RETRACTABLE CASING CENTRALIZER Russian patent published in 2022 - IPC E21B17/10 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil and gas industry and can be used for cementing casing strings during the construction of wells having a variable diameter. The casing string centralizer includes centering metal plates fixed evenly around the perimeter on the upper and lower rings, restrictive upper and lower rings installed on the casing string above and below the centralizer, with cavities. The upper restrictive ring is made with an annular inner recess facing towards the centralizer ring, which is inserted into the annular recess of the upper restrictive ring with the possibility of longitudinal movement under the action of expanding metal plates and fixation in this position. The upper ring has a thickening in which a radial groove is made, in which the retaining ring is installed. In the central part of the centering metal plates, a recess is made with the possibility of installing a steel ring into it.

EFFECT: increased reliability of operation of the casing string centralizer and expansion of its operational capabilities due to the possibility of free passage in narrow sections and exit in the working position in the extended section of the wellbore, isolated by the presence of shafts with varying diameters.

1 cl, 7 dwg