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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

An analysis of the North Sea rigs-to-reefs debate centring on the United Kingdom continental shelf

Baine, Mark January 1998 (has links)
No description available.
2

Human decision-making under uncertainty in the upstream oil and gas industry.

Mackie, Steve January 2007 (has links)
Business under-performance in the upstream oil and gas industry, and the failure of many decisions to return anticipated results, has led to a growing interest over the past few years in understanding the impacts of current decision-making tools and processes and their relationship with decision outcomes. Improving oil and gas decision-making is thus, increasingly, seen as reliant on an understanding of what types of decisions are involved and how they actually are made in the “real world”. There has been significant work carried out within the discipline of cognitive psychology, observing how people actually make decisions. However, little is known as to whether these general observations apply to decision-making in the upstream oil and gas industry. Nor has there been work on how the results might be used to improve decision-making in the industry. This research is a step towards filling this gap by developing two themes – decision-making process and decision type. It distils a “real world” oil and gas decision-making model together with a theoretical decision-making model. Comparing and contrasting the two models yields several prescriptions for improved decision-making in the upstream oil and gas industry. This research also documents the development of an oil and gas decision making taxonomy that lays a decision space within which to judge the processes of decision-making. The taxonomy builds on established ideas in the human decision-making literature, but is itself novel, and involves four different dimensions: 1) complexity; 2) task constraint; 3) value functions; and 4) structure of the information environment. A primary observation is that decision-making processes are tailored to the various types of decisions. It is argued that maximising the chances of a good outcome in “real world” decisions requires the implementation of such tailoring. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1298439 / Thesis (Ph.D.) - University of Adelaide, Australian School of Petroleum, 2007
3

A knowledge base system approach to inspection scheduling for fixed offshore platforms

Peers, Sarah Matilde Catherine January 1998 (has links)
In the offshore oil and gas industry in the UK, one of the most common forms of structure is the fixed steel jacket type of offshore platform. These are highly redundant structures subject to many random or uncertain factors. In particular, they are subject to uncertainties in the load distribution through the components, and to time-varying and cyclic loads leading to deterioration through fatigue. Operators are required to ensure the integrity of these structures by carrying out periodic inspections and repairing when necessary. Decisions on inspection, repair and maintenance (IRM) actions on structures involves making use of various tools and can be a complex problem. Traditionally, engineering judgement is employed to schedule inspections and deterministic analyses are used to confirm decisions. The use of structural reliability methods may lead to more rational scheduling of IRM actions. Applying structural reliability analysis to the production of rational inspection strategies, however, requires understanding the inspection procedure and making use of the appropriate information on inspection techniques. There are difficulties in collecting input data and the interpreted results need to be combined to form a rational global solution for the structure which takes into account practical constraints. The development of a knowledge base system (KBS) for reliability based inspection scheduling (RISC) provides a way of making use of complex quantitative objective analyses for scheduling. This thesis describes the development of a demonstrator RISC KBS. The general problems of knowledge representation and scheduling are discussed and schemes from Artificial Intelligence are proposed. Additionally, a system for automated inspection is described and its role in IRM of platforms is considered. A RISC System integrating suitable databases with fatigue fracture mechanics based reliability analysis within a KBS framework will enable operators to develop rational IRM scheduling strategies.
4

Links between entrepreneurial orientation and corporate governance structures in the South African oil and gas industry

Molokwu, Vincent Brown 19 September 2012 (has links)
This study examines the relationships between entrepreneurial orientation (EO) and four sub-dimensions of corporate governance structures (CGS) in a sample of 173 senior decision-makers representing companies in the South African oil and gas industry. The four attributes of CGS include: board effectiveness and competence, board knowledge and experience, board commitment and recognition of complexities and board involvement in decision-making processes. A series of Canonical correlation analyses assess the strength of relationships between the dimensions of EO and CGS at both univariate and multivariate levels. The results of this study support a positive significant relationship between EO dimensions namely, innovation, proactiveness and risk-taking; and the dimensions of CGS namely, board effectiveness and competence, board knowledge and experience, board commitment and recognition of complexities, and board involvement in decision-making processes. It also indicates a positive link between EO and CGS. The synthesis gleaned from this study is based on the expansive literature review on EO and CGS which provided an insight on the existing knowledge on the relevance of EO in organisational growth and CGS with respect to the nature of the boards, executives and decision-makers roles and responsibilities in strategic entrepreneurial activities within the organisation. This study is of practical use to organisations, enabling them to think and act entrepreneurially, and to policy makers to assist them to keep track of the regulatory guidelines, adopted by boards and executives in monitoring and implementing entrepreneurial culture in their respective organisations. Finally, to researchers and academics, this study allows an extension of knowledge to the EO and CGS and its applicability in one distinct industrial context.
5

Development of formation damage models for oilfield polymers

Idahosa, Patrick E. G. January 2015 (has links)
Polymers are among the most important of various oilfield chemicals and are used for a variety of applications in the oil and gas industry (OGI) including water and gas shutoff, drilling mud viscosity modification, filtration loss control (FLC), swellable packers, loss circulation material (LCM) pills, enhanced oil recovery (EOR), fracture treatment and cleanup, chemical placement, etc. The deposition and retention of polymer molecules in porous media and their interactions with rock and fluids present complex phenomena that can induce formation damage. Formation damage due to polymer retention can occur via mobility reduction in three possible mechanisms of polymer-induced formation damage: 1) pore-throat blocking, 2) wettability alteration (which can alter permeability), and 3) increase in reservoir fluid viscosity. Physical adsorption can also cause permanent permeability impairment (formation damage). This polymer-induced formation damage (causing a reduction in net oil recovery) continues to be a fundamental problem in the industry owing to the rather shallow understanding of the mechanics of polymer-brine-rock interactions and the polymer-aided formation damage mechanisms. Most models available for polymer risk assessments appear to be utilised for all scenarios with unsatisfying results. For example, only very little, if any, is known on how polymer type, particularly in the presence of brine type impact on formation damage. In order words, one of current industry challenges is finding effective polymers for high salinity environments. Also, the effect of polymer charge, as well as charges at the brine-rock interface are issues that require a deeper understanding in order to address the role polymer play in formation damage. Furthermore, no much recognition has been given to polymer rheological behaviour in complex porous media, etc. The OGI therefore still faces the challenge of the inability to correctly predict hydrolysed polyacrylamide (HPAM) viscosity under shear degradation; and consequently have not been able to meet the need of production predictions. The effect of the above mentioned factors, etc have not been fully integrated into the polymer formation damage modelling. In this PhD research work, theoretical, numerical, laboratory experiments and analytical methods were used to further investigate the mechanics of polymer-brine-rock interactions and establish the mechanisms for formation damage related to polymer application. Three different hydrolysed polyacrylamide (HPAM) products (SNF FP3630 S, 3330 S and FloComb C3525) were used in the experiments; while Xanthan gum was used in the simulation work. The following variables were considered: 1) polymer type, 2) effect of concentration, 3) effect of salinity/hardness, 4) effect of permeability and pore size distributions, 5) effect of inaccessible pore volume (IAPV) on retention, 6) effect of flow rate (where a special method was established to quantify the effect of flow rate on polymer retention). Laboratory rheological and adsorption experiments were designed and conducted. Experimental results indicate that higher concentration of calcium divalent ions in brine help promote polymer retention on rock surface. On the basis of the experimental results, empirical models were developed and validated to: 1) predict HPAM rheological behaviour over a wide range of shear rates, 2) predict salinity-dependent polymer-induced formation damage, 3) in addition, a modified screening model that can aid polymer selection for field application design is proposed. Overall, these models can therefore serve as useful tools, and be used for quick look-ahead prediction and evaluation of polymer related formation damage in oil and gas-bearing formations.
6

Residual stresses and thermal spray coating performance /

Greving, Daniel James. January 1995 (has links)
Thesis (Ph.D.)--University of Tulsa, 1995. / Includes bibliographical references (leaves 228-238).
7

Archimedean Screw Turbine Based Energy Harvester and Acoustic Communication in Well Site Applications

Lin, Rui 30 January 2020 (has links)
Wireless Sensor Networks (WSNs) has become increasingly important in the Oil and Gas industry. Despite the various advantages WSN has compared to the wired counter parts, it also faces some critical challenges in the oil fields; one of them is the power supply. The periodic replacement of batteries for the WSN in the downhole environments has been economically inconvenient and the enormous cost induced by the maintenance has turned people's attention to the energy harvesting technology, hoping for a more sustainable solution. Power supply is only half of the problem. To retrieve the data recorded by the various sensors in the downhole environments, a reliable way of wireless communication is required. A new approach utilizing acoustic communication was proposed. This thesis presents an Archimedean Screw Turbine (AST) based energy harvester that takes advantage of the abundant flow energy in the upper stream section of the oil production cycle, especially in the water injection wells and oil extraction wells, with the goal of providing power supply to Wireless Sensor Networks (WSNs) and underwater acoustic modems deployed in the various locations in the downhole environments. Parametric study on the number of blades, screw length, screw pitch, and rotational speed was conducted through CFD analysis using Ansys Fluent in order to determine the optimal geometry and operating conditions. The relationship between power generation and AST geometries, such as AST length and AST pitch, were discovered and the optimal rotational speed was revealed to be solely dependent on the screw pitch. Experiments were conducted in the lab environment with various flow rates and various external resistive loads to verify and determine the maximum power generation of the designed harvester. FEA analysis was conducted using the Acoustic and Structural Interaction Module of COMSOL MULTIPHYSICS to determine the attenuation characteristics of acoustic waves propagating in the water-filled pipes buried in soil. Experiments with and without the harvester integrated in the pipe system were conducted in lab environment using a pair of under water acoustic modems to determine the acoustic communication capability. The impact of the integrated harvester on the acoustic communication was tested. Combining energy harvesting technology and underwater acoustic communication together, this system can potentially achieve real-time monitoring and communication in the oil downhole environment. / Master of Science / Oil and Gas industry has been the primary energy source provider for our society for hundreds of years. As this industry evolves with new technologies, it also faces new challenges. One of the main challenges is the power supply problem in the oil field because of the limited lifespan of traditional batteries used in the oil production process. This study present a novel energy harvesting device that can replace the traditional batteries. By taking advantage of the constant fluid flow in various wells at oil field, the device can provide power for electronic devices, including but not limited to wireless sensors, communication modules, at the oil extraction sites, without needing additional power supply. This novel energy harvesting device can also be integrated with communication modules that uses acoustic wave to achieve wireless acoustic communication between underground and the surface. In this study, the harvester design, optimization, tests, and integration with acoustic modems were presented. With the help of such energy harvesting device, Oil and Gas industry will be one step closer to achieving true wireless, and real-time monitoring and communication. This will not only reduce maintenance cost but also greatly improve the production efficiency.
8

Investing in troubled territories: industry specific political risk analysis and the oil and gas industry

Boshoff, Marc James 03 1900 (has links)
Thesis (MA (Political Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The central research question of this study concerns the level of political risk that the Ogaden region of eastern Ethiopia poses for companies operating in, or intending to operating in the oil and gas industry of that region. The aim is to answer that question as well as two further subquestions. The first sub-question concerns issues pertaining to the factors and indicators that would be included in a political risk model specifically envisaged for the oil and gas industry, and the second concerns the practical application of political risk as a decision-making and management tool for investors. It is practically impossible to gather all the relevant information when undertaking a political risk analysis, to know all the unknowns. It would take an immense amount of time to attempt such an analysis and the costs would be exorbitant. In creating a political risk model specific to the oil and gas industry, a methodological approach is adopted to streamline this process. It is the aim of this research study to engage in this streamlining process; selecting the most salient variables that can then be incorporated into an industry specific model, which will yield realistic and practical results. In terms of the political risk indication, the political risk analysis of the Ogden returned a score putting the region in the high risk indication bracket. In terms of investment indication, the score indicates a moderate to high risk for investments the oil and gas industry. This does not mean that investors should stay away from the region. A high degree of risk, if sufficiently managed, can result in increased opportunities for higher returns for the investor. Beyond the traditional approaches to risk management there are other avenues that the investor may choose to follow, such as a commitment to engage with local stakeholders. These initiatives should extend beyond mere financial incentives to a more genuine form of community interaction, with extensive local consultation. Strategies, policies, and procedures should be developed that ensure that companies engage productively with NGOs and the media at local levels in order create a suitable environment for all involved. Political risk is more than simply providing a report with a risk rating tagged to the end of it. It should be a fully integrated part of the investor’s strategy, essential to the continued success and profitability of the investment. / AFRIKAANSE OPSOMMING: Die sentrale navorsingsvraag van hierdie studie handel oor die vlak van politieke risiko wat maatskappye wat besigheidsbelange in die Ogaden streek van oos Ethiopië het, of wat beplan om besigheidsbelange in die olie- en gasbedryf te begin, in die gesig staar. Die doel is om die vlak van politieke risiko te identifiseer en om verder twee sub-vrae te beantwoord. Die eerste sub-vraag is om die faktore en indikatore te identifiseer wat deel sal vorm van ‘n politieke risikomodel, spesifiek vir die olie- en gasbedryf en die tweede handel oor die praktiese aanwending van politieke risiko as ’n besluitnemings- en risikobestuur-instrument vir beleggers. Dit is prakties onmoontlik om alle relevante informasie in te samel wanneer ’n politieke risiko-analise gedoen word, of om bewus te wees van al die onbekende aspekte. Dit sal ‘n ongelooflike lang tydperk neem asook die kostes sal uiters hoog wees. Wanneer ‘n politieke risikomodel spesifiek vir die olie- en gasindustrie gebou word, word ’n metodologiese benadering om die proses te vergemaklik gevolg. Dit is die doel van hierdie studie om by te dra tot die vereenvoudiging van hierdie metodologiese proses deur die mees prominente aspekte te selekteer wat gevolglik geïnkorporeer kan word in ‘n industrie spesifieke model. Die model sal beide realistiese en praktiese resultate bied. Ten opsigte van die skaal vir belegging en politieke risiko indikasie, het politieke risiko analise van die Ogaden gedui op ’n hoë risiko indikasievlak. Vir belegging dui die risikovlak op ’n medium tot hoë risikovlak vir die olie- en gasindustrie. Dit beteken nie dat beleggers die area noodwendig moet vermy nie. Indien ’n hoë risikovlak aanwesig is, kan suksesvolle bestuur steeds verhoogde winsgeleenthede vir die belegger verseker. Behalwe vir die tradisionele benaderings tot risikobestuur en risikomitigasie is daar ook ander moontlikhede wat die belegger kan volg om die vlak van risiko te verlaag, soos ’n ooreenkoms om saam met plaaslike belanghebbendes te werk. Sulke meganismes moet verby finansiële belonings strek en ‘n opregte vorm van gemeenskapsinteraksie aanneem wat net kan gebeur deur middel van uitgebreide plaaslike konsultasie. Strategie, beleid en prosedure moet ontwikkel word, wat sal verseker dat maatskappye optimaal saamwerk met nie-regerings-organisasies en die media op plaaslike vlak. Dit sal verseker dat ’n geskikte omgewing vir alle partye geskep word. Poltieke risiko is veel meer as net risiko-evaluasie waar ’n vlak van risiko verskaf word. Dit behoort ten volle deel te wees van die belegging en is essensieël tot die sukses en winsvlak vir die belegger.
9

CEO and CSR : business leaders and corporate social responsibility

Russell, Ellina Osseichuk January 2010 (has links)
The increasing commercial and social pressure for business leaders to act in a socially responsible manner is undermined by the lack of standards in Corporate Social Responsibility (CSR) legislation, auditing, indexing, and reporting. Moreover, CSR research is fragmentary and often missing empirical corroboration. It lacks synthesis, uses CSR concepts and terms ambiguously, and is inconsistent in the identification of CSR practices, its formulation and institutionalisation. This study addresses these gaps and discontinuities by first synthesising a range of theories into an explanatory framework. This framework provides the pre-understanding for the collection and analysis of qualitative data drawn from the UK oil and gas industry. The findings highlight the heterogeneous and dynamic nature of CSR operationalisation. The analysis emphasises the dependence of CSR strategy formulation on business leaders’ personal beliefs and biases. These beliefs are tempered by balancing shareholders’ interests and stakeholders’ expectations, and are affected by the global (in the case of corporations) or the local (in the case of corporate subsidiaries and small-medium size enterprises) contexts. These appear to be the main factors influencing leaders’ CSR decisions. The findings also demonstrate a number of challenges that business leaders face when reconciling personal, organisational, industry, global, and societal values and ethical beliefs; and balancing traditional organisational goals, such as profit maximisation, with increased stakeholder empowerment in granting social legitimacy. In addition, the exploration of CSR institutionalisation reveals different approaches in corporate subsidiaries, which fluctuate between the CSR practices of corporate headquarters and those of SMEs. The analysis of these findings results in a proposed hybrid model of CSR Institutionalisation in the oil and gas industry, with a breakdown of identified factors affecting corporate, SMEs’, and subsidiaries’ leaders’ CSR decisions. This thesis contributes to the literature by proposing a number of concepts, including: CSR Nexus and CSR Dynamics models as conceptual syntheses of the theoretical framework; an empirically corroborated CSR Operationalisation model within the studied organisations suggesting a nonconformance with extant CSR research; an observed matrix of business leaders’ CSR Motivations highlighting their diversity in corporations, SMEs, and corporate subsidiaries. Finally, a conceptual CSR Convergence model is proposed, which outlines a comprehensive approach to CSR education and implementation. In a weak and ambiguous CSR regulation and legislation environment, this study endeavours to bridge the gap between CSR research, business organisations, and stakeholders by contributing to the enhancement of CSR understanding, education, and implementation.
10

Modelling of corrosion electrochemistry in sweet environments relevant to oil and gas operations

Sanadhya, Sanskar January 2017 (has links)
The research reported in this doctoral thesis involves constructing physiochemical models that reproduce the transport behaviour of aqueous chemical species present in environments relevant to the oil and gas industry to gain an improved insight into the local electrochemistry near the electroactive surface (uniform corrosion) or inside the pit (pitting corrosion). The first part of the project involved constructing physiochemical models with one dimensional geometry with aqueous chemical species and chemical and electrochemical processes observed in oxygen (O2) containing brine environments to determine the changes in the local electrolyte composition and the potential within an initiated pit for a variety of external physical and chemical conditions. It was determined that the bottom of the pit suffers greatly from the effects of iR drop (Ohmic drop) if the pit geometry is taken to be macroscopic. The model was extended to include additional aqueous chemical species in conjunction with the chemical and electrochemical processes observed in carbon dioxide (CO2) rich environment to investigate the effects of CO2 on the local electrolyte chemistry at the bottom of the pit. It was found that the proton reduction electrochemical process on its own was incapable of supplying the high currents experimentally measured in CO2 environments via the buffering effect. The second part of the project was to investigate the influence of different experimental conditions on the polarisation behaviour of near static carbon steels in CO2 saturated brine electrolyte via multiple electrochemical measurement techniques. The key observation from this study was the presence of two distinct mass transport limited regions on the cathodic polarisation curve at natural pH (3.775). From the physiochemical model fitted to the experimental cathodic curve, the first mass transport limited region, occurring at lower cathodic potentials, was identified to be the direct reduction of carbonic acid while the second wave, occurring at slightly higher cathodic potentials, was shown to be the direct reduction of aqueous carbon dioxide. Based on the polarisation scans under forced convection, the rate of the direct reduction of carbon dioxide was determined to be under neither potential nor mass transport control. The third part of the project involved extending the existing one dimensional models to include the precipitation of salt films (iron chloride – FeCl2(s) and iron carbonate – FeCO3(s)) in O2 and CO2 saturated brine electrolyte respectively along with the capability to track their respective thickness. Furthermore, the ability of the underlying metal to undergo a change in its state from active to passive is implemented in the model via a set of rules based on the Pourbaix diagram. It was determined that the precipitation of salt films is greatly influenced by the mass transport with no or minimal thickness observed under even natural convection conditions. Furthermore the successful precipitation of salt film was determined to be a precursor step to the metal attaining passivation.

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