FLOW RESPONSIVE TIME DELAY PUMP MOTOR CONTROL LOGIC

摘要

An automatically controlled fluid flow responsive method and apparatus for achieving speed control or de-energization of an electric motor operatively connected with a downhole pump being connected to a production tubing string of a well when flow from the downhole pump becomes abnormally low. A selective electronic motor control signal is programmed, representing a selected minimum acceptable rate of discharge flow from the downhole pump. A flow transducer measuring flow through a pump discharge line provides an electronic flow related signal to the logic circuitry, representing actual pump discharge flow, which if below a predetermined value, initiates a preset timing sequence of the logic circuitry. When the flow related signal remains less than the motor speed adjustment setting for the duration of the time delay period the control circuitry will alter the electrical power supply to the pump motor and cause the motor to operate at any one of a number of lower speeds. The time delay motor control logic is provided with an adjustable "set flow" logic and an adjustable "motor control or cut-off delay" logic which establish parameters of allowable minimum pump discharge flow and the time period that the pump will be allowed to operate below a preset minimum allowable flow rate. When the preset "minimum flow" and "time period" settings are met the control logic will provide a control signal to alter or deenergize the electrical power circuit of the pump motor, thus slowing the pump to any of a number of lower speeds or shutting down the pump. The pump motor control logic incorporates a start-up delay which maintains the pump control logic in a deactivated state for a period of time which is selected to permit the well production system to reach its optimum flow rate.