| 摘要 |
An oil well pumping system includes a small positive displacement pump below the fluid interface in a low volume oil well which pumps at a rate to maintain approximately constant fluid level in the well. The system includes at least a pair of sensors in a sensor array that is positioned above the pump and near the flu id interface to unambiguously determine liquid level. By maintaining the pumpin g rate of the positive displacement pump below that required to lower the liquid level to the pump, the pump will not unload and pump power requirements are reduced to a nearly constant low rate. In addition, the pump off control function is accomplished by a microprocessor which is mounted adjacent to the downhole sensor array. Thi s location allows simple direct control of the downhole electric motor and eliminates the requirement that a control element be placed on the surface far from the pum p.
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