Evaluation of skin factor from single-rate gas well test

Skin factor is generally used as an indicator for well flow efficiency and the criterion for performing stimulation treatment to improve well productivity. This skin factor is a composite factor and should be divided into its different components in order to evaluate near-wellbore damage. Therefore, the total skin factor obtained from a gas well pressure transient test has two primary components, rate-independent and rate-dependent skins. Both of these skin factors can be determined directly from the interpretation of pressure transient well tests if several transient tests are performed at different rates. However, the multi-rate tests are time consuming and expensive. It is advantageous to estimate the rate-independent skin factor from a single rate test.;In order to obtain a reliable value for the rate-independent skin from a single-rate test, the rate dependent skin must be evaluated independently. The rate-dependent skin depends on the coefficient of inertial resistance, beta and other parameters. A number of correlations relating beta to permeability are available in the literature. These published correlations are derived from limited set of laboratory measurements on various porous media and do not provide consistent results. Alternatively, beta can be determined from the results of the multi-rate well tests using recorded field data.;The main objective of this study is to generate a dependable and simple technique for estimating the true skin factor from the single rate well tests, such as build-up or fall-off tests, on gas wells. More specifically, the objective is to develop a correlation for beta from field data. Since, the correlation of turbulence factor, beta and permeability, k cannot be applied universally to all reservoirs, so the reservoir-specific correlations will be further developed.;The well tests from several wells in the same reservoir were available and several field-specific correlations for beta were developed. The comparison of skin factor determined from these correlations against the skin factors determined from the well test data indicated that reservoir-specific correlations for beta provide accurate and consistent results

On some generalized ageing orderings

Some partial orderings which compare probability distributions with the expo- nential distribution, are found to be very useful to understand the phenomenon of ageing. Here, we introduce some new generalized partial orderings which de- scribe the same kind of characterization of some generalized ageing classes. We give some equivalent conditions for each of the orderings. Inter-relations among the generalized orderings have also been discussed

Simultaneous Design, Scheduling and Operation Through Process Integration

Processing facilities are normally designed with sufficient flexibility to handle nominal variations. When the process features planned changes in feedstock and products, scheduling is often used to optimize process operation. The objective of this dissertation is to develop a new approach to design and scheduling with economic, environmental, heat integration and inherently safer design objectives. Specifically, this work introduces a systematic framework and the associated mathematical formulation for simultaneous process design and scheduling while simultaneously addressing economic, environmental, heat integration and inherently safer design objectives. Therefore, more than one type of proper tradeoffs are established between these objectives. The environmental issues pertaining to the parameterized process retrofitting, scheduling, and operation strategies are simultaneously considered along with the environmental impact of these changes. Similarly, the design synthesis of heat-exchange networks (HENs) is addressed in the context of optimizing energy consumption under scheduling scenarios. Finally, the goal of inherently safer design is simultaneously considered with the expected schedules of the process. Several optimization formulations are developed for the projected schedules while allowing design modifications and retrofitting changes. The modifications and changes include new environmental management units, synthesis of flexible and optimal HENs, and design of an inherently safer process. Process models with the appropriate level of relevant details are included in the formulations. A discretization approach has been adopted to allow for a multiperiod optimization formulation over a given time horizon. The resulting framework identifies opportunities for synergism between the economic, environmental, heat integration and inherently safer design objectives. It also determines points of diminishing return beyond which tradeoffs between the above mentioned objectives are established. The devised procedure is illustrated with case studies

Knowledge of Risk Factors, Symptoms and Barriers to Seeking Medical Help for Cervical Cancer among Omani Women Attending Sultan Qaboos University Hospital

Objectives: This study aimed to assess knowledge and attitudes among Omani woman regarding cervical cancer risk factors and symptoms as well as barriers to them seeking medical help. Methods: This cross-sectional study was conducted between December 2017 and March 2018 at the Sultan Qaboos University Hospital (SQUH) in Muscat, Oman. A validated Arabic-language version of the Cervical Cancer Awareness Measure questionnaire was used to collect data from 550 Omani women visiting SQUH during the study period. Results: A total of 490 women participated (response rate: 89.1%) in this study. Overall, the women demonstrated low levels of knowledge of cervical cancer risk factors and symptoms (28.5% and 45.0%, respectively). The most frequently recognised risk factor was having many children (36.1%), while the most recognised symptom was unexplained vaginal bleeding (69.8%). Women reported that being too scared was the greatest barrier to seeking medical help (68.0%). Various factors were significantly associated with greater knowledge of cervical cancer signs and symptoms including education level (odds ratio [OR] = 2.85; 95% confidence interval [CI]: 1.0–8.22; P <0.05), income (OR = 4.34; 95% CI: 1.70–11.12; P <0.05), parity (OR = 3.59; 95% CI: 1.38–9.36; P <0.05) and a family history of cancer (OR = 1.71; CI: 1.0–2.90; P <0.05). Conclusion: Overall, Omani women demonstrated poor knowledge with regards to cervical cancer; in addition, they identified several emotional barriers to seeking medical help. Healthcare practitioners should reassure female patients to encourage care-seeking behaviour. A national screening programme is also recommended to increase awareness and early diagnosis of cervical cancer in Oman.Keywords: Cervical Cancer; Knowledge; Awareness; Risk Factors; Health Care Seeking Behavior; Women; Oman

An assessment of health profile and body pain among construction workers

Construction is one of the most hazardous and complex industries worldwide, which may result in the most fatal accidents and occupational illnesses. It is also regarded as a major industry not only in Gulf Cooperation Council (GCC) countries but also worldwide and it is rapidly growing. This study reports an assessment of different body parameters, including physiological factors and body pain of construction workers from GCC countries. Demographic data were collected by way of face-to-face interview followed by the measurement of body mass index, blood pressure and heartbeat. Data for musculoskeletal pain were collected through a structured questionnaire. The results reveal that a majority of workers were overweight or obese. The blood pressure of 43·3% of the participants was more than the threshold and shows hypertensive values. An estimate of 46·6% of the workers experienced body pain in the last three months, while the most frequently reported areas for pain were neck, shoulders, low back, legs and knees. Sleep patterns were one of the causative factors that led to experience of pain among workers. This research study would be helpful to develop strategies to improve the well-being of construction workers in GCC countries