Waterjetting 37d - Underground Drilling with Waterjets

The last post showed some of the experiments that we carried out as we developed a tool for drilling "around corners", demonstrating the ability of a high-pressure water jetting system to turn from a vertical well bore and drill out a lateral well within a turning radius of about 9 inches. This was not our earliest work on drilling, and that earlier effort had been directed to the reaming of geothermal wells.

The earlier project was also funded initially by Sandia Labs, although in this case the objective was slightly different. Overall we set out to show that one could go down a vertical well bore, some 9-inches in diameter, and ream a cavity 6-feet across down in the "hot dry rock" of a geothermal deposit.

When we began we weren't sure that we could drill in stressed rock, or what those effects on drilling rate would be. So we were fortunate to get some help from Doe Run and work in one of their mines, as the following video shows.

Figure 1. Early video on Underground Waterjet Drilling

  It was this series of tests that showed how relatively quiet water jets could be in drilling, unlike the competition at the time. Below the fold I will add the second part of this program, where we demonstrated the technique we planned on using for the reaming program.

Figure 2. Reaming a Geothermal Well Demonstration

Although this program moved on to focus on other aspects of the problem (we also demonstrated that this was practical in cutting granite, which led on to the Stonehenge and Millennium Arch projects) it was not until we were tasked with reaming large scale rocket motors, some years later, that we returned to this program, and developed the tools further.