APPARATUS AND METHOD FOR DETERMINING THE POSITION OF AN ELONGATE MEMBER OF A PUMP ASSEMBLY

摘要

An apparatus and method to measure the position of a portion of a pump assembly within a well particularly for use in an oil or gas well and for downhole pumps driven by a drive shaft running from a surface motor. The apparatus comprises at least one measurement device which senses the position of a portion of a pump assembly downhole. The information can be used to position a rotor of the pump assembly at an optimum position relative to a pump housing of the pump assembly to produce fluids from the well at an increased rate. Where two measurement devices are provided, they can count the number of revolutions of the drive shaft of the pump assembly at two spaced apart points. The strain or torsion within the drive shaft can then be calculated. If the torsion within the drive shaft approaches critical levels the speed of its rotation can be slowed in order to reduce the torsional strain in the drive shaft. The method and apparatus thus reduce the number of failures caused by fractured drive shafts. Since the torsion within the drive shafts can be determined, the speed of rotation of the drive shaft can be increased in normal operating conditions which allows an increased production rate from the well.