The use of conventional downhole batteries, which are intended for low voltage/current, faces hurdles when it comes to operating tools designed for surface power provided through a cable. The high power consumed by some of these tools requires careful characterization of parameters such as current, transients, and battery capacity at different loads and temperatures.

The battery power tool developed for high-power tools uses three battery packs, here used in series, to boost input voltage, with a provision to use three additional packs in parallel for additional current. Battery characterization efforts at currents higher than 1 A were performed at different temperatures (75°C, 100°C, and 150°C) to explore the behavior of lithium battery chemistry, with a total of 48 battery packs tested. The electronics design to boost battery voltage up to 200 V to support a pulsed neutron tool is also presented.

The result of this engineering effort is a system that can provide more than 20 Ah of power and enables more than 10 hours of continuous operation of pulsed neutron tools. It also allows more than 100 hours of operation of conventional production logging tools. A tool planner software is provided for the field users to estimate the battery operation time for a specific job. Those benefits are illustrated by the field deployment results of this solution since 2014, with examples of successful operations in the Kingdom of Saudi Arabia, the Congo, and Gabon.

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