Modeling and Experimental Study of Newtonian Fluid Flow in Annulus

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Mehmet Sorgun ◽  
M. Evren Ozbayoglu ◽  
Ismail Aydin
Keyword(s):  
Experimental Data ◽  
Pressure Loss ◽  
Drilling Fluid ◽  
Mechanistic Model ◽  
Tangential Velocity ◽  
Petroleum Engineering ◽  
Flow Loop ◽  
Pressure Losses ◽  
Laminar And Turbulent Flow ◽  
Drilling Operations

A major concern in drilling operations is the proper determination of frictional pressure loss in order to select a mud pump and avoid any serious problems. In this study, a mechanistic model is proposed for predicting the frictional pressure losses of light drilling fluid, which can be used for concentric annuli. The experimental data that were available in the literature and conducted at the Middle East Technical University-Petroleum Engineering (METU-PETE) flow loop as well as computational fluid dynamics (CFD) software are used to verify the results from the proposed mechanistic model. The results showed that the proposed model can estimate frictional pressure losses within a ±10% error interval when compared with the experimental data. Additionally, the effect of the pipe eccentricity on frictional pressure loss and tangential velocity using CFD for laminar and turbulent flow is also examined. It has been observed that pipe eccentricity drastically increases the tangential velocity inside the annulus; especially, the flow regime is turbulent and frictional pressure loss decreases as the pipe eccentricity increases.

Modeling of Newtonian Fluids in Annular Geometries With Inner Pipe Rotation

2010 ◽  
Author(s):  
Mehmet Sorgun ◽  
Jerome J. Schubert ◽  
Ismail Aydin ◽  
M. Evren Ozbayoglu
Keyword(s):  
Axial Velocity ◽  
Pressure Loss ◽  
Tangential Velocity ◽  
Flow Characteristics ◽  
Newtonian Fluids ◽  
Flow Loop ◽  
Eccentric Annulus ◽  
Pressure Losses ◽  
Proposed Model ◽  
Pipe Rotation

Flow in annular geometries, i.e., flow through the gap between two cylindrical pipes, occurs in many different engineering professions, such as petroleum engineering, chemical engineering, mechanical engineering, food engineering, etc. Analysis of the flow characteristics through annular geometries is more challenging when compared with circular pipes, not only due to the uneven stress distribution on the walls but also due to secondary flows and tangential velocity components, especially when the inner pipe is rotated. In this paper, a mathematical model for predicting flow characteristics of Newtonian fluids in concentric horizontal annulus with drill pipe rotation is proposed. A numerical solution including pipe rotation is developed for calculating frictional pressure loss in concentric annuli for laminar and turbulent regimes. Navier-Stokes equations for turbulent conditions are numerically solved using the finite differences technique to obtain velocity profiles and frictional pressure losses. To verify the proposed model, estimated frictional pressure losses are compared with experimental data which were available in the literature and gathered at Middle East Technical University, Petroleum & Natural Gas Engineering Flow Loop (METU-PETE Flow Loop) as well as Computational Fluid Dynamics (CFD) software. The proposed model predicts frictional pressure losses with an error less than ± 10% in most cases, more accurately than the CFD software models depending on the flow conditions. Also, pipe rotation effects on frictional pressure loss and tangential velocity is investigated using CFD simulations for concentric and fully eccentric annulus. It has been observed that pipe rotation has no noticeable effects on frictional pressure loss for concentric annuli, but it significantly increases frictional pressure losses in an eccentric annulus, especially at low flow rates. For concentric annulus, pipe rotation improves the tangential velocity component, which does not depend on axial velocity. It is also noticed that, as the pipe rotation and axial velocity are increased, tangential velocity drastically increases for an eccentric annulus. The proposed model and the critical analysis conducted on velocity components and stress distributions make it possible to understand the concept of hydro transport and hole cleaning in field applications.

Hydraulics of Drilling With Aerated Muds Under Simulated Borehole Conditions

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
L. Zhou ◽  
R. M. Ahmed ◽  
S. Z. Miska ◽  
N. E. Takach ◽  
M. Yu ◽  
...  
Keyword(s):  
Pressure Loss ◽  
Volume Fraction ◽  
Mechanistic Model ◽  
Liquid Ratio ◽  
Flow Loop ◽  
Pressure Losses ◽  
Flow Parameters ◽  
Underbalanced Drilling ◽  
Measured Flow ◽  
Gas Volume

Maintaining optimum circulation rates is important in aerated mud drilling operations. However, reliable predictions of the optimum rates require accurate modeling of the frictional pressure loss at bottom-hole conditions. This paper presents a mechanistic model for underbalanced drilling with aerated muds. Extensive experiments in a unique field-scale high pressure and high temperature flow loop were performed to verify the predictions of the model. This flow loop has a 150×89 mm2(6″×3.5″) horizontal annular geometry and is 22 m long. In the experiments, cuttings were introduced at a rate of 7.5 kg/min, representing a penetration rate of 15 m/h in the annular test section. The liquid phase flow rates were in the range of 0.30–0.57 m3/min, representing superficial liquid velocities in the range of 0.47–0.90 m/s. The gas liquid ratio (gas volume fraction under in situ condition) was varied from 0.0 to 0.38. Test pressures and temperatures ranged from 1.28 to 3.45 MPa, and 27°C to 80°C, respectively. Gas liquid ratios were chosen to simulate practical gas liquid ratios under downhole conditions. For all the test runs, pressure drop and cuttings bed height over the entire annular section were measured. Flow patterns were identified by visual observations through a view port. The hydraulic model determines the flow pattern and predicts frictional pressure losses in a horizontal concentric annulus. The influences of the gas liquid ratio and other flow parameters on the frictional pressure loss are analyzed using this model. Comparisons between the model predictions and experimental measurements show a satisfactory agreement. The present model is useful for the design of underbalanced drilling applications in a horizontal wellbore.

Effect of Drillstring Deflection and Rotary Speed on Annular Frictional Pressure Losses

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Oney Erge ◽  
Mehmet E. Ozbayoglu ◽  
Stefan Z. Miska ◽  
Mengjiao Yu ◽  
Nicholas Takach ◽  
...  
Keyword(s):  
Power Law ◽  
Pressure Loss ◽  
Drilling Fluid ◽  
Hole Drilling ◽  
Accurate Estimation ◽  
Turbulent Friction ◽  
Horizontal Drilling ◽  
Pressure Losses ◽  
Power Law Fluids ◽  
Drilling Operations

Keeping the drilling fluid equivalent circulating density in the operating window between the pore and fracture pressure is a challenge, particularly when the gap between these two is narrow, such as in offshore, extended reach, and slim hole drilling applications usually encountered in shale gas and/or oil drilling. To overcome this challenge, accurate estimation of frictional pressure loss in the annulus is essential. A better estimation of frictional pressure losses will enable improved well control, optimized bit hydraulics, a better drilling fluid program, and pump selection. Field and experimental measurements show that pressure loss in annuli is strongly affected by the pipe rotation and eccentricity. The major focus of this project is on a horizontal well setup with drillstring under compression, considering the influence of rotation on frictional pressure losses of yield power law fluids. The test matrix includes flow through the annulus for various buckling modes with and without the rotation of the inner pipe. Sinusoidal, helical, and transition from sinusoidal to helical configurations with and without the drillstring rotation were investigated. Helical configurations with two different pitch lengths are compared. Eight yield power law fluids are tested and consistent results are observed. The drillstring rotation patterns and buckling can be observed due to experimental facility's relatively longer and transparent test section. At the initial position, inner pipe is lying at the bottom due to its extensive length, suggesting a fully eccentric annular geometry. When the drillstring is rotated, whirling, snaking, irregular motions are observed. This state is considered as a free drillstring configuration since there is no prefixed eccentricity imposed on the drillstring. The reason for such design is to simulate the actual drilling operations, especially the highly inclined and horizontal drilling operations. Results show that rotating the drillstring can either increase or decrease the frictional pressure losses. The most pronounced effect of rotation is observed in the transition region from laminar to turbulent flow. The experiments with the buckled drillstring showed significantly reduced frictional pressure losses compared to the free drillstring configuration. Decreasing the length of the pitch caused a further reduction in pressure losses. Using the experimental database, turbulent friction factors for buckled and rotating drillstrings are presented. The drilling industry has recently been involved in incidents that show the need for critical improvements for evaluating and avoiding risks in oil/gas drilling. The information obtained from this study can be used to improve the control of bottomhole pressures during extended reach, horizontal, managed pressure, offshore, and slim hole drilling applications. This will lead to improved safety and enhanced optimization of drilling operations.

Annular Frictional Pressure Losses During Drilling—Predicting the Effect of Drillstring Rotation

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Arild Saasen
Keyword(s):  
Rheological Properties ◽  
Pressure Loss ◽  
Drilling Fluid ◽  
Axial Flow ◽  
Drilling Fluids ◽  
Unstable Flow ◽  
Pressure Losses ◽  
Shear Dependent Viscosity ◽  
Water Based ◽  
Dependent Viscosity

Controlling the annular frictional pressure losses is important in order to drill safely with overpressure without fracturing the formation. To predict these pressure losses, however, is not straightforward. First of all, the pressure losses depend on the annulus eccentricity. Moving the drillstring to the wall generates a wider flow channel in part of the annulus which reduces the frictional pressure losses significantly. The drillstring motion itself also affects the pressure loss significantly. The drillstring rotation, even for fairly small rotation rates, creates unstable flow and sometimes turbulence in the annulus even without axial flow. Transversal motion of the drillstring creates vortices that destabilize the flow. Consequently, the annular frictional pressure loss is increased even though the drilling fluid becomes thinner because of added shear rate. Naturally, the rheological properties of the drilling fluid play an important role. These rheological properties include more properties than the viscosity as measured by API procedures. It is impossible to use the same frictional pressure loss model for water based and oil based drilling fluids even if their viscosity profile is equal because of the different ways these fluids build viscosity. Water based drilling fluids are normally constructed as a polymer solution while the oil based are combinations of emulsions and dispersions. Furthermore, within both water based and oil based drilling fluids there are functional differences. These differences may be sufficiently large to require different models for two water based drilling fluids built with different types of polymers. In addition to these phenomena washouts and tool joints will create localised pressure losses. These localised pressure losses will again be coupled with the rheological properties of the drilling fluids. In this paper, all the above mentioned phenomena and their consequences for annular pressure losses will be discussed in detail. North Sea field data is used as an example. It is not straightforward to build general annular pressure loss models. This argument is based on flow stability analysis and the consequences of using drilling fluids with different rheological properties. These different rheological properties include shear dependent viscosity, elongational viscosity and other viscoelastic properties.

Pressure Losses and Limiting Reynolds Numbers for Non-Newtonian Fluids in Short Square-Edged Orifice Plates

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Butteur Ntamba Ntamba ◽  
Veruscha Fester
Keyword(s):  
Pressure Loss ◽  
Reynolds Numbers ◽  
Newtonian Fluids ◽  
Pressure Losses ◽  
Pressure Loss Coefficient ◽  
Stable Operating ◽  
Piping Systems ◽  
Laminar And Turbulent Flow ◽  
Loss Coefficients ◽  
Industrial Problem

Correlations predicting the pressure loss coefficient along with the laminar, transitional, and turbulent limiting Reynolds numbers with the β ratio are presented for short square-edged orifice plates. The knowledge of pressure losses across orifices is a very important industrial problem while predicting pressure losses in piping systems. Similarly, it is important to define stable operating regions for the application of a short orifice at lower Reynolds numbers. This work experimentally determined pressure loss coefficients for square-edged orifices for orifice-to-diameter ratios of β = 0.2, 0.3, 0.57, and 0.7 for Newtonian and non-Newtonian fluids in both laminar and turbulent flow regimes.

scholarly journals CFD Method for Predicting Annular Pressure Losses and Cuttings Concentration in Eccentric Horizontal Wells

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Titus N. Ofei ◽  
Sonny Irawan ◽  
William Pao
Keyword(s):  
Experimental Data ◽  
Oil And Gas ◽  
Current Model ◽  
Fluid Velocity ◽  
Pipe Diameter ◽  
Pressure Losses ◽  
Gas Drilling ◽  
Drilling Parameters ◽  
Drilling Operations ◽  
Oil And Gas Drilling

In oil and gas drilling operations, predictions of pressure losses and cuttings concentration in the annulus are very complex due to the combination of interacting drilling parameters. Past studies have proposed many empirical correlations to estimate pressure losses and cuttings concentration. However, these developed correlations are limited to their experimental data range and setup, and hence, they cannot be applicable to all cases. CFD methods have the advantages of handling complex multiphase flow problems, as well as, an unlimited number of physical and operational conditions. The present study employs the inhomogeneous (Eulerian-Eulerian) model to simulate a two-phase solid-fluid flow and predict pressure losses and cuttings concentration in eccentric horizontal annuli as a function of varying drilling parameters: fluid velocity, diameter ratio (ratio of inner pipe diameter to outer pipe diameter), inner pipe rotation speed, and fluid type. Experimental data for pressure losses and cuttings concentration from previous literature compared very well with simulation data, confirming the validity of the current model. The study shows how reliable CFD methods can replicate the actual, yet complex oil and gas drilling operations.

Buoyancy Induced Convection of Riser Gas in Deepwater Drilling Operations

2019 ◽  
Author(s):  
Syed Y. Nahri ◽  
Yuanhang Chen ◽  
Wesley Williams ◽  
Otto Santos ◽  
Ting Sun
Keyword(s):  
Mass Transfer ◽  
Natural Gas ◽  
Drilling Fluid ◽  
Gas Absorption ◽  
Petroleum Engineering ◽  
Drilling Fluids ◽  
Engineering Research ◽  
Deepwater Drilling ◽  
Area Of Interest ◽  
Drilling Operations

Abstract Riser gas migration has been an area of interest since the last three decades due to its importance in gas handling in deepwater drilling operations. A previously conducted full-scale test at LSU Petroleum Engineering Research & Technology Transfer (PERTT) well facility indicates, as contrary to traditional belief, significant migration of dissolved gas taking place even when circulation had ceased. In order to understand whether a reduction in density of the underlying contaminated mud resulting from gas absorption is the contributing factor to the above-mentioned phenomenon, a computational fluid dynamics (CFD) analysis was conducted to study the transport of the gas influx while in solution due to buoyancy induced convective mass transfer and simultaneous diffusion. Simulations performed in this study include the hydrodynamics of the upward moving gas cut mud and simultaneous mass transfer of natural gas into the under-saturated drilling fluid. The parameters studied here are the distance traveled of the gas cut mud and saturation levels in the drilling fluid along the length of the riser. The dense phase behavior was shown to have considerable effects on gas loading capacities which in turn affected the density of the gas cut mud, and at pressures upwards of 5,000 psi, the solubility of a natural gas influx can be seen to be infinite in certain synthetic and oil-based drilling fluids. The rate and extent of mass transfer are dependent on drilling fluid density gradients, which in turn are based on gas influx saturation level. Results obtained from this study can help better comprehend migration phenomena of a dissolved influx in oil-based muds in a riser with the BOP shut in and when circulation has ceased.

Effect of Drillstring Deflection and Rotary Speed on Annular Frictional Pressure Losses

2013 ◽  
Author(s):  
Oney Erge ◽  
Mehmet E. Ozbayoglu ◽  
Stefan Z. Miska ◽  
Mengjiao Yu ◽  
Nicholas Takach ◽  
...  
Keyword(s):  
Pressure Loss ◽  
Drilling Fluid ◽  
Flow Behavior ◽  
Hole Drilling ◽  
Accurate Estimation ◽  
Drilling Fluids ◽  
Limited Information ◽  
Pressure Losses ◽  
Gas Drilling ◽  
Fracture Pressure

Keeping the drilling fluid equivalent circulating density in the operating window between the pore and fracture pressure is a challenge, particularly when the gap between these two is narrow, such as in offshore applications. To overcome this challenge, accurate estimation of frictional pressure loss in the annulus is essential, especially for multilateral, extended reach and slim hole drilling applications usually encountered in shale gas and/or oil drilling. A better estimation of frictional pressure losses will provide improved well control, optimized bit hydraulics, a better drilling fluid program and pump selection. Field and experimental measurements showed that pressure loss in the annulus is strongly affected by the pipe rotation and eccentricity. Eccentricity will not be constant throughout a wellbore, especially in highly inclined and horizontal sections. In an actual wellbore, because of rotation speed and the applied weight, some portion of the drillstring will undergo compression. As a result, variable eccentricity will be encountered. At high compression, the drillstring will buckle, resulting in sinusoidal or helical buckling configurations. Most of the drilling fluids used today show highly non-Newtonian flow behavior, which can be characterized using the Yield Power Law (YPL). Nevertheless, in the literature, there is limited information and research on YPL fluids flowing through annular geometries with the inner pipe buckled, rotating, and eccentric. Furthermore, there are discrepancies reported between the estimated and measured frictional pressure losses with or without drillstring rotation of YPL fluids, even when the inner pipe is straight. The major focus of this project is on a horizontal well setup with drillstring under compression, considering the influence of rotation on frictional pressure losses of YPL fluids. The test matrix includes flow through the annulus for various buckling modes with and without rotation of the inner pipe. Sinusoidal, helical and transition from sinusoidal to helical configurations with and without the rotation of the drillstring are investigated. Results show a substantial difference of frictional pressure losses between the non-compressed and compressed drillstring. The drilling industry has recently been involved in incidents that show the need for critical improvements for evaluating and avoiding risks in oil/gas drilling. The information obtained from this study can be used to improve the control of bottomhole pressures during extended reach, horizontal, managed pressure, offshore and slim hole drilling applications. This will lead to safer and enhanced optimization of drilling operations.

Experimental Investigation of Friction and Hydraulics in Circular and Non-Circular Wellbores With Oil Based Drilling Fluids

2017 ◽  
Author(s):  
Ali Taghipour ◽  
Bjørnar Lund ◽  
Jan David Ytrehus
Keyword(s):  
Test Section ◽  
Drilling Fluid ◽  
Drilling Fluids ◽  
Drilling Process ◽  
Operational Parameters ◽  
Flow Loop ◽  
Cuttings Transport ◽  
Hole Cleaning ◽  
Experimental Laboratory ◽  
Drilling Operations

Borehole hydraulics, hole cleaning and mechanical friction are important factors for well planning and drilling operations. Many studies aim to exploit and optimize the effect of different operational parameters. The effect of wellbore geometry on hole cleaning and mechanical friction has so far not received much attention. This paper presents results from experimental laboratory tests where hydraulics, hole cleaning and mechanical friction have been investigated for circular and non-circular wellbore geometries with a relevant oil-based field drilling fluid (OBM). The non-circular wellbore geometry was made by adding spiral grooves to the wellbore walls in order to investigate the effects on cuttings transport and mechanical friction. The study contributes to describe the function and ability of deliberately induced non-circular geometry in wellbores as means to achieve a more efficient drilling and well construction. Improving hole cleaning will improve drilling efficiency in general, and will in particular enable longer reach for ERD wells. Reduced mechanical friction may improve the drilling process and many operations during the completion phase. The laboratory experiments were performed in an advanced flow loop setup reproducing field-relevant flow conditions. The flow loop consists of a 10 m long 4” inner diameter borehole made of concrete. A free whirling rotational string with 2” diameter provides a realistic down hole annular geometry. A field-relevant oil based drilling fluid (OBM) was circulated through the test section at different flow rates. To represent the effect of rate of penetration, synthetic drilling cuttings (quartz sand particles) were injected at different rates through the annulus in the horizontal test section. The test results show that borehole hydraulics and cutting transport properties are significantly improved in the non-circular wellbore relative to the circular wellbore. The effect of the mechanical friction is more complex, yet significantly different for the two geometries.

Experimental Investigation of Friction and Hydraulics in Circular and Non-Circular Wellbores With Oil Based Drilling Fluids

2016 ◽  
Author(s):  
Ali Taghipour ◽  
Bjørnar Lund ◽  
Jan David Ytrehus
Keyword(s):  
Test Section ◽  
Drilling Fluid ◽  
Drilling Fluids ◽  
Drilling Process ◽  
Operational Parameters ◽  
Flow Loop ◽  
Cuttings Transport ◽  
Hole Cleaning ◽  
Experimental Laboratory ◽  
Drilling Operations

Borehole hydraulics, hole cleaning and mechanical friction are important factors for well planning and drilling operations. Many studies aim to exploit and optimize the effect of different operational parameters. The effect of wellbore geometry on hole cleaning and mechanical friction has so far not received much attention. This paper presents results from experimental laboratory tests where hydraulics, hole cleaning and mechanical friction have been investigated for circular and non-circular wellbore geometries with a relevant oil-based field drilling fluid (OBM). The non-circular wellbore geometry was made by adding spiral grooves to the wellbore walls in order to investigate the effects on cuttings transport and mechanical friction. The study contributes to describe the function and ability of deliberately induced non-circular geometry in wellbores as means to achieve a more efficient drilling and well construction. Improving hole cleaning will improve drilling efficiency in general, and will in particular enable longer reach for ERD wells. Reduced mechanical friction may improve the drilling process and many operations during the completion phase. The laboratory experiments were performed in an advanced flow loop setup reproducing field-relevant flow conditions. The flow loop consists of a 10 m long 4″ inner diameter borehole made of concrete. A free whirling rotational string with 2″ diameter provides a realistic down hole annular geometry. A field-relevant oil based drilling fluid (OBM) was circulated through the test section at different flow rates. To represent the effect of rate of penetration, synthetic drilling cuttings (quartz sand particles) were injected at different rates through the annulus in the horizontal test section. The test results show that borehole hydraulics and cutting transport properties are significantly improved in the non-circular wellbore relative to the circular wellbore. The effect of the mechanical friction is more complex, yet significantly different for the two geometries.

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