Fabrication, assembly, bench and drilling tests of two prototype downhole pneumatic turbine motors: Final technical report

The first and second prototype downhole pneumatic turbine motors have been fabricated, assembled and tested. All bench tests showed that the motor will produce horsepower and bit speeds approximating the predicted values. Specifically, the downhole pneumatic turbine motor produced approximately 50 horsepower at 100 rpm, while being supplied with about 3600 SCFM of compressed air. The first prototype was used in a drilling test from a depth of 389 feet to a depth of 789 feet in the Kirtland formation. This first prototype motor drilled at a rate exceeding 180 ft/hr, utilizing only 3000 SCFM of compressed air. High temperature tests (at approximately 460/sup 0/F) were carried out on the thrust assembly and the gearboxes for the two prototypes. These components operated successfully at these temperatures. Although the bench and drilling tests were successful, the tests revealed design changes that should be made before drilling tests are carried out in geothermal boreholes at the Geysers area, near Santa Rosa, California.