Calculation Of Pressure Losses Research Articles

A generalized hydraulic calculation model for non-newtonian fluid pipe flow and its application evaluation

A generalized hydraulic model that is independent of the rheological model is presented for non-Newtonian fluids flow in pipes. The generalized model was developed without assuming that the generalized flow index (n’) remains constant over all shear rates. Based on the pipe flow control equation, the explicit equations between the wall shear stress and volumetric flow of all common rheological models flowing in pipe were obtained, such as the Casson model, HerschelBulkley model and the Robertson-Stiff model, and they all can be solved numerically to obtain the accurate wall shear rate and shear stress. We give the theoretic calculation method of n’ for all time-independent non-Newtonian fluids. This method is applicable to all common rheological models without the assumption that n’ is constant. Moreover, we derived the general expression of generalized Reynolds number and then gave a utility pressure loss calculation model. A set of measured hydraulic data were utilized to evaluate this model. The results show that it can precisely calculate pipe flow parameters for all types of different non-Newtonian fluid. The proposed model will lay a foundation for the application and more extensive use of complex but more precise rheological models in engineering.

A new utility calculation model for axial flow of non‐Newtonian fluid in concentric annuli

A new utility approach that is independent of the rheological model is presented for the flow of non‐Newtonian fluids in concentric annulus. The novel model was developed without assuming that the generalised flow index remains constant over all shear rate ranges. Based on the slot model, the flow rate expressions for all common rheological models flowing in annuli were obtained, such as the Herschel–Bulkley model, the Robertson–Stiff model, and the Four‐parameter model, and they all can be solved numerically to obtain accurate wall shear rate and shear stress. Following Metzner and Reed's study, we defined a generalised flow index for non‐Newtonian fluid flow in annuli. Through a theoretical analysis, we also defined a new effective diameter for non‐Newtonian fluid flow in annuli, which accounts for the effects both of annulus geometry and fluid rheology but which is different from that was proposed by Reed and Pilehvari. Through the generalised effective diameter we linked non‐Newtonian annular flow with Newtonian pipe flow. A general annular Reynolds number expression was derived from this method for conditions under which the generalised flow index is variable. A theoretical calculation method for the generalised flow index and a uniform pressure loss calculation model for non‐Newtonian flow in concentric annuli were developed, which are applicable to all time‐independent non‐Newtonian fluid. The predictions of this model have been compared with an extensive set of data from the literature. The comparisons of different fluids in different size annuli show very good agreement over the entire range of flow types.

Urine Flow Dynamics Through Prostatic Urethra With Tubular Organ Modeling Using Endoscopic Imagery.

Voiding dysfunction is common in the aged male population. However, the obstruction mechanism in the lower urinary tract and critical points for obstruction remains uncertain. The aim of this paper was to develop a system to investigate the relationship between voiding dysfunction and alteration of the shape of the prostatic urethra by processing endoscopic video images of the urethra and analyzing the fluid dynamics of the urine stream. A panoramic image of the prostatic urethra was generated from cystourethroscopic video images. A virtual 3-D model of the urethra was constructed using the luminance values in the image. Fluid dynamics using the constructed model was then calculated assuming a static urethra and maximum urine flow rate. Cystourethroscopic videos from 11 patients with benign prostatic hyperplasia were recorded around administration of an alpha-1 adrenoceptor antagonist. The calculated pressure loss through the prostatic urethra in each model corresponded to the prostatic volume, and the improvements of the pressure loss after treatment correlated to the conventional clinical indices. As shown by the proposed method, the shape of the prostatic urethra affects the transporting urine fluid energy, and this paper implies a possible method for detecting critical lesions responsible for voiding dysfunction. The proposed method provides critical information about deformation of the prostatic urethra on voiding function. Detailed differences in the various types of relaxants for the lower urinary tract could be estimated.

Application of SVM Algorithm for Frictional Pressure Loss Calculation of Three Phase Flow in Inclined Annuli

In Underbalanced Drilling (UBD) operation, the presence of three phases including, drilling fluid, air and cuttings, makes the estimation of equivalent circulation density more difficult. This study presents a novel computer-based model namely Lease Square Support Vector Machine (LS-SVM), for frictional loss calculation of two-phase gas based drilling fluids with the presence of cuttings as the third phase in inclined section of wellbore. This model is based on extensive experimental data collected from published literature. This model is account for in situ flow rate of each phase, Rate of Penetration (ROP), pipe rotation, and hole inclination. The results show that the proposed model is predicting frictional pressure losses in acceptable agreement with experimental data with very high correlation coefficient (>0.99) and small average relative error. Moreover, a trend analysis was carried out to check the validity of the developed model. Results of the present study show that implementation of this developed model can be incorporated in drilling simulators for accurate estimation of frictional pressure loss of three phase flow.

Influence of viscosity modifier nature and concentration on the viscous flow behaviour of oil-based drilling fluids at high pressure

This work deals with the effect of viscosity modifier nature and concentration on the rheological properties of model oil-based drilling fluids (OBM) submitted to high pressure. The oil-based fluids were formulated by dispersing, with a high shear mixer, two selected organobentonites in a mineral oil, at room temperature. The viscous flow behaviour of the corresponding dispersions was characterised as a function of pressure, organoclay nature and organoclay concentration, using a controlled-stress rheometer equipped with both pressure cell and coaxial cylinder geometries. A factorial Sisko–Barus model, which takes into account both shear and pressure effects in the same equation, fitted the experimental pressure–viscosity data fairly well.The influence of disperse phase concentration on the shear-thinning characteristics of these organoclay dispersions is related to the development of different microstructures, which depend on organoclay nature. In this sense, the resulting microstructure has been attributed to the cohesion energy between microgels domains. From the experimental results obtained, it can be concluded that the viscous flow behaviour of the OBM investigated is strongly affected by organoclay nature and concentration. The pressure–viscosity behaviour of these dispersions is mainly influenced by the piezoviscous properties of the oil and the properties of the continuous phase. The Sisko–Barus model proposed can be a useful tool, from an engineering point of view, for calculating pressure losses in the different sections of the bore, as well as being of significant help to solve other additional problems, such as hole cleaning, induced fracturing, and hole erosion during the drilling operation.

Numerical implementation of the Cheng and Todreas correlation for wire wrapped bundle friction factors-desirable improvements in the transition flow region

The Cheng and Todreas (1986) correlation is widely used for calculation of pressure loss in wire wrapped hexagonal rod bundles. Recent application indicates that the transition region friction factor calculated causes reverse pressure drop as flow rate increases in the vicinity of the transition to turbulent boundary. A modified friction factor formula for the transition region is proposed to avoid this anomalous behavior. The newly introduced exponent in this formula was calibrated by 58 available bundle data sets to be 13. This modified formula not only achieves the original objective but also slightly improves the accuracy of prediction in the transition region.

Experimental investigation of the role of struts in high speed mixing

AbstractThis paper presents the experimental results of the role of struts in supersonic mixing. Experiments were carried out with novel strut configurations to show their capabilities on mixing with reasonable total pressure losses. The performances were compared with the Baseline Strut configurations (BSPI and BSNI). The analysis presented includes the mixing quantifications using Mie scattering signature, flow field visualisation, measurement of wall static pressure and the total pressure loss calculations. The results clearly demonstrated that the proposed strut configurations achieved increased mixing (7-8%) compared to BSPI with increase in total pressure loss (2%). On the other hand, when compared with BSNI, the mixing performance was found to be decreased by 6% with reduced total pressure loss (12%).

Hydraulics Analysis System for Extended Reach Drilling in China and its Application

The extended reach drilling (ERD) is being adopted widely as an effective and economical way of developing oilfields in China. But it also brought a series of technical difficulties because of its own characteristics. Some progresses were made after several years of hard work in China about Hydraulics for extended reach drilling, which included cuttings transport models and rules, precise model of circulating system pressure loss calculation, hole cleaning calculating models and monitoring method, hydraulic extended limit calculation model and analysis, hydraulics design and optimization method for ERD. Based on the above studies, the author finally developed a system of hole cleaning monitoring and hydraulics design and its risk analysis which could provide theoretical support and useful tool for engineering design and risk assess before drilling. These researches are helpful to ERD and have enriched the hydraulic theory of ERD.

Research of Wet Gas Experimental Facility with Adjustable and Intermediate Pressure

In order to better simulate the flowing condition of wet gas, Tianjin University has designed and built up a wet gas flow experimental facility with adjustable and intermediate pressure in the flow laboratory. The designed pressure of the facility which used standard meter method and dual closed-loop design is 4MPa. The experiment medium is air and water, and the highest operation pressure is 1.6MPa. The gas flow rate range is 3~1000m3/h, and the liquid flow rate range is 0.05~8 m3/h. This article includes the structure introduction of the facility and the calculation of pressure loss of the system, etc. By the uncertainty assessment for the discussed facility, the conclusion is stated that the facility’s gas measurement uncertainty is 1% and the facility’s liquid measurement uncertainty is 0.35%.

Research Progresses of Hydraulics for Extended Reach Drilling in China, Part I: Cuttings Transport and Precise Calculation of Pressure Loss

The extended reach drilling (ERD) is being adopted widely as an effective and economical way of developing oilfields in China. But it also brought a series of technical difficulties because of its own characteristics. Some progresses were made after several years of hard work in China about Hydraulics for extended reach drilling, which included cuttings transport models and rules, precise model of circulating system pressure loss calculation, hole cleaning calculating models and monitoring method, hydraulic extended limit calculation model and analysis, hydraulics design and optimization method for ERD. Based on the above studies, the author finally developed a system of hole cleaning monitoring and hydraulics design and its risk analysis which could provide theoretical support and useful tool for engineering design and risk assess before drilling. These researches are helpful to ERD and have enriched the hydraulic theory of ERD. Due to space limitations, this article could only demonstrate part of these progresses, as the subtitle showed.

Research Progresses of Hydraulics for Extended Reach Drilling in China, Part III: Hydraulics Design Method and Risk Analysis System

The extended reach drilling (ERD) is being adopted widely in China. But it also brought a series of technical difficulties because of its own characteristics. Some progresses were made after several years of hard work in China about Hydraulics for ERD. In the paper of “Research Progresses and Perspectives of Hydraulics for Extended Reach Drilling in China, Part I” and “ Part II”, the author demenstrated part of these progresses including cuttings transport model, precise model of pressure loss calculation, hole cleaning monitoring method and hydraulic extended limit calculation model and analysis. In this paper, the rest were presented which inlcuding hydraulics design method and risk analysis system for ERD. Based on the above studies, the author finally developed a system of hole cleaning monitoring and hydraulics design and its risk analysis which could provide theoretical support and useful tool for engineering design and risk analysis before drilling. These researches are helpful to ERD and have enriched the hydraulic theory of ERD.

Research Progresses of Hydraulics for Extended Reach Drilling in China Part II: Hole Cleaning Monitoring and Hydraulic Extended Limit

The extended reach drilling (ERD) is being adopted widely in China. But it also brought a series of technical difficulties because of its own characteristics. Some progresses were made after several years of hard work in China about Hydraulics for ERD. In the paper of “Research Progresses and Perspectives of Hydraulics for Extended Reach Drilling in China, Part I”, the author demenstrated part of these progresses including cuttings transport model and precise model of pressure loss calculation. In this paper, the part of rest were presented which inlcuding hydraulic extended limit calculation model and analysis and hole cleaning monitoring method for ERD. Based on the above studies, the author finally developed a system of hole cleaning monitoring and hydraulics design and its risk analysis which could provide theoretical support and useful tool for engineering design and risk analysis before drilling. These researches are helpful to ERD and have enriched the hydraulic theory of ERD.

Szemcsés anyagok – csővezetékben – folyadékárammal való szállításának méretezése. 2. rész: A nyomásveszteség számítása

Szemcsés anyagok – csővezetékben – folyadékárammal való szállításának méretezése. 2. rész: A nyomásveszteség számítása

Structure Analyses and Flow Rate Model of Peristaltic Pump of Cement Foaming Machine

With the constant development in the fields of Greenness, Environmental Protection and Energy Conservation all over the world, the improvement of foam cement technology is to bring about a revolution in the architectural material industry. The main component of the cement foaming machine is the delivery pump system, in which the peristaltic pump is the most important part. In this thesis, on the bases of study of peristaltic pump in imported machines, mathematical models are made and an approximate calculation of flow rate of the peristaltic pump is given through exhaustive analyses of the structure and the changes in the cross section before and after compression rolling. This research will also make it possible to analyze the pressure in the exit of the pump and deduce the power needed by the driven peristaltic pump according to the factors like the calculation of on-way pressure loss with the consideration of working altitude. This research is expected to provide a theoretic principle for the development of cement foaming technology.

Sensitivity of Slug Flow Mechanistic Models on Slug Length

Slug flow is one of the common flow patterns in gas and oil production and transportation. One of the closure relationships required by the multiphase flow mechanistic models is slug length correlation. There are several closure relationships proposed in the literature as function of pipe geometry, pipe diameter, and inclination angle, and to a lesser extent to the flow rates and fluid properties. In this paper, we show that most of the frequently used mechanistic models are insensitive to slug length information. The only exception to this is identified as the Zhang et al. (2003, “Unified Model for Gas-Liquid Pipe Flow via Slug Dynamics—Part 1: Model Development,” ASME J. Energy Resour. Technol., 125, pp. 266–272). The unified model shows sensitivity at high gas flow rates, while displaying a negligible sensitivity at low gas flow rates. In conclusion, the slug length closure relationship is not crucial for pressure loss and holdup calculations. It can be speculated that the success of the unit cell slug flow modeling approach could be attributed to insensitivity of the models to slug length considering the highly probabilistic nature of the slug length.

Numerical Investigation of the Influence of Real World Blade Profile Variations on the Aerodynamic Performance of Transonic Nozzle Guide Vanes

This paper addresses the issue of aerodynamic consequences of small variations in airfoil profile. A numerical comparison of flow field and cascade pressure losses for two representative repaired profiles and a reference new vane were made. Coordinates for the three airfoil profiles were obtained from the nozzle guide vanes of refurbished turboshaft engines using 3D optical scanning and digital modeling. The repaired profiles showed differences in geometry in comparison with the new vane, particularly near the leading and trailing edges. A numerical simulation was conducted using a commercial CFD code, which uses the finite volume approach for solving the governing equations. The computational predictions of the aerodynamic performance were compared with experimental results obtained from a cascade consisting of blades with the same airfoil profiles. The CFD analysis was performed for the cascade at subsonic inlet and transonic exit conditions. Boundary layer growth, wake formation, and shock boundary layer interactions were observed in the two-dimensional computations. The flow field showed the presence of shock waves downstream of the passage throat and near the trailing edges of the blades. A conspicuous change in flow pattern due to subtle variation in airfoil profile was observed. The calculated flow field was compared with the flow pattern visualized in the experimental test rig using the schlieren method. The total pressure calculation for the cascade exit showed an increase in pressure loss for one of the off-design profiles. The pressure loss calculations were also compared with the multihole total pressure probe measurement in the transonic cascade rig.

Friction factors for hydraulic calculations considering presence of cuttings and pipe rotation in horizontal/highly-inclined wellbores

Pressure loss calculations have a vital role for determining hydraulic horsepower requirements and to predict bottomhole treating pressure. One of the major concerns in developing hydraulic programs is to estimate the frictional pressure losses while cuttings are present in the annulus during pipe rotation. An experimental work has been carried out in a cuttings transport flow loop capable of operating at various inclinations. The pressure drop in the test section was recorded for variable flow rates, cuttings concentrations, pipe inclinations and rotation speeds. Existence of cuttings increase the pressure drop due to decrease in flow area inside the wellbore. As there are cuttings in the system, pipe rotation decreases the frictional pressure loss considerably in particular if the pipe is making an orbital motion in the eccentric annulus. Cuttings bed thickness defined as the ratio of cuttings bed area to the wellbore area is expressed in terms of dimensionless parameters obtained from dimensional analysis. Empirical expressions and charts for friction factor are proposed for low and high viscosity fluids in terms of combined Reynolds number and stationary cuttings bed thickness.

Laminar flow control via utilization of pipe entrance inserts (a comment on entrance length concept)

Flow field measurements behind pipe entrance inserts called as flow conditioners in a mean flow Reynolds number range 547 ≤ Re ≤ 9000 are presented herein. A tube bundle, a Laws’ perforated plate and an etoile were located at the entrance of a smooth circular pipe of inner diameter, D = 26.6 mm . The covered ranges of open area ratio, β and non-dimensional length, L / D were 0.49 ≤ β ≤ 0.74 and 0.123 ≤ L / D ≤ 2 respectively. The cross-sectional axial velocity u = u ( r ) profiles at the downstream stations of X / D = 75 , X / D = 375 , X / D = 680 together with pressure losses Δ P are referred to determine the influence of utilized designs. The flow conditioners have a single performance characteristic expressed through a relationship of pressure loss coefficient K = K ( Re β ) which provides a practical method for the calculation of time-averaged pressure loss, Δ P ̄ in an average error margin of ±18%. The laminar flow inside the pipe without an insert in the range of Re < 2450 is not fully developed sensed with u = u ( r ) profiles having a ±20% deviation from the Blasius profile for the lengths X / D < 680 . Meanwhile flow conditioners provide a fully developed laminar flow independent of Re and X observed in terms of downstream u = u ( r ) profiles with a better fit to the Blasius profile in a mean error margin of ±10%. The laminar flow control via flow conditioners is analyzed through a discussion in terms of the introduced local non-dimensional velocity parameters. The used methodology is based on the definition of entrance length Reynolds Number; Re X = ( X / D ) Re . The proposed equations “ Re X β = C ” (where C is a constant) can be used for the estimation of settling distance of the flow conditioners and laminar entrance length. The experimental data are in conformity with the magnitudes of C = 2.87 × 10 4 and C = 3 × 10 5 with the corresponding error margins of ±4% and ±6% respectively.

Generalized Hydraulic Calculation Method for Axial Flow of Non-Newtonian Fluids in Eccentric Annuli

Summary The flow of non-Newtonian fluids through eccentric annuii is prevalent during drilling and cementing operations of directional and horizontal wells. The flow pattern in an eccentric annulus can differ greatly from that in a concentric annulus, and this difference affects both the pressure drop and the flow rate at which the laminar-turbulent transition occurs. Errors resulting from ignoring the effect of eccentricity on frictional pressure drop and equivalent circulating density can lead to formation fracture or well-control problems in some situations. In this paper, a new method is presented for calculating pressure losses in eccentric annuli. The method is based on an effective diameter that accounts for the effects of both conduit geometry and fluid rheology. Predictions of the method are compared with an extensive set of data for drilling fluids obtained from a large-scale flow loop. The results demonstrate that the new method is capable of reliably predicting the pressure drop of most drilling fluids in both laminar and turbulent flow regimes for eccentric annular geometries of practical interest.

Real-Time Drilling-Process Optimization

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 119650, "Real-Time Optimization of the Drilling Process - Challenges in Industrialization," by E. Cayeux, SPE, E.W. Dvergsnes, SPE, and F. Iversen, SPE, International Research Institute of Stavanger, originally prepared for the 2009 SPE/IADC Drilling Conference and Exhibition, Amsterdam, 17-19 March. The paper has not been peer reviewed. A new drilling-control system for real-time optimization and automation has been developed in an ongoing research project, which now will enter an industrialization phase. The system, which is based on application of advanced real-time process models for calculation of both hydraulic and mechanical forces, requires an extensive set of input data. Results from the calculation modules are applied directly in the drilling-control system, affecting parameters such as pipe acceleration, velocity and deceleration, and the pump-startup profile. Introduction During the last decade, computer-controlled machinery have made it possible to control the drawworks, the topdrive, mud pumps, and the iron roughneck or pipe-handling equipment from a drilling workstation by use of joysticks and keypads. Recent developments enable control of the machinery within safe-guard boundaries through application of model simulations, accounting for the effects of fluid and pipe movements in the wellbore. These new extended systems have the potential to reduce the risk of damaging the well and the downhole equipment and, subsequently, to reduce nonproductive time. For such extended systems to function properly, a more precise description of the drillstring components is required to calculate pressure losses, mechanical loads, and heat transfer. Furthermore, complete descriptions of the wellbore architecture, formation prognosis, trajectory, and drilling-fluid properties are needed for configuration of the applied models. Most of this information is not available in standard rig systems, and no standard work process has been established to make this information available before actual operations. For such systems to achieve their full potential, the necessary information must be quality controlled and made available at the right time, because an error in this information could lead to potentially serious incidents. In January 2008, a field test of a new system for automated control of the drilling process was performed on the Statfjord C platform in the North Sea. Because the system was developed through a research project, the focus up to now has been on robustness. The system now is entering the industrialization phase, with a stronger focus on system application, including the following.Sensor quality and reliability.Availability of wellbore description including information exchange between different systems.Work processes for updating well bore description and quality control of data.User friendliness.Personnel training.