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dc.contributor.advisorBryant, David
dc.contributor.advisorLi, Jian-Ping
dc.contributor.advisorRahmanian, Nejat
dc.contributor.authorAlkaragoolee, Mohammed Y.A.*
dc.date.accessioned2019-02-27T16:15:08Z
dc.date.available2019-02-27T16:15:08Z
dc.date.issued2018
dc.identifier.urihttp://hdl.handle.net/10454/16859
dc.description.abstractThe failure of oil well drillstrings due to torsional and longitudinal stresses caused by stick-slip phenomena during the drilling operation causes great expense to industry. Due to the complicated and harsh drilling environment, modelling of the drillstring becomes an essential requirement in studies. Currently, this is achieved by modelling the drillstring as a torsional lumped model (which ignores the length of the drillstring) for real-time measurement and control. In this thesis, a distributed-lumped model including the effects of drillstring length was developed to represent the drillstring, and was used to simulate stick-slip vibration. The model was developed with increasing levels of detail and the resultant models were validated against typical measured signals from the published literature. The stick-slip model describes the friction model that exists between the cutting tool and the rock. Based on theoretical analysis and mathematical formulation an efficient and adaptable model was created which was then used in the application of a method of species conserving genetic algorithm (SCGA) to optimise the drilling parameters. In conclusion, it was shown that the distributed-lumped model showed improved detail in predicting the transient response and demonstrated the importance of including the drillstring length. Predicting the response of different parameters along the drillstring is now possible and this showed the significant effect of modelling the drillcollar. The model was shown to better represent real system and was therefore far more suited to use with real time measurements.en_US
dc.description.sponsorshipIraqi Government, Ministry of Higher Education and Scientific Research.en_US
dc.language.isoenen_US
dc.rights<a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />The University of Bradford theses are licenced under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/">Creative Commons Licence</a>.eng
dc.subjectDrillingen_US
dc.subjectOIl rigen_US
dc.subjectDrillstringen_US
dc.subjectStick-slipen_US
dc.subjectModellingen_US
dc.subjectSimulationen_US
dc.subjectDistributed-lumpeden_US
dc.subjectOptimisationen_US
dc.subjectGenetic algorithmsen_US
dc.titleHybrid Modelling and Optimisation of Oil Well Drillstringsen_US
dc.type.qualificationleveldoctoralen_US
dc.publisher.institutionUniversity of Bradfordeng
dc.publisher.departmentFaculty of Engineering and Informaticsen_US
dc.typeThesiseng
dc.type.qualificationnamePhDen_US
dc.date.awarded2018
refterms.dateFOA2019-02-27T16:15:08Z


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