Abstract: Control of borehole deviation is significant to underground water-sealed oil storage and rock anchorage engineering. We present some comprehensive methods to control the borehole deviation with horizontal drilling (depth 45-105m) at Huangdao underground water-sealed oil cavern as a case study. The techniques include drilling machine with high guiding efficiency, drill pipe with big rigidity, reasonable drill pipe centralizer, tightly fixed drilling machine, meticulous survey, adjustment of drilling parameters in time according to rock condition, borehole inclinometer and borehole TV used in time. By using these techniques, we conclude that the deviation rate of boreholes shorter than 20m and 40m can be controlled within 0.45%, 0.9%, respectively, which is a leading level internationally; the deviation rate of boreholes shorter than 60m could be limited in 2%, which is an internationally advanced level; and the deviation rate of boreholes shorter than 80, 100 m can be limited in 3%, 4%, respectively.

Key words: long borehole, deviation rate, control technique, underground water-sealed oil storage, rock anchorage