Abstract: The present invention is a tubing centralizer for use within casing within a wellbore. The tubing centralizer has a tubing centralizer cage comprising a top ring, a middle ring, and a bottom ring and a plurality of springs, where each spring connects the top ring to the middle ring and the middle ring to the bottom ring and where each spring has a double arcuate shape such that the springs arc radially outward between the top ring and the middle ring and again between the middle ring and the bottom ring. The springs may be sized such that they exert outward pressure against the inside wall of the casing such that the tubing centralizer resists movement along the casing. The tubing centralizer may further comprise a tubing centralizer mandrel, where the tubing centralizer mandrel is part of the tubing string and extends through the tubing centralizer cage.

Abstract: A connector to secure to the end of a cylindrical rod to transfer and distribute stress uniformly from the connector to the rod with a recess to cooperate with a retrieval tool to allow recovery of fractured rod strings or broken connectors. The connector includes an elongated body having a receptacle with a cylindrical wall, a top end and a recess where the recess is adjacent to the top end. A plurality of axially aligned tapered annuluses, coaxial with the receptacle, extends from the cylindrical wall into the body. Each annulus has a cross-section that is radially arcuate with one end tangentially approaching the cylindrical wall and the other end arcuately approaching the cylindrical wall.

Abstract: A connector to secure to the end of a cylindrical rod to transfer and distribute stress uniformly from the connector to the rod with a recess to cooperate with a retrieval tool to allow recovery of fractured rod strings or broken connectors. The connector includes an elongated body having a receptacle with a cylindrical wall, a top end and a recess where the recess is adjacent to the top end. A plurality of axially aligned tapered annuluses, coaxial with the receptacle, extends from the cylindrical wall into the body. Each annulus has a cross-section that is radially arcuate with one end tangentially approaching the cylindrical wall and the other end arcuately approaching the cylindrical wall.

Abstract: The present invention is a tubing centralizer for use within casing within a wellbore. The tubing centralizer has a tubing centralizer cage comprising a top ring, a middle ring, and a bottom ring and a plurality of springs, where each spring connects the top ring to the middle ring and the middle ring to the bottom ring and where each spring has a double arcuate shape such that the springs arc radially outward between the top ring and the middle ring and again between the middle ring and the bottom ring. The springs may be sized such that they exert outward pressure against the inside wall of the casing such that the tubing centralizer resists movement along the casing. The tubing centralizer may further comprise a tubing centralizer mandrel, where the tubing centralizer mandrel is part of the tubing string and extends through the tubing centralizer cage.