Optimization of FPSO Glen Lyon Mooring Lines

During oil and gas inspection and extraction operations both in deep and ultra-deep water, vessel mooring is a very important factor for the development of oil fields. For these depths, standard stand-alone surface facilities e.g. jack up rigs or offshore fixed platforms are not suitable due to the harsh collinear and non-collinear environment in-situ (location, waves, surface and underwater current, sea tides, ice, etc.). For deep sea wells clusters, it is usual to use floating production storage offloading (FPSO) as surface platforms for long time exploitation periods. Subsea expenditure, refers the cost of the subsea project and generally includes the capital expenditures (capex) and operational expenditures (opex). In the production of hydrocarbons capex and opex exponentially increases with increasing depth, resulting in a need for precise detailed design phase for analysis of systems to verify components strength, ductility and fatigue, stiffness, instabilities, corrosion etc. The design of oilfields is most of the times overrated (in a very conservative way) due to several requirements and complex models of costs evaluation. After detailed phase and installation of all facilities and components, as well as due to the expected life design for hydrocarbons exploitation all anchoring system shall withstand the environmental loads in order to not compromise the operation. Each oilfield has a unique development, since environmental phenomena are unique in each earth location. This work refers to the optimization process of an anchoring system for deep waters in the Schiehallion Field, or in other words, the complete development of the mooring system for a FPSO, from the positioning in-situ with environmental conditions and vessel characteristics (Orcaflex), further optimization of the mooring system for an equivalent system (Matlab), mechanical design of the mooring system (CATIA), structural detailed analysis (Altair and Nastran) as fatigue life analysis. In order to reproduce all the mooring process, it is performed and initial comparison of the former FPSO (Schiehallion FPSO) that has been working in-situ since 1993 till its replacement for the new vessel (Glen Lyon FPSO). Due to the latest discoveries in the oilfield, the project has to be redesigned alongside with former wells and having in consideration recent discovered wells. Further optimization of the complete fixation system was verified as well as finally detailed structural analysis of specific components in key locations with higher margin of failure. Within this work, all the methodology which led to the optimization of Glen Lyon mooring lines was fully detailed from vessel analysis to detailed mooring mechanical design, constraints and requirements were applied, trade-offs and assumptions made during this critical development phase are presented and discussed.Durante as operações de prospeção e extração de petróleo e gas em águas profundas e ultra profundas, o fundeamento de navios é um importante fator para o desenvolvimento do campo petrolífero. Para estas profundidades, infra-estruturas convencionais e.g. plataformas petrolíferas não são aplicáveis devido ao ambiente violento colinear e não colinear do local (localização, ondas, correntes subaquáticas e de superfície, marés, etc.). Para conjuntos de poços subaquáticos, é comum o uso de Platformas de produção, armazenamento e descarga (FPSO) como plataforma de superficie para periodos de exploração longos. Os custos subaquaticos referem-se ao custo do projeto marinho e normalmente incluem os custos de capital capex e custos operacionais opex. Na produção de hidrocarbonetos os capex e os opex aumentam exponencialmente com o aumento da profundidade, resultando na necessidade do desenvolvimento da fase de projeto detalhado necessário para análises de componentes para verificar a resistência dos mesmos, dutilidade e fadiga, quer na rigidez, instabilidade, corrosão, etc. O projeto de campos petrolíferos são na maioria das vezes sobreestimados (de forma bastante conservativa) devido a imensos requisitos e modelos complexos de avaliação de custos. Após projeto e instalação de todas as infraestruturas e componentes, assim como durante o longo periodo útil de extração de hidrocarbonetos, toda a ancoragem deve suportar as cargas ambientais de forma a não comprometer a operação. Cada campo petrolífero possui um desenvolvimento singular, uma vez que os fenómenos ambientais são únicos em cada localização do globo terrestre. Este trabalho refere a optimização de um sistema de amarração para águas profundas para o campo de Schiehallion, ou por outras palavras, todo o desenvolvimento de ancoragem de um navio FPSO, desde o posicionamento no local com as forças ambientais e as caracteristicas do navio (Orcaflex), posterior otimização do sistema de ancoragem por um sistema equivalente (Matlab), desenho mecânico do sistema de ancoragem (CATIA), cálculo estrutural detalhado (Altair e Nastran) e análise de vida à fadiga. De forma a reproduzir o processo de ancoragem, é efetuada uma comparação inicial do FPSO inicial (Schiehallion FPSO) que esteve em operação no local desde 1993 até à sua substituição pelo novo navio (Glen Lyon FPSO), através da implementação e gestão do campo petrolífero de acordo com os poços antigos como os poços descobertos recentemente. A posterior otimização de todo o sistema de fixação foi verificada assim como a análise estrutural final detalhada dos componentes específicos em localizações especificas com grande probabilidade de falha. Através deste trabalho, todo o processo que leva à otimização das linhas de amarração do Glen Lyon é completamente detalhado desde a análise do navio ao detalhamento do desenho mecânico, os constrangimentos e requisitos que foram aplicados, estudos e opções efetuadas durante a fase de desenvolvimento crítico são apresentados e discutidos

The active role of cerebrospinal fluid, brain cells and tissue homogenates from the mid-brain of the chick embryo in negotiating physiological changes in osmotic pressure and viscosity via selective secretion of macromolecules, 1981

In this investigation changes in inferred protein synthetic activity and its association with hyaluronic acid changes in chick brain development from 4 day-old embryos to 8 day-old embryos were studied in three parts: cerebrospinal fluid, brain cells and homogenized brain tissue. With the use of S-Methionine, it is apparent that during chick brain development the increase and changes associated with protein synthesis activity closely resembles the changes in all three components of the brain studied. The activity of hyaluronic acid was adequately assessed using C-Glucosamine and H-Glucosamine. The hyaluronic acid appeared strongly bound to the protein, and it appears that day 6 and 7 are critical periods in which protein synthesis and hyaluronic acid synthesis are either retarded or accelerated. Moreover, it is suggested that the changes noted in hyaluronic acid synthesis may be affected by changes in cell type, size, number, specific enzymes or waves of neuronal migration and differentiation during embryonic brain development

Investigation of swine dysentery associated with Brachyspira hampsonii strain EB107 and comparison of diagnostic methods

Swine dysentery (SD) is an important cause of mucohemorrhagic diarrhea in pigs. Swine dysentery is associated with infection by Brachyspira hyodysenteriae which has historically been the only recognized strongly beta-hemolytic Brachyspira sp. However, in recent years, not all strongly beta-hemolytic isolates have been identified as B. hyodysenteriae using PCR assays specific for this species. Several reports have described putatively novel strongly beta-hemolytic Brachyspira spp. including Brachyspira hampsonii associated with SD. A pig inoculation study was used to compare lesions and colonic mucin expression associated with infection by B. hyodysenteriae or B. hampsonii. Diagnosis of SD commonly includes culture which while sensitive is time-consuming and PCR which while rapid can be limited by fecal inhibition. Due to the limitations of these assays, a same-day fluorescent in situ hybridization (FISH) assay was developed to detect B. hyodysenteriae and B. hampsonii in pig feces and the threshold of detection was compared to PCR and culture. Little is published about the pathogenesis of SD; yet the interaction between the colonic microbiota and diet seems to be important. Recently, distillers dried grains with solubles (DDGS), a source of insoluble fiber, has been increasingly included in swine diets. A randomized complete block experiment was used to examine the effect of DDGS on the incidence of Brachyspira-associated colitis in pigs. Gross and microscopic lesions are similar following infection with B. hampsonii or B. hyodysenteriae. Histochemical and immunohistochemical evaluation of the colon revealed decreased expression of sulphomucins and mucin 4 and increased expression of mucin 5AC in diseased pigs compared to controls. The FISH assay effectively detected both Brachyspira spp. in formalin-fixed feces from pigs with SD. Spirochetes were also readily detectable in pen level samples from clinical pigs. Although culture remains the diagnostic assay of choice for surveillance, clinically affected pigs may be identified in a timelier manner using either qPCR or FISH. Pigs receiving 30% DDGS shed on average one day prior to and developed SD nearly twice as fast as pigs receiving 0% DDGS. These data suggest a reduction in insoluble fiber should be considered a part of any effective disease elimination strategy for SD

Tendons: structure, function and challenges to clinical treatment

As dense connective tissues, tendons play a vital role in the transmission of contractile forces from muscle to bone. This link between muscles and bones provides the means in transferring tensile forces produced by muscles on to the connected bone. During movement, tendons slide over surrounding bony and articular surfaces and are thus commonly subjected to shear and compression forces in addition to tensile force. Fibrillar collagen, proteoglycan and various glycoproteins make up the composition of tendinous tissue and contribute to its ability to withstand these forces. Tendons contain a distinct population of cells, called tenocytes. Tenocytes undertake a flattened morphology within the tendon matrix and contain cytoplasmic projections which extend longitudinally and laterally towards other tenocytes. An intercellular network of cells thus maintains the extracellular environment of the tendon and allows a coordinated response to external mechanical stimuli. Defects to load-bearing connective tissue elements such as tendons whether due to trauma, overuse, age-related diseases or degenerative diseases, are often limited in their healing potential and thus contributes often to persistent, chronic clinical symptoms. Chronic disease, overuse or acute injuries damages the tendon. This damage compromises the transmission of tensile forces and because of the hypovascularity of some tendinous tissues and many other reasons, a healing response often is severely insufficient in regenerating tissue back to its original constitution. Even the best treatment options for such tendinopathies, supplemented with the body’s own healing response fail to produce quality outcomes. An understanding of the molecular, cellular and mechanical characteristics of tenocytes, tendon matrix and the tendon system as a whole will be vital for the development of effective therapies for all tendinopathies. It is the goal of this current work to outline the current molecular, cellular, mechanical and clinical understanding of tendons. A broad address to tendon biology should help illustrate the key dimensional aspects that must be considered when attempting the effective translation of research into useful clinical therapies

Design, Development and Biomechanical Analysis of Scaffolds for Augmentation of Rotator Cuff Repairs

Rotator cuff tears are a source of debilitating pain that commonly affects more than 40 of our aging population. Despite advances in surgical treatment, the failure rate of rotator cuff repairs is as high as 20-90 . Extracellular matrix (ECM) derived scaffolds have recently been investigated as augmentation devices for rotator cuff repairs, but none has yet demonstrated both the appropriate biological and mechanical properties for mitigating re-tears and enhancing healing. This dissertation proposes to engineer the mechanical properties of allograft fascia lata in a manner that will allow its use as an augmentation device for rotator cuff repairs. This dissertation also aims to develop a simple quasi-linear spring-network model for rotator cuff repairs to elucidate the basic biomechanics of these repairs. The central hypothesis is that engineered fascia lata will have suture retention strength similar to that of human rotator cuff tendon (̃250N), even after in vivo implantation. The specific aims are to engineer the mechanical properties of allograft fascia lata ECM and to subsequently evaluate the host response and concomitant mechanical properties of the engineered (reinforced) fascia in a rat model. Further, this dissertation will also develop and validate a spring-network model for simplified rotator cuff repairs. Studies presented in this dissertation demonstrate stitching as a technology to engineer the suture retention and stiffness of allograft (human derived) fascia lata ECM. Stitching fascia ECM with braided, resorbable, polymer fibers in a unique, controlled manner increased the suture retention load of reinforced fascia scaffolds by six fold over non-reinforced fascia. Additionally, the suture retention properties of reinforced fascia scaffolds were comparable to that of human rotator cuff tendon (̃250N) at time zero and even after in vivo implantation for twelve weeks. Except for the increased presence of foreign body giant cells in areas concentrated around the polymer fibers, the host re

Design, Development and Biomechanical Analysis of Scaffolds for Augmentation of Rotator Cuff Repairs

Rotator cuff tears are a source of debilitating pain that commonly affects more than 40 of our aging population. Despite advances in surgical treatment, the failure rate of rotator cuff repairs is as high as 20-90 . Extracellular matrix (ECM) derived scaffolds have recently been investigated as augmentation devices for rotator cuff repairs, but none has yet demonstrated both the appropriate biological and mechanical properties for mitigating re-tears and enhancing healing. This dissertation proposes to engineer the mechanical properties of allograft fascia lata in a manner that will allow its use as an augmentation device for rotator cuff repairs. This dissertation also aims to develop a simple quasi-linear spring-network model for rotator cuff repairs to elucidate the basic biomechanics of these repairs. The central hypothesis is that engineered fascia lata will have suture retention strength similar to that of human rotator cuff tendon (̃250N), even after in vivo implantation. The specific aims are to engineer the mechanical properties of allograft fascia lata ECM and to subsequently evaluate the host response and concomitant mechanical properties of the engineered (reinforced) fascia in a rat model. Further, this dissertation will also develop and validate a spring-network model for simplified rotator cuff repairs. Studies presented in this dissertation demonstrate stitching as a technology to engineer the suture retention and stiffness of allograft (human derived) fascia lata ECM. Stitching fascia ECM with braided, resorbable, polymer fibers in a unique, controlled manner increased the suture retention load of reinforced fascia scaffolds by six fold over non-reinforced fascia. Additionally, the suture retention properties of reinforced fascia scaffolds were comparable to that of human rotator cuff tendon (̃250N) at time zero and even after in vivo implantation for twelve weeks. Except for the increased presence of foreign body giant cells in areas concentrated around the polymer fibers, the host re

Development Of Granulation Tissue Mimetic Scaffolds For Skin Healing

Impaired skin healing is a significant and growing clinical concern, particularly in relation to diabetes, venous insufficiency and immobility. Previously, we developed electrospun scaffolds for the delivery of periostin (POSTN) and connective tissue growth factor 2 (CCN2), matricellular proteins involved in the proliferative phase of healing. This study aimed to design and validate a novel electrosprayed coaxial microsphere for the encapsulation of fibroblast growth factor 9 (FGF9), as a component of the POSTN/CCN2 scaffold, to promote angiogenic stability during wound healing. For the first time, we observed a pro-proliferative effect of FGF9 on human dermal fibroblasts (HDF) in vitro, indicating a potential cellular mechanism of action during wound healing. POSTN/CCN2 scaffolds containing encapsulated FGF9 decreased wound diameter, with no negative or adverse effects at day 7, in a porcine model of acute cutaneous wound healing. Future work is required to investigate the effect of the POSTN/CCN2/FGF9 scaffold during impaired healing