Numerical Study on the Impact of Spiral Tortuous Hole on Cuttings Removal in Horizontal Wells

2021 ◽  
pp. 1-16
Author(s):  
Mohamed Shafik Khaled ◽  
Hicham Ferroudji ◽  
Mohammad Azizur Rahman ◽  
Ibrahim Hasan Galal ◽  
A. Rashid Hasan
Keyword(s):  
Numerical Study ◽  
Flow Behavior ◽  
Fluid Velocity ◽  
Horizontal Wells ◽  
Relative Magnitude ◽  
Hole Cleaning ◽  
Critical Range ◽  
Spiral Geometry ◽  
Polyhedral Mesh ◽  
The Impact

Summary Horizontal wells are designed to have smooth (straight), curved, and lateral sections. However, the actual drilled path usually suffers from unwanted undulations from the planned well trajectory known as wellbore tortuosity. Wellbore tortuosity can slow the drilling penetration rate, aggravate drillstring vibration and buckling, complicate the casing and cement job, and lead to inaccurate wellbore position. This paper presents a validated computational fluid dynamics (CFD) model to investigate the impact of wellbore tortuosity on hole cleaning. The Eulerian-Eulerian approach is used to simulate solid-liquid laminar flow in annular geometry using polyhedral mesh. Then, the impact of wellbore tortuosity on cuttings accumulation, annular pressure loss, and fluid velocity was investigated and compared with the flow behavior in a straight horizontal well. A parametric analysis of spiral period length, spiral amplitude, drillstring rotation, flow rate, annular eccentricity, drilling rate of penetration (ROP), and cuttings size was conducted to assess their influence on cuttings transport in spiral tortuous holes and their relative magnitude to other design or operating factors. Simulation results show that polyhedral mesh is an optimum meshing technique for spiral profile geometry. Wellbore tortuosity aggravates hole cleaning in lateral sections based on the length of the spiral period and/or the spiral amplitude. Reduction in cuttings velocity was observed in the top part of the spiral geometry (crest), causing large deposition of cuttings in this area compared to the spiral lower part (trough). Drillstring rotation from 0 to 200 rev/min is the critical range for efficient hole cleaning in spiral geometry. Cuttings size can improve cuttings accumulation if the particle size is larger than the viscous layer located near the bed velocity profile. The drilling ROP and annular eccentricity aggravate cuttings accumulation and bed deposition in a spiral hole, similar to what is normally observed in straight horizontal wells.

scholarly journals Analysis of Arrhenius Kinetics on Multiphase Flow between a Pair of Rotating Circular Plates

2020 ◽  
Vol 2020 ◽  
pp. 1-17 ◽  
Author(s):  
M. B. Arain ◽  
M. M. Bhatti ◽  
A. Zeeshan ◽  
Tareq Saeed ◽  
Aatef Hobiny
Keyword(s):  
Flow Behavior ◽  
Fluid Velocity ◽  
Shear Thickening ◽  
Shear Thinning ◽  
Three Dimensions ◽  
Fluid Viscosity ◽  
Circular Plates ◽  
Carreau Fluid ◽  
Moving Plate ◽  
The Impact

In this study, we aim to deal with the flow behavior betwixt a pair of rotating circular plates filled with Carreau fluid under the suspension of nanoparticles and motile gyrotactic microorganisms in the presence of generalized magnetic Reynolds number. The activation energy is also contemplated with the nanoparticle concentration equation. The appropriate similarity transformations are used to formulate the proposed mathematical modeling in the three dimensions. The outcomes of the torque on both plates, i.e., the fix and the moving plate, are also contemplated. A well-known differential transform method (DTM) with a combination of Padé approximation will be implemented to get solutions to the coupled nonlinear ordinary differential equations (ODEs). The impact of different nondimensional physical aspects on velocity profile, temperature, concentration, and motile gyrotactic microorganism functions is discussed. The shear-thinning fluid viscosity decreases with shear strain due to its high velocity compared to the Newtonian and shear-thickening case. The impact of Carreau fluid velocity for shear-thinning n < 1 , Newtonian case n = 0 , and shear-thickening n > 1 cases on axial velocity distribution f ′ λ has been discussed in tabular form and graphical figures. For the validation of the current methodology, a comparison is made between DTM-Padé and the numerical shooting scheme.

Aerodynamic performance analysis and optimization of a turbine duct with low degree of partial admission

2017 ◽  
Vol 232 (5) ◽  
pp. 988-1001 ◽  
Author(s):  
Xiuming Sui ◽  
Wei Zhao ◽  
Xiaolei Sun ◽  
Weiwei Luo ◽  
Qingjun Zhao
Keyword(s):  
Pressure Gradient ◽  
Negative Impact ◽  
Numerical Study ◽  
Flow Behavior ◽  
Adverse Pressure Gradient ◽  
Partial Admission ◽  
Duct Geometry ◽  
Inlet Conditions ◽  
Comparative Results ◽  
The Impact

A partial admission turbine duct with outlet-to-inlet area ratio greater than unity can increase the admission degree of the downstream turbine stage and, thus improve the performance of a multistage turbine with a low partial admission degree. However, the upstream flow structures of ducts, such as secondary flow, especially the circumferential nonuniformities originating from the effect of the partial admission, make the flow in ducts complex. The complexity of the flow has a negative impact on the performance of ducts. In the present investigation, numerical study of the flow behavior within ducts is done to evaluate the effect of the partial admission on the performance of the ducts. The study is carried out with regard to two cases, i.e. which are with the same duct geometry but are at different working conditions to highlight the impact of partial admission on the performance of ducts. Case 1 is used as baseline. It is designed based on circumferential mass-averaged flow conditions at ducts inlet. It causes the circumferential nonuniformities originating from the partial admission to have no impact on the performance of case 1. Case 2, which considers partial admission, is compared with case 1 to know the impact of the partial admission on the performance of ducts, and to give guidelines to design a duct for the partial admission turbines. Since the duct inlet conditions is a result of the interaction between partial admission turbine and duct, a straightforward way to consider the effect of the partial admission is to simulate the flows in ducts and upstream turbines contemporaneously. Comparative results indicate that the mixing of main flow in the admitted channel and the windage fluid from the unadmitted channel occurs at the duct inlet close to the duct circumferential wall. The adverse pressure gradient of case 2 in that region becomes larger than that of case 1. As a result, the flow separates at that region deteriorating the performance of ducts. Based on the simulation results of the previous cases, case 2’s circumferential wall surface, which is along the gas swirling direction is shrunk to accelerate the flow and, thereby, overcome the adverse pressure gradient imposed by the effect of the partial admission. The results show that the separation is restrained and the decrease in total pressure loss is 52.9%.

A Combined Experimental and Numerical Study of the Turbine Blade Tip Film Cooling Effectiveness Under Rotation Condition

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Mohsen Rezasoltani ◽  
Kun Lu ◽  
Meinhard T. Schobeiri ◽  
Je-Chin Han
Keyword(s):  
Film Cooling ◽  
Numerical Study ◽  
Flow Behavior ◽  
Experimental Investigations ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Rotor Imbalance ◽  
Blade Tip ◽  
The Impact ◽  
Compound Angle

Detailed numerical and experimental investigations of film cooling effectiveness were conducted on the blade tips of the first rotor row pertaining to a three-stage research turbine. Four different blade tip ejection configurations were utilized to determine the impact of the hole arrangements on the film cooling effectiveness. Plane tip with tip hole cooling, squealer tip with tip hole cooling, plane tip with pressure side (PS) edge compound angle hole cooling, and squealer tip with PS-edge compound angle hole cooling. To avoid rotor imbalance, every pair is installed radially. Film cooling effectiveness measurements were performed for three blowing ratios (M) of 0.75, 1.25, and 1.75. Film cooling data was also obtained for three rotational speeds; 3000 rpm (reference condition), 2550 rpm and 2000 rpm. Film cooling measurements were performed using pressure sensitive paint (PSP) technique. In a parallel effort, extensive numerical investigations of the above configurations were performed to give a better view of flow behavior using a commercially available code. The experimental investigations were performed in the three-stage multipurpose turbine research facility at the Turbomachinery Performance and Flow Research Laboratory (TPFL), Texas A&M University.

scholarly journals On Interactions Between Wind Turbines and the Marine Boundary Layer

2017 ◽  
Author(s):  
M. Salman Siddiqui ◽  
Adil Rasheed ◽  
Mandar Tabib ◽  
Eivind Fonn ◽  
Trond Kvamsdal
Keyword(s):  
Wind Turbines ◽  
Wind Farm ◽  
Marine Boundary Layer ◽  
Turbulent Flux ◽  
Numerical Study ◽  
Flow Behavior ◽  
Spatial Averaging ◽  
Governing Equations ◽  
Dispersive Fluxes ◽  
The Impact

Most mesoscale models are developed with grid resolution in the range of kilometers. Therefore, they may require spatial averaging to analyze flow behavior over the domain of interest. In doing so, certain important features of sub-grid scales are lost. Moreover, spatial averaging on the governing equations results in additional terms known as dispersive fluxes. These fluxes are ignored in the analysis. The aim of this paper is to identify the significance of these fluxes for accurate assessment of flow fields related to wind farm applications. The research objectives are hence twofold: 1) to quantify the impact of wind turbines on MBL characteristics. 2) to account for the magnitude of dispersive fluxes arising from spatial averaging and make a comparison against the turbulent flux values. To conduct the numerical study the NREL 5MW reference wind turbine model is employed with a RANS approach using k-ε turbulence model. The results are presented concerning spatially averaged velocity, wake deficit behind the turbine, dispersive and turbulent fluxes.

scholarly journals A Comparative Study of Pressure Losses and Hole Cleaning Efficiency of Water and Polymer solutions in Horizontal Wells

2019 ◽  
Vol 20 (4) ◽  
pp. 35-40
Author(s):  
Karrar Ahmed Mohammed ◽  
Ayad A. Al-Haleem
Keyword(s):  
Pressure Drop ◽  
Test Section ◽  
Fluid Velocity ◽  
Polymer Concentration ◽  
Horizontal Wells ◽  
Flow Loop ◽  
Cleaning Efficiency ◽  
Hole Cleaning ◽  
Pressure Losses ◽  
Pressure Transmitter

The main objective of this study is to experimentally investigate the effect of the CMC polymeric drag reducer on the pressure drop occurred along the annulus of the wellbore in drilling operation and investigate the optimum polymer concentration that give the minimum pressure drop. A flow loop was designed for this purpose consist from 14 m long with transparent test section and differential pressure transmitter that allows to sense and measure the pressure losses along the test section. The results from the experimental work show that increasing in polymer concentration help to reduce the pressure drop in annulus and the optimum polymer concentration with the maximum drag reducing is 0.8 kg/m3. Also increasing in flow rate and corresponding fluid velocity in the gap of the annulus helped to reduce the pressure losses due to fluid flow.

scholarly journals IMPACT OF CHANGING ABSORBER SHAPE ON AN AIR FLOW BEHAVIOR IN A THERMO-SOLAR CONVERTER

2021 ◽  
Vol 5 (6) ◽  
pp. 74-86
Author(s):  
Hamidou Benzenine ◽  
Said Abboudi ◽  
Rachid Saim
Keyword(s):  
Numerical Study ◽  
Volume Flow Rate ◽  
Flow Behavior ◽  
Volume Flow ◽  
Low Flow ◽  
Solar Air Heater ◽  
Flow Rates ◽  
Average Temperature ◽  
Axial Variation ◽  
The Impact

In this paper, a two-dimensional numerical study of heat exchange by forced convection of an incompressible laminar flow in a solar air heater duct (SAH), which is equipped with a shoulder attached to the absorber, was performed. The impact of three locations of this shoulder and their three heights on friction losses, as well as the drag coefficient, the variations of velocity, and temperature at the exit section of the SAH, were analyzed for a volume flow rate in the range [20-80 m3/h.]. The results obtained numerically prove that the insertion of a shoulder on the absorber improves the heat transfer and the dynamics of the flow very significantly. An average temperature difference (inlet-outlet) of the collector of 23.51 °C at 29.94 °C and 50.64 °C at 67.53 °C is acquired respectively for the high and the low flow rates. This paper also showed that the height of the shoulder used can ensure an acceleration of the flow with an axial variation of the order of 1.25 up to 2.5 times (> twice) compared with the simple case.

Investigation on the control of multiphase flow behavior in a continuous casting tundish during ladle change

2020 ◽  
Vol 117 (6) ◽  
pp. 619
Author(s):  
Rui Xu ◽  
Haitao Ling ◽  
Haijun Wang ◽  
Lizhong Chang ◽  
Shengtao Qiu
Keyword(s):  
Multiphase Flow ◽  
Flow Behavior ◽  
Rolled Strip ◽  
Impact Zone ◽  
Steel Cleanliness ◽  
Carry Over ◽  
Slag Carry Over ◽  
Hot Rolled ◽  
Turbulence Inhibitor ◽  
The Impact

The transient multiphase flow behavior in a single-strand tundish during ladle change was studied using physical modeling. The water and silicon oil were employed to simulate the liquid steel and slag. The effect of the turbulence inhibitor on the slag entrainment and the steel exposure during ladle change were evaluated and discussed. The effect of the slag carry-over on the water-oil-air flow was also analyzed. For the original tundish, the top oil phase in the impact zone was continuously dragged into the tundish bath and opened during ladle change, forming an emulsification phenomenon. By decreasing the liquid velocities in the upper part of the impact zone, the turbulence inhibitor decreased considerably the amount of entrained slag and the steel exposure during ladle change, thereby eliminating the emulsification phenomenon. Furthermore, the use of the TI-2 effectively lowered the effect of the slag carry-over on the steel cleanliness by controlling the movement of slag droplets. The results from industrial trials indicated that the application of the TI-2 reduced considerably the number of linear inclusions caused by ladle change in hot-rolled strip coils.

Numerical study of the flow of a mixture of reacting gases in an inhomogeneous catalyst layer

2003 ◽  
Vol 3 ◽  
pp. 246-254
Author(s):  
C.I. Mikhaylenko ◽  
S.F. Urmancheev
Keyword(s):  
Velocity Field ◽  
Chemical Reactions ◽  
Porous Layer ◽  
Computational Experiment ◽  
Numerical Study ◽  
Fluid Velocity ◽  
Catalyst Layer ◽  
Granular Catalyst ◽  
Fluid Velocity Field

The behavior of a liquid flowing through a fixed bulk porous layer of a granular catalyst is considered. The effects of the nonuniformity of the fluid velocity field, which arise when the surface of the layer is curved, and the effect of the resulting inhomogeneity on the speed and nature of the course of chemical reactions are investigated by the methods of a computational experiment.

scholarly journals Model of thermal buoyancy in cavity-ventilated roof constructions

2021 ◽  
pp. 174425912098418
Author(s):  
Toivo Säwén ◽  
Martina Stockhaus ◽  
Carl-Eric Hagentoft ◽  
Nora Schjøth Bunkholt ◽  
Paula Wahlgren
Keyword(s):  
Analytical Model ◽  
Flow Rate ◽  
Numerical Study ◽  
Air Flow ◽  
Wind Pressure ◽  
Air Flow Rate ◽  
Test Set ◽  
Air Cavity ◽  
Thermal Buoyancy ◽  
The Impact

Timber roof constructions are commonly ventilated through an air cavity beneath the roof sheathing in order to remove heat and moisture from the construction. The driving forces for this ventilation are wind pressure and thermal buoyancy. The wind driven ventilation has been studied extensively, while models for predicting buoyant flow are less developed. In the present study, a novel analytical model is presented to predict the air flow caused by thermal buoyancy in a ventilated roof construction. The model provides means to calculate the cavity Rayleigh number for the roof construction, which is then correlated with the air flow rate. The model predictions are compared to the results of an experimental and a numerical study examining the effect of different cavity designs and inclinations on the air flow rate in a ventilated roof subjected to varying heat loads. Over 80 different test set-ups, the analytical model was found to replicate both experimental and numerical results within an acceptable margin. The effect of an increased total roof height, air cavity height and solar heat load for a given construction is an increased air flow rate through the air cavity. On average, the analytical model predicts a 3% higher air flow rate than found in the numerical study, and a 20% lower air flow rate than found in the experimental study, for comparable test set-ups. The model provided can be used to predict the air flow rate in cavities of varying design, and to quantify the impact of suggested roof design changes. The result can be used as a basis for estimating the moisture safety of a roof construction.

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