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Investigation and Evaluation of Metal Powder Characterization Techniques : Currently available at the KTH Department of Material Science and EngineeringHultén, Leo, Jansson, Philip January 2018 (has links)
The KTH Department of Materials Science and Engineering has lacked powder metallurgy research for many years, and as this field is constantly gaining in importance, such research needs to be reestablished. This requires the department to be able to accurately and efficiently characterize the properties of a powder, such as size distribution and composition, and in the short term, this needs to be done using non-specialized equipment. This project aimed to assess the availability and usefulness of both traditional and novel characterization methods by way of trial characterization experiments as well as a literature review. The experiments resulted in some data about three sample powders, as well as the conclusions that size distribution could be effectively characterized by automatized image analysis, composition could be characterized using Energy Dispersive X-ray Spectroscopy and that sample preparation was key to good results. It was concluded that the department could conceivably evaluate the most important properties, but that sampling and sample preparation routines need to be established to ensure efficient characterization and representative data. / Materialinstitutionen på Kungliga Tekniska högskolan har i många år helt saknat pulvermetallurgiforskning och eftersom detta fält ständigt blir mer relevant behöver denna forskning återetableras. Detta kräver att institutionen med tillräcklig noggrannhet och effektivitet kan bestämma egenskaper hos ett pulver, såsom storleksfördelning och sammansättning, och på kort sikt behöver detta ske med ickespecialiserad utrustning. I detta projekt har tillgänglighet och användbarhet hos både traditionella och innovativa analysmetoder utvärderats med hjälp av experimentell karaktärisering av pulver samt en litteraturstudie. Experimenten gav data om de tre undersökta pulvren och resulterade även i slutsatsen att storleksfördelning kunde bestämmas med automatiserad bildanalys, att samansättning kunde bestämmas med Energi Dispersiv Röntgen Spektroskopi och att provpreparering äravgörande för bra resultat. Av detta följer att institutionen rimligtvis kan bestämma de viktigaste egenskaperna hos ett pulver, men att rutiner för provtagning och provpreparering behöver etableras för att säkerställa effektiv analys och representativ data.
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Characterisation of granule structure and strength made in a high shear granulatorRahmanian, Nejat, Ghadiri, M., Jia, X., Stepanek, F. January 2009 (has links)
No / Results of a study of the influence of impeller speed on the strength, structure and morphology of granules produced in a type of high shear mixer granulators are reported. Calcium carbonate particles (Durcal 65) have been granulated in a Cyclomix with a capacity of 5 L. An aqueous solution of polyethylene glycol was used as the binder. The granules produced have been dried and their structure visualized using X-ray micro-tomography equipment, Nanotom, with a resolution of less than 1 μm. It is shown that the operation of the granulator at high impeller tip speeds produces granules with a higher strength and lower porosity than those produced at medium and low impeller speeds. Two different granule micro-structures and morphologies are produced at high and low impeller speeds. Structure descriptors such as phase volume fraction (as representative of porosity), chord length distribution and auto-correlation function (as indices of homogeneity of structure) are used to quantify the internal structure of granules in 3D, which in turn affects the granule strength.
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Novel nanocarbon based sensor platformsOikonomou, Antonios January 2015 (has links)
In the present thesis, research work to tackle challenges such as large-scale integration, selectivity and low efficiency around different types of nanocarbon based sensors is performed. The findings of these studies are given in the form of peer-reviewed publications and conclusions with future recommendations proposed as a summary. The work focuses on three key sensors types, gas sensors, biosensors and photodetectors. The first key aspect is dielectrophoretic (DEP) deposition of nitrogen doped single-walled carbon nanotubes (N-SWCNTs) and it is used as a route to large-scale assembly of increased reactivity, and thus selectivity, gas sensors. Furthermore, suspended SWCNTs and few layer graphene (FLG) devices are fabricated through a novel process which results in increased surface area transducers and low resistance SWCNTs based devices. Moreover, biosensors face similar challenges to gas sensors with the addition that their selectivity needs to be engineered through the formation of a biomimetic interface due to the nature of the analytes they are destined to investigate. Non-covalent functionalization of graphene using self-assembled phospholipid membranes delivered in a controlled and precise manner by dip-pen nanolithography (DPN) was demonstrated together with a high-speed fabrication process of bioassays onto patterned CVD graphene using a parallel tips system. Lastly, for the case of photodetectors, a SWCNT – nanoplasmonic system is proposed as a solution to the major issue of low quantum efficiency in low dimensionality materials. First, the performance of various geometries and arrangements of Au nanoparticles is explored by transferring a micromechanically exfoliated graphene flake onto them and studying the Raman enhancement that arises due to uncoupled and coupled near-fields. An increase of graphene Raman signal of 103 was observed for the areas suspended between two closely spaced dimers as a result of strong near field coupling when the polarisation of the incident light is parallel to the nanostructures axis. A large-scale integration of SWCNTs positioned in between the dimers using DEP is performed as a demonstration of the scalability of the system.
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A molecular, morphological and biological characterisation of the genus Globodera (Nematoda: Heteroderidae) in South AfricaKnoetze, Rinus 03 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: A molecular, morphological and biological characterisation of the genus Globodera (Nematoda: Heteroderidae) in South Africa is presented. The aims of the study were to determine the spread of the genus in South Africa; to study the systematics and describe the characteristics of the group and to gain a more complete understanding of the biology of the group as agricultural pests. Surveys were conducted in the Cape Floristic Region and in all the potato-producing areas of South Africa. The surveys unearthed new species of cyst nematodes and determined the spread of Globodera rostochiensis in the country. Phylogenetic analysis of sequences from ITS-rDNA was used to infer phylogenetic relationships among cyst nematodes from South Africa. The analyses established the distinct phylogenetic positions of cyst nematode populations from South Africa relative to an array of other cyst nematode species and indicated the existence of four new species of cyst nematodes. Analysis of random amplified polymorphic DNA (RAPD) banding patterns revealed intraspecific genetic variation amongst populations of Globodera rostochiensis. In order to provide molecular protocols for the accurate identification of South African cyst nematodes, species-specific primers and restriction enzymes were tested for their ability to discriminate between local Globodera spp. A combination of the molecular, morphological and morphometric characteristics of these populations were used to describe three new species of cyst nematodes. Experiments to determine the effect of storage temperature on the viability and hatching of South African populations of G. rostochiensis, showed differences in the responses of different populations to different storage temperatures. Experiments to determine the effect of field conditions on the viability and hatching of South African populations of G. rostochiensis, indicated that a decline in viable eggs in cysts from different populations occur, but suggests that the cysts will be able to survive for much longer in these soils than was expected. Spontaneous hatch was the main contributor to the decline of viability of cysts in the soil. Recording of soil temperatures in different locations indicated that the average temperature at 20 cm depth was approximately 20°C, the optimum temperature for the reproduction of G. rostochiensis, as confirmed by in vitro reproduction tests, which also showed that multiplication and survival is influenced negatively when the temperatures rise above 25°C. Reproduction on differential potato clones confirmed the pathotype of all the South African populations of G. rostochiensis as Ro1. After assessing the reproduction of G. rostochiensis on indigenous solanaceous plants, it was concluded that none of these plants induce substantial hatch in G. rostochiensis, nor do they support multiplication of the nematode. The results of this project have an impact on inquiries at all taxonomic levels, while also having an essential practical application in nematology. Knowledge of the distribution, pathogenicity, survival potential and reproduction capacity of Globodera species in South African soils are valuable for the design of effective management strategies as well as regulatory measures. / AFRIKAANSE OPSOMMING: ‘n Molekulêre, morfologiese en biologiese karakterisering van die genus Globodera (Nematoda: Heteroderidae) in Suid-Afrika word aangebied. Die doelwitte van die studieprojek was om die verspreiding van die genus in Suid-Afrika vas te stel, om die sistematiek van die groep te bestudeer en om ‘n meer volledige begrip van die biologie van die groep te bekom. Opnames is in die Kaapse Floristiese streek en in al die aartappelproduserende gebiede in die land gedoen. Tydens die opnames is nuwe sist nematode spesies gevind en die verspreiding van Globodera rostochiensis in Suid-Afrika is vasgestel. Filogenetiese analises van die basispaar opeenvolgings van ITS-rDNS is gebruik om die filogenetiese verwantskappe tussen die sist nematodes van Suid-Afrika vas te stel. Die spesifieke filogenetiese posisies van die nematodes, relatief tot ander spesies het gedui op die teenwoordigheid van 4 nuwe spesies. ‘n Analise van “random amplified polymorphic DNA” (RAPD) bandpatrone het intraspesifieke variasie tussen populasies van G. rostochiensis uitgewys. Diagnostiese tegnieke, aan die hand van spesies-spesifieke inleiers en restriksie-ensieme, is geevalueer vir hul vermoë om Globodera spesies van mekaar te onderskei. ‘n Kombinasie van molekulére, morfologiese en morfometriese karaktertrekke is gebruik vir die beskrywing van drie nuwe Globodera spesies. Eksperimente om die effek van verskillende temperature op die lewenskragtigheid en uitbroei van Suid-Afrikaanse populasies van G. rostochiensis vas te stel, het verskille in die reaksies van die poulasies uitgewys. Eksperimente om die effek van veldtoestande op die lewenskragtigheid en uitbroei van Suid-Afrikaanse populasies van G. rostochiensis vas te stel, het gewys dat alhoewel ‘n afname in die lewenskragtigheid van eiers plaasvind, sal die siste nog steeds langer in die grond oorleef as wat verwag is. Spontane uitbroei van eiers was die grootste oorsaak van die afname in lewenskragtigheid van siste in die grond. Die monitoring van grondtemperature in verskillende lokaliteite, het gewys dat die gemiddelde temperatuur, 20 cm onder die grond, nagenoeg 20°C was. Die optimum temperatuur vir die aanteling van G. rostochiensis, soos gewys deur in vitro toetse is ook 20°C, maar ‘n skerp daling vind plaas by temperature hoer as 25°C. Aanteling op verskillende aartappel cultivars, het gewys dat die patotipe van plaaslike populasies van G. rostochiensis, Ro1 is. Toetse op inheemse Solanum plante het gewys dat die plante nie goeie gashere vir G. rostochiensis is nie. Die bevindings van hierdie studieprojek het ‘n impak op die taksonomie van die groep en kennis van die verspreiding, patogenisiteit en oorlewing van die nematodes onder Suid-Afrikaanse toestande is van waarde vir die daarstelling van effektiewe beheerstrategiee en wetstoepaslike regulasies.
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'Mysterious figures' : character and characterisation in the work of Virginia WoolfSandberg, Eric Peter January 2010 (has links)
This thesis argues for a reading of Virginia Woolf’s work based on notions of character and characterisation as a primary interpretative perspective. The bulk of Woolf scholarship, particularly in recent years, has not been directed towards the study of character, due to both general theoretical discomfort with the category of character, and a sense that Woolf’s work in particular, as that of a feminist and modernist writer, may not respond well to traditional readings of character. However, Woolf’s exploration of the human self and its relations with other people is best understood by looking at her formal experiments in characterisation. Her writing was consistently engaged with questions of character, as an examination of her early journalism makes clear. In the years before the publication of her first novel, Woolf articulated a broad theory of character in her reviews of contemporary literature and in essays on Gissing and Dostoyevsky. In The Voyage Out, Woolf began a writing career of experiment in character, examining a continuum of character ranging from complete nonidentification to a consuming over-identification. A key element here is the introduction of the notion of the Theophrastan type as an alternative form of fictional characterisation that corresponds to a way of knowing real people. In Jacob’s Room, Woolf continued to focus on the speculative nature of characterisation and its demands for imaginative identification demonstrated by her short story collection Monday & Tuesday. The importance of this issue is clear from the debates she engaged in with Arnold Bennett during the 1920s, a debate re-framed in this paper as focussing on characterisation. Jacob’s Room initiates a quest for an elusive ‘essence’ of character that may, or may not, exist outside of the structuring forms of social life, and may or may not be accessible through speculative imaginative identification. This elusive essence of character is a primary focus of Mrs. Dalloway, a novel which explores the ways the self can be shaped under social pressures into more permanent and stable structures. This is explored in the novel in a series of metaphors circling around treasure and jewels. While alert to the role of exterior factors, including time and memory, the novel maintains at least the possibility that some more internal form of the self exists and can be represented in fiction. This possibility is explored further in Woolf’s short story cycle Mrs. Dalloway’s Party, and leads into To the Lighthouse’s study of character and its ability to represent essential or internal aspects of self, the self as it exists in relation to other selves, and ultimately a projected or created version of character that reconciles this complexity. This is again carried out through the use of a extensive chain of metaphors which function symbolically in the text, and through a meditation on the nature of the relationship between real people and their fictional counterparts. While the novel offers no clear resolution, it gestures towards a type of characterisation, and hence a type of relationship, based on limited understanding and acceptance. This notion is picked up in The Waves, a novel which both explores the continuity of the self as represented by character over time - something that is also important in The Years - and explores the ways that characters can be represented and the implications this has for the types of unity that can, for good or for ill, be achieved. Again, a notion of a limited character, closer in form to caricature than to the whole and rounded characters often associated with Woolf, is proposed by the novel as a possible solution to the problem of character. In Woolf’s last two novels, The Years and Between the Acts, many of these themes reappear, and Woolf simultaneously situates her characters more firmly than ever in a comprehensible physical and social context, and uses them to explore areas where language and rationality cease to function.
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An Extrapolation Technique of Cloud Characteristics Using Tropical Cloud RegimesEliasson, Salomon January 2006 (has links)
This thesis tests a technique based on objectively identified tropical cloud regimes, in which some cloud characteristics are extrapolated from a single site in the tropics to the entire tropics. Information on cloud top pressure, cloud optical thickness and total cloud cover from 1985-2000 has been derived from the ISCCP D1 data set and has been used to create maps of tropical cloud regimes and maps of total cloud cover over the tropics. The distribution and characteristics of the tropical cloud regimes has been discussed after which total cloud cover values were extrapolated to the cloud regimes over the tropics. After a qualitative and quantitative assessment was used to evaluate the success of the extrapolating method, it was found that the method worked especially well for time averaged extrapolated data sets using the median values of total cloud cover values. / I detta magisterexamensarbete testas en metod som baseras på objektivt framtagna molnregimer, där några molnegenskaper extrapoleras från en plats i tropikerna till resten av tropikerna. Informationen om molntoppstrycket, molnens optiska djup och det totala molntäcket från 1985-2000 har hämtats från ISCCP D1 data set och har använts till att skapa kartor för tropiska molnregimer och för det totala molntäcket över tropikerna. Distributionen och egenskaperna av de tropiska molnregimerna har diskuterats och användes sedan för att extrapolera det totala molntäcket över tropikerna. En kvalitativ och kvantitativ undersökning användes för att utvärdera framgångarna med extrapoleringsmetoden. Det framkom att metoden fungerade särskilt bra för extrapolerade data set med median totala molntäcksvärden över längre tidsperioder.
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The structural characterisation of porous media for use as model reservoir rocks, adsorbents and catalystsEvbuomwan, Irene Osagie January 2009 (has links)
The concept of creating heterogeneous structures by nanocasting techniques from a combination of several homogeneous surfactant templated structures to model reservoir rock properties has not been approached prior to this research project, and will be used to test and provide better understanding of gas adsorption theories such as the pore blocking phenomenon (Seaton, 1991). Porous media with controlled pore sizes and geometry can be used to mimic a variety of reservoir rock structures, as it can be engineered to consist of a network of elements which, individually, could have either regular or irregular converging and diverging portions. The restrictions in these elements are called throats, and the bulges pores. Catalysts developed from a range of Nanotechnology applications could be used in down-hole catalytic upgrading of heavy oil. They could also be used as catalyst supports or to analyse the coking performance of catalysts. These studies will highlight the pore structure effects associated with capillary trapping mechanisms in rocks, and potentially allow the manipulation of transport rates of fluids within the pore structure of catalysts. Mercury-injection capillary pressure is typically favoured for geological applications such as inferring the size and sorting of pore throats. The difference between mercury injection and withdrawal curves will be used to provide information on recovery efficiency, and also to investigate pore level heterogeneity. Mercury porosimetry studies are carried out to provide a better understanding of the retraction curve and the mechanisms controlling the extrusion process and subsequently the entrapment of the non-wetting phase. The use of model porous media with controlled pore size and surface chemistry allows these two effects to be de-convolved and studied separately. The nanotechnology techniques employed mean that uncertainty regarding exact pore geometry is alleviated because tight control of pore geometry is possible. Trapping of oil and gas on a microscopic scale in a petroleum reservoir rock is affected by the geometric and topologic properties of the pores, by the properties of the fluids and by properties related to fluid-rock interaction such as wettability. Several distinct mechanisms of trapping may occur during displacement of one fluid by another in a porous media, however in strongly water-wet rocks with large aspect ratios, trapping in individual pores caused by associated restricting throats (may be/is) the most important mechanism of trapping. The results of the proposed research will be both relevant to the Irene Osagie Evbuomwan PhD. Thesis (2009) 9 oil and gas as well as the solid mineral sector for application as catalyst or catalyst supports. By providing a better understanding of the relationship between reservoir rock pore space geometry and surface chemistry on the residual oil levels, a more accurate assessment of the potential of a particular reservoir could be generated. The analysis of gas adsorption/desorption isotherms is widely used for the characterization of porous materials with regard to their surface area, pore size, pore size distribution and porosity, which is important for optimizing their use in many practical applications. Although nitrogen adsorption at liquid nitrogen temperature is considered to be the standard procedure, recent studies clearly reveal that the use of additional probe molecules (e.g. argon, butane, carbon dioxide, water, hydrogen, and hydrocarbons e.g. cyclohexane and ethane) allows not only to check for consistency, but also leads to a more comprehensive and accurate micro/mesopore size analysis of many adsorbents. Furthermore, significant progress has been achieved during recent years with regard to the understanding of the adsorption mechanism of fluids in materials with highly ordered pore structures (e.g., M41S materials, SBA-15). This has led to major improvements in the pore size analysis of nanoporous materials. However, there are still many open questions concerning the phase and sorption behaviour of fluids in more complex pore systems, such as materials of a heterogeneous nature/differing pore structures, which are of interest for practical applications in catalysis, separation, and adsorption. In order to address some of these open questions, we have performed systematic adsorption experiments on novel nanoporous materials with well defined pore structure synthesised within this research and also on commercial porous silicas. The results of this study and experiments allow understanding and separating in detail the influence of phenomena such as, pore blocking, advanced condensation and delayed condensation on adsorption hysteresis and consequently the shape of the adsorption isotherms. The consequences of these results for an accurate and comprehensive pore size analysis of nanomaterials consisting of more complex nanoporous pore networks are also investigated.
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Investigation of genetic susceptibility to Rheumatoid ArthritisDuffus, Kate January 2014 (has links)
RA is a chronic and disabling disease with no known cure. The disease has a strong genetic component and modern genetic studies have successfully identified over 100 loci associated with the onset of RA. Despite the number of associations identified, the full genetic component of RA is not known, and for the majority of the loci the causal variant remains unknown. The overall aim of this study was to utilise well-powered genetic data, in order to identify novel loci, refine genetic associations, and generate robust evidence for the causal SNP and causal gene at a selected RA locus. An initial analysis was undertaken utilising 3870 RA cases and 8430 controls from the UK-ImmunoChip, a study designed for comprehensive fine-mapping of confirmed RA susceptibility loci. Analysis of the UK-ImmunoChip data identified a novel finding with the TYK2 locus, and proved informative to refining association signals, illustrating the utility of fine-mapping and implicated SNPs with putative regulatory function. The UK-ImmunoChip was subsequently expanded to incorporate samples from five additional cohorts in a study led by Dr. Stephen Eyre. In additional to novel loci discovery, this study provided evidence for SNPs putatively associated with RA (P smaller or equal to5E-05 < 5E-08). In a combined meta-analysis of 17,581 cases and 20,160 controls, convincing evidence was obtained for two novel RA loci, BACH2 and RAD51B.The newly identified genes implicate two novel pathways in RA (B-cell differentiation and DNA repair) and add to the growing number of loci associated with multiple AIDs. These findings are important to aid comprehensive pathway analysis and add to the knowledge of RA risk genes. The third most associated RA locus in both serological subtypes of disease, with an uncharacterised protein, ANKRD55, was subsequently selected for in-depth characterisation. Utilising genetic and haplotypic analysis the association at this locus was refined to a single signal, with four SNPs in strong LD (r2 > 0.8). Through bioinformatic analysis, two SNPs rs6859219 and rs10065637 showed evidence for functional activity, with evidence of being located in an enhancer element, supported by histone marks, DNAse hypersensitivity, evidence of transcription factor binding and eQTL. The use of RNA and ChIP experiments have established a testable hypothesis that the presence of the putative causal variants rs6859219 and rs10065637, act to weaken the strength of the enhancer element in which they are located, (evidenced by diminished H3k4me1 modification), which in turn down-regulates the transcriptional output of the target gene ANKRD55 (evidenced by eQTL in both whole blood and CD4+ T cells).In summary this study has led to the identification of three novel loci, highlighted the importance of fine-mapping and developed a successful systemic strategy for the characterisation of the 5q11 risk locus associated with RA.
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Structural characterisation of aggrecan in cartilaginous tissues and tissue engineered constructsCraddock, Russell January 2018 (has links)
Collagen II and the proteoglycan aggrecan are key extracellular matrix (ECM) proteins in cartilaginous tissues such as the intervertebral disc (IVD). Given the functional role that these structural and functional proteins have in the IVD, ECM in tissue engineered intervertebral disc (TE IVD) constructs needs to recapitulate native tissue. As such, there is a need to understand the structure and mechanical function of these molecules in native tissue to inform TE strategies. The aims here were to characterise aggrecan and collagen II using atomic force microscopy (AFM), size-exclusion chromatography multi angle light scattering (SEC-MALS), histology, quantitative PCR, nanomechanical and computational modelling in: (i) skeletally immature and mature bovine articular cartilage (AC) and nucleus pulposus (NP), (ii) TE IVD constructs cultured in hypoxia or treated with transforming growth factor beta [TGFÎ23] or growth differentiation factor [GDF6]), and (iii) porcine AC and NP tissue. No variation in collagen II structure was observed although the proportion of organised fibrillar collagen varied between tissues. Both intact (containing all three globular domains) and non-intact (fragmented) aggrecan monomers were isolated from both AC and IVD and TE IVD constructs. Mature intact native NP aggrecan was ~60 nm shorter (core protein length) compared to AC. In skeletally mature bovine NP and AC tissue, most aggrecan monomers were fragmented (99% and 95%, respectively) with fragments smaller and more structurally heterogeneous in NP. Similar fragmentation was observed in skeletally immature bovine AC (99.5%), indicating fragmentation occurs developmentally at an early age. Fragmentation was not a result of enhanced gelatinase activity. Aggrecan monomers isolated from notochordal cell rich porcine NP were also highly fragmented, similar to bovine NP. Application of a computational packing model suggested fragmentation may affect porosity and nutrient transfer. The reduced modulus was greater in AC than NP (497 kPa and 76.7 kPa, respectively) with the difference likely due to the organisation and abundance of ECM molecules, rather than individual structure. Growth factors (GDF6 and TGFÎ23), and not oxygen tension treated TE IVD constructs were structurally (with >95% fragmented monomers), histologically and mechanically (GDF6: 60.2 kPa; TGFÎ23; 69.9 kPa) similar to native NP tissue (76.7 kPa) and there was evidence of gelatinase activity. To conclude, these results show that the ultrastructure of intact aggrecan was tissue and cell dependent, and could be modified by manipulation of cell culture conditions, specifically GDF6 which may play a role in aggrecan glycosylation.
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Geometry and geobody extraction of a submarine channel complex in the Sable Field, Bredasdorp BasinStoltenkamp, Razeen January 2015 (has links)
>Magister Scientiae - MSc / The Sable Field constitutes a Basin Floor Channel (BFC) complex (E-BD reservoir) and a Basin Floor Fan (BFF) complex (E-CE reservoir). The reservoir sands were deposited during early-drift sedimentation in the Bredasdorp Basin. Paleo-current flows from the west, filling the basin with sediments that are eroded off the continental shelf (Agulhus Arch) and deposited on the base of the continental slope and basin floor. Turbidite flows off the Agulhus arch have deposited the Sable Fields reservoirs, where the larger channelized reservoir body takes an 80° bend off the continental slope and flows onto the basin floor. This 3-D reservoir highlights the reservoirs internal heterogeneity and complexity at the well bore and away from the well bore. Well tops tie wells to the 3-D seismic cube for; reservoir location and delineation, velocity modelling and subsequent conversion of the mapped surfaces from time to depth. Core and petro-physical analysis were used to outline the depositional facies within the investigated wells namely: E-BD5, E-BD2, E-BD1 and E-CE1. Correlation of depositional facies at the well bore with their corresponding seismic facies, allows for extrapolation of facies away from the well bore. The internal heterogeneity of the reservoir is outlined using an integrated methodology, which is based on log scale depositional features (channels, sheets, lobes) that are extrapolated to field scale (sand rich complex) using corresponding top and base reservoir seismic responses. The investigated thick region of sediment accumulation on: the continental slope, the base of the continental slope and basin floor is deposited on the 13AT1 early drift unconformity. The reservoir is outlined from the up-dip to the down-dip reaches of the field. Well E–BD5 has tapped into the proximal region (up-dip), with reservoir comprising of amalgamated channel sands that are deposited by laterally switching and stacking channelized sand bodies. Channel meander facies are seen in the upper portion of the reservoir, with massive channel fill in the lower parts. The channel fill constitutes a high net to gross with little to no lateral facies variations. This confined environment is dominated by amalgamated massive sands (on-axis) that are thinner bedded towards the banks of the channels (off-axis). A high degree of channel
amalgamation has been interpreted in both up-dip wells E-BD5 and E-BD2. This channelized reservoir is at least 2km wide and 6km long, before the larger channel makes a rapid 80° change in paleo-current direction. This is possibly the result of basin floor topography and the stacking of previously deposited sand complexes which alter local sea floor topography. The vertical and lateral continuity of the channelised reservoir is generally excellent due to the high degree of channel amalgamation. The stacked channel complex constitutes a gross thickness of 76.2m (68.5m Net sand) in well E-BD5, and a gross thickness 25m (23m Net sand) in well E-BD2. Channel sands in well E-BD5 have an average porosity of 15% while the average porosity of channel sands in well E-BD2 (further down-dip) is 17%. This up-dip channelised region results in high amplitude reflections due to hydrocarbon charged sand juxtaposed against hemipelagic muds and silty levee facies. Well E-BD1 has tapped into a relatively confined sand complex deposited at the base of the continental slope. The amalgamated lobe and sheet sand complex is entirely encased in hemi pelagic mud. These reservoir sands are interpreted to be deposited in the Channel Lobe Transition Zone (CLTZ), thus the reservoir sands are interpreted to have a transitional depositional style (generally channelized sheets). The CLTZ region is thus dominated by both channel complex and lobe complex elements. The E-BD1 reservoir constitutes a number of amalgamated elements that result in a reservoir zone with an average porosity of 16.4%. These include: amalgamated thick bedded sheet sand (lobe axis) associated with deep depositional feeder channels; thin bedded sheet sands (off lobe axis), broad thin amalgamated lobe elements, layered thick bedded sand sheets and deep broad depositional channels. The low sinuosity broad depositional-channels and elongate lobe elements are expressed as lobate amalgamated sheets
of sand which is up to 2-3km wide, 5km long and 30m thick (29.7m nett sand) at the well
bore. Well E-CE1 has intersected 50m thick reservoir sand (50m nett sand) which constitutes the axis of a lobe complex where the reservoir zone has an average porosity of 14%. The sand rich complex is deposited on the unconfined basin floor. This reservoir complex constitutes amalgamated thick bedded lobe architectural elements which are massive in nature. The laterally continuous hydrocarbon charged lobe elements result in bright parallel seismic reflections. The amalgamated lobe complex is more than 5km wide. Sub-parallel horizons are attributed to the thin bedded off axis portion of the lobe complex where the net to gross is considerably less than the highly amalgamated axis of the lobe complex. The lobe complex has a moderate to good net to gross of 40-60%. The high aspect ratio of the lobe complex severely impacts the reservoirs vertical permeability, however horizontal permeability is quite good due to the extensive lateral continuity of good quality sheet sands. Based on the nature deep water architectural elements observed in this study, the internal heterogeneity of the Basin floor Fan and Basin floor channel complex’s may constitute an entire sand rich reservoir zone. All the sands may be in hydraulic communication if they are genetically related. These sands and stretch from the up-dip (wells E-BD5 & E-BD2) through to the transitional (E-BD2) and pinching out in the distal regions (E-CE1) on the basin floor. The seal constitutes a prominent shale horizon T13PW3 (8-10m thick) which is draped over the entire reservoir complex. This top seal is extrapolated from all the wells and correlated with seismic facies, thus outlining the lateral continuity and thickness variations of the top seal.
This draped shale horizon exposes the thick axial portion of the amalgamated channel
complex and amalgamated lobe complex.
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