Schlumberger has introduced degradable alloy frac balls for multistage stimulation treatments. The technology demonstrates predictable and complete degradation of the alloy balls ensuring maximum well productivity, the company says. The complete degradation of the aluminum-based material within hours or days eliminates the risk of stuck frac balls and the need to mill them. Because the balls don’t stick, they don’t delay or hinder production.
Frac balls are small spheres designed to seal perforations that are accepting the most fluid, thereby diverting reservoir treatments to other portions of the target zone. Ball sealers are incorporated into the treatment fluid and pumped with it. This Schlumberger video provides a good visual of the role frac balls play in the process.
|ELEMENTAL degradable alloy. Click to enlarge.|
The ELEMENTAL alloy balls degrade predictably in a wide range of downhole conditions, well depths, temperatures, pressures and well fluids. Controlled degradation takes place without the need for chemical additives, low pH environment, retrieval operations or milling after fracturing.
The ELEMENTAL degradable alloy technology can be used with Schlumberger multistage stimulation systems. The technology has been deployed with the Falcon multistage stimulation system for uncemented wells in formations representing a significant challenge to degradation times, such as Gold Creek, Slave Point, Glauconite, Cardium, Montney and Lower Montney with bottom hole temperatures as low as 30 °C (86 °F).
The ELEMENTAL alloy technology has also been used in the Bakken basin, where formation temperatures are around 127 °C (260 °F). One customer used the technology to complete and fracture a multi-lateral wellbore containing 42 Falcon stages, 21 per lateral. After each lateral was fractured, the well was allowed to flow back without any of the alloy balls being recovered at surface, validating the swift degradation behavior of the technology.
The ELEMENTAL degradable alloy technology enables high-stage-count jobs to be carried out in both cemented and uncemented wells by eliminating the risk of stuck balls and the need to mill them out. This technology provides our customers with a step-change increase in operation efficiency, bringing production online faster in conventional and unconventional reservoirs.—Mike Garding, president, Completions, Schlumberger
Schlumberger is the world’s leading supplier of technology, integrated project management and information solutions to customers working in the oil and gas industry worldwide.