A carbon silica gel self-sealing core for drilling

Abstract

The invention discloses a carbon silica gel self-sealing core for drilling. The carbon silica gel self-sealing core for drilling comprises a core body; the core body includes a cap portion and a sealing portion arranged at the upper end; a via hole is arranged in the middle portion of the core body; the core body is mainly composed of the components of 12% to 18% carbon, 40% to 50% silica gel, 14%to 20% graphite nanometer, and 20% to 25% nitrile rubber by mass percentage; the inner wall of the sealing portion is a curved shape with staggered heights; sealing grooves are arranged on the convexportions of the inner wall of the sealing portion, wherein the widths of the seal grooves at the lowest end and highest end are greater than the widths of the seal grooves in the middle; sealing rings are arranged inside the sealing grooves; the adjacent sealing rings are arranged at intervals, and the interval distance is more than 4 times the sum of the widths of adjacent seal grooves; and theouter wall of the sealing portion is provided with deformation compensation grooves at positions corresponding to the seal grooves, and the inner wall of each deformation compensation groove is an arccurve. The carbon silica gel self-sealing core for drilling can adapt to temperature from tens of degrees centigrade below zero to tens of degrees centigrade above zero, which is not limited by the temperature and season; and the service life is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of petroleum drilling, and in particular provides a carbon silica gel self-sealing core for drilling. Background technique [0002] In the process of drilling or workover, it is necessary to install the self-sealing core to the wellhead to prevent blowout accidents in the workover operation. [0003] From the material selection of self-styled cores, it is roughly divided into two processes. A few years ago, self-styled cores were generally made of ordinary rubber, but cores made of ordinary rubber generally have wear resistance, strength, wear resistance, and resistance to wear. The aging property is low, and the service life of the core is relatively short; later, through the development of material science, scientific and technological workers invented the polyurethane self-sealing core, and its various properties have been greatly improved. For example, the publication number is CN101481452A, and the publ...

AI Technical Summary

Problems solved by technology

However, they are all made of rubber, and use the boss or sealing ring on the inner wall to clamp the polished rod to seal. Due to the relatively low strength of the rubber core, the wear is very large during the working process. ACCIDENT

In addition, in order to enhance the sealing, the former needs to increase the height of the boss to increase the clamping force and sealing performance, but the strength will be further reduced after increasing the height, so the height selection of the boss becomes a difficult problem in the process

For the latter, the space between the adjacent sealing rings is small, and the sealing oil accommodation space is small, and the relative lubricating performance is poor.

Images