System and method for determination of polished rod position for reciprocating rod pumps

摘要

A system and method for measurement of a polished rod movement in a reciprocating rod pumping system comprising reciprocal motive elements is provided. A proximity sensor target is mounted on the polished rod while a corresponding sensor element, is mounted in fixed relation to the pumping system, for example in fixed relation to the wellhead or ground. The sensor detects passage of the proximity sensor target, and thus the polished rod, as it moves in opposite directions during a single stroke cycle. The time of passage and the speed of the polished rod, as determined from its kinematic relationship with other pumping system components, is used to determine the position of the polished rod at any point during the cycle. The proximity sensor target may be mounted on a walking beam or other reciprocally moving element, with the sensor positioned in a corresponding fixed location.

主权项

1. A system for determining position of a polished rod of a reciprocating rod pumping system having a prime mover driving reciprocating motion of the polished rod using one or more components transferring prime mover motion to the polished rod, the reciprocating motion of the polished rod comprising a stroke cycle, the system comprising:
a proximity sensor and a proximity sensor target, one of the proximity sensor and the proximity sensor target being mountable on a selected point on a reciprocally moving component of the reciprocating rod pumping system and the other of the proximity sensor and the proximity sensor target being mountable on a corresponding selected fixed location, the proximity sensor being configured to transmit a detection signal on detection of the proximity sensor target, the reciprocally moving component comprising the polished rod or one of the one or more components; and a receiving system configured to receive a plurality of detection signals form the proximity sensor, the plurality of detection signals comprising a detection signal resulting from detection of the proximity sensor target during a downstroke portion of the stroke cycle and a detection signal resulting from detection of the proximity sensor target during an upstroke portion of the stroke cycle, the receiving system further being configured to determine a time of each of the plurality of detection signals, and to determine from said times a position of said polished rod for at least one point of the stroke cycle.