48 research outputs found
The technology of radial drilling as a method of improved oil recovery
Currently, the volume of difficult oil in the world is increase and amasses close to 70%. Electric submersible pumps (ESPs) and jack pumps (SRP) used ever more 80% of the wells. Mechanical method of production is not always effective due to the low coefficient of efficiency pump units operating in marginal wells. There is a limit for well production rate below which produce oil is technically impossible or economically unprofitable. Many wells, currently stopped oil production due to unprofitability of oil wells with hard to recover reserves. It leads to their conservation or liquidation. The number of such wells is of these wells is about 25000-30 000. Pressure communication suffers from lack of quality in a "well-formation". It is caused by technological problems in the construction of wells, particularly in the productive intervals. It leads to excessive pressure in the reservoir, and then plugging reservoir mud filtrate or the cement slurry reaches a depth of several meters
XYZ-polarisation analysis of diffuse magnetic neutron scattering from single crystals
Studies of diffuse magnetic scattering largely benefit from the use of a
multi-detector covering wide scattering angles. Therefore, the different
contributions to the diffuse scattering that originate from magnetic, nuclear
coherent, and nuclear spin-incoherent scattering can be separated by the
so-called XYZ-polarization analysis. In the past this method has been
successfully applied to the analysis of diffuse scattering by polycrystalline
samples of magnetic disordered materials. Single crystal studies that exploit
the vector properties of spin correlations are of particular interest for
furthering our understanding of frustration effects in magnetism. Based on the
symmetry properties of polarised scattering a suitable extension of the
conventional XYZ method has been derived, which allows for the complete
separation and the analysis of features of diffuse magnetic scattering from
single crystals.Comment: 6 pages 2 figures, revised as published, one Eq. removed, minor
corrections, typos correcte
Stern-Gerlach effect without magnetic-field gradient
The Stern-Gerlach effect is the well-known spin-dependent splitting of a
neutral particle beam by a magnetic-field gradient. Guided by the
pseudomagnetic analogy, we performed a similar experiment where no magnetic-field
gradient is involved. The effect is due to the spin-dependence of
neutron scattering from polarised nuclei, i.e. caused by the strong
interaction between neutrons and nuclei. The beam splitting is proportional
to the nuclear polarisation and to the spin-dependent part of the neutron
scattering length. Thus it can be used to measure one of both quantities
Change of magnetic short range order at metal insulator phase transition
The wavenumber dependent susceptibility in V5O9 shows that the jump of susceptibility at the metal insulator transition is not due to antiferromagnetic correlations expected in a Mott insulator but to the onset of ferromagnetic correlations in the metallic phase with a small, intinerant type V moment of 0.6 amp; 956;B in both phase