Reducing Horizontal Hole Size from 8.5 to 6.75 Reduces Unconventional Well Construction Cost by 25%

Slim hole well design can reduce well construction cost through a reduction in steel, fluids, and disposal costs. In the industry, there has been a misconception that slim hole size possesses the tradeoff of slower ROP and less efficient fracture treatment. Improvements in downhole tools, drill strings, rig capability, and drilling fluid design have been implemented to improve ROP in slim holes. Completions designs were refined for slimmer holes to avoid any significant loss in stimulation effectiveness and maintain well value. Through systematic replication of learnings and designs across basins, slim hole well design has advanced. Slim hole well design (transition from 8.5" / 7.875" hole and 5.5" production casing to 6.75" hole and 5.5" / 4.5" production casing) can reduce Unconventional well cost by over 25% which reduces well unit development cost (UDC).