Schlumberger proposed two technologies, StageFRAC multistage fracturing and completion services and ClearFRAC XT polymer-free frac fluid, to meet Petrom’s needs.
StageFRAC technology permits precise placement of multiple fractures in a single pumping treatment. Openhole packers run on conventional casing are used to segment the reservoir. Hydraulically activated sliding sleeves are located between each set of packers. Balls dropped from the surface during pumping open each sleeve, isolating previously fractured zones.
ClearFRAC XT stimulation
Petrom chose to use ClearFRAC XT extended-temperature fracturing fluid. This polymer- and solids-free viscoelastic fracturing fluid was less damaging than the polymer-based systems used previously in the area. ClearFRAC XT fluid significantly reduces fracture cleanup. It is insensitive to water quality and can be mixed with produced water. The fluid was formulated with seawater and mixed continuously during the operation. This flexibility enabled preparation of more than 1,100 m3 of fracturing fluid without the interruption of trips to port to refill the boat’s internal tanks, making it a very cost-efficient solution.