Rheological parameters of drilling fluids, such as yield point and plastic viscosity, are required to determine the hydrodynamic components of pressure at various points in the circulation system during technological operations. It is essential to ensure a simple and accurate measurement of these parameters in the construction of oil and gas wells, however, existing methods are relatively expensive and the results obtained can be subjective. This article describes a newly developed method for measuring the plastic viscosity and yield point of the drilling fluid using a Marsh funnel, which will greatly simplify the procedure for determining the rheological parameters of drilling fluids and allow them to be measured directly on drilling rigs. When the geometrical parameters of the funnel are determined, the true viscosity parameters are calculated using simple formulas. The Marsh funnel is traditionally used on the drilling rig to measure the relative viscosity of the drilling fluid and is an inexpensive and simple device. The article provides comparative studies with standard methods for determining the rheological parameters of the drilling fluid. According to the results of the test method, comparisons are made of pressure losses in the circulation system of the drilling fluid on drilling rigs.

The aim of this work was to study resistance to helium accumulation processes in the structure of the surface layer of lithium-containing ceramics and the subsequent destruction and embrittlement processes, depending on radiation fluence. The objects of study were Li2TiO3-type ceramics obtained by thermal sintering. The fluence dependency of changes in the structural and strength properties of ceramics was determined to be in the range from 1018 to 1022 ion/m2, which corresponded to the concentration of implanted helium from 0.01% to 0.8–1 at.%. Irradiation was carried out at a temperature of 700 °C, which made it possible to simulate the processes of radiation damage that were closest to the real conditions in the reactor core. During the studies carried out, it was found that, at irradiation fluences of 1018–1020 ion/m2, the formation of point radiation defects was equaled by the process of thermal annealing of defects, as a result of which the concentration of defects and their effect on the change in the structural and strength properties of ceramics were insignificant. An increase in the concentration of implanted helium in the structure of the surface layer to above 0.5 at.% led to the dominance of radiation damage processes over the annealing of defects and the formation of gas-filled cavities, which negatively affects the strength of ceramics.