scholarly journals Simulation of steady-state cuttings transport through a horizontal annulus channel

2019 ◽  
Vol 196 ◽  
pp. 00011 ◽  
Author(s):  
Yaroslav Ignatenko ◽  
Andrey Gavrilov ◽  
Oleg Bocharov ◽  
Roland May
Keyword(s):  
Steady State ◽  
Pressure Gradient ◽  
Yield Stress ◽  
Cross Section ◽  
Drilling Fluid ◽  
Drill Pipe ◽  
Axial Flow ◽  
Cuttings Transport ◽  
Rigid Spheres ◽  
Pipe Rotation

The current study is devoted to simulating cuttings transport by drilling fluid through a horizontal section of borehole with an annular cross section. Drill pipe rotates in fixed eccentric position. Steady-state flow is considered. Cuttings are rigid spheres with equal diameters. The carrying fluid is drilling mud with Herschel-Bulkley rheology. Suspension rheology depends on local shear rate and particles concentration. Continuous mixture model with algebraic equation for particles slipping velocity is used. Two hydrodynamic regimes are considered: axial flow without drill pipe rotation and with drill pipe rotation. In the case of axial flow was shown that increasing of power index n and consistency factor k increases pressure gradient and decreases cuttings concentration. Increasing of yield stress leads to increasing of pressure gradient and cuttings concentration. Cuttings concentration achieves constant value for high yield stress and not depends on it. Rotation of the drill pipe significantly changes the flow structure: pressure loss occurs and particles concentration decreases in the cross section. Two basic regimes of rotational flow are observed: domination of primary vortex around drill pipe and domination secondary vorticity structures. Transition between regimes leads to significant changes of flow integral parameters.

Scaling Formulae for the Wellbore Hydraulics Similitude with Drill Pipe Rotation and Eccentricity

2021 ◽  
Author(s):  
Thad Nosar ◽  
Pooya Khodaparast ◽  
Wei Zhang ◽  
Amin Mehrabian
Keyword(s):  
Power Law ◽  
Flow Rate ◽  
Annular Flow ◽  
Rotation Speed ◽  
Drilling Fluid ◽  
Drill Pipe ◽  
Flow Loop ◽  
Annular Flows ◽  
Fluid Rheology ◽  
Pipe Rotation

Abstract Equivalent circulation density of the fluid circulation system in drilling rigs is determined by the frictional pressure losses in the wellbore annulus. Flow loop experiments are commonly used to simulate the annular wellbore hydraulics in the laboratory. However, proper scaling of the experiment design parameters including the drill pipe rotation and eccentricity has been a weak link in the literature. Our study uses the similarity laws and dimensional analysis to obtain a complete set of scaling formulae that would relate the pressure loss gradients of annular flows at the laboratory and wellbore scales while considering the effects of inner pipe rotation and eccentricity. Dimensional analysis is conducted for commonly encountered types of drilling fluid rheology, namely, Newtonian, power-law, and yield power-law. Appropriate dimensionless groups of the involved variables are developed to characterize fluid flow in an eccentric annulus with a rotating inner pipe. Characteristic shear strain rate at the pipe walls is obtained from the characteristic velocity and length scale of the considered annular flow. The relation between lab-scale and wellbore scale variables are obtained by imposing the geometric, kinematic, and dynamic similarities between the laboratory flow loop and wellbore annular flows. The outcomes of the considered scaling scheme is expressed in terms of closed-form formulae that would determine the flow rate and inner pipe rotation speed of the laboratory experiments in terms of the wellbore flow rate and drill pipe rotation speed, as well as other parameters of the problem, in such a way that the resulting Fanning friction factors of the laboratory and wellbore-scale annular flows become identical. Findings suggest that the appropriate value for lab flow rate and pipe rotation speed are linearly related to those of the field condition for all fluid types. The length ratio, density ratio, consistency index ratio, and power index determine the proportionality constant. Attaining complete similarity between the similitude and wellbore-scale annular flow may require the fluid rheology of the lab experiments to be different from the drilling fluid. The expressions of lab flow rate and rotational speed for the yield power-law fluid are identical to those of the power-law fluid case, provided that the yield stress of the lab fluid is constrained to a proper value.

Cuttings Transport Simulation in Large-Diameter Inclined Borehole

2019 ◽  
Author(s):  
Yaroslav Ignatenko ◽  
Andrey Gavrilov ◽  
Oleg Bocharov ◽  
Roland May
Keyword(s):  
Steady State ◽  
Unsteady Flow ◽  
Large Diameter ◽  
Drill Pipe ◽  
Stationary Flow ◽  
Problem Formulation ◽  
Cuttings Transport ◽  
Two Phase ◽  
Transport Simulation ◽  
Inclined Boreholes

Abstract An Eulerian mixture model of the two-phase flow was used for cuttings transport simulation. The model was tested using experimental data for particles transport in pipes. Three types of problem statements were analyzed: steady-state flow, non-stationary flow in a short-length channel with periodic boundary conditions, and non-stationary flow in a long channel. Simulation of cuttings transport by Herschel-Bulkley fluid through an inclined 21-inch borehole/–6.5-inch drillpipe annulus was performed. All problem statements showed very close results, even for unsteady flow. These results demonstrated the applicability of 2D steady-state problem formulation for cuttings transport simulation. The unsteady flow was observed for an inclination of less than 20 degrees. Slow downward sliding of cuttings in the lower part of inclined boreholes was observed simultaneously with upstream dunes movement. Drill pipe rotation significantly decreased the cuttings concentration and pressure gradient, and shifted the maximum cuttings transport downward sliding rate from a 20- to 40-degree inclination.

Comprehensive experimental investigation of hole cleaning performance in horizontal wells including the effects of drillstring eccentricity, pipe rotation and cuttings size

2021 ◽  
pp. 1-11
Author(s):  
Ahmed K. Abbas ◽  
Mortadha T. Alsaba ◽  
Mohammed F. Al Dushaishi
Keyword(s):  
Flow Rate ◽  
Oil And Gas ◽  
Drilling Fluid ◽  
Drill Pipe ◽  
Real Field ◽  
Operational Parameters ◽  
Cleaning Efficiency ◽  
Hole Cleaning ◽  
Cleaning Performance ◽  
Pipe Rotation

Abstract Extended reach (ERD) wells with a horizontal and highly deviated section are widely applied in the oil and gas industry because they provide higher drainage area than vertical wells; and hence, increase the productivity or injectivity of the well. Among many issues encountered in a complex well trajectory, poor hole cleaning is the most common problem, which occurs mainly in the deviated and horizontal section of oil and gas wells. There are significant parameters that have a serious impact on hole cleaning performance in high-angle and horizontal sections. These include flow rate, rheology and density of the drilling fluid, drillstring eccentricity, pipe rotation, and cuttings size. It has been recognized that the action of most of these parameters to transport drilled cuttings is constantly a point of controversy among oilfield engineers. In the present study, extensive experiments were conducted in an advanced purpose-built flow rig to identify the main parameters affecting on circulate the cuttings out of the test section in a horizontal position. The flow-loop simulator has been designed to allow easy variation of operational parameters in terms of flow rate, mud density, drillstring eccentricity, pipe rotation, and cuttings size. In addition, the study covers the impacts of laminar, transition, and turbulent flow regimes. The goal of such variation in the operational conditions is to simulate real field situations. The results have shown that drill string rotation and flow rate were the operational parameters with the highest positive influence on the cuttings transports process. In contrast, drill pipe eccentricity has a negative influence on cuttings removal efficiency. The cuttings transportation performance is further improved by pipe rotation at different levels of eccentricity, especially at fully eccentric annuli. It was also shown that larger cuttings appeared to be easier to remove in a horizontal annulus than smaller ones. The experimental results would provide a more in-depth understanding of the relationship between drilling operation parameters and hole cleaning efficiency in ERD operations. This will help the drilling teams to realize what action is better to take for efficient cutting transportation.

Experimental Investigation of Mechanical Friction and Hydraulics for Liner Drilling and Liner Running

2016 ◽  
Author(s):  
Jan David Ytrehus ◽  
Ali Taghipour ◽  
Bjørnar Lund ◽  
Knud Richard Gyland ◽  
Arild Saasen
Keyword(s):  
Experimental Investigation ◽  
Friction Coefficient ◽  
Drilling Fluid ◽  
Drill Pipe ◽  
Drilling Fluids ◽  
Flow Loop ◽  
Cuttings Transport ◽  
Transport Efficiency ◽  
Sand Particles ◽  
Norwegian Continental Shelf

The mechanical friction of liner operations is investigated and compared to what is expected for a conventional drill pipe. In addition the cuttings transport efficiency for realistic conditions is studied. The work is also relevant for running completion strings. This article is based on results from laboratory scale flow loop for drilling applications. Sand particles were injected while circulating the drilling fluid through the test section in some of the tests. The procedures used to conduct the experiments are explained and experimental results and observations are discussed. The drilling fluids and additives in these experiments are similar to those used in in fields on the Norwegian Continental Shelf (NCS). Friction coefficient is calculated from the measured torque for different flow velocities and rotational velocities and the force perpendicular to the surface caused by the buoyed weight of the string.

scholarly journals Investigation: Cutting Transport Mechanism in Inclined Well Section under Pulsed Drilling Fluid Action

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2141
Author(s):  
Xiaohua Zhu ◽  
Keyu Shen ◽  
Bo Li
Keyword(s):  
Drilling Fluid ◽  
Drill Pipe ◽  
Friction Torque ◽  
Drilling Fluids ◽  
Cuttings Transport ◽  
Turbulent Dissipation ◽  
Duty Cycles ◽  
Transport Velocity ◽  
Cuttings Bed ◽  
Conventional Drilling

Due to gravity, drilling cuttings are easily accumulated in an inclined well section, ultimately forming a cuttings bed, which places the drill pipe under strong friction torque. In severe cases, this can cause dragging, stuck drills, and broken drill tools. Because conventional drilling fluids are difficult to prevent the formation of cuttings in inclined well sections, a method of carrying cuttings with the pulsed drilling fluid to improve wellbore cleanness is proposed. Experiments and numerical simulations are conducted to investigate the effects of cuttings bed transport velocity, cuttings size, cuttings height, drill pipe rotation speed, cuttings bed mass, and roughness height. The optimal pulse parameters are determined per their respective impact on cuttings transport concerning varied periods, amplitudes, and duty cycles of the pulsed drilling fluid. Compared to cuttings transport under the conventional drilling fluid flow rate, the pulsed drilling fluid produces the turbulent dissipation rate, increases cuttings transport velocity, and thus improves the wellbore clearance rate.

Steady-State Cuttings Transport Simulation in Horizontal Borehole Annulus

2018 ◽  
Author(s):  
Yaroslav Ignatenko ◽  
Oleg Bocharov ◽  
Andrey Gavrilov ◽  
Roland May
Keyword(s):  
Steady State ◽  
Pressure Drop ◽  
Flow Structure ◽  
Structural Changes ◽  
Drilling Fluid ◽  
Drill String ◽  
Cuttings Transport ◽  
Horizontal Drilling ◽  
Fluid Properties ◽  
Cuttings Bed

The paper presents the results of modeling the steady-state flow of drilling fluid with cuttings in an annulus for the flow regimes typical for horizontal drilling. The studied parameters include effects like fluid rheology, drillstring rotation and eccentricity on flow regime, pressure drop and cuttings bed. It has been demonstrated that increasing the drilling fluid’s effective viscosity increases the pressure drop, but it decreases the cuttings bed area, while drillstring rotation significantly changes the flow structure, improving cuttings transport and reducing the pressure drop. The considered flow structure can change abruptly due to changed drill string positioning and rheological fluid properties. Such structural changes are followed by abrupt changes in the pressure drop and cuttings bed area.

scholarly journals The effect of drill–pipe rotation on improving hole cleaning using polypropylene beads in water-based mud at different hole angles

2019 ◽  
Vol 10 (3) ◽  
pp. 1253-1262 ◽  
Author(s):  
A. Katende ◽  
B. Segar ◽  
I. Ismail ◽  
F. Sagala ◽  
H. H. A. R. Saadiah ◽  
...  
Keyword(s):  
Buoyancy Force ◽  
Drilling Fluid ◽  
Drill Pipe ◽  
Drilling Mud ◽  
Hole Cleaning ◽  
Drag Forces ◽  
Water Based ◽  
Drilling Operations ◽  
Cost Efficient ◽  
Pipe Rotation

AbstractHole cleaning is always a problem, particularly during drilling operations, and drilling fluid plays an important role in transporting drill cuttings through an annular section of wellbore to the surface. To transport the cuttings, a water-based mud with added polypropylene beads was selected since it is environmentally friendly and cost efficient. The polypropylene beads help to transport cuttings by providing an additional buoyancy force that lifts the cuttings to the surface via the influence of collision and drag forces. This experiment was performed using a 20 ft test section, 10 ppg drilling mud and 0.86 m/s annular velocity in a laboratory scale rig simulator, and the concentration of polypropylene beads was varied from 0 to 8 ppb. As the concentration of polypropylene increases, the cutting transport ratio also increases. It was observed that the fewest cuttings are lifted at a critical angle of 60°, followed by 45°, 30°, 90° and 0°. Additionally, cutting sizes had moderate effects on the cutting lifting efficiency, where smaller cutting sizes (0.5–1.0 mm) are easier to lift than larger cutting sizes (2.0–2.8 mm). Furthermore, a study of buoyancy force and impulsive force was conducted to investigate the cutting lifting efficiencies of various concentrations of polypropylene beads. This lifting capacity was also assisted by the presence of polyanionic cellulose (PAC), which increases the mud carrying capacity and is effective for smaller cuttings. The results show that in the presence of pipe rotation, the cutting lifting efficiency is slightly enhanced due to the orbital motion provided by the drill pipe for better hole cleaning. In conclusion, polypropylene beads combined with pipe rotation increase the cutting transport ratio in the wellbore.

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