Abstract
Conventional gas development wells in prolific carbonate reservoirs before bigbore completions were introduced do not produce to full potential due to tubing constraints. This phenomenon is observed today in several mature, carbonate basins offshore Malaysia developed back in the early 1980s. At that time, the typical tubing configuration was a 7" completion string run in 9 5/8" production casing. This configuration limits subsequent tubing change out workover options to 7 5/8" tubulars resulting in only a modest 10% gain in well capacity through improved outflow performance.
The advent of solid expandable tubular (SET) technology in the new millennium has opened up a revolutionary possibility for transforming a conventional well with 7" tubing to a modern bigbore producer. The concept involves installing and expanding a long section of 7 5/8" solid expandable tubulars inside 9 5/8" casing and using the SET as a gas flow conduit. For a mature gas field offshore Sarawak where this concept was applied in a pilot well, such a well transformation yielded a production conduit with an internal diameter 24% larger than conventional 7" tubulars, a 61% increase in flow area, and a significant increase in well production.
Results of this field trial carried out to test this novel re-completion concept in a gas field offshore Sarawak showed a 40-50% increase in well deliverability. The technical concept was proven successful, and it is now planned to implement this novel SET re-completion design in other tubing constrained gas wells in the area.
This paper will present the results and economic benefits of this field trial, which is the first of its kind in the world. Details encompassing the conceptual solid expandable completion design, modifications and improvisation required for this first-of-its-kind SET gas well workover, and the required SET installation sequence will also be discussed.
