The fastest way to the bottom:straighthole drilling device -drillin concept,design considerations,and field experience

摘要

A straight top hole section in many cases is a strict requirement to be able to drill deeper sections with complex well geometries.Especially in an environment where the geological parameters tend to deviate the course,and if the hole stability is a risk,drilling of a straight surfac eportion of hole is a must.Conventionally,this will be achieved by applying steerable motors and changing between sliding mode for directional changes and rotary mode to drill straight ahead.The Straighthole Drilling Device,SDD,has bene developed as a fully automated instrumented downhole motor with integral expanddable ribs to steer a permaent vertical well path without any supervision required from the surface operator.