Method for mitigating rod float in rod pumped wells
US7547196B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 2005 |
| Grant date | Jun 16, 2009 |
| Priority date | — |
| Expiry date | May 7, 2027 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF04B2203/0209
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
Rod Float Mitigation (RFM) methods for rod-pumped oil wells having a variable frequency drive which controls the speed of the motor for the pump. Each method monitors rod loads or a similar condition and takes action only when rod load drops below a predefined minimum load. A first method reduces the speed of the motor to a preset level. A second method fixes the torque level on the pump downstroke by adjusting motor speed based on a calculated gearbox torque compared to a programmed fixed limit. Another method includes a program in the variable frequency drive which includes a preferred RFM Torque Curve for the pump to follow on its downstroke. When rod float occurs, the program monitors gearbox torque and adjusts the speed to follow the predetermined RFM Torque Curve thereby mitigating rod float with minimum decrease in production.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.