42 research outputs found
Modeling of gas flow in confined formations at different scales
No full textGas flow in fractured nano-porous shale formations is complicated by a hierarchy of structural features, ranging from nanopores to hydraulic fractures, and by several transport mechanisms that differ from standard viscous flow used in reservoir modeling. The use of accurate simulation techniques that honor the physical complexity of these reservoirs and capture the associated dynamics of nanopores is required. However, these simulations often necessitate a large amount of computational resources for field scale models and therefore require upscaling. Usually, the upscaling techniques are based on idealizations that do not reflect the discrete features of the reservoir. In this work, we first incorporate the physics model that describe dynamics of shale gas into a numerical Discrete Fracture and Matrix (DFM) model. The formulation of our DFM model applies an unstructured control volume finite difference approach with a two-point flux approximation. We then propose to upscale these detailed descriptions using two different techniques, with the major difference in their coarse-grid geometry. The first approach, referred to as Embedded DFM upscaling, relies on a structured Cartesian coarse grid. The second method, which we call the Multiple Sub-Regions (MSR) upscaling, introduces a flow based coarse grid to replicate the diffusive character of the pressure in the matrix. The required parameters for the coarse-scale model in both methods and the geometry of the subregions in the second method are determined using numerical homogenization of the underlying discrete fracture model. An accurate comparison with the fine-scale representation indicates an existence of an additional transient phenomenon at coarse scale. To account for this effect, the transmissibility of both types of coarse models is related to the pressure in our approach. Both upscaling methods are applied to simulate a shale-gas flow in 2D fractured reservoir models and are shown to provide results in close agreement with the underlying fine-scale model and with a considerable reduction in the computational time.Reservoir Engineerin
Modeling and Upscaling of Shale Gas Using a Discrete Fracture Modeling Approach
No full textGas flow in fractured nano-porous shale formations is complicated by a hierarchy of structural features, ranging from nanopores to microseismic and hydraulic fractures, and by several transport mechanisms that differ from standard viscous flow used in reservoir modelling. In small pores, self-diffusion becomes more important than advection, also slippage effect and Knudsen diffusion becomes relevant at this scale. The characteristics and properties of the fracture networks plays a major role in the performance of shale gas reservoirs, therefore the use of accurate simulation technique that honor the complexity of these reservoirs and capture the associated dynamics of nanopores is strongly required. However, these accurate simulations often necessitate a large amount of computations for field scale models and therefore require upscaling. Yet the upscalling techniques generally in use are based on idealizations that do not reflect the discrete features of the reservoir. In this work, we first incorporate the formulations of a statistical bundle of dual tube model to describe the dynamics of shale gas into a discrete fracture model. The formulation of the DFM model we use applies an unstructured control volume finite difference approach with a two point flux approximation. We then propose to upscale these detailed descriptions using two different techniques, with the major difference in their coarse grid geometry. The first approach, referred to as EDFM upscaling, relies on a structured Cartesian coarse grid. While the second method, which we call the multiple subregion (MSR) upscaling, introduces a flow based coarse grid to replicate the diffusive character of the pressure in the matrix. The required parameters for the coarse scale model in both methods and the geometry of the subregions in the second method are determined efficiently from global single-phase flow solution using the underlying discrete fracture model. The methods are applied to simulate single-phase gas flow in 2D fractured reservoir models, and are shown to provide results in close agreement with the underlying DFM and with considerable reduction in the computational time. We notice that in order to account for the prevailing transient effects in low permeability shale, the upscaled transmissibility need to be related to pressure for better results. Finally, we consider the EDFM upscaling we propose as an easier approach in its implementation, while the MSR technique as a more accurate method.Civil Engineering and GeosciencesGeoscience & Engineerin
Structural studies of some mixed metal oxides
No full textThis thesis was scanned from the print manuscript for digital preservation and is copyright the author.
Researchers can access this thesis by asking their local university, institution or public library to
make a request on their behalf. Monash staff and postgraduate students can use the link in the References field
Author Correction: High-coverage whole-genome analysis of 1220 cancers reveals hundreds of genes deregulated by rearrangement-mediated cis-regulatory alterations
No full textAuthor Correction: Genomic basis for RNA alterations in cancer
No full textAuthor Correction: Genomic basis for RNA alterations in cance
Construction of ovine GH-pmKate2N expression vector and its uptake by ovine spermatozoa using different methods
No full textThis study aims to produce transgenic ovine spermatozoa bearing Ossimi sheep growth hormone (Os_GH) cDNA using different methods. The complete coding sequence of Os_GH has been registered in GenBank accession no. KP221575. The sequence of Os_GH cDNA has been subcloned into pmkate2-N expression vectors to construct Os_GH-pmKate2-N vector. Five groups of sperm uptake were submitted. All groups were incubated at 37 °C for 1 h: Control (sperm cells were incubated without vector), Traditional incubation (sperm cells were incubated with vector), Heat shock (sperm cells were incubated with vector at 4 °C for 20 min and heated for 2 min at 42 °C), Heat shock + Dimethyl sulfoxide (DMSO) (sperm cells were incubated with vector and supplemented with 3% of DMSO and then submitted to heat shock regime) and DMSO (sperm cells were incubated with vector and supplemented with 3% DMSO). The sperm genomic DNA in groups was extracted. The Os_GH-pmKate2-N vector was introduced efficiently into the head of sperm cells in all treated groups. Adding DMSO either with or without heat shock increased the sperm uptake. The progressive motility was reduced (P < 0.05) by 29.9% in heat shock group compared to the control. Adding DMSO improved (P < 0.05) the total and progressive motilities by 8.2% and 19.8%, respectively in heat shock group compared to the heat shock group without DMSO. The results documented the ability of ovine spermatozoa to uptake the exogenous vector. Also, sperm incubation with 3% DMSO is the best method to introduce the exogenous vector into spermatozoa without notable adverse effects on sperm motilities
Author Correction: Comprehensive analysis of chromothripsis in 2,658 human cancers using whole-genome sequencing
No full textauthor correctio
Association of genetic variants with primary angle closure glaucoma in two different populations
No full textThis is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.PURPOSE:
A recent large genome-wide association study (GWAS) identified multiple variants associated with primary angle-closure glaucoma (PACG). The present study investigated the role of these variants in two cohorts with PACG recruited from Australia and Nepal.
METHOD:
Patients with PACG and appropriate controls were recruited from eye clinics in Australia (n = 232 cases and n = 288 controls) and Nepal (n = 106 cases and 204 controls). Single nucleotide polymorphisms (SNPs) rs3753841 (COL11A1), rs1015213 (located between PCMTD1 and ST18), rs11024102 (PLEKHA7), and rs3788317 (TXNRD2) were selected and genotyped on the Sequenom. Analyses were conducted using PLINK and METAL.
RESULTS:
After adjustment for age and sex, SNP rs3753841 was found to be significantly associated with PACG in the Australian cohort (p = 0.017; OR = 1.34). SNPs rs1015213 (p = 0.014; OR 2.35) and rs11024102 (p = 0.039; OR 1.43) were significantly associated with the disease development in the Nepalese cohort. None of these SNPs survived Bonferroni correction (p = 0.05/4 = 0.013). However, in the combined analysis, of both cohorts, rs3753841 and rs1015213 showed significant association with p-values of 0.009 and 0.004, respectively both surviving Bonferroni correction. SNP rs11024102 showed suggestive association with PACG (p-value 0.035) and no association was found with rs3788317.
CONCLUSION:
The present results support the initial GWAS findings, and confirm the SNP's contribution to PACG. This is the first study to investigate these loci in both Australian Caucasian and Nepalese populations
Field and Laboratory Permeability of Asphalt Concrete Pavements
No full textHot mix asphalt pavements that have been poorly designed, compacted, and (or) constructed have higher chances of experiencing moisture-related damage. This research evaluates the interrelationship between field–laboratory permeability and other mechanical and physical pavement characteristics. Eight sites in Eastern Ontario were selected for evaluating the pavement’s field permeability and core extraction. Laboratory specimens of the same mixes studied in the field were prepared using the Superpave gyratory compactor (SGC). The relative density (RD), lab permeability, and indirect tensile strength (IDT) tests were performed on the field-recovered cores and SGC specimens. Permeability, RD, and IDT were found to be related such that as RD and (or) IDT decreases, the permeability increases exponentially. The strength of these relationships varied for the three test settings (SGC, field-recovered cores, and field measurements). The coefficients of field permeability and laboratory permeability using field-recovered cores were statistically different, with a fair relationship between these two test settings.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
