Auger TLP Well System Challenges and Innovations

ABSTRACT The Auger TLP well system has successfully employed novel features to satisfy challenging design requirements of drilling, completing, and producing nearly four miles deep geopressured wells in deep water Gulf of Mexico (2860 feet). The well system is based on a unique combination of deepwater drilling technology and existing completion technology similar to bottom supported platforms. This proven well system technology will increase the industry's confidence in safely and cost effectively developing the future deep, geopressured wells in the deepwater environment. An overview of the Auger TLP well system will be presented with emphasis on:Predrill program,Design and Installation of the production riser system, andRecentering the predrilled wells and tieing back the production liner to the TLP to prepare the wells for completion operations. INTRODUCTION The predrill program extended from May 1990 to September 1992 to have completeable wells ready for the TLP immediately after installation to accelerate first production and maximize the project profitability. After the TLP installation was completed in mid- February 1994, the ten predrilled wells were successfully tied back from subsea wellheads to the TLP deck using 9.625-inch production risers and 7-inch production casing. These wells were completed and are currently producing oil and gas at an average of about 10,000 BOPD and 20 MMCFGPD per well. The total production is currently facility constrained to about 55,000 BOPD and 115 MMCFGPD(8). The Auger Team's new challenge is now to increase the facility capacity to 70,000 BOPD and 170 MMCFGPD. Effective application of new technologies, planning, and sustaining the synergistic effortsand expertise of the Auger Team resulted in early production and significant reductions in number of completion days from 46 days to an average of 23 days per well (Fig. 1). The Auger production risers and production casing strings are the most important components of the well system to ensure safety and long term operability of the wells. Riser interference, vortex-induced vibrations, tubular interaction, and riser connections were modeled and laboratory tested before field installation to have a field life of 30 years and a fatigue design life of 300 years. To minimize the dynamically supported load on the TLP structure, load distribution of production riser, production casing, and tubing was carefully hared between the mudline (at about 3000 feet) and the surface wellhead system. PREDRILL PROGRAM Figure 2 shows the schematic of a typical A well ready to be completed from the TLP 1,3 The main objectives of the predrill program were:Predrill 10 wells to total depth and install the production liner. These wells would be ready for completion from the TLP to fill the production facility.Batch set 10 additional wells through 20-inch casing to minimize open sea operation from the TLP, thus minimizing production downtime during drilling and completion program cycles.To accommodate the Auger TLP well system for producing operations concurrent with well completion, drilling, and workover operations.