in petroleum production, a graph of the load change at the point of suspension of pump crossbars in relation to their displacement during subsurface oil well pumping operations.
Dynamograms are recorded either by a portable instrument called a dynamometer or remotely by a teledynamometric dispatch control system. Under normal pump operating conditions, the dynamogram is similar in shape to a parallelogram. Deviation from the normal shape of the dynamogram indicates various defects in the operation of the subsurface pump installation (such as entry of gas into the pump, leakage in the delivery or suction valve, or jamming); the deviation may also indicate a decrease in pump piston stroke efficiency in comparison with that of the operation at the crossbar suspension point, caused by elastic deformations of the crossbars and pipes. At great pump depths (approximately 1,600 m and more), the detection of operating defects according to the shape of the dynamogram is complicated because of the oscillating processes in the pump crossbars and piping.
V. I. SHUROV