Due to capillary pressure, reservoir heterogeneity, oil mobility, and lack of reservoir energy, typically more than 50 % of the original oil in place is left in the reservoir after primary and secondary recovery oil production. With relatively easy-to-get conventional oil resources diminishing and the price of oil hovering around triple digits, enhanced oil recovery methods, such as polymer flooding, have become very attractive ways to recover oil effectively from existing reservoirs. Enhanced oil recovery methods can be categorized into three categories: water or chemical based, gas based, and thermal based. This thesis will focus on the chemical injection of surfactants, alkali, and polymer of the water based methods. Surfactants are used to alter the interfacial tension of the aqueous and oleic phases in order to facility oil production. Alkali chemicals are used to create surfactants by reacting with acidic oil. And polymer is used to reduce injection water mobility to effectively displace the contacted oil in heterogeneous reservoirs by improving the volumetric and displacement sweep efficiencies. This research presents several laboratory results of polymer and alkali/surfactant/polymer core floods performed in the Center for Petroleum and Geosystems Engineering laboratories. Properties of polymer and surfactant phase behavior were measured and modeled and each coreflood was history matched with UTCHEM, a three-dimensional chemical flooding simulator. The coreflood results and the history matched model parameters were then upscaled to a pilot case for viscous oil in offshore environment with four wells in a line drive pattern. The potential of polymer flooding was investigated and several sensitivity cases were performed to evaluate the effect of various physical property parameters on oil recovery. Water salinity and hardness (i.e. amount of calcium and magnesium) has detrimental effects on polymer viscosity and its stability. The potential benefits of low salinity water injection by desalinization of seawater for polymer flood projects have been discussed in recent publications. The effect of low salinity polymer flood was also investigated. A series of sensitivity studies on well pattern and well spacing is carried out to investigate the impact on recovery factor and recovery time. / text

The objective of this research was to determine whether the use of polymer compounds with elastic properties can reduce residual oil saturation in porous media below that of brine or inelastic polymerized solutions. One hypothesis is that long-chain polymer molecules experience stress and a resulting strain when they flow through pore throat constrictions. If the fluid residence time in larger pore spaces is insufficient to allow full relaxation, then strain can accumulate. Sufficient strain results in normal forces which can impinge on oil interfaces and potentially mobilize them. A second hypothesis suggests that polymerized solutions can temporarily protect flowing oil filaments from snap off, allowing them to flow longer and de-saturate further than they would otherwise. The approach taken in this thesis was to conduct a series of core floods in several different sandstones using displacement fluids with elasticity ranging from none to those with extremely high relaxation times. Accelerated flow rate was also employed to reduce residence time and maximize the accumulation of elastic strain and normal force potential. Experiments were designed to provide direct comparisons between both non-elastic and elastic floods but also multiple floods with increasing elasticity. The results were inconclusive with some experiments showing additional oil recovery that could be attributed to elastic mechanisms. Most experiments, however, showed no significant difference between elastic and non-elastic floods when experimental parameters were controlled within narrow limits. This research did refine the experimental context in which elastic effects are most likely to be observed. As such, it can serve as a precursor to additional core flooding in oil-wet systems, experiments conducted at reservoir temperature, and those where the pressure gradient of the flood is held constant and the flow rate allowed to vary. Computer aided tomography could also be employed to visualize the mobilization of oil with different displacement fluids, identify where bypassed oil occurs with unstable floods, and determine how oil is subsequently mobilized with better conformance and or elasticity. / text

The objective of this work was to evaluate chemical interactions in phase behavior experiments that make surfactant-polymer formulations with alkali complex to design. This experimental study of sodium carbonate shows improvement of microemulsion phase behavior with many crude oils in addition to its classical use to produce soap in-situ and raise pH to reduce potential for surfactant adsorption. Soap is generally not sufficient by itself for chemical flooding because it has low tolerance to calcium ions and low optimal salinity. The blending of synthetic surfactant with sodium carbonate is needed to increase the optimum salinity, increase the tolerance to calcium, and reduce the sensitivity to changes in salinity by broadening the active salinity window. Sodium carbonate can also be added to the surfactant formulation to adjust electrolyte concentration for optimal salinity. Evidence suggests that additional consideration should be given to sodium carbonate in enhanced oil recovery applications because of benefits that extend beyond the traditional application. The research presented in this work discusses experiments that were conducted for the purpose of studying the benefits of sodium carbonate on surfactant phase behavior. After phase behavior screening, the formulations were tested to demonstrate their performance in porous media. Core floods were conducted to test the potential use of chemical flooding for a field application with several low acid crude oils. Two of the core flood experiments with Berea sandstone reduced the residual oil below 1% with chemical injection. An acceptable pressure gradient was maintained and good sweep was obtained using an AMPS polymer at high temperature. Polymer was needed to make the slug and drive sufficiently viscous to recover the mobilized oil and reduce surfactant retention through good sweep efficiency. The experiments reported in this research have contributed to an ongoing effort to design a suitable alkali-surfactant-polymer chemical formulation for the application in a high permeability, high temperature (85 ºC) sandstone reservoir located in Indonesia. / text

The movement of low viscosity fluid through a porous medium containing extremely viscous fluid is emerging as an important phenomenon in several petroleum engineering applications. These include the recovery of heavy oil by solvent injection, the preferential reduction of water flow using polymer gels, and the enhancement of acid fracturing treatments. The displacement of one fluid from a porous medium by a second, immiscible fluid has been extensively studied in two cases: when capillary forces are dominant, and when viscous forces are comparable to capillary forces. This dissertation research examines a third case: when viscous forces are dominant. The viscosity of the fluid initially present in the porous medium is four or more orders of magnitude greater than the viscosity of the displacing fluid. Consequently, the displacement through an individual pore will be dictated by the hydrodynamic forces required to move the high viscosity fluid. However, very little is known about grain-scale behavior of such displacements. The research will develop a mathematical model of the viscosity-dominated displacement in a network of conduits. By neglecting pressure drop within the low viscosity fluid, the model will treat the displacement as a moving boundary problem. The high viscosity fluid will be assumed Newtonian and will move in response to the pressure gradient imposed via the low viscosity fluid. The movement can be treated as pseudo-steady state flow of the highviscosity fluid. The flow field will be updated whenever the low viscosity fluid advances into a pore previously occupied by high-viscosity fluid. Swept volume will be calculated in each run for comparison and further investigation. We will use classical methods for direct and iterative solutions of large, sparse linear systems to compute these steady states. Key practical insights to be obtained from the model are the nature of the displacement and effects of geometry and hydraulic conductivities on the sweep efficiency. The model will form the basis for examining additional physical processes, notably mass transfer between fluids, and the possibility that fingering of the low viscosity fluid occurs within individual pore throats.

Functional neuroimaging research on language recovery in patients with aphasia due to left hemisphere damage has generated some intriguing results. However, it is still not clear what role the right hemisphere plays in supporting language functions in chronic phase for patients with different site and size of lesion when different tasks are used. The present study was aimed at exploring the role of perilesional, ipsilesional and contralesional regions in neural recovery in participants with aphasia with different site and size of lesion using three different language tasks. All patients in the present study were in the chronic stage who had achieved high levels of recovery. Functional magnetic resonance imaging (fMRI) was used to characterize cortical activation in eight stroke patients and eight age/gender matched controls during lexical decision, semantic judgment and picture naming. An event related design using jittered interstimulus intervals (ISIs) was employed to present the stimuli. The fMRI scans revealed differences in activation patterns across the three tasks. Normal control participants and participants with aphasia mainly activated the left perisylvian region during the lexical decision task and the semantic judgment task. However, during the picture naming task, all participants activated bilateral posterior regions irrespective of the site or size of lesion. Subsequent regions of interest analysis and laterality index analysis revealed that patients with larger lesions produced greater right hemisphere activation than patients with smaller lesions during the picture naming task. The results of this study demonstrate that recovery is task, lesion site and lesion size specific. Further, the findings of the present study indicate a role for both homologous contralesional cortex and perilesional and ipsilesional regions as efficient mechanisms for supporting language functions in chronic stroke patients. / text

Context: Backup and Disaster Recovery, DR play a vital role in day-to-day IT operations. They define extensive aspects of business continuity plan in an enterprise. There is a continuous need to improve backup and recovery performance concerning attributes such as backup window size, high availability, security, etc. Definitive information is what enterprises strive for and rely upon to deviate from traditional methods towards advancing technologies, which are an intrinsic segment of business mundane actions. Objectives: In this study, we investigate Backup and DR plans on an enterprise level. They are compared in terms of performance metrics such as Recovery Time Objective, Recovery Point Objective, Time taken to backup, Time taken to recover and Total cost of ownership. Also, how CPU and memory utilization conduct differ in both tape-based, cloud-based Backup and DR. Methods: Literature study was the first step to formulate research questions by understanding present technologies in Backup and DR. This led us to conduct a survey for further understanding of challenges faced in industries gaining a more practical exposure. A case study was conducted in an enterprise to capture accurate values. An experiment had been deployed to compare performance of both scenarios and analyze which methodology elevates Backup and DR performance by overcoming challenges. Results: The results attained through this thesis encompass performance related metrics and also the load in terms of CPU and memory utilizations. Survey results were observed to gain better understanding of current technologies and challenges with Backup and DR in enterprises. The cloudbased backup has proved to be better in considered enterprise environment during experimentation in terms of RPO, RTO, CPU, memory utilizations and Total Cost of ownership. Conclusions: There have been numerous research works conducted on how backup and DR plans can be made better. But, they lack accurate information on how their performances vary, what all parameters can be improved by shifting towards advanced and contemporary methodologies withaddressing features such as scalability, flexibility and adaptability, which is provided in this study.

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There is increasing awareness that mental health consumers may have important information for the development of services. In this qualitative study, I interviewed 10 consumers with the purpose of exploring in depth their experiences in interacting with service providers in the greater Vancouver area. Using constant comparative analysis, I found that the data suggested participants’ experiences of recovery developed largely out of connecting with other consumers rather than with service providers. Current services were portrayed as primarily reliant on the use of psychiatric medication. Consumers pointed to numerous difficulties in seeking help, including a lack of treatment alternatives, stigma and isolation. They also presented a strong demand for services and policies that promote an individual sense of recovery and support their fundamental human rights. Mental health service providers need to critically reflect on their current practices and policies, and how they may negatively impact their clients' lives by failing to properly listen to their narratives, grievances, experiences and perceptions. This study suggests further inclusion of consumer's views and participation in services to foster collaborative, recovery-oriented practices.

The relationship between mental health and public health has been debated for decades. But when services are delivered through publically funded mental health clinics, it clearly becomes a public health endeavor. One of the latest trends in mental health service delivery is the recovery concept. Developed in the 1990’s, the recovery concept represents a paradigm shift where successful treatment is defined by self-awareness, self-care, and self-fulfillment. Furthermore, patients are encouraged to assess their own progress in the recovery process. There are currently nine unique assessment tools to measure recovery progress, including the Mental Health Recovery Measure (MHRM), which was used in this study. The current study followed the implementation of the recovery model in the DeKalb Community Service Board (DeKalb CSB). DeKalb CSB has 12 locations that serve 10,000 patients with mental illness, substance abuse, and developmental disabilities each year. Only patients with primary diagnoses of mental health or substance abuse disorders were considered for this study. Implementation of the MHRM began in December 2008 and included all DeKalb CSB patients, however only new DeKalb CSB patients were considered for this study. During 13 months of data collection 960 clients completed 2 assessments and 196 completed 3 assessments. A new consumer is defined as someone who has just completed the intake process and has no record of previous service at DeKalb CSB. The current study examined trends in MHRM data in the DeKalb CSB population; and offered recommendations for future implementation.

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