Abstract
This paper describes development and application of a new design mudline tubing hanger (MLTH) for suspending tubing weight below the mudline in offshore wells. The new design has been deployed in fifteen Auger wells with 100% success. A total of 1,005,000 lbs of tubing weight is currently isolated from the tension leg platform (TLP) using these devices. Though there were notable lessons learned throughout the deployment of the MLTH in the Auger development, there have been no failures of this equipment throughout the project.
The Shell deepwater Auger development in the Gulf of Mexico consists of six main reservoirs ranging in depth from 15,000 ft to 19,500 ft. The TLP lies in 2,860 ft of water, 137 miles off the Louisiana coast. (Figure 1, 2) The TLP was installed and development commenced in 1994, with the completion of the A-6 well. To date nineteen producers have been drilled in the field. On record days the field has produced 109,000 BO/day and 431 MMcf/day. Current production flows from 13 wells, including 6 subsea.
The Auger TLP has 32 subsea slots with twenty slots predrilled for wells. The TLP displaces 73,000 tons. Suspension of weight below the mudline permits more efficient use of buoyancy capacity. A device known generically as a Mudline Tubing Hanger (MLTH) is used to accomplish this by suspending tubing weight into the casing below the mudline. In July 1997, following experience on two Auger wells with another tubing hanger system, a new Mudline Tubing Hanger design was deployed for the first time on the A-20 well.
