EP 1008718 B1 20040915 - Rotary drag-type drill bits and methods of designing such bits
Title (en)
Rotary drag-type drill bits and methods of designing such bits
Title (de)
Drehbohr-Fräsmeissel und Verfahren zu deren Entwicklung
Title (fr)
Trépans racleurs rotatifs et méthodes pour leur conception
Publication
Application
Priority
US 21051898 A 19981211
Abstract (en)
[origin: EP1008718A2] The invention provides a rotary drag-type drill bit in which the relationship of torque to rotary bit speed is such that torque generally increases with bit speed. Such a bit has a reduced tendency to exhibit the phenomenon known as "stick-slip" while drilling, when compared with bits having a different torque /speed characteristic, as a result of the positive damping effect of the torque/speed relationship. One method of designing such a drill bit comprises ascertaining the torque/rotary bit speed relationship, or other correlated relationships, for a number of different drill bit designs and then selecting from those designs a design having the desired type of relationship. Examples of drill bit structures specifically designed to achieve the desired torque/speed relationship are also disclosed. <IMAGE>
IPC 1-7
IPC 8 full level
E21B 10/42 (2006.01)
CPC (source: EP US)
E21B 10/42 (2013.01 - EP US); E21B 10/62 (2013.01 - EP US)
DOCDB simple family (publication)
EP 1008718 A2 20000614; EP 1008718 A3 20010411; EP 1008718 B1 20040915; DE 69920145 D1 20041021; DE 69920145 T2 20050922
DOCDB simple family (application)
EP 99309759 A 19991203; DE 69920145 T 19991203