Multiple branch completion with common drilling and casing template
US4396075A · kind A · utility
Inventors
Key dates
| Filing date | Jun 23, 1981 |
| Grant date | Aug 2, 1983 |
| Priority date | — |
| Expiry date | Jun 23, 2001 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B41/0035
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A method of drilling and completing multiple branch wells extending from a main generally vertical hole. This invention finds its primary applicability in in situ leach mining of deep (500 to several thousand feet) lying ore bodies such as uranium, copper, etc. Initially, the main generally vertical hole is drilled, cased, and cemented. Whipstock drilling guides are placed to extend downwardly and outwardly from the bottom of the casing for this hole and cemented in place. These guides are the same in number as the branch holes to be drilled. In addition, the well bore casing contains an indexing dog just above the whipstock drilling guide. The actual drilling of the branch wells is accomplished with a floating index collar and a drill bit assembly which runs therewith. The indexing dog is fixed in the main hole and engages the indexing collar so that the drill bit is oriented to drill into one of the whipstock drilling guides. After a particular branchis drilled, the collar and bit are retrieved from the main hole. The bit is then placed in another hole of the collar and the combination reinserted in the main hole where it again engages the indexing dog and allows drilling of anot…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.