Paper: Downhole Dynamometer Update

The Downhole Dynamometer is a tool designed for making dynagraph measurements at any point in the rod string. The tool is completely sealed, battery-operated, and microprocessor-controlled to sample axial load, position, lateral acceleration, fluid pressure, and temperature at preprogrammed times and sampling rates and to store the data digitally in a non-volatile memory (Figure 1). Load is measured at three points spaced radially equidistant around the body of the tool enabling the derivation of bending and buckling loads. Rod velocity and acceleration are also measured. The tool is used in the industry as a diagnostic device and to validate predictive and diagnostic codes. Any number of tools can be used simultaneously at different points in the string. 1994 was a maturing year for the tool. This presentation one year ago was devoted to the evolution of the downhole device. The focus this year is on the present state of the tool, calibration, accuracy and how to use it.