Air lift system for large diameter borehole drilling
US4134463A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 22, 1977 |
| Grant date | Jan 16, 1979 |
| Priority date | — |
| Expiry date | Jun 22, 1997 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B43/305
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An air lift system for large diameter borehole drilling is disclosed. The system is applicable in drilling operations where a vertical pilot hole is drilled below the point to which the borehole will later be enlarged and a slant hole is drilled obliquely to intersect the pilot hole near its nether position. During the drilling operation, the circulation system pumps drilling fluid down the annulus of the borehole to cool the cutterhead and to mix with the cuttings. The drilling fluid carrying the cuttings then moves down the pilot hole and up through the slant hole. A plenum is located in the slant hole to assist in the lifting of the drilling fluid. The plenum includes a tapered transition pipe, a tapered discharge horn, and an air diffusion ring located at the throat of the discharge horn. The diffusion ring is utilized to inject outside air into the drilling fluid passing therethrough. The discharge horn is shaped to enable the discharge velocity of the drilling fluid passing through the discharge horn to be constant over the entire length thereof.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.