Challenges in Designing the World’s First 15,000 PSI Subsea Completion (SPE 71682)

Summary

Despite a depth exceeding 17,500 feet, a negative skin was obtained in a fracpack completion utilizing 30/60 HSP.

Abstract

This paper describes the challenges confronted and the solutions / conclusions drawn during the completion design and implementation phases of the Gyrfalcon Project, Green Canyon 20, Well #1.

Gyrfalcon (JUR-fal-con), Green Canyon 20 Well #1, is the world's first 15,000 psi, subsea, frac pack completion. The well was drilled in 880 feet of water and temporarily abandoned by Shell Offshore Inc. in 1997. Shell believed at the time that the field wasn't large enough to justify immediate development. At a later date Reading and Bates Development Company (Devco) proposed the field could be economically developed using a subsea tieback to the nearby Shell Boxer platform . After a financial agreement was reached, Devco took over as operator to complete the well. (Note: After the well was initially brought on production, Devco sold their interests in Green Canyon 20 to Enterprise Oil Gulf of Mexico Inc.) Applied Drilling Technology Incorporated (ADTI) was selected by Devco to design and implement the downhole completion on a project management basis.

This gas well has a bottom hole pressure of 14,752 psi at 17,856 feet md/tvd and a maximum shut-in surface pressure of 12,200 psi. This high pressure required a 16.2 ppg ZnBr completion fluid. The bottom hole temperature of 220° F and a low mudline temperature indicated thermal expansion effects may be significant at high production rates. There were 82 feet of perforations in a relatively straight hole. Associated condensate was expected at 46 bbls/mmcf. There is some CO2 and water production. The well was frac packed and tested prior to the installation of production tubing. The well was completed with 3-1/2", 13 chrome, production tubing. It's a 2.8 mile tieback to the production platform through a 6" flowline.

After assignment of project management responsibilities, completion review and analysis began in earnest. As a small independent operator with limited staff, Devco focused on reliability, rather than redundancy or innovation. Although conventional methods are the preferred option, the extreme well pressure presented special design problems. Some of these challenges resulted in unique tools and complex completion procedures.

This paper lists some of the technical issues confronted, notes the decision making criteria, and describes the solutions and conclusions.

Author(s): Dick Grant, Greg Sones, Steve Speegle, ADTI; Terrell Clark, Argonauta Energy

Paper Number: SPE 71682

URL: https://www.onepetro.org/conference-paper/SPE-71682-MS

 

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