Practice and cognition of multi-branched horizontal well geo-steering in CBM well

In order to develop the coal bed methane reservoir in low cost, comprehensive mud logging combining with MWD was first conducted in feather-shaped multi-branched horizontal wells drilling by Bohai Drilling Engineering Company in 2010. Through analyzing characteristics of coal bed, optimizing oriented parameters combination, building geo- steering workflow to study and practice surrounding rock recognition and trace controlling technologies near the bit. And based on that, the preliminary trial in 2 wells is performed successfully. The depth was 3105 m in Well ZP02 while drilling with coal bed and probability of penetration was up to 88.08%, meanwhile, while drilling with coal bed in Well ZP02 the depth was 3169 m and probability of penetration was 89.4%. The successful application in these 2 wells has showed that comprehensive logging and MWD combination must be feasible in drilling feather-shaped multi-branched horizontal well.