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dc.contributor.advisorWu, David T.
dc.contributor.advisorKoh, Carolyn A. (Carolyn Ann)
dc.contributor.authorDapena, J. Alejandro
dc.date.accessioned2019-10-15T17:46:34Z
dc.date.accessioned2022-02-03T13:17:45Z
dc.date.available2020-10-09T17:46:38Z
dc.date.available2022-02-03T13:17:45Z
dc.date.issued2019
dc.identifierDapena_mines_0052E_11819.pdf
dc.identifierT 8806
dc.identifier.urihttps://hdl.handle.net/11124/173290
dc.descriptionIncludes bibliographical references.
dc.description2019 Fall.
dc.description.abstractNatural gas hydrates are clathrate compounds consisting of a network of hydrogen-bonded water molecules that host small hydrocarbons within the resulting structure. Subsea oil & gas production pipelines can provide the required thermodynamic conditions for hydrate formation; consequently, natural gas hydrate crystals can be present in a wide variety of shapes and sizes ranging from colloidal hydrate suspensions to macroscopic hydrate particles resulting from phenomena such as hydrate deposit sloughing and hydrate particle agglomeration. Such variability in the properties of the hydrate particles in the pipeline turns several phenomena into potential mechanisms for hydrate plug formation. These phenomena can involve, for example, the emergence of a sample-spanning skeleton of particles resistant to applied stresses (i.e. yield stress materials), or the accumulation and eventual clogging of discrete macroscopic hydrate particles due to the formation of stabilizing mechanical structures at flow path constrictions. Accordingly, a sound assessment of the hydrate plugging risk in a given scenario needs to consider all the possible mechanisms that could result in the kinetic arrest of hydrate particles in the system. A series of investigations looking at the aforementioned phenomena were carried out aimed to advance the understanding of hydrate plugging risk in subsea oil & gas production. These studies included laboratory experiments involving a variety of multiple length-scale equipment, as well as numerical simulations implementing the discrete element method (DEM). The experimental investigations encompassed low-volume apparatuses (e.g. high-pressure rheometer (HP-rheometer)), or even surface chemistry level tools (e.g. micro-mechanical forces apparatus (HP-MMF) and water/hydrate surface contact angle measurements), all the way up to pilot-scale equipment, such as Tulsa University and ExxonMobil flowloop facilities. The combined information and understanding resulting from these investigations derived in several outcomes, which can ultimately turn into useful tools in the daily life of flow assurance engineers. On the one hand, the HP-rheometer studies looking at the performance of hydrate dispersants both under flowing and static conditions lead to the development of an experimental protocol for the quantitative assessment of the performance these chemicals in continuous and transient operations. The multiple length scale investigations using similar fluid compositions to those previously utilized in the HP-rheometer tests provided further validation for the proposed protocols to assess hydrate dispersant performance. A qualitative agreement was observed between HP-MMF, HP-rheometer, and high-pressure autoclave (HP-autoclave) regarding the range of hydrate dispersant concentration leading to a transition from fully- to under-inhibited hydrate particle agglomeration. Furthermore, a quantitative comparison of the hydrate cohesive forces obtained from HP-MMF experiments and those derived from HP-rheometer yield stress measurements resulted in an order of magnitude agreement between these equipment. On the other hand, the bench-scale flowloop tests and DEM simulations looking at particle accumulation and clogging at flow path constrictions lead to an advanced understanding of the interconnection between the behavior of intrinsic properties of the system (e.g. pressure drop and kinetic energy fluctuations) and the macroscopic phenomena visually observed during the experiments (e.g. intermittent particle flow and arch breakage). Using signal processing techniques to analyze the continuous output data generated during the experiments showed that the clogging risk in the system could be monitored in real-time through easily accessible information, such as pressure drop evolution. Finally, using survival analysis tools, such as Weibull analysis, to interpret the results obtained from numerical simulations provided further insights into the failure of avalanches and clogs during the intermittent flow of particles across a flow path constriction. Ultimately, the experimental results, data processing methods, and analysis techniques derived from these investigations might provide the foundation for a new generation of probability-based risk analysis tools that can be used by flow assurance engineers in the field. These tools could help to effectively assess the potential consequences of deploying novel hydrate management strategies in a given scenario having a significant impact on the economics of both future field developments, as well as in current brown fields utilizing over-conservative hydrate plug mitigation methods.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado School of Mines. Arthur Lakes Library
dc.rightsCopyright of the original work is retained by the author.
dc.subjectDEM
dc.subjecthydrates
dc.subjectrheology
dc.subjectflow assurance
dc.subjectclogging
dc.subjectjamming
dc.titleOn the kinetic arrest of hydrate slurries
dc.typeText
dc.contributor.committeememberMustoe, Graham G. W.
dc.contributor.committeememberNakagawa, Masami
dc.contributor.committeememberWu, Ning
dc.contributor.committeememberTurner, Douglas J.
dcterms.embargo.terms2020-10-09
dcterms.embargo.expires2020-10-09
thesis.degree.nameDoctor of Philosophy (Ph.D.)
thesis.degree.levelDoctoral
thesis.degree.disciplineChemical and Biological Engineering
thesis.degree.grantorColorado School of Mines
dc.rights.accessEmbargo Expires: 10/09/2020


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