Eos, Transactions American Geophysical Union

Scientific drilling: Limitations to drilling and logging in thermal regimes



Although many investigators are eager to explore thermal regimes of Earth's crust by drilling, present technologies limit these activities to relatively benign environments. This article enumerates areas of difficulty and offers suggestions as to how they may be addressed.

Over the past century two drilling technologies have evolved, primarily to support extractive industries. The most common involves the “rotary drilling” machinery that is used in the hydrocarbon production industry. It features big rigs capable of drilling deeper than 10 km and is the least expensive way to make large holes necessary for production. Unfortunately, when this equipment is used to take core, costs mount rapidly because the drill string must be removed from the hole after each core run. Thus formation analysis usually depends on downhole measurements that are provided by an aggressive logging service industry. Many of these measurements are, understandably, directed toward hydrocarbon applications. This situation is not always advantageous to scientific drilling programs in volcanic formations [Lysne, 1989].