Process and installation for drilling holes in the earth's crust under freezing conditions
US4191266A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 28, 1978 |
| Grant date | Mar 4, 1980 |
| Priority date | — |
| Expiry date | Feb 28, 1998 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B36/001
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Process for drilling a hole in the earth's crust in which the bottom of the drill hole is frozen in front of or near the drill bit by a cold driling liquid in which liquid particles that have been frozen to solid parts or have been solidified have been taken up whether or not by addition. In this way the bottom of the drill hole is always so hard -- also upon drilling in soft or plastic formations, such as clays, -- that use can be made of diamond drill bits or other drill bits normally used for hard formations, in order that the number of times a drill bit is to be replaced can be strongly reduced. The purpose of adding ice is to make it possible for a sufficient amount of frigories per unit of time to be introduced into the drill hole, so that at greater depths the temperatures at the drill bit are decreased to such a degree that here, too, use can be made of drill bits for hard formations here described. By preference, the drilling liquid is a mud consisting of an eutectic salt water solution with plastering properties, to which ice of the same composition has been added. The pressure in the drilling liquid in the bottom of the drill hole is somewhat lower than the pressure of t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.