Reservoirs Modeling of Gas hydrate deposits in North Slope of Alaska and Gulf of Mexico

In order to address the world\u27s growing energy demand, the necessity to explore more and more unconventional sources of energy arises. Recently there has been increased interest in the potential of natural gas hydrates as an alternate energy resource. Methane hydrates are crystalline solids, very similar to ice, in which non-polar molecules are trapped inside the cages formed by water molecules. Methane hydrates could be potentially a vast source of energy. The production of natural gas from hydrates economically poses a big challenge to today\u27s scientific world. Two sites for greatest potential for gas production from gas hydrates as identified by USGS and NETL/DOE are North Slope (ANS) Alaska and the Gulf of Mexico (GOM). In this work specific locations of hydrate deposits are examined, namely the Prudhoe Bay L Pad (PBU L-Pad) and Walker Ridge 313 (WR313) deposits in the ANS and GOM. Reservoir modeling in this work is primarily based on these two gas hydrate deposits.;The uncertainty of reservoir parameters such as hydrate reaction kinetics, the permeability of hydrate bearing sediment, Porosity and permeability of the shale layer boundary on gas production is studied in this work. Gas production from a horizontal well as opposed to a vertical well is evaluated using a mechanistic well bore model. A preliminary assessment of thermal disturbance due to a hot well bore penetrating hydrate deposits in the PBU L pad site is performed using CMG STARS coupled geotechnical model. The results of this study indicate that the extent of hydrate dissociation around a hot wellbore is limited by the thermal diffusion of heat moving radially away from the casing and cement.;In April and May of 2009, the U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL) in collaboration with the U.S. Geological Survey (USGS), the U.S. Minerals Management Service, an industry research consortium led by Chevron, and others completed a marine hydrate drilling expedition in the Gulf of Mexico called the Joint Industry Project (Leg II) expedition. A complex heterogeneous 3-D model using well log data seismic data are constructed and simulated using CMG STARS and Petrel. An uncertainty assessment of gas production from the WR313 G well on reservoir parameters is performed using a Latin-hyper cube Monte Carlo sampling. Results of the reservoir simulations indicate very high potential for producing methane from these marine hydrate deposits using depressurization due to in situ temperature and pressure related to the great depth of the deposits. The predicted production rates display high (5-40 MMscf/day) rates making the reservoirs to be attractive locations for further exploration. Special cases were considered to estimate influence of permeable over- and under burden on production

Code comparison of methane hydrate reservoir simulators using CMG STARS

Natural gas is an important energy source contributing to 23% of the total energy consumption in United States. Domestic conventional natural gas production does not keep pace with increase in natural gas demand. Development of new alternatives like natural gas from methane hydrate can play a major role in ensuring adequate future energy supplies in the United States.;Methane hydrates are crystalline solids, very similar to ice, in which non-polar molecules are trapped inside the cages of water molecules. Methane hydrates could be potentially a vast source of energy. It is estimated that the total amount of natural gas trapped inside the hydrate is approximately two times the total unconventional oil-gas reserves in the world. The production of natural gas from hydrates economically poses a big challenge to today\u27s scientific world. Over the years, different reservoir simulators were developed and different approaches have been used to model the gas hydrate dissociation behavior. The National Energy Technology Laboratory (NETL) and the U.S Geological Survey (USGS) gas hydrate code comparison project is the first of its kind and it aims at a worldwide understanding of the hypotheses involved in the gas hydrate modeling and problem solving. This code comparison study is conducted to compare various hydrate reservoir simulators like CMG STARS, TOUGH-Fx/Hydrate, MH21, STOMP, HydrateResSim and a code form University of Houston.;The objective of this Project is to generate results for different problems set by the code comparison participants using CMG STARS and to validate its results with other reservoir simulators. Results obtained are in good agreement with other simulators in the study. However minor differences were observed for a problem with ice in the system. Long term simulations were conducted for Mt Elbert, Prudhoe Bay L-PAD like deposits. The Production rates obtained using CMG STARS were in good agreement with other packages.;In addition to the code comparison problems, simulations to analyze the sensitivity to various parameters were performed. Studies were carried out with heterogeneity introduced in the reservoir properties using the Mt. Elbert stratigraphic test well data and results showed that higher production was observed with the incorporation of heterogeneity. Sensitivity analysis of seven reservoir parameters was done using Plackett-Burman design to gain a better understanding on production performance. The reservoir parameters were ranked based on effects of the reservoir parameters on production rates

Image morphological processing

Mathematical Morphology with applications in image processing and analysis has been becoming increasingly important in today\u27s technology. Mathematical Morphological operations, which are based on set theory, can extract object features by suitably shaped structuring elements. Mathematical Morphological filters are combinations of morphological operations that transform an image into a quantitative description of its geometrical structure based on structuring elements. Important applications of morphological operations are shape description, shape recognition, nonlinear filtering, industrial parts inspection, and medical image processing. In this dissertation, basic morphological operations, properties and fuzzy morphology are reviewed. Existing techniques for solving corner and edge detection are presented. A new approach to solve corner detection using regulated mathematical morphology is presented and is shown that it is more efficient in binary images than the existing mathematical morphology based asymmetric closing for corner detection. A new class of morphological operations called sweep mathematical morphological operations is developed. The theoretical framework for representation, computation and analysis of sweep morphology is presented. The basic sweep morphological operations, sweep dilation and sweep erosion, are defined and their properties are studied. It is shown that considering only the boundaries and performing operations on the boundaries can substantially reduce the computation. Various applications of this new class of morphological operations are discussed, including the blending of swept surfaces with deformations, image enhancement, edge linking and shortest path planning for rotating objects. Sweep mathematical morphology is an efficient tool for geometric modeling and representation. The sweep dilation/erosion provides a natural representation of sweep motion in the manufacturing processes. A set of grammatical rules that govern the generation of objects belonging to the same group are defined. Earley\u27s parser serves in the screening process to determine whether a pattern is a part of the language. Finally, summary and future research of this dissertation are provided

Aligning an ISO/EIC 42010 System Architecture Model and Agile Practice

The ISO/EIC 42010 system architecture description standard evolved over a number of years with substantial practitioner inputs. It presents a high level, top-down view of requirements that may be interpreted as needed for different applications. Agile system development methods have proved effective in practice, but represent a bottom up view drawing on user stories. The question considered in this paper is how they might be harmonised. Experience from using these tools over several years in practical masters degree student projects has been used to explore this question. We suggest a logical compatibility lies in their core themes: stakeholder needs (who) frame architecture descriptions (what) and the associated rationale (why). A particular interpretation of ISO/EIC 42010 and a model outlining the evolution of architecture in an agile environment are presented. Several suggestions for future research are made

Smc5 depletion impedes cell cycle progression, induces DNA damage, and causes genomic instability in mouse embryonic fibroblasts

Introduction: The structural maintenance of chromosomes 5/6 (Smc5/6) complex plays a critical role in maintaining genomic integrity. More specifically, Smc5/6 is involved in DNA replication, DNA damage repair via homologous recombination (HR), and chromosome segregation. Although its function has been extensively studied in yeast, few studies have evaluated Smc5/6 in mammalian models. Based on existing literature, we hypothesized that Smc5/6-deficient mouse embryonic fibroblasts (MEF) would accumulate DNA damage and, as a result, demonstrate abnormal mitotic progression and show evidence of replication stress. Methods: We used transgenic mice harboring a floxed exon 4 of the Smc5 gene (Smc5flox/flox and Smc5+/del, Ert2-Cretg/0 ) to breed and establish immortalized MEF cell lines with genotypes of Smc5flox/del, Ert2-Cretg/0 (experimental), Smc5+/flox, Ert2-Cretg/0 (control #1), and Smc5flox/del (control #2). Smc5 exon 4 was deleted by addition of 0.2µM 4-OH tamoxifen for nine days. Deletion was confirmed by PCR and protein depletion by western blot. Cells were analyzed on day 3, 6 and 9. MEF growth characteristics and cell cycle progression were evaluated by performing cell counts and FACS analysis, respectively. We also used immunofluorescence microscopy to observe micronuclei formation and DNA bridges. Additionally, we analyzed Rad51, Sumo1, and Sumo2/3 after treating cells with hydroxyurea. Finally, we used western blot analysis to evaluate expression of the stress response marker, p53. Results: Smc5-depleted MEFs demonstrated several mitotic abnormalities. After six days of 4-OH tamoxifen treatment, we observed a sustained, two-fold decrease in cell proliferation compared to controls. FACS analysis showed delayed entry into S phase. DAPI staining of Smc5-depleted cells showed 12% increase in micronuclei formation and 33% increase in DNA bridges. Hydroxyurea treated cells showed an accumulation of Rad51 foci, suggesting impaired HR mechanisms. Mutation of Smc5 also resulted in a decline in Sumo1 but not Sumo2/3 foci. Lastly, western blot analysis showed significant p53 upregulation. Conclusions: For the first time, we have demonstrated the importance of the Smc5/6 complex in somatic mouse cells. Smc5 depletion in MEF cells compromises genomic integrity, affects cell cycle progression and leads to chromosome missegregation. We also demonstrate hypersensitivity to DNA damage agents and activation of the p53 pathway

Holographic Adaptive Laser Optics System (HALOS): Fast, autonomous aberration correction

ABSTRACT We present a Holographic Adaptive Laser Optics System (HALOS) that uses a multiplexed hologram to deconvolve the phase aberrations in an input beam. This wavefront characterization is extremely fast as it is based on simple measurements of the intensity of focal spots and does not require any computations. Furthermore, the system does not require a computer in the loop and is thus much cheaper, less complex and more robust than conventional methods. A fully functional, closed-loop prototype incorporating a 32-element MEMS mirror has been constructed. The unit has a footprint no larger than a laptop but runs at a bandwidth of 10kHz. Additionally, since the sensing is based on parallel, all-optical processing, the speed is independent of actuator number -running at the same bandwidth for one actuator as for a million. INTRODUCTION Ground-based space surveillance can greatly benefit from adaptive optics systems to remove the distorting effects of atmospheric turbulence. Improved performance can be achieved with increases in speed and actuator number (spatial resolution) but with conventional techniques this comes with an increase in complexity and cost. For example, the typical sensing method uses a Shack-Hartmann sensor which breaks a wavefront into subapertures created by a lenslet array. The local slope of each subaperture is then measured as the displacement of the foci compared to their ideal locations previously calibrated using a flat wavefront. A complete picture of the wavefront is generated by stitching together all the subapertures -usually with a further step of rendering the result in terms of Zernike polynomials. Correction can then be applied to the wavefront by deconvolving the Zernike-based wavefront error into actuator motions for a deformable mirror. Each of these steps requires many complex calculations and the process is greatly slowed as the spatial resolution is increased. Here we present an approach that uses a multiplexed hologram that, in effect, acts as an all-optical processor, removing the need for a complex computer. HALOS The operation of the holographic adaptive laser optics system (HALOS) is best understood in terms of how it is constructed. We begin with a deformable mirror with an actuator that is driven to its maximum extent in one direction. A localized plane wave reflecting off this subaperture will experience a phase shift. A hologram is recorded using this object beam and a reference beam focused to some distant point A a. b

Visual Interaction in Acoustic-structural Analysis of Automobiles

This paper describes a graphical technique used for investigating the effects of structural design changes on the sound pressure levels generated in an automobile compartment. Low frequency noise in the passenger compartment (in approximately the 20-85 Hz frequency range) is of primary interest, and particularly that noise which is generated by the structural vibrations of the wall panels and various other smaller parts of the compartment. A designer faced with reducing the noise levels at various frequencies typically has several hundred design variables as candidates for change. This paper describes a computer interface that facilitates understanding of the effect various design changes have on the noise levels. This interface allows the designer to investigate the design space to determine which variables hold the most promise for achieving the objectives of noise reduction and allows the designer to set targets or constraints, to a desired confidence level, using the sensitivity information of these design variables. The design targets set in this manner are then input to an optimization algorithm which solves for the optimized sound pressure level

Structural reorganisation of cellulose fibrils in hydrothermally deconstructed lignocellulosic biomass and relationships with enzyme digestibility

Background: The investigation of structural organisation in lignocellulose materials is important to understand changes in cellulase accessibility and reactivity resulting from hydrothermal deconstruction, to allow development of strategies to maximise bioethanol process efficiencies. To achieve progress, wheat straw lignocellulose and comparative model wood cellulose were characterised following increasing severity of hydrothermal treatment. Powder and fibre wide-angle X-ray diffraction techniques were employed (WAXD), complemented by enzyme kinetic measurements up to high conversion. Results: Evidence from WAXD indicated that cellulose fibrils are not perfectly crystalline. A reduction in fibril crystallinity occurred due to hydrothermal treatment, although dimensional and orientational data showed that fibril coherency and alignment were largely retained. The hypothetical inter-fibril spacing created by hydrothermal deconstruction of straw was calculated to be insufficient for complete access by cellulases, although total digestion of cellulose in both treated straw and model pulp was observed. Both treated straw and model pulps were subjected to wet mechanical attrition, which caused separation of smaller fibril aggregates and fragments, significantly increasing enzyme hydrolysis rate. No evidence from WAXD measurements was found for preferential hydrolysis of non-crystalline cellulose at intermediate extent of digestion, for both wood pulp and hydrothermally treated straw. Conclusions: The increased efficiency of enzyme digestion of cellulose in the lignocellulosic cell wall following hydrothermal treatment is a consequence of the improved fibril accessibility due to the loss of hemicellulose and disruption of lignin. However, incomplete accessibility of cellulase at the internal surfaces of fibrillar aggregates implies that etching type mechanisms will be important in achieving complete hydrolysis. The reduction in crystalline perfection following hydrothermal treatment may lead to an increase in fibril reactivity, which could amplify the overall improvement in rate of digestion due to accessibility gains. The lack of preferential digestion of non-crystalline cellulose is consistent with the existence of localised conformational disorder, at surfaces and defects, according to proposed semicrystalline fibril models. Cellulases may not interact in a fully selective manner with such disordered environments, so fibril reactivity may be considered as a function of average conformational states

Massive Pulmonary Embolism from worsening of Gouty Arthritis due to the COVID-19 Pandemic

Abstract: Gout is the most common inflammatory arthritis in men and is associated with increased mortality and is an independent risk factor for cardiovascular disease such as myocardial infarction and stroke. In addition, several other types of inflammatory arthritis have been linked to increased risk of venous thromboembolism (VTE). VTE is associated high mortality of around 9.7% for PE and 4.6% for DVT. However, only a handful of studies have been conducted to estimate the risk of VTE in patients with gout before or after diagnosis. Most recent study in Canada concluded that patients with gout have around a 20% increase in risk compared to the general population for VTE. However, they stated not all gout patients carry the same risk and further research is needed to identify high risk factors and implement prophylactic therapy. In addition to that, multiple studies have concluded that alcohol sales, mental health illness, and drug use has increased dramatically during the COVID-19 pandemic. We present an interesting case of a 64-year-old patient with history of chronic gout which worsened within the last six months, first leading to DVT and a few months later a massive pulmonary embolism (PE). The patient had multiple high-risk factors for PE including chronic gout with worsening flare ups due to the excessive alcohol drinking since the COVID-19 pandemic and recent non-adherence to DVT anticoagulant medication for a month. We highlight the importance to monitor for high-risk factors such as excessive alcohol use and immobility in patients with inflammatory condition such as gout especially during the COVID pandemic

The Use of a Novel Heart Failure Agent in the Treatment of Pregnancy-Associated Cardiomyopathy

Peripartum cardiomyopathy is an uncommon, pregnancy-related form of dilated cardiomyopathy that is associated with development of new-onset left ventricular dysfunction. Its etiology is presently unknown, but current standard of care involves the use of typical drug therapy for the treatment of heart failure. Pregnancy-associated cardiomyopathy (PACM) is a similar condition that refers to patients who develop such symptoms prior to the last month of pregnancy. We report the case of a nulliparous Caucasian female who develops early, severe PACM during her first pregnancy with postpartum persistence of New York Heart Association class II-III symptoms despite medical therapy. The use of the novel heart failure agent, sacubitril/valsartan (Entresto), is initiated with near-complete resolution of her symptoms