What does the HH, DR, stand for or mean?"

In this drill permit. Dewey County
REAY #1-36-1H, January 25 2017
01 18N 14W N2N2NENE API: 04323497
Lat: 36.0719928926364, Long: -98.63864317799889
COMANCHE EXPLORATION CO LLC.
HH, DR, 14800 ft, MISSISSIPPI LIME(9800)