An Experimental Study of the Effects of Drilling Solids on Frictional Pressure Losses in Coiled Tubing

Author(s):  
Subhash N. Shah ◽  
Y. Zhou
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.


2002 ◽  
Author(s):  
Y. Zhou ◽  
S. N. Shah

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.


2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Daniel Feseker ◽  
Mats Kinell ◽  
Matthias Neef

The ability to understand and predict the pressure losses of orifices is important in order to improve the air flow within the secondary air system. This experimental study investigates the behavior of the discharge coefficient for circular orifices with inlet cross flow which is a common flow case in gas turbines. Examples of this are at the inlet of a film cooling hole or the feeding of air to a blade through an orifice in a rotor disk. Measurements were conducted for a total number of 38 orifices, covering a wide range of length-to-diameter ratios, including short and long orifices with varying inlet geometries. Up to five different chamfer-to-diameter and radius-to-diameter ratios were tested per orifice length. Furthermore, the static pressure ratio across the orifice was varied between 1.05 and 1.6 for all examined orifices. The results of this comprehensive investigation demonstrate the beneficial influence of rounded inlet geometries and the ability to decrease pressure losses, which is especially true for higher cross flow ratios where the reduction of the pressure loss in comparison to sharp-edged holes can be as high as 54%. With some exceptions, the chamfered orifices show a similar behavior as the rounded ones but with generally lower discharge coefficients. Nevertheless, a chamfered inlet yields lower pressure losses than a sharp-edged inlet. The obtained experimental data were used to develop two correlations for the discharge coefficient as a function of geometrical as well as flow properties.


2020 ◽  
Vol 4 (394) ◽  
pp. 121-128
Author(s):  
Nikolay N. Ponomarev

Object and purpose of research. The object of this work is gas turbine outlet consisting of axial-radial diffuser with the struts and the volute. The purpose is to create a methodology for engineering calculations, taking into account the mutual influence of the diffuser and the volute. Materials and methods. Experimental study of the flow in the models of outlets by measuring total and static pressure in characteristic sections. Calculation of integral and averaged flow parameters in measurement sections. Visualization of boundary flows. Based on the experimental results, development of regression models for the correction factors to be applied in the theoretical model, with selection of relevant factors. Main results. An experimental study of 23 variants of models with a total volume of 112 experimental points (modes) was carried out. On the basis of the experiment, methodology and program for engineering calculation of total pressure losses in the outlets were developed. It was found that the installation of guide blades and radial ribs in the diffuser in order to reduce local expansion angles with the ultimate purpose of mitigating total pressure losses actually does not lead to this result due to the because the flow in the diffuser becomes asymmetric due to its interaction with the volute. Visualization of boundary flows in the diffusers and the volutes has been performed, which makes it possible to identify the locations of separations causing increased pressure losses. Conclusion. An engineering method for calculating the total pressure loss in gas turbine outlet has been developed. The technique makes it possible, taking size restrictions into account, to select the geometry of the flow section that ensures minimum total pressure loss.


IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 48241-48251
Author(s):  
Zhaoming Zhou ◽  
Mian Qin ◽  
Yuedong Xie ◽  
Jinsong Tan ◽  
Hailong Bao

2020 ◽  
Author(s):  
Ahmed K. Abbas ◽  
Hayder A. Alhameedi ◽  
Mortadha Alsaba ◽  
Mohammed F. Al Dushaishi ◽  
Ralph Flori

Author(s):  
Yingchun Chen ◽  
Shimin Zhang ◽  
Wenming Wang ◽  
Minghao Xiong ◽  
Hang Zhang

Coiled tubing can be used for steel catenary riser pigging operations to remove wax and other debris attached on the interior of steel catenary riser to recover production and ensure safety. Due to its low rigidity, coiled tubing would deform which might finally damage coiled tubing and steel catenary riser. Thus, in order to ensure safety and reliability of the operation, this article proceeded experimental study on the axial load transfer behavior of a coiled tubing stuck in a steel catenary riser when the coiled tubing has not yet helical buckled. According to the experimental results, the inner pipe’s axial force transfer efficiency is always less than 1; the outer pipe of “unfixed steel catenary riser boundary” would elongate forced by the inner pipe within it, which makes the injected displacement of inner pipe within outer pipe of “unfixed steel catenary riser boundary” bigger than the injected displacement of inner pipe within outer pipe of “fixed steel catenary riser boundary” system at the same force-out; before the inner pipe helical buckles, inner pipe’s force transfer efficiency for unfixed and fixed system can be considered as the same. The research done above might provide important theoretical supports for the steel catenary riser pigging operation.


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