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Ofei Titus Ntow,Ngouamba Elie,Opedal Nils,Lund Bjørnar,Saasen Arild 한국유변학회 2023 Korea-Australia rheology journal Vol.35 No.2
The occurrence of barite sag in drilling fluids has relatively often been the cause for gas kicks in oilwell drilling. The subsequent absorption of gas into drilling fluid could lower the density and reduce the viscosity of the drilling fluid, thereby aggravating both pressure control and hole cleaning. In this paper, we present experimental measurements of rheological properties and barite sag in a typical North Sea oil-based drilling fluid at downhole pressure and temperature conditions. A new experimental apparatus was setup for barite sag measurements at static condition with operational temperature and pressure capabilities up to 200 °C (392°F) and 1000 bar (14,503.8 psi), respectively. Rheometry measurements were conducted on fluid samples with and without barite particles at operating conditions up to 90 °C and 100 bar. We observed that at a typical shear rate of 250 s−1, which is experienced in 8.5″ hole annulus, the viscosity of fluid sample with barite increased nearly three times as that of the fluid sample without barite as the temperature and pressure increased. However, temperature effect on viscosity dominates at high shear rates compared to pressure effect. Furthermore, the fluid samples showed more shear-thinning effect with increasing yield stress as the temperature increased. On the other hand, barite sag measurements revealed that whereas fluid samples under high pressure are less prone to sag, high temperature fluid samples, however, promote sag significantly. The data from this study are useful to validate extrapolations used in computational models and to improve understanding and operational safety of sag phenomena at downhole conditions. We also discuss the importance of this study in optimizing drilling operations.
Occupational Health and Safety Management and Turnover Intention in the Ghanaian Mining Sector
Amponsah-Tawiah, Kwesi,Ntow, Michael Akomeah Ofori,Mensah, Justice Occupational Safety and Health Research Institute 2016 Safety and health at work Vol.7 No.1
Background: The mining industry is considered as one of the most dangerous and hazardous industries and the need for effective and efficient occupational health and safety management is critical to safeguard workers and the industry. Despite the dangers and hazards present in the mining industry, only few studies have focused on how occupational health and safety and turnover intentions in the mines. Method: The study suing a cross-sectional survey design collected quantitative data from the 255 mine workers that were conveniently sampled from the Ghanaian mining industry. The data collection tools were standardized questionnaires that measured occupational health and safety management and turnover intentions. These scales were also pretested before their usage in actual data collection. Results: The correlation coefficient showed that a negative relationship existed between dimensions of occupational health and safety management and turnover intention; safety leadership (r = -0.33, p < 0.01); supervision (r = -0.26, p < 0.01); safety facilities and equipment (r = -0.32, p < 0.01); safety procedure (r = -0.27, p < 0.01). Among these dimensions, safety leadership and safety facility were significant predictors of turnover intention, (${\beta}=-0.28$, p < 0.01) and (${\beta}=-0.24$, p < 0.01) respectively. The study also found that turnover intention of employees is heavily influenced by the commitment of safety leadership in ensuring the effective formulation of policies and supervision of occupational health and safety at the workplace. Conclusion: The present study demonstrates that safety leadership is crucial in the administration of occupational health and safety and reducing turnover intention in organizations.
Occupational Health and Safety Management and Turnover Intention in the Ghanaian Mining Sector
Kwesi Amponsah-Tawiah,Michael Akomeah Ofori Ntow,Justice Mensah 한국산업안전보건공단 산업안전보건연구원 2016 Safety and health at work Vol.7 No.1
Background: The mining industry is considered as one of the most dangerous and hazardous industries and the need for effective and efficient occupational health and safety management is critical to safeguard workers and the industry. Despite the dangers and hazards present in the mining industry, only few studies have focused on how occupational health and safety and turnover intentions in the mines. Method: The study suing a cross-sectional survey design collected quantitative data from the 255 mine workers that were conveniently sampled from the Ghanaian mining industry. The data collection tools were standardized questionnaires that measured occupational health and safety management and turnover intentions. These scales were also pretested before their usage in actual data collection. Results: The correlation coefficient showed that a negative relationship existed between dimensions of occupational health and safety management and turnover intention; safety leadership (r = -0.33, p < 0.01); supervision (r = -0.26, p < 0.01); safety facilities and equipment (r = -0.32, p < 0.01); safety procedure (r = -0.27, p < 0.01). Among these dimensions, safety leadership and safety facility were significant predictors of turnover intention, (b = -0.28, p < 0.01) and (b = -0.24, p < 0.01) respectively. The study also found that turnover intention of employees is heavily influenced by the commitment of safety leadership in ensuring the effective formulation of policies and supervision of occupational health and safety at the workplace. Conclusion: The present study demonstrates that safety leadership is crucial in the administration of occupational health and safety and reducing turnover intention in organizations.