Use of Conventional Dynamometer Cards in the Analysis of Sucker-rod Pumped Installations

A conventional dynamometer (the most common type of measuring device in rod pumping well analysis) records polished rod loads versus rod displacement during the pumping cycle on a plot called dynamometer card. Calculations requiring rod loads and displacements as input variables must rely on information retrieved from these cards. There are many conditions that prevent the pumping analyst from getting the right type and the desired amount of reliable measurement data from dynamometer cards. These include: (a) the card's small physical size, (b) visual reading of the card can be insufficient, and (c) additional information not readily available from the card may also be needed. The goal set forth in this paper is to present a novel technique for processing conventional dynamometer cards. The calculation method and the computer program developed for this purpose: (a) uses a simple computer configuration, (b) involves a simple, easy-to-learn procedure, (c) ensures the required accuracy, and (d) allows the retrieval of special information from the card that cannot be reached with other methods.