Abstract
The latest generation of ultra-deepwater and other critical wells represents drilling projects that demand advanced technology, careful planning and precise execution. With water depths up to 7,000 ft and well depths exceeding 30,000 ft, several projects benefited from a new 3rd Generation Double-Shoulder Connection (3rd Gen. DSC).
A key objective for the 3rd Gen. DSC was to significantly improve connection make-up/break-out speeds relative to 2nd Gen. DSCs. The new connection incorporates a double-start thread that reduces the number of revolutions to assemble the connection by half. Physical comparison testing shows up to 11 second time savings in stab to shoulder 3rd Gen. compared to 2nd Gen DSCs. 3rd Gen. DSCs provide increased mechanical and hydraulic performance while also providing enhanced fatigue performance.
A learning curve was experienced with the new connection. Key to achieving drilling efficiency improvements was rig crew training on best practices to safely optimize running, handling and make-up times. Additionally, a rigorous maintenance program was implemented to ensure handling equipment such as iron roughnecks were in proper order. Equipment characteristics that impacted connection running speed were identified and are discussed.
A key benefit was a reduction in connection damages. Several projects realized ninety percent lower repair costs compared to similar wells using 2nd Gen. DSC.
This paper describes the planning, well design, drilling challenges and lessons learned on several challenging projects in Vietnam, Malaysia and Gulf of Mexico. It provides comparison data between the projects drilled with the 3rd Gen. DSC and similar wells that used 2nd Gen. DSC. Comparisons include running and tripping speed analysis and repair cost considerations related to connection handling damage. The paper summarizes drilling efficiency results and provides recommendations to maximize the effectiveness of the new connection technology on future projects.
As existing ultra-deepwater fields mature and new fields are discovered around the world, the significance of efficiency enhancing drilling technology is paramount. As discussed in this paper, the application of higher specification drillpipe connections working in concert with a variety of pipe handling tools and improved running and handling practices creates a more efficient drilling system.
