A New Means of Diagnosing Pumping Well Problems

In an everyday review of well and reservoir performance there is a wealth of interpretive tools such as the one given in SPE Monograph No. 1 on build-up interpretation and in many articles in the SPE journals. Too often, however, the meager data available for analysis causes concern as to the reliability of the conclusions. A typical problem involves the declining production rate of older wells, where the engineer is faced with the problem of determining what remedial steps, if any, can be justified. Several possible problems come to mind. 1. The pump may not be operating efficiently. 2. Scale deposits may be forming in the well, causing skin damage. 3. The reservoir pressure may be lower than expected. 4. The formation may be tighter than expected. This paper describes a new practical service for acoustically determining build-up curves for pumping wells. Included in the service is a rapid standardized analysis that provides the client with measures of pump efficiency, estimates of skin damage, formation permeability and reservoir pressure. Figure 23 shows a summary of the reservoir data obtained in this analysis.