Next-Generation High-Torque Connection for Extended-Reach Wells

Abstract

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 183415, “Development of Next-Generation High-Torque Oil-Country-Tubular-Goods Premium Connection for Extended-Reach Wells,” by Jerry Buster and Justin Perkins, VAM, and Leonardo Azeredo, Vallourec, prepared for the 2016 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, 7–10 November. The paper has not been peer reviewed. Long laterals (>6,000 ft) are generating industry challenges that do not exist with shorter lateral wells (2,000–5,000 ft). These longer lateral wells require connections to be exposed to extreme torques, bending, and rotational loads that may render some commercially available connections ineffective in getting the string to location and could compromise sealability. This paper demonstrates how the latest generation of those connections has been tested and validated to extreme loads before being installed in the wellbore. Introduction Extended-reach drilling (ERD) has existed since the 1970s, and continuous development has pushed the lengths of the laterals. One of the main challenges in ERD is the drag friction force, mainly because of the string weight during its deployment in deviated sections and long horizontal laterals. As a consequence, conventional standard running practices are not effective for running the casing and liner. To cope with this and reduce drag, one technical alternative used by operators is string rotation for casing and production liners and even for lower completions. Torque-and-drag analysis is one of the key factors to success on such projects. The longer the horizontal lateral departure, the higher the probability of requiring high torque. Torque also can be used to improve cementing quality, by use of string rotation during cementation. Because high torque is required for ERD, both the connection and the tubular need to be able to withstand the high torque level and the connection needs to maintain its mechanical and sealability performance. Methods Connection Basics. The innovative connection presented in this paper was developed to meet the increasing challenges of ERD. The connection uses a threaded-and-coupled design that allows for maximum tensile efficiency along with maximum torque capacity (Fig. 1). The thread design is a self-locking dovetail concept that has excellent torque capacity. The seal design is a single internal metal-to-metal seal with radius-to-cone contact surfaces. This provides stable seal contact during all loading sequences and robust make-and-break performance.