EP 0996810 A1 20000503 - REVERSE CIRCULATION DRILLING SYSTEM WITH BIT LOCKED UNDERREAMER ARMS
Title (en)
REVERSE CIRCULATION DRILLING SYSTEM WITH BIT LOCKED UNDERREAMER ARMS
Title (de)
UMKEHRSPULUNGSEINRICHTUNG MIT BOHRMEISSEL MIT VERRIEGELTEN ERWEITERUNGSARMEN
Title (fr)
SYSTEME DE FORAGE A INJECTION INVERSE DOTE DE BRAS ELARGISSEURS VERROUILLES PAR OUTIL
Publication
Application
Priority
- US 9814651 W 19980717
- US 89678797 A 19970718
Abstract (en)
[origin: WO9904130A1] An underreamer drill bit assembly including a pilot bit (82) and extendable underreaming arms (88) operatively connected to the pilot bit (82). The underreaming arms (88) have an extended position for underreaming, and a retracted position in which the overall diameter of the underreamer drill bit assembly is less than the inside diameter of the well casing, permitting the entire bit assembly to be withdrawn through the well casing. In another aspect of the invention, the bit assembly is operatively connected to a dual wall pipe assembly (12). A supply of compressed air is conducted through the annulus (24) of the dual wall pipe assembly (12) to a down hole pneumatic hammer (13). Exhaust air from the down hole hammer (13) is directed to the bit assembly for continuous removal of drilling debris through a central evacuation tube (43) of the dual wall pipe assembly.
IPC 1-7
IPC 8 full level
E21B 10/32 (2006.01); E21B 10/66 (2006.01)
CPC (source: EP KR)
E21B 10/66 (2013.01 - EP KR)
Designated contracting state (EPC)
DE ES FI GB IT SE
DOCDB simple family (publication)
WO 9904130 A1 19990128; AU 755442 B2 20021212; AU 755442 C 20030612; AU 8487398 A 19990210; BR 9815553 A 20011211; CA 2296470 A1 19990128; CN 1263937 C 20060712; CN 1270655 A 20001018; EP 0996810 A1 20000503; HK 1030253 A1 20010427; JP 2001510256 A 20010731; KR 20010021997 A 20010315
DOCDB simple family (application)
US 9814651 W 19980717; AU 8487398 A 19980717; BR 9815553 A 19980717; CA 2296470 A 19980717; CN 98809208 A 19980717; EP 98935684 A 19980717; HK 01101223 A 20010220; JP 2000503316 A 19980717; KR 20007000564 A 20000118