Borehole Deviation Correcting and Controlling Technical Measures in Heishan Mining Area of Chengde
///Azimuth error and borehole top angle oversize were the difficult problems in drilling construction in Heishan mining area of Chengde. LZ-73(89)whipstock was used for deviation correction with good effect. Based on the analysis on the causes of borehole running deviation and summary on the construction experience, the technical measures of borehole deviation prevention were put forward.