Title:
【発明の名称】告知組立体
Document Type and Number:
Japanese Patent JPH0663416
Kind Code:
B2
Abstract:
A whipstock mill for milling through the casing wall which incorporates a pressure drop tattletale to signal the operator that the milling operation should be halted. The milling tool includes a longitudinal fluid passageway which communicates with a lateral port formed below the mill blades. A replaceable plug is utilized to initially close the port thereby restricting fluid flow into the well hole. The starter mill is preferably run into the hole with a whipstock which can be set in the hole using an integral packer. As the mill travels down the set whipstock, a shear block mounted to the whipstock will shear the plug at a predetermined depth of the mill opening the lateral port. The resulting pressure drop within the milling tool signifies that the mill has reached the desired depth. Accordingly, the milling operation can be halted and the mill retrieved to permit further operations through the casing wall.
Inventors:
Thomas F. Bailly
John E. Campbell
Edmond Cuggler, Junior
John E. Campbell
Edmond Cuggler, Junior
Application Number:
JP30785189A
Publication Date:
August 22, 1994
Filing Date:
November 29, 1989
Export Citation:
Assignee:
Drillex Systems, Incorporated
International Classes:
E21B3/00; E21B7/06; E21B7/08; E21B21/10; E21B29/06; E21B34/06; E21B47/02; E21B47/09; E21B47/18; (IPC1-7): E21B29/06; E21B7/08; E21B47/02
Domestic Patent References:
| JP63184692A |
Attorney, Agent or Firm:
Akira Asamura (3 outside)
Next Patent: トンネル掘削時における余掘低減方法