Drilling fluid processing: preparation, maintenance and continuous conditioning
The following discussion is an overview of the operation of drilling fluids at the rig site, giving an insight to those less versed in the art of drilling oil and gas wells. Fluid processing at the rig site is currently a prime target for higher levels of mechanization and process control, leading towards automation. The drilling fluids' composition influences its properties and dynamic behaviour, and the various drilling fluid components and additives all have specific purposes related to the drilling process. The process of drilling fluid preparation and mixing on the drilling rig is described, and the means of maintaining suitable properties during the drilling process are discussed. Means and requirements are presented for enabling continuous conditioning of the drilling fluid to suit the variations in the wellbore and formation, pointing out current challenges in measurement, instrumentation, mechanization, and control that need to be solved. It is clear that a higher level of automation is required if we wish to achieve this goal.
Highly automated drilling fluids system improves HSE and efficiency, reduces personnel needs
Manual mud-mixing equipment have a higher risk of imprecision in the mixing process compared with highly automated systems.
Microstructure of the solder-casting zone in bridges of dental gold alloys.
The composition and structure were studied in the cast and in the solder of bridges which had failed clinically. Both materials were gold alloys but with different contents of Pt, Ag and Zn. The metallographic investigation revealed defects mostly in the solder, situated in the subsurface layer. SEM studied of the fracture surface revealed large porosites and a structure of dense parallel lines--striations--, indicating that the material had failed from fatigue. The materials in the fractured bridges were identified by micro-probe measurements. It was stated that cast material and solder material used together, were of different composition.