, Completion, and Stimulation Fluids in Coiled Tubing

2004 ◽  
Vol 126 (2) ◽  
pp. 153-161 ◽  
Author(s):  
Yunxu Zhou ◽  
Subhash N. Shah
Keyword(s):  
Drag Reduction ◽  
Rheological Properties ◽  
Pressure Loss ◽  
Hydroxyethyl Cellulose ◽  
Test Facility ◽  
Drilling Mud ◽  
Polymeric Fluids ◽  
Pressure Losses ◽  
Coiled Tubing ◽  
Friction Pressure

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.

Maximum Drag Reduction Asymptote of Polymeric Fluid Flow in Coiled Tubing

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Subhash N. Shah ◽  
Yunxu Zhou
Keyword(s):  
Drag Reduction ◽  
Oil And Gas ◽  
Guar Gum ◽  
Oil And Gas Industry ◽  
Flow Loop ◽  
Polymeric Fluids ◽  
Curvature Ratio ◽  
Coiled Tubing ◽  
Industry Applications ◽  
Maximum Drag Reduction

This study experimentally investigates the drag reduction characteristics of the most commonly used polymer fluids in coiled tubing applications. The flow loop employed consists of 12.7mm straight and coiled tubing sections. The curvature ratio (a∕R, where a and R are the radii of the tubing and the reel drum, respectively) investigated is from 0.01 to 0.076, which covers the typical curvature ratio range encountered in the oil and gas industry applications. Fluids tested include xanthan gum, guar gum, and hydroxypropyl guar at various polymer concentrations. It is found that the drag reduction in coiled tubing is significantly lower than that in straight tubing, probably due to the effect of secondary flow in curved geometry. The onset of drag reduction is also found to be delayed as the curvature ratio was increased. A correlation for the maximum drag reduction (MDR) asymptote in coiled tubing is developed. When the curvature ratio is set to zero, the new correlation reduces to the well-known Virk’s MDR asymptote for dilute polymer solutions in straight pipes. A new drag reduction envelope is proposed for the analysis of drag reduction behavior of polymeric fluids in coiled tubing. Application of the new drag reduction envelope is also discussed.

Rheological and Hydraulic Properties of Drilling, Completion, and Stimulation Fluids in Straight and Coiled Tubings

2002 ◽  
Author(s):  
Y. Zhou ◽  
S. N. Shah
Keyword(s):  
Drag Reduction ◽  
Guar Gum ◽  
Polymer Concentration ◽  
Hydroxyethyl Cellulose ◽  
Test Facility ◽  
Drilling Mud ◽  
Polymeric Fluids ◽  
Pressure Losses ◽  
Coiled Tubing ◽  
Friction Pressure

The rheological properties and friction pressure losses of several fluids that are most commonly used as 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. It was found that the drag reduction (DR) in coiled tubing is much lower than that in straight tubing. 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.

A Comparative Investigation of Rheological and Flow Behavior Among Clean Polymeric and Surfactant Based Fluids

2016 ◽  
Author(s):  
Ahmed H. Kamel
Keyword(s):  
Drag Reduction ◽  
Elastic Properties ◽  
Large Scale ◽  
Flow Behavior ◽  
Secondary Flows ◽  
Theory Approach ◽  
Hydraulic Characteristics ◽  
Polymeric Fluids ◽  
Coiled Tubing ◽  
Reduction Characteristics

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.

Maximum Drag Reduction Asymptote of Polymeric Fluid Flow in Coiled Tubing

2006 ◽  
Author(s):  
Subhash N. Shah ◽  
Yunxu Zhou
Keyword(s):  
Drag Reduction ◽  
Oil And Gas ◽  
Guar Gum ◽  
Oil And Gas Industry ◽  
Flow Loop ◽  
Polymeric Fluids ◽  
Curvature Ratio ◽  
Coiled Tubing ◽  
Industry Applications ◽  
Maximum Drag Reduction

This study experimentally investigates the drag reduction characteristics of the most commonly used polymer fluids in coiled tubing applications. The flow loop employed consists of 1/2-in. straight and coiled tubing sections. The curvature ratio (a/R where a and R are the radii of the tubing and the reel drum respectively) investigated is from 0.01 to 0.076 which covers the typical curvature ratio range encountered in the oil and gas industry applications. Fluids tested include xanthan gum, guar gum, and HPG (hydroxypropyl guar) at various polymer concentrations. It is found that the drag reduction in coiled tubing is significantly lower than that in straight tubing, probably due to the effect of secondary flow in curved geometry. The onset of drag reduction is also found to be delayed as the curvature ratio was increased. A correlation for the maximum drag reduction (MDR) asymptote in coiled tubing is developed. When the curvature ratio is set to zero, the new correlation reduces to the famous Virk's MDR asymptote for dilute polymer solutions in straight pipes. A new drag reduction envelope is also proposed for the analysis of drag reduction behavior of polymeric fluids in coiled tubing. Application of the new drag reduction envelope is also discussed.

Maximum Drag Reduction Asymptote for Surfactant-Based Fluids in Circular Coiled Tubing

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Ahmed H. Kamel ◽  
Subhash N. Shah
Keyword(s):  
Drag Reduction ◽  
Group Structure ◽  
Scale Up ◽  
Gelling Agent ◽  
Head Group ◽  
Polymeric Fluids ◽  
Curvature Ratio ◽  
Coiled Tubing ◽  
Maximum Drag Reduction ◽  
Reduction Characteristics

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.

Mechanical Impact Effects of Fluid Hammer Effects on Drag Reduction of Coiled Tubing

2021 ◽  
pp. 1-10
Author(s):  
Yongsheng Liu ◽  
Xing Qin ◽  
Yuchen Sun ◽  
Zijun Dou ◽  
Jiansong Zhang ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Drag Reduction ◽  
Flow Rate ◽  
Fluid Velocity ◽  
Fluid Pressure ◽  
Great Influence ◽  
Radial Force ◽  
Fluid Flow Rate ◽  
Normal Contact ◽  
Coiled Tubing

Abstract Aiming at the oscillation drag reduction tool that improves the extension limit of coiled tubing downhole operations, the fluid hammer equation of the oscillation drag reducer is established based on the fluid hammer effect. The fluid hammer equation is solved by the asymptotic method, and the distribution of fluid pressure and flow velocity in coiled tubing with oscillation drag reducers is obtained. At the same time, the axial force and radial force of the coiled tubing caused by the fluid hammer oscillator are calculated according to the momentum theorem. The radial force will change the normal contact force of the coiled tubing which has a great influence on frictional drag. The results show that the fluid flow rate and pressure decrease stepwise from the oscillator position to the wellhead position, and the fluid flow rate and pressure will change abruptly during each valve opening and closing time. When the fluid passes through the oscillator, the unit mass fluid will generate an instantaneous axial tension due to the change in the fluid velocity, thereby converting the static friction into dynamic friction, which is conducive to the extend limit of coiled tubing.

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