Author : Kirk Eldon Christensen
Publisher :
Page : 632 pages
File Size : 26,52 MB
Release : 1987
Category : Bits (Drilling and boring)
ISBN :
Author : Wade H. Shafer
Publisher : Springer Science & Business Media
Page : 411 pages
File Size : 15,15 MB
Release : 2012-12-06
Category : Science
ISBN : 1461305993
Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1 957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna tional publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 32 (thesis year 1987) a total of 12,483 theses titles from 22 Canadian and 176 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work. While Volume 32 reports theses submitted in 1987, on occasion, certain univer sities do report theses submitted in previous years but not reported at the time.
Author : Hongyuan Qiu
Publisher :
Page : pages
File Size : 33,41 MB
Release : 2014
Category :
ISBN :
Drill-strings are slender structures used to dig into the rock in search of oil and gas. Failures of drill-strings are time and money consuming and therefore the dynamics of drill-strings must be investigated and carefully controlled. In the thesis, a dynamic model of the drill-string that is suitable for predicting axial, torsional and lateral vibrations is built using Euler-Bernoulli beam theory. The drillstring is driven by a DC motor on the top and is subjected to distributed loads due to its own weight as well as bit/formation interaction. The model is axial-torsional, lateral-torsional coupled. Under deterministic excitations, the model captures stickslip behavior in drilling operation. Analysis on its negative effect on drilling performance is made, and potential mitigation measures are also discussed. In random model, the excitations to the drill-bit are modeled as combination of deterministic and random components. Monte Carlo (MC) simulation is employed to obtain the statistics of the response. Two cases of random excitation with different intensities are investigated. The results from MC simulation are compared against that from deterministic case. Secondly, the thesis focuses on the drill-string torsional vibration and its stick-slip analysis. A finite element model of the drillstring with inclusion of both deterministic and random excitations is also developed. Simulation is carried out under certain parameters and it is shown that in deterministic case the torsional vibration may behave stick-slip. With change of some parameters, bifurcation and chaos of the system are observed. In the random case, Monte Carlo simulation and path integration method are used to capture the probabilistic information of the response. The results of path integration match well to those of deterministic cases. Although there are some limitations, this thesis will help the author better understand drill-string downhole behaviors and lay a foundation for further research work.
Author : Rosana A. Reyes Nava
Publisher :
Page : pages
File Size : 20,34 MB
Release : 2017
Category :
ISBN :
This investigation describes the dynamic model of a rotary drilling system equipped with a PDC bit. Torsional and axial dynamics are modeled separately with the bond graph technique and coupled is given by a bit-rock interaction model that considers cutting and friction components at the bit cutters. The cases for contact loss are analyzed and included as numerical functions to account for bit-bounce and stick-slip during drilling. Cosimulation of the drillstring and bit-rock models is proposed to simplify the numerical implementation. Verification confirmed that the model was captured with sufficient accuracy and yields predictable results for known inputs. A methodology for bit-rock parameter acquisition is suggested. Simulation of a real drilling setup was performed and validated against experimental tests. For the analyzed ranges, simulations were in agreement with experimental results. This shows that a close prediction of the drilling response of a PDC bit is possible with the considered model.
Author : Murat Karakus
Publisher :
Page : 17 pages
File Size : 28,50 MB
Release : 2014
Category : Acoustic emission testing
ISBN :
One of the main problems encountered in impregnated diamond core drilling operations for deep mineral explorations is to remotely infer bit wear state and to drill with optimal performance at great depth. Currently the optimal drilling performance relies heavily on operator experience. This paper aims to assess the feasibility of acoustic emission (AE) monitoring of the impregnated diamond drilling process and to establish relations between AE signals and diamond drill bit wear to improve overall drilling performance. AE relations with various drilling parameters have also been investigated to understand signal characteristics in relation to operational parameters. Echidna drill apparatus that simulates field exploration diamond drilling on a small scale is used to monitor AE during rock bit interaction. AE sensors were attached to both the drill and the rock in question to record acoustic signals being emitted whilst drilling. Two different tests viz. 'step tests' and 'wear tests' were carried out. Step tests on the Echidna drill include stepping down the depth of cut from 130μm to 0μm, while cutting speed is constant. Secondly, wear tests performed on the Echidna drill, involves accelerating the wear rate of the drill bit via two different types of tests, both in highly abrasive rock. Based on the step test results, a series of linear relations were developed. These relations are capable of estimating the depth of cut, weight on the bit (WOB) and torque on the bit (TOB) by simply using time spectrum of the AE signals. Wear tests also showed that AE amplitudes start to trend down over the time of accelerated wear.
Author : Ahmad Ghasemloonia
Publisher :
Page : 658 pages
File Size : 11,29 MB
Release : 2013
Category : Finite element method
ISBN :
Author : Jane Wang
Publisher : CRC Press
Page : 636 pages
File Size : 21,96 MB
Release : 2019-12-06
Category : Technology & Engineering
ISBN : 1439815119
Understanding the characteristics of material contact and lubrication at tribological interfaces is of great importance to engineering researchers and machine designers. Traditionally, contact and lubrication are separately studied due to technical difficulties, although they often coexist in reality and they are actually on the same physical ground. Fast research advancements in recent years have enabled the development and application of unified models and numerical approaches to simulate contact and lubrication, merging their studies into the domain of Interfacial Mechanics. This book provides updated information based on recent research progresses in related areas, which includes new concepts, theories, methods, and results for contact and lubrication problems involving elastic or inelastic materials, homogeneous or inhomogeneous contacting bodies, using stochastic or deterministic models for dealing with rough surfaces. It also contains unified models and numerical methods for mixed lubrication studies, analyses of interfacial frictional and thermal behaviors, as well as theories for studying the effects of multiple fields on interfacial characteristics. The book intends to reflect the recent trends of research by focusing on numerical simulation and problem solving techniques for practical interfaces of engineered surfaces and materials. This book is written primarily for graduate and senior undergraduate students, engineers, and researchers in the fields of tribology, lubrication, surface engineering, materials science and engineering, and mechanical engineering.
Author : Thiago Ritto
Publisher :
Page : 0 pages
File Size : 13,11 MB
Release : 2010
Category :
ISBN :
This thesis analyzes the nonlinear dynamics of a drill-string including uncertainty modeling. A drill-string is a slender flexible structure that rotates and digs into the rock in search of oil. A mathematical-mechanical model is developed for this structure including fluid-structure interaction, impact, geometrical nonlinearities and bit-rock interaction. After the derivation of the equations of motion, the system is discretized by means of the finite element method and a computer code is developed for the numerical computations using the software MATLAB. The normal modes of the dynamical system in the prestressed configuration are used to construct a reduced order model for the system. To take into account uncertainties, the nonparametric probabilistic approach, which is able to take into account both system-parameter and model uncertainties, is used. The probability density functions related to the random variables are constructed using the maximum entropy principle and the stochastic response of the system is calculated using the Monte Carlo method. A novel approach to take into account model uncertainties in a nonlinear constitutive equation (bit-rock interaction model) is developed using the nonparametric probabilistic approach. To identify the probabilistic model of the bit-rock interaction model, the maximum likelihood method together with a statistical reduction in the frequency domain (using the Principal Component Analysis) is applied. Finally, a robust optimization problem is performed to find the operational parameters of the system that maximizes its performance, respecting the integrity limits of the system, such as fatigue and instability.
Author :
Publisher :
Page : pages
File Size : 44,11 MB
Release : 1984
Category :
ISBN :
The Theoretical Description for the GEODYN interactive finite-element computer program is presented. The program is capable of performing the analysis of the three-dimensional transient dynamic response of a Polycrystalline Diamond Compact Bit-Bit Sub arising from the intermittent contact of the bit with the downhole rock formations. The program accommodates nonlinear, time-dependent, loading and boundary conditions.
Author : Sagar Chandrakant Kadam
Publisher :
Page : pages
File Size : 25,62 MB
Release : 2007
Category :
ISBN :
