Buoyancy Force on a Plain or Perforated Portion of a Pipe

2021 ◽  
Author(s):  
Eric Cayeux ◽  
Sigmund Stokka
Keyword(s):  
Buoyancy Force ◽  
Construction Operations ◽  
Drilling Operation ◽  
Drill Stem ◽  
Shallow Wells ◽  
Plain Tube ◽  
End Caps ◽  
Drag Models ◽  
The One ◽  
Perforated Tube

Abstract Torque and drag models have been used for many decades to calculate tensions and torques along drill-strings, casing strings and liner strings. However, when applied to sand-screens, it is important to check that all the initial hypotheses used for torque and drag calculations are still valid. In particular, it should be checked whether the buoyancy force on a perforated tube may differ from the one applied to a plain tube. The buoyancy force applied on a pipe, contributes to the sum of efforts at the contact between the pipe and the borehole and therefore influences torque and drag calculations. This contact force is local and should account for localized effects as well as the material internal forces, torques and moments on each side of the contact. As the buoyancy force is the result of the gravitational component of the pressure gradient on the surface of the pipe that is in contact with the fluid, the presence of holes in the pipe also influences the buoyancy force. When applied to a portion of a pipe, buoyancy does not have contributions at the end caps of that portion of the drill-stem since these end caps are not in contact with the fluid, except at positions with a change of diameter. Therefore, one shall be cautious when calculating the local buoyancy force either on a plain or a perforated tube. The paper describes how to calculate the local buoyancy force on a portion of a drill-stem by application of the Gauss theorem accounting for the necessary corrections arising from the end caps not being exposed to the fluid. An experimental setup has been built to verify that the tension inside a pipe subject to buoyancy does follow the derived mathematical calculations. With complex well construction operations, for instance during extended reach drilling or when drilling very shallow wells with high kick-off rates, the slightest error in torques and drag calculations may end up in jeopardizing the chance of success of the drilling operation. It is therefore important to check that all initial calculation hypotheses are still valid in those contexts and that for instance, sand-screens may be run in hole safely after a successful drilling operation.

Buoyancy Force on a Plain or Perforated Portion of a Pipe

SPE Journal ◽  
2021 ◽  
pp. 1-22
Author(s):  
E. Cayeux ◽  
S. Stokka ◽  
E. W. Dvergsnes ◽  
J. L. Thorogood
Keyword(s):  
Cross Sections ◽  
Buoyancy Force ◽  
Construction Operations ◽  
Drilling Operation ◽  
Buoyancy Forces ◽  
Shallow Wells ◽  
The Cross ◽  
Drag Models ◽  
Design Calculations ◽  
Extended Reach Drilling

Summary Torque and drag models have been used for several decades to calculate tension and torque profiles along drillstrings, casing strings, and liner strings. Buoyancy forces contribute to the loads acting on the pipe and affect its interaction with the borehole wall. Torque and drag calculations account for these localized effects, as well as the material internal forces, torques, and moments on each side of the contact. When the analysis is applied to a discrete length of pipe, the cross sections at each end do not contribute to the buoyancy forces because they are not in contact with the fluid, except where there is a change in diameter or at the end of the string of pipe. We argue that it is important to check that the models used for solid pipe torque and drag calculations remain valid for sand screens, in particular, the extent to which the buoyancy forces acting on a perforated tube might differ from those on a solid pipe. Because the buoyancy force is the result of the pressure gradient acting on the surface of the pipe, the presence of holes may also influence the buoyancy force. We propose that there are theoretical differences between local buoyancy forces acting on plain or perforated tubes. This paper describes how to calculate the local buoyancy force on a portion of a drillstem by the application of Gauss’ theorem and accounting for the necessary corrections arising from the cross sections not being exposed to the fluid. We built an experimental setup to verify that the tension inside a pipe subject to buoyancy behaves in accordance with the derived mathematical analysis. With complex well construction operations, for instance during extended-reach drilling or when drilling very shallow wells with high buildup rates, the slightest error in torques and drag calculations may end up jeopardizing the chances of success of the drilling operation. It is therefore important to check that the basis of design calculations remain valid in those contexts and that, for instance, sand screens or slotted liners may be run in hole safely after a successful drilling operation.

A Technical Approach to Safe Mode Management for a Smooth Transition from Automatic to Manual Drilling

2021 ◽  
Author(s):  
Eric Cayeux ◽  
Rodica Mihai ◽  
Liv Carlsen ◽  
Morten Ørevik ◽  
Kjartan Birgisson ◽  
...  
Keyword(s):  
Transition State ◽  
Situation Awareness ◽  
Smooth Transition ◽  
Human Operator ◽  
Manual Control ◽  
Construction Operations ◽  
System Failures ◽  
Autonomous Function ◽  
Current State ◽  
The One

Abstract Unexpected situations and system failures during well construction operations are always possible. In the context of drilling automation, or even autonomous drilling, proper automatic management of these situations is of critical importance as the situation awareness of the human operator is very much reduced. The proper management of the transition between automatic and manual modes is necessary to improve the safety of automation solutions. An important characteristic of drilling automation solutions is their ability to cope with unexpected situations. This also encompasses, placing the drilling system in a state that is easy and intuitive for the human operator when manual control is required. Our approach to safe mode management is dependent on a good state estimation of the current conditions of the process. If for any reason, manual control must be regained, then the automated function itself triggers the necessary actions that will ensure a stable current state. In case of a drilling problem or a system failure, the human operator may have to regain control when the context might be totally different from the one left when the automation or autonomous function was enabled. It may even be a different human operator that has to take control, if a crew change has taken place. To make the transition from the automated/autonomous context to manual control, the automation/autonomous system sets the drilling machines in a so-called safe transition state. A safe transition state is one for which leaving the current setpoints of drilling machines untouched for a reasonable amount of time, will not immediately jeopardize the safety of the drilling operation. A safe transition state is contextual as it is not necessarily the same sequence of actions that must be performed to reach the safe transition state every time. The novel safe modes management method is integrated into existing drilling automation solutions. In a drilling automation context, the situation awareness of the human operator is considerably reduced as the automated functions control the process and the human operator is not actively driving the drilling machines. Without active safe mode management, there is a risk that drilling automation solutions may lead to serious situations as the driller may be totally unprepared to regain control in the middle of a critical situation. When it is needed to return to manual mode in the middle of the execution of an automatic procedure, an adequate procedure is executed. The choice of the procedure and its parameters depend on the current state of the process and system.

scholarly journals Reagents Activity in a Copper Droplets / Post-Processing Slag Suspension

2016 ◽  
Vol 16 (3) ◽  
pp. 147-150
Author(s):  
W. Wołczyński ◽  
J. Karwan-Baczewska ◽  
K. Najman ◽  
A.W. Bydałek
Keyword(s):  
Buoyancy Force ◽  
Liquid Slag ◽  
The Other ◽  
Slag Viscosity ◽  
Flash Furnace ◽  
Special Treatment ◽  
Post Processing ◽  
Industrial Chemicals ◽  
Crucible Bottom ◽  
The One

Abstract The suspension of the copper droplets in the post-processing slag taken directly from the KGHM-Polska Miedź S.A. Factory (from the direct-to-blister technology as performed in the flash furnace) was subjected to the special treatment with the use of the one of the typical industrial reagent and with the complex reagent newly patented by the authors. This treatment was performed in the BOLMET S.A. Company in the semi-industrial conditions. The result of the CaCO3, and Na2CO3 chemicals influence on the coagulation and subsequent sedimentation of copper droplets on the crucible bottom were subjected to comparison with the sedimentation forced by the mentioned complex reagent. The industrial chemicals promoted the agglomeration of copper droplets but the coagulation was arrested / blocked by the formation of the lead envelope. Therefore, buoyancy force forced the motion of the partially coagulated copper droplets towards the liquid slag surface rather than sedimentation on the crucible bottom. On the other hand, the complex reagent was able to influence the mechanical equilibrium between copper droplets and some particles of the liquid slag as well as improve the slag viscosity. Finally, the copper droplets coagulated successfully and generally, were subjected to a settlement on the crucible bottom as desired / requested.

ACOUSTIC ATTENUATION CHARACTERISTICS OF STRAIGHT-THROUGH PERFORATED TUBE SILENCERS AND RESONATORS

2008 ◽  
Vol 16 (03) ◽  
pp. 361-379 ◽  
Author(s):  
Z. L. JI
Keyword(s):  
Performance Prediction ◽  
Transmission Loss ◽  
Three Dimensional ◽  
Geometrical Parameters ◽  
Mean Flow ◽  
Acoustic Attenuation ◽  
One Dimensional ◽  
The One ◽  
Attenuation Characteristics ◽  
Perforated Tube

The one-dimensional analytical solutions are derived and three-dimensional substructure boundary element approaches are developed to predict and analyze the acoustic attenuation characteristics of straight-through perforated tube silencers and folded resonators without mean flow, as well as to examine the effect of nonplanar waves in the silencers and resonators on the acoustic attenuation performance. Comparisons of transmission loss predictions with the experimental results for prototype straight-through perforated tube silencers demonstrated that the three-dimensional approach is needed for accurate acoustic attenuation performance prediction at higher frequencies, while the simple one-dimensional theory is sufficient at lower frequencies. The BEM is then used to investigate the effects of geometrical parameters on the acoustic attenuation characteristics of straight-through perforated tube silencers and folded resonators in detail.

A New Model to Simulate Gas Injection in Gas Chamber Pumps

2004 ◽  
Vol 126 (4) ◽  
pp. 279-284 ◽  
Author(s):  
S. Pilo-Restuccia ◽  
L. Rojas-Solo´rzano
Keyword(s):  
Heavy Oil ◽  
Gas Injection ◽  
Oil Reserves ◽  
Coiled Tubing ◽  
Artificial Lift ◽  
Shallow Wells ◽  
The One ◽  
Key Aspects ◽  
Year 2000 ◽  
Gas Chamber

Currently, there exist large heavy-oil reserves in countries like Venezuela and Canada. In Venezuela, heavy oil represents 69% of the reserves, and its exploitation is not always feasible using traditional pumping technologies. In particular, this is the case of some in-lake oil wells in Venezuela, which are impossible to exploit by means of any known efficient way of oil lifting. An alternative is the gas-chamber pumping (GCP), an intermittent artificial lift method used in diverse areas of USA, in shallow wells with heavy oil and in areas where a source of high-pressure gas exists. Few works are reported on the modeling of the phenomena associated to GCP, the most rigorous being the one published by PDVSA-Intevep in the year 2000. This model, however, omits some key aspects related with gas injection, which affects its precision to simulate or design GCP systems. The present work develops a model to rigorously simulate the stage of gas injection into the chamber, incorporating aspects like the flow of gas from the supply manifold up to the wellhead, the gas expansion within the injection valve, the descending flow along a coiled tubing, and the heat transfer associated. The pressurization process and chamber venting are also modeled. The model predictions are in excellent agreement with experimental data [1].

Note on Selection of Coordinate Systems for Geodynamics

1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen
Keyword(s):  
Sea Level ◽  
The Other ◽  
Coordinate Systems ◽  
Mean Sea Level ◽  
The Earth ◽  
The One ◽  
Static Systems ◽  
Selection Of

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

Fundamental Research into Thin Films in a Developing Country

1972 ◽  
Vol 30 ◽  
pp. 500-501
Author(s):  
J.A. Eades ◽  
E. Grünbaum
Keyword(s):  
Thin Films ◽  
Growth Process ◽  
Empirical Process ◽  
Nucleation And Growth ◽  
Research Groups ◽  
Film Research ◽  
Fundamental Research ◽  
Controlled Deposition ◽  
The One ◽  
The University

In the last decade and a half, thin film research, particularly research into problems associated with epitaxy, has developed from a simple empirical process of determining the conditions for epitaxy into a complex analytical and experimental study of the nucleation and growth process on the one hand and a technology of very great importance on the other. During this period the thin films group of the University of Chile has studied the epitaxy of metals on metal and insulating substrates. The development of the group, one of the first research groups in physics to be established in the country, has parallelled the increasing complexity of the field.The elaborate techniques and equipment now needed for research into thin films may be illustrated by considering the plant and facilities of this group as characteristic of a good system for the controlled deposition and study of thin films.

STM studies of crystal growth

1991 ◽  
Vol 49 ◽  
pp. 374-375
Author(s):  
M. G. Lagally
Keyword(s):  
Crystal Growth ◽  
Molecular Beam ◽  
Chemical Vapor ◽  
Sputter Deposition ◽  
Field Of View ◽  
Scanning Tunneling ◽  
Wide Field ◽  
Tunneling Microscopy ◽  
Wide Field Of View ◽  
The One

It has been recognized since the earliest days of crystal growth that kinetic processes of all Kinds control the nature of the growth. As the technology of crystal growth has become ever more refined, with the advent of such atomistic processes as molecular beam epitaxy, chemical vapor deposition, sputter deposition, and plasma enhanced techniques for the creation of “crystals” as little as one or a few atomic layers thick, multilayer structures, and novel materials combinations, the need to understand the mechanisms controlling the growth process is becoming more critical. Unfortunately, available techniques have not lent themselves well to obtaining a truly microscopic picture of such processes. Because of its atomic resolution on the one hand, and the achievable wide field of view on the other (of the order of micrometers) scanning tunneling microscopy (STM) gives us this opportunity. In this talk, we briefly review the types of growth kinetics measurements that can be made using STM. The use of STM for studies of kinetics is one of the more recent applications of what is itself still a very young field.

Preparation of Electron Transparent Metal-Matrix Composites

1968 ◽  
Vol 26 ◽  
pp. 334-335 ◽  
Author(s):  
M. R. Pinnel ◽  
A. Lawley
Keyword(s):  
Stainless Steel ◽  
Load Transfer ◽  
Volume Fraction ◽  
Steel Wire ◽  
Initial Step ◽  
Interfacial Region ◽  
Matrix Composites ◽  
Specific Test ◽  
The Matrix ◽  
The One

Numerous phenomenological descriptions of the mechanical behavior of composite materials have been developed. There is now an urgent need to study and interpret deformation behavior, load transfer, and strain distribution, in terms of micromechanisms at the atomic level. One approach is to characterize dislocation substructure resulting from specific test conditions by the various techniques of transmission electron microscopy. The present paper describes a technique for the preparation of electron transparent composites of aluminum-stainless steel, such that examination of the matrix-fiber (wire), or interfacial region is possible. Dislocation substructures are currently under examination following tensile, compressive, and creep loading. The technique complements and extends the one other study in this area by Hancock.The composite examined was hot-pressed (argon atmosphere) 99.99% aluminum reinforced with 15% volume fraction stainless steel wire (0.006″ dia.).Foils were prepared so that the stainless steel wires run longitudinally in the plane of the specimen i.e. the electron beam is perpendicular to the axes of the wires. The initial step involves cutting slices ∼0.040″ in thickness on a diamond slitting wheel.

Sign in / Sign up

Export Citation Format

Share Document