Auto Indexer Auto-Indexer for Percussive Hammers: Vane Motor Dynamometer Testing

Objectives
Options associated with geothermal drilling operations are generally limited by factors such as formation temperature and rock strength. The objective of the research is to expand the "tool box" available to the geothermal driller by furthering the development of a high-temperature drilling motor that can be used in directional drilling applications for drilling high temperature geothermal formations. The motor is specifically designed to operate in conjunction with a pneumatic down-the-hole-hammer. It provides a more compact design compared to traditional drilling motors such as PDMs (positive displacement motors). The packaging can help to enhance directional drilling capabilities. It uses no elastomeric components, which enables it to operate in higher temperatures (greater than 250 degrees F). Current work on the motor has shown that is a capable of operating under pneumatic power with a down-the-hole-hammer. Further development work will include continued testing and refining motor components and evaluating motor capabilities.

Targets/Milestones
Complete testing current motor - 12/31/2010
Make final material and design decisions - 01/31/2011
Build and test final prototype - 04/31/2011
Final demonstration - 07/31/2011
Impacts
The development of the motor will help to achieve program technical objectives by improving well construction capabilities. This includes enabling high-temperature drilling as well as enhancing directional drilling.

A key component in the auto indexer is the drive motor. It is an air-driven vane motor that converts the energy stored in the compressed air to mechanical energy. The motor is attached to hammer-like components which impart an impulsive load onto the drive shaft. The impulsive force on the drive shaft in turn creates an indexing action.

A controlled test was performed to characterize the performance of the the vane motor for a given pressure. The Sandia dynamometer test station was used to determine the performance of the motor for a given input pressure.