Inferring interwell connectivity from injection and production data using frequency domain analysis

This project estimates interwell connectivity, a characteristic that is crucial to determine reservoir continuity while developing a waterflooding project. It tests the combination of Fourier transforms (FTâÂÂs) of the flow rate data and analytical solutions from analog electrical circuits to infer the inverse diffusivity coefficient (IDC). I solved the transmission line equation analytically for 0D, 1D, and 2D resistance/capacitance (RC) network models and used those solutions to compare with the flow rate FTâÂÂs to determine the diffusivity parameters. I used the analogy between the electrical response of RC networks and the fluid response of permeable reservoirs on the basis of the similarities in the governing equations. I conclude that the analogy works accurately in simple reservoirs, where the assumptions of an analytical solution are met, i.e. single-phase fluid and a homogeneous system. For two-phase liquid cases, I determined that the analogy remains applicable because we still could produce accurate interwell connectivity information. When I investigated cases with dissolved-gas production around the wellbore, however, the analogy broke down and the results were not as good as the liquid systems

Electrochemical Synthesis of High Chromium Fe-Based TiC Composite Coating

In order to investigate the effect of M7C3 and TiC carbides on electrochemical synthesis behavior of Fe-Cr-C and Fe-Cr-C/TiC coatings, Fe-based composite layer was prepared on medium carbon steel surface by using tungsten inert gas coating technique. The microstructure and phase structure of the coatings were analyzed by optical microscope with clemex image analyse, scanning electron microscope (SEM) equipped with an energy-dispersive spectroscopy (EDS) and X-ray diffractometer (XRD). The samples were exposed EIS (electrochemical impedance spectroscopy) method in sea water. Frequence diagrams and Nyquist diagrams were obtained. As a result, adding TiC improved the electrochemical behavior of FeCrC coating.Canakkale Onsekiz Mart University Scientific Searches and Project Department (COMUBAP) [FHD-2020-3338]This study was supported by project number FHD-2020-3338 of Canakkale Onsekiz Mart University Scientific Searches and Project Department (COMUBAP)

Impact of Ethics Education on Nursing Students' Ethical Sensitivity and Patient Advocacy: A Quasi-Experimental Study

Nurses who try to reduce inequalities in health care by defending individuals they care for should be able to perceive ethical situations sensitively as patient advocates. This study aimed to examine the effects of ethics education provided to nursing students on ethical sensitivity and patient advocacy. The study adopted a pre-test, post-test, one-group quasi-experimental design and was conducted at a public university in Turkey. The sample comprised 44 nursing students taking the Professional Ethics course. Data were collected from October 13, 2021, to January 6, 2022, using a Descriptive Characteristics Form, the Moral Sensitivity Questionnaire, and the Patient Advocacy Scale for Nurses. The study was approved by an ethics committee. While no significant difference was found between the pre-test and post-test mean Moral Sensitivity Questionnaire scores (t = 0.426, p > 0.05), a significant difference was noted between the total mean Patient Advocacy Scale for Nurses scores (Z = - 2.443, p < 0.05). The findings showed that ethics education provided to the nursing students did not affect ethical sensitivity but increased patient advocacy

Evaluation of Perceptions About Medical Educator and Medical Student Through Metaphors

Objective: In the study, it was aimed to reveal the mental images of faculty members in different medical faculties regarding the concept of medical educator and medical student through metaphors.Methods: A total of 248 faculty members from five different faculties participated in this qualitative research in phenomenology design. The data were collected with a questionnaire form. Faculty members were asked to describe the medical educator and student with a metaphor and to state the reason for the metaphor they used. The research was conducted on a voluntary basis. Content analysis was made on the metaphors. Ethics committee approval was obtained for the study.Results: Faculty members produced 134 medical educator metaphors. These metaphors were grouped under nine conceptual categories; source/transmitter of information; shaper; raiser/ feeder/grower; guiding/inspiring; professional; altruist/ altruistic/developing identity; role model; counselor and scary medical educator. One hundred and twenty-nine metaphors developed for medical student were collected under seven categories. The categories of medical students were recipient/reflector of knowledge, the constructor/transformer of knowledge, growing/developing, processed/valued, working/making effort, discoverer and negatively connotating.Conclusion: It was observed that traditional understanding was dominant about learning and teaching among all the medical faculties. Medical educators continue to maintain their traditional educator-centered understanding, despite the paradigmatic transformation in medical education

Feasibility Study of Standalone PV-Wind-Diesel Energy Systems for Coastal Residential Application in Pekan, Pahang

Techno economic study is feasible to optimize the usage of renewable energy components that targeting low cost of electricity generation system. The selected case study area is coastal area in Pekan, Pahang, Malaysia. The autonomous system designed in this study is hybrid standalone PV-wind-diesel energy system to fulfil a basic power demand of 20.1 kWh/day. Such power system was designed and optimized further to meet the power demand at a minimum cost of energy using energy optimization software, Hybrid Optimization Model for Electric Renewables (HOMER). The analysis focused on the operational characteristics and economics. The standalone PV-wind-diesel energy system has total net present cost about $61, 911 with cost of energy$0.66/kWh. Apparently, the generation of electricity from both wind turbine and PV can be inflated with the diesel generator. In comparison, return of investment (ROI) value turned out lower for Feed in Tariff (FIT) as compared to self-sustained house. Payback period also longer for FIT program that makes the selling back of electricity generated to Tenaga National Berhad (TNB) is considered not favourable

Interwell Connectivity and Diagnosis Using Correlation of Production and Injection Rate Data in Hydrocarbon Production

This report details progress and results on inferring interwell communication from well rate fluctuations. Starting with the procedure of Albertoni and Lake (2003) as a foundation, the goal of the project was to develop further procedures to infer reservoir properties through weights derived from correlations between injection and production rates. A modified method, described in Yousef and others (2006a,b), and herein referred to as the 'capacitance model', is the primary product of this research project. The capacitance model (CM) produces two quantities, {lambda} and {tau}, for each injector-producer well pair. For the CM, we have focused on the following items: (1) Methods to estimate {lambda} and {tau} from simulated and field well rates. The original method uses both non-linear and linear regression and lacks the ability to include constraints on {lambda} and {tau}. The revised method uses only non-linear regression, permitting constraints to be included as well as accelerating the solution so that problems with large numbers of wells are more tractable. (2) Approaches to integrate {lambda} and {tau} to improve connectivity evaluations. Interpretations have been developed using Lorenz-style and log-log plots to assess heterogeneity. Testing shows the interpretations can identify whether interwell connectivity is controlled by flow through fractures, high-permeability layers, or due to partial completion of wells. Applications to the South Wasson and North Buck Draw Fields show promising results. (3) Optimization of waterflood injection rates using the CM and a power law relationship for watercut to maximize economic return. Tests using simulated data and a range of oil prices show the approach is working. (4) Investigation of methods to increase the robustness of {lambda} and {tau} estimates. Human interventions, such as workovers, also cause rate fluctuations and can be misinterpreted by the model if bottom hole pressure data are not available. A revised method, called the 'segmented capacitance model', identifies times when production changes might not be caused strictly by water injection changes. Application to data from Monument Butte Field shows encouraging results. Our results show the CM and its modified forms can be an important tool for waterflood management. We have moved beyond the proof of principle stage to show it can actually be applied to assess connectivity in field situations. Several shortcomings, however, remain to be addressed before the CM can be routinely applied by field operators. The CM and its modifications analyze well rates in the time domain. We also explored the assessment of interwell connectivity in the spectral domain. We applied conventional methods, based on analyzing passive linear electrical networks, to the analysis of injection and production data. In particular, we assessed the effects of near-wellbore gas on the apparent connectivity. With only oil and water in the system, the results were as expected, giving good connectivity estimates. In the presence of gas, however, the methods could not produce useful estimates of connectivity

Global and local corrosion of welded joints of high-strength low-alloy automotive steel

Global and local corrosion techniques were used to study the corrosion behaviour of weld joints of a high strength low alloy steel (LNE500), typically employed in the automotive industry, in Brazil. The welded joints were prepared by gas metal arc welding (GMAW). Two welding transfer modes were used in order to obtain different heat inputs (HI): pulsed (PUL) and cold metal transfer (CMT). Local and global corrosion analysis techniques presented complementary information. While the local in-situ analysis (scanning vibrating electrode technique) revealed the weld metal (WM) as the region where corrosion started, conventional electrochemical techniques (Potentiodynamic polarization (PP) and electrochemical impedance spectroscopy (EIS)) revealed a higher corrosion rate in the coarse-grained heat affected zone (CGHAZ), which was preferentially corroded. A superior corrosion resistance of the weld metal obtained using CMT over the PUL transfer mode was revealed by EIS and PP. In addition, the results from CMT and PUL samples show that austenite grain size affects the propagation of the corrosion process. The results are discussed based on microstructural and compositional aspects of the different regions that characterize the welded joints

Beneficial use of immunoglobulins in the treatment of Sydenham chorea

This double case report indicates that treatment with intravenous immunoglobulins (IVIG) is effective in patients with Sydenham chorea (SC). SC is a rare but impressive clinical manifestation following streptococcal infection. This movement disorder characterised by chorea, emotional lability and muscle weakness, is one of the major criteria of acute rheumatic fever. Treatment of SC is typically limited to supportive care and palliative medications. Curative treatment is still in the experimental stage. Recent research on patients with SC proved that antibodies against the group A streptococcus cross-react with epitopes of neurons in the basal ganglia, namely, intracellular tubulin and extracellular lysoganglioside. Therefore, immune modulating therapy by means of prednisone, plasma exchange and IVIG are mentioned in the literature as possible effective treatment. Beneficial effect of IVIG has been shown in several diseases with molecular mimicry as the underlying pathophysiology. In this paper, we describe two girls aged 11 and 13 years, respectively, who presented with SC having severe disabilities in their daily live. We treated both patients with IVIG 400 mg/kg/day for 5 days. Treatment was tolerated well and had a pronounced positive effect. Shortly after the drug was administered, all signs and symptoms disappeared in both patients. Based upon these patients, we highlight IVIG as a serious treatment option for SC

Veterinary students’ perceptions of their learning environment as measured by the Dundee Ready Education Environment Measure

BACKGROUND: The Dundee Ready Education Environment Measure (DREEM) has been widely used to evaluate the learning environment within health sciences education, however, this tool has not been applied in veterinary medical education. The aim of this study was to evaluate the reliability and validity of the DREEM tool in a veterinary medical program and to determine veterinary students’ perceptions of their learning environment. METHODS: The DREEM is a survey tool which quantitatively measures students’ perceptions of their learning environment. The survey consists of 50 items, each scored 0–4 on a Likert Scale. The 50 items are subsequently analysed within five subscales related to students’ perceptions of learning, faculty (teachers), academic atmosphere, and self-perceptions (academic and social). An overall score is obtained by summing the mean score for each subscale, with an overall possible score of 200. All students in the program were asked to complete the DREEM. Means and standard deviations were calculated for the 50 items, the five subscale scores and the overall score. Cronbach’s alpha was determined for the five subscales and overall score to evaluate reliability. Confirmatory factor analysis was used to evaluate construct validity. RESULTS: 224 responses (53%) were received. The Cronbach’s alpha for the overall score was 0.93 and for the five subscales were; perceptions of learning 0.85, perceptions of faculty 0.79, perceptions of atmosphere 0.81, academic self-perceptions 0.68, and social self-perceptions 0.72. Construct validity was determined to be acceptable (p < 0.001) and all items contributed to the overall validity of the DREEM. The overall DREEM score was 128.9/200, which is a positive result based on the developers’ descriptors and comparable to other health science education programs. Four individual items of concern were identified by students. CONCLUSIONS: In this setting the DREEM was a reliable and valid tool to measure veterinary students’ perceptions of their learning environment. The four items identified as concerning originated from four of the five subscales, but all related to workload. Negative perceptions regarding workload is a common concern of students in health education programs. If not addressed, this perception may have an unfavourable impact on veterinary students’ learning environment