A casing centralizer is a device that is mounted on a casing string to center the casing string within the wellbore. It is one of the casing accessories.
It is divided into two types: rigid centralizer and spring centralizer. The casing centralizer has the characteristics of simple structure, convenient use, long service life and low relative cost. In addition to ensuring a certain thickness of the cement ring outside the casing string, the casing centralizer can also reduce the resistance when the casing is under the casing. To avoid sticking the tube, which is beneficial to improve the cementing quality.
The casing centralizer is mainly composed of a central pipe, a liquid cylinder, a connecting sleeve, a driving chain plate, a driven chain plate, a supporting bracket, a lower bracket, a pin, a sealing ring, a retaining ring, and a retaining ring cap. The center tube is provided with a liquid inlet hole. The liquid cylinder and the retaining ring seat are connected by a connecting sleeve, and the retaining ring seat and the center tube are connected by a pin. The active link plate and the driven link plate are connected by pins to form a hinge. The upper and lower brackets are respectively connected to the upper and lower ends of the hinge. The hinged casing centralizer ensures that the hinged casing centralizer is safely lowered to the well design position, which can effectively improve the casing centering and improve the cementing quality.