Top Drive Casing Running: Challenges and Solutions
Authors: Shute D.M. 
Published: March 2010

Opportunities to improve rig floor safety, reduce risks and reduce costs have motivated operators to utilize the top drive for casing running operations. Simple and easy approaches for applying make-up torque and hoisting loads to the casing string have been used with some success, but in some applications performing these functions safely, economically and without connection damage has not been trivial.

Operational logistics, management of loads that cause casing thread damage and prevention of pipe body damage are examples of challenges requiring sound technical solutions. Pipe handling logistics, including engagement of the casing grip, must be executed efficiently without damaging casing threads or sealing surfaces. Similarly, bending loads resulting from rig misalignment or casing curvature can initiate thread damage if uncertainties remain unmanaged. Finally, local cold working of pipe body material increases stress cracking susceptibility, particularly on inner surfaces, and may reduce casing string reliability.

Successful use of casing running technology depends on selecting a system that meets the technical requirements of the application. A sound understanding of casing thread make-up, drilling rig operations and the interaction between the two enables critical evaluation of emerging technologies and reduces the risk of commercial failure. This paper presents the background behind such evaluation and discusses a range of technologies in the context of that background.

Introduction

A desire to improve rig floor safety and eliminate unnecessary expenses has motivated oilfield operators to utilize the top drive for casing running operations. Applying make-up torque and hoisting the casing string can be accomplished quite easily, but performing these functions safely, economically and without damaging the casing body or connection threads and seals is not a trivial task. Several top drive casing running systems are commercially available, but consistently successful deployment requires that users carefully match technology with applications. Technical challenges are described here and solutions are characterized in an application- specific context. Successful exploitation of this emerging technology will occur more reliably with an understanding of the relationships between pipe, casing threads, running equipment and drilling rig operations.

The simplest way to transfer torsion and axial load from the top drive quill to the casing is with a crossover, commonly referred to as a nubbin or make-up quill, from the top drive to the casing thread. This approach is widely used in western Canadian shallow hole applications, but fails to capture the full safety and economic benefit available through top drive casing running systems that engagethe pipe body rather than the casing threads(1).

Specific top drive casing running tools are used in a broad range of applications. Success has been reported for casing runs in:highly deviated Gulf of Mexico wells(2);river crossings(2);onshore horizontal wells(2);desert wells(3); and,the North Sea(4).Compelling business cases for adopting top drive casing running systems have been published previously(1–4) and the subject will be treated here at a summary level only.

The positive economic impact of using top drive casing running systems is evident in three areas.