Application of CBM multi-branch horizontal well for drilling technology in Fanzhuang Block

Based on analysis of the basic geological and mechanical features of No.3 coalbeds in Fanzhuang Block,it is found that the multi-branch horizontal well is fit for No.3 coalbeds in this block.The technology difficulties of that wells drilled in Fanzhuang Block are analyzed,such as safety drilling and reservoir protection,well path con-trol,complex accident,also new type well drilling tools and equipments.Through actual drilling engineering of two wells,some conclusions can be derived.It’s a better way to use near balance drilling(drilling fluid is water) when drilling in horizontal and branch coalbed sections;keeping well path near to roof of coalbeds and speeding drilling;reducing the time of coalbeds dipping in drilling fluid;making use of AG-itator in horizontal sections and branch sections;finishing drilling ahead of schedule when drilling across faults and fractured zones.