Dewaxing control apparatus for oil well
US4995462A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 1990 |
| Grant date | Feb 26, 1991 |
| Priority date | — |
| Expiry date | Mar 30, 2010 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B37/00
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Dewaxing control apparatus is adapted for use in a well casing containing a production tubing string defining an annulus within the well casing and a down hole pump which pumps oil upwardly through the production tubing. The apparatus has a housing adapted to be installed in-line with the production tubing. A passage in the housing places the annulus in communication with the interior of the production tubing for purposes of circulating a hot dewaxing oil. A cup packer positioned below the passage closes the annulus against downward liquid flows. A gas by-pass passage in the housing permits gases to be exhausted upwardly through the annulus during oil production despite the presence of the packer. A valve mechanism responsive to pressure developed by pumping hot dewaxing oil down the annulus closes the gas by-pass passage and opens the liquid transfer passage so that the dewaxing oil can flow into the production tubing and back up to the surface. Flow of dewaxing oil into the oil-bearing formation is prevented.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.