Window-cutting system for downhole tubulars
US5881808A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 21, 1997 |
| Grant date | Mar 16, 1999 |
| Priority date | — |
| Expiry date | Aug 21, 2017 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B7/061
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A guide lug for a starting or window mill is provided at the upper end of the whipstock. A back-up shoulder is provided to act against any tendencies of the mill to whirl. A taper is provided for use in guiding the mill toward the casing for the cutting of the window. The lug is configured to be worn by a guide for the window mill or starter mill rather than being milled away. As a result of the use of the lug, the upper sections of the whipstock are protected from the mill. In turn, any holes or other projections provided for subsequent retrieval of the whipstock are functional for such a retrieval at the conclusion of the milling process for the window.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.