Safety drilling system and method for preventing collapse of water-sensitive formation in upper part of high-pressure saltwater layer
US11236562B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 10, 2020 |
| Grant date | Feb 1, 2022 |
| Priority date | — |
| Expiry date | Mar 10, 2040 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B41/0099
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A safety drilling system for preventing collapse of water-sensitive formation in the upper part of a high-pressure saltwater layer, which includes a wellhead equipment, a downhole drilling tool, a first injection pipeline, a second injection pipeline, a first return pipeline and a second return pipeline. Upon encountering a high-pressure saltwater layer while drilling, the system injects heavy mud into the annulus of a wellhead through the first injection pipeline to form a heavy mud cap, such that a fluid column pressure in the annulus balances the pressure of the high-pressure saltwater layer. In this case, a fluid column pressure in a drill string is lower than the pressure of the high-pressure saltwater layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.