Smooth bore collar

Abstract

A friction-reducing device for use in a well bore, the friction-reducing device being cylindrically shaped with a tapered and partially threaded upper section, cylindrical middle section, and tapered and partially threaded lower section. The middle section comprises a cylindrical outer surface, cylindrical inner surface, solid portion between the cylindrical outer surface and the cylindrical inner surface, and first plurality of friction-reducing units. The friction-reducing units are installed at equally-spaced angular intervals into ports within the solid portion of the middle section in a circular array that lies in a first plane that is perpendicular to a longitudinal axis of the cylindrical bore in the friction-reducing device. Each friction-reducing unit comprises a rear bearing seat, an array of miniature ball hearings, and a main ball bearing with a protruding portion that extends through the inner surface of the middle section into the cylindrical bore.

I claim: 
     
         1 . A friction-reducing device for use in a well bore, the friction-reducing device being cylindrically shaped with a tapered and partially threaded upper section, a cylindrical middle section, and a tapered and partially threaded lower section;
 wherein the middle section comprises a cylindrical outer surface, a cylindrical inner surface, a solid portion between the cylindrical outer surface and the cylindrical inner surface, and a first plurality of friction-reducing units;   wherein the inner surface of the middle section forms a cylindrical bore in the center of the friction-reducing device, the cylindrical bore having a constant diameter from top to bottom;   wherein the friction-reducing units are installed at equally-spaced angular intervals into ports within the solid portion of the middle section in a circular array that lies in a first plane that is perpendicular to a longitudinal axis of the cylindrical bore;   wherein each friction-reducing unit comprises a rear bearing seat, an array of miniature ball bearings, and a main ball bearing with a protruding portion that extends through the inner surface of the middle section into the cylindrical bore of the friction-reducing device;   wherein each port extends through the solid portion and penetrates both the outer surface and the inner surface of the middle section;   wherein each port comprises a three-dimensional concave portion that penetrates the inner surface of the middle section;   wherein the rear bearing seat of each friction-reducing unit comprises male threads around an outside circumference of the rear bearing seat that mate with female threads on an inside surface of the port;   wherein the rear bearing sear further comprises a hex socket on an outside end of the rear bearing seat and a three-dimensional concave indentation on an inside end of the rear bearing seat;   wherein the main ball bearing is positioned against the three-dimensional concave portion of the port, the three-dimensional concave portion of the port forming a front bearing seat for the main ball bearing;   wherein the plurality of miniature ball bearings is situated between the three-dimensional concave indentation of the rear bearing seat and a portion of the main ball bearing that faces toward the outer surface of the middle section, and wherein the plurality of miniature ball bearings provides a low-friction rolling surface between the rear bearing seat and the main hall bearing;   wherein the main ball bearing is free to rotate in any direction about any three-dimensional axis; and   wherein the friction-reducing device is threadably inserted in-line between two adjacent lengths of production tubing, wherein a sucker rod is inserted through, the cylindrical bore of the friction-reducing device, and wherein the friction-reducing device maintains a gap between an inside wall of the production tubing and the sucker rod.   
     
     
         2 . The friction-reducing device of  claim 1 , wherein the upper section, the middle section, and the lower section are manufactured as a single unit from a single piece of machined steel. 
     
     
         3 . The friction-reducing device of  claim 1 , further comprising a second array of friction-reducing units identical to the first array of friction-reducing units except that the second array of friction-reducing units is installed in a circular array that lies in a second plane that is perpendicular to the longitudinal axis of the cylindrical bore, wherein the first and second arrays of friction-reducing units each has an angular orientation, and wherein the angular orientation of the second array of friction-reducing units is shifted by a certain angle in relation to the angular orientation of the first array of friction-reducing units. 
     
     
         4 . The friction-reducing device of  claim 1 , wherein the middle section further comprises a plurality of threaded holes that extend from the outer surface into the solid portion of the middle section but do not extend to the inner surface of the middle section, and wherein the threaded holes are configured to receive attachment screws for a stabilizer;
 the friction-reducing device further comprising a stabilizer that is secured to the middle section of the friction-reducing device via the attachment screws, wherein the production tubing has an outside diameter and a magnitude of pulsation movement within a well casing, the stabilizer being configured to increase the outside diameter of the production tubing, thereby reducing the magnitude of pulsation movement of the production tubing inside the well casing.