Patent ID: 6230827
Filing Date: 2001-05-15
Classification: E21B

Abstract:
A rotary drag bit for drilling a subterranean formation, comprising:a bit body having a longitudinal axis and a face extending radially outwardly from the longitudinal axis at one end of the bit body;a plurality of blades extending above and generally radially over the face and outwardly of the bit body, the plurality of blades separating and defining a plurality of fluid courses leading to a plurality of junk slots extending longitudinally away from the face;a plurality of cutters mounted to each of the plurality of blades, the plurality of cutters of at least one blade differing in at least one of number, size and exposure from a plurality of cutters mounted to at least one other blade such that a different formation cuttings volume is to be generated from engagement of the subterranean formation by the at least one blade cutters and the at least one other blade cutters; anda plurality of nozzles disposed on said bit body and located to discharge drilling fluid between the bit face and the subterranean formation, at least one of the plurality of nozzles being located and oriented to apportion a discharge of drilling fluid between a fluid course positioned to receive formation cuttings generated by the at least one blade cutters and a fluid course positioned to receive formation cuttings generated by the at least one other blade cutters in general proportion to the relative volumes of formation cuttings generated by each of the at least one blade cutters and the at least one other blade cutters.