Hydraulic fracturing offshore
Using the StageFRAC service, openhole packers are run on conventional casing to segment the reservoir. Ball-activated sleeves are placed between each set of openhole packers. During pumping, balls are dropped from the surface to shift each sliding sleeve open, isolating the previously fractured stages. This mechanical diversion, combined with advanced Schlumberger fracturing fluid systems, allows for precise fluid placement, complete zonal coverage, and more effective fracture conductivity. A large stimulation vessel capable of fracturing six or more zones sequentially using the StageFRAC service can perform an operation in 6 hours that once took 6 weeks. At a rig cost of USD 300,000 per day, the total rig cost would be reduced to USD 75,000 from USD 12.6 million using the StageFRAC service.
Over a 3-month period, eight hydraulic fractures were placed in three recompleted cased hole wells in the Kitina Field, with encouraging stabilized production increases. As a result of the successful treatment in the Kitina field, two subhorizontal openhole wells in the Foukanda field were completed using the StageFRAC service.
Before fracturing, production from the Kitina field wells was approximately 590 bbl/d. Ninety days after treatment, there was an overall steady-state increase in production to 1,950 bbl/d, a fold of increase of 230%. The wells in the Foukanda field delivered an initial production rate of 3,000 bbl/d, which stabilized to 2,000 bbl/d after 90 days.
Eni plans to use the StageFRAC service for future offshore completions to achieve higher levels of production, to cut fracturing completion times from weeks to hours, to cut fracturing costs from millions to thousands of dollars, and to shorten production time to market.