We propose a scalable state estimator with wave filter for surface vessels. The filter is shown to be either globally or locally exponentially stable depending on configuration. Performance is illustrated using actual data from a full scale semi-submersible drilling rig.

The rheological regulation of the “three high” (high temperature, high density and high salinity) water-based drilling fluid is a worldwide problem due to the combined influence of temperature, solid content and salinity. This paper investigates the factors and regulation methods about rheological property of “three high” water based drilling fluid, and the effects of clay, salinity and weighti...

The rate of penetration (ROP) is one of the vital parameters which directly affects the drilling time and costs. There are various parameters that influence the drilling rate; they include weight on bit, rotational speed, mud weight, bit type, formation type, and bit hydraulic. Several approaches, including mathematical models and artificial intelligence have been proposed to predict the rate o...

The article discusses researches performed in the Well Drilling Department of the St. Petersburg Mining University. The directions of development of the department are shown. Special attention in this article is paid to research in the field of developing drilling fluids for drilling wells in various mining and geological conditions. It is shown that the gas-liquid mixtures studied by the depar...

Filtration index of the drilling fluid is an important parameter of well drilling, especially at drilling-in the reservoirs. Standard parameter in the study of drilling fluids is static filtration index. At the same time, it is more feasible to determine dynamic filtration index, if considering actual conditions of the well. Use of polymer carbonate-weighted drilling fluids is advisable at dril...

introduction: excessive temperature rise during drilling of the mandible for dental implant placement might damage adjacent osseous tissues. various factors affect temperature rise, including the geometrical parameters of surgical drills, one of which is the drill bit head angle. the aim of this research was to determine suitable drill bit head angle to induce minimum temperature rise during ma...

PURPOSE It is essential to have sufficient bone bulk and density at the implant site in order to achieve good bone-to-implant contact and primary stability, which are crucial for osseointegration. A new osteotomy preparation technique was recently introduced that uses a bone preservation method that creates a layer of compacted bone along the surface of the osteotomy. The hypothesis of this stu...

Designing drilling fluids for drilling in deep gas reservoirs and geothermal wells is a major challenge. Cooling drilling fluids and preparing stable mud with high thermal conductivity are of great concern. Drilling nanofluids, i.e. a low fraction of carbon nanotube (CNT) well dispersed in mud, may enhance the mixture thermal conductivity compared to the base fluids. Thus, they are potentially ...

Nirschl release appears to be a very successful technique for surgically suitable cases of tennis elbow. However, although the drilling or decortication aspect of the procedure was thought to be of benefit to the immediate outcome, this has not actually been confirmed. This randomised double blind comparative prospective trial shows that drilling confers no benefit and actually causes more pain...