Method and apparatus for forming boreholes
US4558750A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 3, 1984 |
| Grant date | Dec 17, 1985 |
| Priority date | — |
| Expiry date | Aug 3, 2004 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B4/02
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A method and apparatus is disclosed for deviated hole drilling upwardly and outwardly from beneath a shallow hydrocarbon formation pay zone. A large diameter vertical hole is first formed as by drilling below the pay zone. A first casing having a directional window provided in its wall is cemented in the large diameter hole. One or more casings are then provided in the borehole below the first casing. A carriage assembly loaded with drilling tools for drilling upwardly and outwardly is then lowered by means of a working drill string and landed within the first casing. The carriage assembly has a first passage in fluid communication with the drill string. The drilling tools are loaded within a second passage of the carriage assembly. The top opening of the second passage is below the directional window when the carriage assembly is landed and angularly oriented in the first casing. A drill string extends from the drilling tools through the bottom of the carriage assembly and into the cased hole below the first casing. A stripper packer assembly at the lower end of the carriage assembly prevents the incoming high pressure mud from entering the second passage of the carriage assembly.…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.