A Computational Model for Drilled Cutting Transport in Air (or Gas) Drilling Operations

1986 ◽  
Vol 108 (1) ◽  
pp. 8-14 ◽  
Author(s):  
M. P. Sharma ◽  
D. V. Chowdhry
Keyword(s):  
Computational Model ◽  
Carrying Capacity ◽  
Drill Pipe ◽  
One Dimensional ◽  
Gas Drilling ◽  
Solids Suspension ◽  
Solid Suspension ◽  
Air Drilling ◽  
Drilling Operations ◽  
Flow Stream

The hydrodynamics of isothermal, one-dimensional gas-solids suspension is theoretically analyzed. A computational model is developed. The model is applied in predicting the pressure drop distribution in air-sandstone mixture flows through a vertical annular space (simulating the flow stream between a bore hole and a drill pipe). The model can be applied to any isothermal, one-dimensional flow of gas-solid suspension. The numerical results are in satisfactory agreement with the experimental data collected from studies done on drilled cutting carrying capacity of air in air-drilling operations.

Experimental and Numerical Study of Motion of Rotating Drill Pipe Owing to Magnus Effect

2019 ◽  
Author(s):  
Tomoya Inoue ◽  
Hiroyoshi Suzuki ◽  
Tokihiro Katsui ◽  
Keita Tsuchiya ◽  
Yusuke Notani
Keyword(s):  
Analytical Model ◽  
Rotational Speed ◽  
Numerical Study ◽  
Flow Direction ◽  
Drill Pipe ◽  
Ocean Current ◽  
Gas Drilling ◽  
Pipe Model ◽  
Magnus Effect ◽  
Drilling Operations

Abstract During riserless drilling operations conducted in some scientific drillings and the initial stages of all oil and gas drilling operations, drill pipe motions such as vortex induced vibration, whirl motion, and motion due to the Magnus effect are generated. The last motion represents an interesting and important phenomenon that generates a lift force in addition to a drag force due to the ocean current and the rotation of the drill pipe. Accordingly, this study focuses on the drill pipe motions owing to the Magnus effect. An analytical model of a drill pipe was established by applying an absolute nodal coordinate formulation (ANCF) that can capture the behavior of a relatively flexible and long pipe, such as a drill pipe. The lifting and drag forces are calculated using computational fluid dynamics (CFD), and the lift and drag coefficients are calculated for several different drill pipe rotational velocities and ocean current velocities. A series of model experiments were conducted in a towing tank, with changing water flow velocities and rotational speed of the drill pipe model to observe the corresponding changes in the Magnus effect and to measure the resulting drill pipe motions. Additionally, the resulting drag and lift forces were measured. It was observed from the experiments that the motions in the cross-flow direction increased as the rotational speed of the drill pipe model increased, and that the lifting force increased as the rotational speed increased. The drill pipe motions were then simulated using a previously established analytical model and the results of the CFD simulations. The results of the simulations were evaluated against the results of the experiments, and reasons for observed discrepancies are discussed.

scholarly journals LATTICE THREE-SPECIES MODELS OF THE SPATIAL SPREAD OF RABIES AMONG FOXES

1999 ◽  
Vol 10 (06) ◽  
pp. 1025-1038 ◽  
Author(s):  
A. BENYOUSSEF ◽  
N. BOCCARA ◽  
H. CHAKIB ◽  
H. EZ-ZAHRAOUY
Keyword(s):  
Carrying Capacity ◽  
Short Range ◽  
Lattice Models ◽  
Infection Process ◽  
Spatial Spread ◽  
One Dimensional ◽  
Sense Of Direction ◽  
Speed Of Propagation ◽  
Automata Network ◽  
And Diffusion

Lattice models describing the spatial spread of rabies among foxes are studied. In these models, the fox population is divided into three-species: susceptible (S), infected or incubating (I), and infectious or rabid (R). They are based on the fact that susceptible and incubating foxes are territorial while rabid foxes have lost their sense of direction and move erratically. Two different models are investigated: a one-dimensional coupled-map lattice model, and a two-dimensional automata network model. Both models take into account the short-range character of the infection process and the diffusive motion of rabid foxes. Numerical simulations show how the spatial distribution of rabies, and the speed of propagation of the epizootic front depend upon the carrying capacity of the environment and diffusion of rabid foxes out of their territory.

Analytical and experimental research on erosion wear law of drill pipe in gas drilling

2017 ◽  
Vol 79 ◽  
pp. 615-624 ◽  
Author(s):  
Zhiqiang Huang ◽  
Dou Xie ◽  
Xiaobing Huang ◽  
Gang Li ◽  
Song Xie
Keyword(s):  
Experimental Research ◽  
Drill Pipe ◽  
Erosion Wear ◽  
Gas Drilling ◽  
Wear Law

Hole-Cleaning Fibers Improve Cuttings-Carrying Capacity

2021 ◽  
Vol 73 (05) ◽  
pp. 63-64
Author(s):  
Chris Carpenter
Keyword(s):  
Flow Regime ◽  
Carrying Capacity ◽  
Rheological Model ◽  
Drilling Fluid ◽  
Test Method ◽  
Abu Dhabi ◽  
Rheological Parameters ◽  
Cleaning Efficiency ◽  
Hole Cleaning ◽  
Drilling Operations

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 203147, “Investigating Hole-Cleaning Fibers’ Mechanism To Improve Cutting Carrying Capacity and Comparing Their Effectiveness With Common Polymeric Pills,” by Mohammad Saeed Karimi Rad, Mojtaba Kalhor Mohammadi, SPE, and Kourosh Tahmasbi Nowtarki, International Drilling Fluids, prepared for the 2020 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, held virtually 9–12 November. The paper has not been peer reviewed. Hole cleaning in deviated wells is more challenging than in vertical wells because of the boycott effect or the eccentricity of the drillpipe. Poor hole cleaning can result in problems such as borehole packoff or excessive equivalent circulating density. The complete paper investigates a specialized fibrous material (Fiber 1) for hole-cleaning characteristics. The primary goal is to identify significant mechanisms of hole-cleaning fibers and their merits compared with polymeric high-viscosity pills. Hole-Cleaning Indices Based on a review of the literature, most effective parameters regarding hole cleaning in different well types were investigated. These parameters can be classified into the following five categories: - Well design (e.g., hole angle, drillpipe eccentricity, well trajectory) - Drilling-fluid properties (e.g., gel strength, mud weight) - Formation properties (e.g., lithology, cutting specific gravity, cuttings size and shape) - Hydraulic optimizations (e.g., flow regime, nozzle size, number of nozzles) - Drilling practices (e.g., drillpipe rotation speed, wellbore tortuosity, bit type, rate of penetration, pump rate) In this research, rheological parameters and parameters of the Herschel-Bulkley rheological model are considered to be optimization inputs to increase hole-cleaning efficiency of commonly used pills in drilling operations. The complete paper offers a detailed discussion of both the importance of flow regime and the role of the Herschel-Bulkley rheological model in reaching a better prognosis of drilling-fluid behavior at low shear rates. The properties of the fibrous hole-cleaning agent used in the complete paper are provided in Table 1. Test Method Two series of tests were performed. The medium of the first series is drilling water, with the goal of evaluating the efficiency of Fiber 1 in fresh pills. The second series of tests was per-formed with a simple polymeric mud as a medium common in drilling operations. Formulations and rheological properties of both test series are provided in Tables 4 and 5 of the complete paper, respectively.

Air Drilling Operations Improved by Percussion-Bit/Hammer-Tool Tandem

1986 ◽  
Vol 1 (05) ◽  
pp. 377-382 ◽  
Author(s):  
Maxwell C. Whiteley ◽  
William P. England
Keyword(s):  
Air Drilling ◽  
Drilling Operations

Global Environmental Issue and Sustainable Development

2019 ◽  
Vol 2019 (4) ◽  
pp. 8-23
Author(s):  
Viktor Danilov-Danilyan
Keyword(s):  
Sustainable Development ◽  
Carrying Capacity ◽  
Consumer Society ◽  
Anthropogenic Pressure ◽  
New Approach ◽  
One Dimensional ◽  
Global Environmental Issue ◽  
Mass Consciousness ◽  
Global Environmental ◽  
Definition Of

The problem of increasing anthropogenic pressure on the biosphere is considered in the framework of ideas about the carrying capacity of the ecosystem. The possibility of giving an exact definition of the carrying capacity is discussed, the concept of its one-dimensional projection is introduced, and examples of one-dimensional projections are given. In relation to the biosphere, they relate, in particular, to the limits of growth. The traditional definition of the concept “sustainable development” is criticized, this definition is associated with the ideology of the consumer society. The features of the perception of environmental issues by the mass consciousness in a consumer society are described. Extensions of the notion “environment” and a new approach to the interpretation of the notion “sustainable development” due to this expansion are considered.

scholarly journals Unique features of the generation–recombination noise in quasi-one-dimensional van der Waals nanoribbons

Nanoscale ◽  
2018 ◽  
Vol 10 (42) ◽  
pp. 19749-19756 ◽  
Author(s):  
Adane K. Geremew ◽  
Sergey Rumyantsev ◽  
Matthew A. Bloodgood ◽  
Tina T. Salguero ◽  
Alexander A. Balandin
Keyword(s):  
Carrying Capacity ◽  
Van Der Waals ◽  
Low Frequency ◽  
Current Fluctuations ◽  
Electronic Noise ◽  
High Current ◽  
One Dimensional ◽  
Frequency Current

We describe the low-frequency current fluctuations, i.e. electronic noise, in quasi-one-dimensional ZrTe3 van der Waals nanoribbons, which have recently attracted attention owing to their extraordinary high current carrying capacity.

scholarly journals SUBLINEARLY SPACE BOUNDED ITERATIVE ARRAYS

2010 ◽  
Vol 21 (05) ◽  
pp. 843-858 ◽  
Author(s):  
ANDREAS MALCHER ◽  
CARLO MEREGHETTI ◽  
BEATRICE PALANO
Keyword(s):  
Lower Bound ◽  
Computational Model ◽  
Regular Language ◽  
Finite Automata ◽  
Complexity Classes ◽  
Language Recognition ◽  
Deterministic Finite Automata ◽  
One Dimensional ◽  
Sequential Processing ◽  
Trade Offs

Iterative arrays (IAs) are a parallel computational model with a sequential processing of the input. They are one-dimensional arrays of interacting identical deterministic finite automata. In this paper, realtime-IAs with sublinear space bounds are used to recognize formal languages. The existence of an infinite proper hierarchy of space complexity classes between logarithmic and linear space bounds is proved. Some decidability questions on logarithmically space bounded realtime-IAs are investigated, and an optimal logarithmic space lower bound for non-regular language recognition on realtime-IAs is shown. Finally, some non-recursive trade-offs between space bounded realtime-IAs are emphasized.

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