New electronic sliding sleeve helps increase flexibility, reliability, mechanical simplicity, and robustness for multistage hydraulic fracturing
A new electronic sliding sleeve has been developed for hydraulic fracturing that provides the operational efficiency of sliding sleeves while enabling an unlimited number of fracturing zones and eliminating the milling of the baffle seat. This system uses electronic sensors and battery power to determine when the next stage of the fracture is ready for pumping. The reliability of the sensors, electronics, and batteries must be addressed to achieve a reliable fracturing system.
Traditional sliding sleeves use a series of progressively smaller-sized balls that shift sleeves by landing on progressively smaller-sized baffles. The new electronic sliding sleeve has the intelligence to enable opening the sleeve without the use of progressively sized balls and baffles. The result is a monobore construction that enables stimulating an unlimited number of zones and simplifies well completion design and installation. The electronic implementation improves the mechanical reliability beyond mechanical monobore fracturing tools but introduces other concerns of reliability. This paper reports on the reliability testing of the electrical components including the electronics, sensor, and battery.
Electrical reliability of the new sliding sleeve was evaluated at high temperature, extended service duration, and high pump rates. The sleeve operates by counting the passage of frac balls and then shifting the sleeve when the programmed number of balls has passed. This battery-powered electronic sliding sleeve has an onboard sensor and processor equipped to count the balls. Once the programmed number of balls has been detected, an actuator commands the sleeve to shift. The sliding sleeve requires reliable operation of all components. A probabilistic model is used to account for stochastic variation in batteries and electronics. The magnetic sensors detected the frac ball over a wide temperature range and at flow rates ranging from near static to more than 100 bbl/min. The batteries were characterized for operating life, passivation, and self-discharge. Power consumption and reliability of the electronics were tested to accurately predict remaining operational life of the electronic system under a wide range of conditions. The resulting electronic sliding sleeve also increases mechanical reliability.
A programmable battery-powered electronic sliding sleeve increases flexibility, reliability, mechanical simplicity, and robustness for multistage hydraulic fracturing. This new fracturing system is particularly applicable in extended reach applications by offering an unlimited number of zones with a simple monobore construction.
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Source: SPE Annual Technical Conference and Exhibition, 24-26 September, Dallas, Texas, USA
Authors: Zachary Walton (Halliburton) | Michael Fripp (Halliburton)