Oscillatory flow method for improved well cementing
US4548271A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 7, 1983 |
| Grant date | Oct 22, 1985 |
| Priority date | — |
| Expiry date | Oct 7, 2003 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B33/16
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
The present invention is a method for improving well cementing. A fluid such as drilling mud or preflush fluid is oscillated in the annulus prior to introduction of cement slurry into the annular interval to be cemented. The fluid is oscillated by changing its direction of flow at least twice. The oscillatory flow of the fluid flushes gelled drilling mud and filter cake from the annulus more effectively than conventional unidirectional flow. Following the oscillatory phase, cement slurry is pumped into the annular interval to be cemented, thus displacing the fluid, and is allowed to set. The fluid can be oscillated in the annulus either before or after the cement slurry is introduced into the casing. A selective check valve is also described which permits all fluids to flow in the forward direction out of the casing and into the annulus and which permits all fluids other than cement slurry to flow in the reverse direction out of the annulus and into the casing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.