Method for prudent penetration of a casing through sensible overburden or sensible structures
US4765416A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 2, 1986 |
| Grant date | Aug 23, 1988 |
| Priority date | — |
| Expiry date | Jun 2, 2006 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE02D27/48
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
In a subterranean drilling operation, a drill stem and drill bit are advanced downwardly while conducting compressed air downwardly through the drill stem. A minor part of the air flow is discharged from the drill bit downwardly against the sensible overburden, and a major part of the air flow is discharged upwardly through passages in the drill stem. A casing is disposed around the drill stem and advanced therewith so that the sensible overburden is shielded from the air discharged from the upwardly directed passages. The upwardly directed passages contain removable inserts which can be exchanged for different inserts in order to vary the amount of air discharged from the upwardly directed passages, and thereby vary the amount of air discharged downwardly from the drill bit against the overburden. In that way, the amount of air acting against the overburden can be adapted to the type of material in the overburden in order to control the amount of disruption to the overburden.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.