Wells – Processes – Producing the well
Patent
1998-05-06
2000-11-28
Suchfield, George
Wells
Processes
Producing the well
166 685, 418 48, 418 69, E21B 420, E21B 4300, F04C 1100, F04C 1504
Patent
active
061522317
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates generally to the oil production industry, and has to do particularly with improving the safety of rotary downhole pumps, particularly upon shut down or power failure.
BACKGROUND OF THE INVENTION
In the past, many conventional oil wells were operated by a downhole pump at or close to the bottom of the well, the pump being of a conventional reciprocating kind actuated by a rod string, in turn reciprocated vertically by a pump jack.
Many of these older reciprocating pumps have been recently replaced by rotary-drive progressive cavity pumps. Such rotary pumps are particularly suited for the production of crude oil laden with sand and water.
However, because of the typical depth of an oil well, the torque applied at the top of the rod string, and the resistance of the pump at the bottom, can cause the rod string to wind up like a spring, thus storing the torque energy. Whenever there is a power failure or the system is shut down, this stored torque energy, along with the energy created by the fluid head on the pump, must release itself. Without any control on the rate of backspin of the rod string, serious problems have occurred. The problems tend to be as follows: pulley arrangement, may reach reverse speeds exceeding safe limits. These speeds tend to damage the motor, and can even cause it to explode. drive, the projecting portion can bend and break, and the broken-off portion will then be flung away from the installation, due to centrifugal force. result that the rod string and the pump would be lost down the hole.
GENERAL DESCRIPTION OF THIS INVENTION
In view of the foregoing disadvantages, it is an object of one aspect of this invention to provide a braking mechanism for use with a rotary pumping system.
More particularly, this invention provides, for use with a pumping system in which a downhole pump has a rotor which is rotated by the bottom end of a rod string of which the top end is in turn rotated by torque energy derived from a prime mover, and in which twist energy is stored in the rod string during operation,
a braking mechanism for avoiding a too sudden release of said twist energy in the rod string on shut down or power failure, the mechanism comprising: and direction with respect to the top end of the rod string, intake of said fluid pump, output of said fluid pump, that, when the top end of the rod string rotates in the direction corresponding to normal operating of the downhole pump, no pumping work is done by the fluid pump, but when the top end of the rod string rotates in the direction opposite that corresponding to normal operation of the downhole pump, the fluid pump does the work of pumping the fluid out of and then back to said reservoir against a resistance determined by the setting of the valve,
whereby if the stored energy in the rod string is suddenly released, the energy is dissipated in a controlled manner.
This invention further provides a pumping system comprising: connected to, supporting and rotating said rotor, twist energy is stored in the rod string during operation, and in the rod string on shut down or power failure, the mechanism including: the top end of the rod string, such that the rotary member rotates at a consistent speed ratio and direction with respect to the top end of the rod string, connected such that when the top end of the rod string rotates in the direction corresponding to normal operation of the downhole pump, the clutch slips and does not run the fluid pump, but when the top end of the rod string rotates in the direction opposite that corresponding to normal operation of the downhole pump, the clutch powers the fluid pump, intake of said fluid pump, output of said fluid pump, and
whereby the stored energy, when being released from the rod string, is made to do the work of pumping fluid around a closed circuit which includes a resistance in the form of said valve, thus dissipating said stored energy in a controlled manner.
GENERAL DESCRIPTION OF THE DRAWINGS
One embodiment of this invention is illus
REFERENCES:
patent: 4475872 (1984-10-01), Foughty
patent: 4797075 (1989-01-01), Edwards et al.
patent: 4927333 (1990-05-01), Kato
patent: 4993276 (1991-02-01), Edwards
patent: 4997346 (1991-03-01), Bohon
patent: 5251696 (1993-10-01), Boone et al.
patent: 5358036 (1994-10-01), Mills
LandOfFree
Wellhead drive brake system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Wellhead drive brake system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Wellhead drive brake system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1715394