| 摘要 |
The present invention discloses an apparatus and method for periodically and automatically introducing fluid into a producing well through a tubing drain valve in the production tubing. The apparatus and method of the present invention employ a tubing drain valve actuated to its open position by pressurizing the interior of the production string. The system further includes apparatus for introducing a fluid, e.g., a paraffin solvent or formation treating chemical, into the production tubing and into the formation through the opened tubing drain valve. After completion of this operation, the tubing drain valve is closed and production resumed by a mechanical actuator, preferably an actuator carried by the sucker rods for operating the downhole pump. A control device, including optional monitoring devices, provides a system for introducing such fluids at periodic intervals. Although these intervals may be predetermined and constant, it is preferred that the system include timing and monitoring devices so that fluid introduction occurs at variable intervals determined by one or more production characteristics, e.g., only when the rate of production decreases below a predetermined minimum acceptable value.
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