development drilling: Drilling in a known producing field as opposed to exploratory drilling.
All traps around Niuxintuo have been evaluated and 3 favorable traps are considered to have exploratory drilling potential.
Even the Badlands Guardian, it seems, isn't immune to exploratory drilling.
In 2008 workers doing exploratory drilling for a geothermal plant reported that they had accidentally broken through to a shallow magma chamber near the Big Island's Kilauea volcano.