Overview
Challenges
- Aging gas field in the Adriatic Sea
- Conventional cased-hole workover options had become uneconomic
- Multilayer reservoir with significant variance in thickness of sand layers
- Low reservoir porosity ranging from 22 to 33%
- Wells required sand control and isolation of gas-water contacts
Results
- Provided an effective alternative to cased-hole frac-pack operations
- Completed four to six zones in each well, and in a single trip
- Reduced operational time by 40%
- Reduced overall well cost by 35%
- Enabled precise zonal isolation and selective production
- Enabled economic, sand-free production of residual reserves
To extract additional reserves from an aging well stock offshore Italy, a customer had been performing conventional sidetracked operations followed by stacked cased-hole, frac- pack completions. Despite continuous efficiency gains, the frac-pack operations were too time consuming and costly, and the system designs inherently limited how the wells could be completed. Multiple vertical wells had to be drilled to intersect the multilayered pay zone, and only three to five large, evenly spaced intervals could be completed per well. The well profiles were also limited to low inclination due to gravel pumping.
These practices went on for many years until declining economics— derived from a combination of unfavorable market conditions and high-cost workover operations— paved the way for a new approach.
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