Coring with tubing run tools from a producing well
US5211715A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 30, 1991 |
| Grant date | May 18, 1993 |
| Priority date | — |
| Expiry date | Aug 30, 2011 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B21/085
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Core samples are obtained through production wells by inserting a milling tool through the production tubing string on the distal end of coilable tubing to mill out a window in the well casing. The milling tool is deflected by a whipstock set in the casing at a predetermined point and encased in cement which, upon setting, is bored to form a pilot bore for the milling tool. A fluid-motor-driven core barrel is provided on the end of the tubing after the milling operation is complete and core drilling is carried out in an underbalanced condition by reducing wellbore pressure through a gas lift so as to minimize core invasion by wellbore fluids including spent milling motor and core drilling motor fluids.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.