Application of hydraulic power percussive-rotary drilling technology in Qingxi Area

Qingxi block belongs to piedmont structure-lithofacies zone with complicated geological structure,especially the over-thrust nappe of KuLongshan has characteristics of high angle and poor drilliability, which lead to this result, such as low drilling, long well drilling time and high drilling cost. The technique of percussive-rotary drilling made use of the function of impact laod and static pressure rotation to broken rock by bit. The mode of percussive-rotary drilling broken rock could achieve high effective broken rock, made bit with long life and borehole keep regulation. In order to solved the technical problems of low drilling and difficult control hole deviation, combined practical situation in drilling in QingXi Area, introduced the drilling technology of percussive-rotary, which also included jet impactor by improved and design prevent-avoid drilling components to increase drill speed at old formation on the top, also to control hole deviation by low bit weight. Many field tests show that the hydraulic percussive-rotary drilling trechnology can increase the ROP more than 31 percent, decrease drilling well period at top section,and it is effectively control well inclination at the overthrust nappe. keep high borehole quality and good drilling performance.