EP 1008718 A3 20010411 - 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)
Citation (search report)
- [A] US 5842149 A 19981124 - HARRELL JOHN W [US], et al
- [A] EP 0386810 A2 19900912 - ANADRILL INT SA [PA], et al
- [PA] US 5864058 A 19990126 - CHEN CHEN-KANG DAVID [US]
- [A] EP 0467580 A1 19920122 - AMOCO CORP [US]
Designated contracting state (EPC)
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
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