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Sedimentation solutions for the Port of PascagoulaJohnson, Hunter Neal 13 December 2008 (has links)
The purpose of this work, which is designed for the Port of Pascagoula, is to locate sedimentation problems, identify sediment characteristics, and devise a method to decrease the port’s dredging costs. In order to understand what sediment problems are typical of the Port of Pascagoula the characteristics that are associated with sediment transportation in the port’s harbors are examined. This examination consists of a field investigation followed by an extensive evaluation of the data. Once the characteristics that are unique to the harbors are identified, potential solutions are examined. These potential solutions are evaluated until a feasible and efficient plan is devised to reduce the ports dependency on dredging. Recommendations include agitation, a fluid mud trap, and the practice of active nautical depth. Each of these solutions would allow the port to reduce its dredge costs.
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Environmental Reconstructions From Structures and Fabrics Within Thick Mudstone Layers (Fluid Muds), Tilje Formation (Jurassic), Norwegian Continental ShelfReith, Geoffrey 16 September 2013 (has links)
The Jurassic Tilje Formation located on the Norwegian continental shelf contains many thick (>10 mm) and macroscopically homogenous mudstone layers. These mudstone layers are interpreted to have accumulated rapidly from “fluid-mud,” a highly concentrated aqueous suspension of fine-grained sediment. Fluid muds in the Tilje are recognized in tidal-fluvial channel, mouth-bar and distal delta-front environments. From detailed thin-section work it is clear that these mudstone layers are not homogenous. Three facies are observed: unstratified mudstone (UM), some of which contain “floating” coarse grains, planar-laminated mudstone (PLM) and cross-laminated mudstone (CLM). Each facies represents deposition at differing suspended-sediment concentrations (SSC) (UM−high SSC, PLM−low-moderate SSC and CLM−low SSC).
The thickest mudstone layers are always associated with underlying dune-scale cross-bedding, which has led to a proposed model where fluid mud can accumulate and is protected from the over-riding flow in the troughs of large dunes. This model is most relevant to tidal-fluvial channels where large dunes occur in the deepest water and in terminal distributary channels in mouth bars.
The vertical stacking of facies within a single mudstone layer allows reconstruction of changes of the near-bed SSC values and current velocities that reflect deceleration and acceleration of the tidal currents over the tidal cycle or waning wave energy following a storm. Based on repeating patters termed “vertical successions” and “succession combinations,” individual tidal cycles can be observed within single mudstone layers and the relative strength of subordinate and dominant currents can be
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inferred.
To aide in the understanding of how mud can accumulate over the complete range of SSCs, current velocities and grain sizes, a preliminary three-dimensional bedform phase diagram has been constructed for fine-grained sediment based on recent flumes studies. The phase diagram can be applied to mudrocks beyond the Tilje Formation. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2013-09-15 17:14:19.827
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Fluid Mud Formation in the Petitcodiac River, New Brunswick, CanadaHeath, Kristy Marie January 2009 (has links)
Thesis advisor: Gail C. Kineke / Experiments were conducted in the Petitcodiac River in New Brunswick, Canada during June and August 2006 to study high-concentrations of suspended sediment in a turbulent system. This study will evaluate the conditions necessary for fluid mud formation by investigating 1) the suppression of turbulence at gradient Richardson numbers greater than 0.25; 2) a threshold condition for the amount of sediment a flow can maintain in a turbulent suspension; and 3) the influence of flocculation on vertical suspended-sediment transport. Direct measurements of salinity, temperature, current velocity, and suspended-sediment concentration were collected during accelerating and decelerating flows and when fluid mud formed. In June, current velocities were typically above 1 m s<super>-1</super> and suspended-sediment concentrations were generally less than 10 g l <super>-1</super>. In August, current velocities were typically less than 1.5 m s<super>-1</super>, suspended-sediment concentrations were greater than 10 g l <super>-1</super>, and a high-concentration bottom layer formed rapidly during decelerating flood currents. Gradient Richardson numbers for concentrations greater than 10 g l <super>-1</super> were generally greater than 0.25, suggesting strong density gradients have the ability to suppress turbulence. Results from the Petitcodiac suggest a carrying capacity threshold might exist, but is based on a critical gradient Richardson number between 1.0 and 2.0 rather than the previously accepted value of 0.25. Differences in the evolution of disaggregated grain size distributions for settling suspensions suggest flocculation plays an important role for fluid mud formation by enhancing settling of fine sediments. / Thesis (MS) — Boston College, 2009. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Geology and Geophysics.
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Performance Analysis Of Drilling Fluid Liquid LubricantsSonmez, Ahmet 01 September 2011 (has links) (PDF)
Excessive torque is one of the most important problems in oil/gas drilling industry. Friction between wellbore/casing and drill string causes excessive torque. This study discusses performance analysis of drilling fluid lubricants, which are used as friction reducers in well-bore. Three different types of commercial chemical lubricants, which are fatty acid and glycerid based, triglycerid and vegetable oil based and polypropylene glycol based, diesel oil, and crude oil, which consists of different API gravity, paraffin and asphaltene value samples, were selected for the analysis.
In the analysis, different lubricant compositions with the mixture of commercial chemical lubricants, crude oil and diesel oil, which were added to water based lignosulfonate mud, are tested on metal-metal contact surface by Ofite Lubricity Tester to determine the best lubricity/cost ratio of lubricant compositions.
Moreover, effects of the lubricants on mud rheology and API fluid loss of mud, foam forming potential and cheesing/greasing of the lubricants and the influence of mud properties on lubricants (calcium, salt, pH and mud density) are examined.
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Observação do transporte de sedimentos em suspensão ao longo do Canal Norte do rio Amazonas durante condições de baixa descarga (outubro 2008) / Observation of suspended sediment transport along North Channel of Amazon river during low discharge (October 2008)Edgard Villarinho Garcia Neto 21 October 2011 (has links)
Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / The Amazon river, located in northernBrazil, discharges between 80,000 and 250,000 m3s-1 of water onto the adjacent shelf, creating a plume of brackish water that extends hundreds of kilometers away from the river mouth. This river also carries a large amount of fine sediments to the ocean where fluid mud has been found in the topset and upper foreset layers of the subaqueous delta formed on the mid-shelf. One of the main goals of this dissertation is to describe how turbulence and suspended sediment concentration vary along the Northern Channel of the Amazon river. Water column measurements were carried out in October 2008 at six anchor stations (P1, P3, P5, P6, P8 e P9) located seaward of the river mouth; P1 and P9 were 125 km apart. Each station was occupied during 13 hours during which current speed and direction were continuously sampled with a 600 kHz Teledyne-RDI ADCP; hourly profiles of temperature, salinity, turbidity and depth were also obtained. Water samples were collected for determination of Suspended Particulate Matter (SPM) concentration and calibration of the turbidity sensor. Current speed reached values above 1.5 m s1 in the along-channel direction (NE-SW); a remarkable ebb-flood asymmetry was observed and flows were strongly ebb-dominated. Throughout the water column, SPM concentration at stations P1 and P3 varied between 100 and 300 mg L1 in association with the presence of freshwater. In contrast, a strong salinity gradient was observed between stations P6 and P9, coinciding with the occurrence of concentrations of SPM above 10 g L-1 (fluid mud). At stations P3, P5 and P6, interface between freshwater from the Amazon river and salt water from the continental shelf, shear stresses wereestimated through four diferents methods: Reynolds, Turbulent Kinetic Energy (TKE), modified TKE and Quadratic Law; in the nearbed region (3 mab) the computed values varied between 0 and 3 Pa. At the three stations (P3, P5 and P6) the lowest and the highest shear stress values were obtained through, respectively, the Reynolds and the TKE methods. Over the whole water column turbulence intensity was estimated through the standard deviation of the turbulent component of the along-channel current velocity (root-mean square of u); from these values, it was estimated the turbulent dissipation of energy (G), whose values at 3 mab varied between zero and 20 s1.
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Observação do transporte de sedimentos em suspensão ao longo do Canal Norte do rio Amazonas durante condições de baixa descarga (outubro 2008) / Observation of suspended sediment transport along North Channel of Amazon river during low discharge (October 2008)Edgard Villarinho Garcia Neto 21 October 2011 (has links)
Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / The Amazon river, located in northernBrazil, discharges between 80,000 and 250,000 m3s-1 of water onto the adjacent shelf, creating a plume of brackish water that extends hundreds of kilometers away from the river mouth. This river also carries a large amount of fine sediments to the ocean where fluid mud has been found in the topset and upper foreset layers of the subaqueous delta formed on the mid-shelf. One of the main goals of this dissertation is to describe how turbulence and suspended sediment concentration vary along the Northern Channel of the Amazon river. Water column measurements were carried out in October 2008 at six anchor stations (P1, P3, P5, P6, P8 e P9) located seaward of the river mouth; P1 and P9 were 125 km apart. Each station was occupied during 13 hours during which current speed and direction were continuously sampled with a 600 kHz Teledyne-RDI ADCP; hourly profiles of temperature, salinity, turbidity and depth were also obtained. Water samples were collected for determination of Suspended Particulate Matter (SPM) concentration and calibration of the turbidity sensor. Current speed reached values above 1.5 m s1 in the along-channel direction (NE-SW); a remarkable ebb-flood asymmetry was observed and flows were strongly ebb-dominated. Throughout the water column, SPM concentration at stations P1 and P3 varied between 100 and 300 mg L1 in association with the presence of freshwater. In contrast, a strong salinity gradient was observed between stations P6 and P9, coinciding with the occurrence of concentrations of SPM above 10 g L-1 (fluid mud). At stations P3, P5 and P6, interface between freshwater from the Amazon river and salt water from the continental shelf, shear stresses wereestimated through four diferents methods: Reynolds, Turbulent Kinetic Energy (TKE), modified TKE and Quadratic Law; in the nearbed region (3 mab) the computed values varied between 0 and 3 Pa. At the three stations (P3, P5 and P6) the lowest and the highest shear stress values were obtained through, respectively, the Reynolds and the TKE methods. Over the whole water column turbulence intensity was estimated through the standard deviation of the turbulent component of the along-channel current velocity (root-mean square of u); from these values, it was estimated the turbulent dissipation of energy (G), whose values at 3 mab varied between zero and 20 s1.
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