Tubular Member Coupling and Lining Systems and Methods

Abstract

For use in assembling a tubing string for a production well, a rigid pre-formed liner is configured for simple drop-in place installation at each tubing joint during assembly of the tubing string in to protect the inside of the tubing string from wear caused by operation of a sucker rod inside the same. At a threaded connection in the finished tubing string, where an externally threaded top end of a section of production tubing is engaged with an internally threaded bottom end of a box coupler or collar, the tubular portion of a respective liner hangs downward from a larger-diameter collar portion of the liner that sits atop the annular top end of the section of production tubing. The liner is installed by simply dropping its tubular portion into the section of tubing and then threading the box coupler onto the section tubing around the upper end of the liner.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims benefit under 35 U.S.C. 119(e) of Provisional Application Ser. No. 61 / 721,248, filed Nov. 1, 2012.FIELD OF THE INVENTION[0002]The present invention relates generally to well tube liners for use in well production, and more particularly to well tube liner inserts configured for easy drop-in installation during joining of tubing sections or joints for the purpose of providing a buffer between the tubing and a sucker rod deployed therein to operate downhole equipment.BACKGROUND OF THE INVENTION[0003]In pumping of fluids from a wellbore for production to the surface, a string of sucker rods connected end to end is used as a mechanical link between drive equipment at the surface and a downhole pump in the wellbore for driven operation thereof. Conventionally, sucker rods are typically each externally threaded at pin ends of the rod and are interconnected by internally threaded box couplings each threadingly receiving en...

AI Technical Summary

Benefits of technology

The invention is a system for coupling and lining well tubular members in a well. The system includes first and second tubular members with externally threaded ends, a rigid liner with a smaller tubular portion and a collar portion, and an internal passage through the rigid liner. The collar portion is designed to fit between the first and second tubular members and contain the rigid liner in a way that maintains the tubular portion in the first tubular member. The system also includes a method for assembling the tubular members and liner in a way that allows for fluid communication between them. The technical effects of the invention include improved protection of the inner surface of the first tubular member during drilling and better fluid communication between the tubular members in a well tubing string.

Problems solved by technology

A common problem in such installations is that the sucker rod string does not extend entirely linearly in the wellbore, and accordingly box couplings between the rods, which are of larger outer diameter than the rods themselves and thus form the radially outermost extents of the string, will tend to bump or rub against the production tubing wall during the driven rotation of the rod string and thus cause significant wear to the production tubing.

One prior art solution has been to bond elastomeric materials to the hard outer surfaces of sucker rod couplers to reduce wear to the tubing, which is more difficult and costly to replace than a coupler.

However, the coating may quickly wear away, requiring frequent replacement or recoating of sucker rod couplers.

Installation of the prior art wear-prevention solutions can be time intensive, and thus inefficient.

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