Chapter 13: Production Logging

Production logs have the potential for providing an array of valuable information about the well or near-wellbore formation throughout the life of a well. This array of information includes well performance evaluation, workover and completion evaluation, and reservoir performance monitoring.

Conventional production logging as practiced today traces its origin to the introduction of temperature logs by Schlumberger et al. (1937) and, subsequently, to the use of other sensors by Wade et al. (1965). Over the past five decades, continuous enhancement of sensor resolution paved the way for improved downhole diagnosis. One cornerstone to the early success lay in the ability to run multiple sensors in one run, although surface transmission of only one sensor response at a time was permitted early on, as reported by Meunier et al. (1971). Approximately a decade later, simultaneous transmission of signals from all sensors to the surface became possible (Anderson et al. 1980). Advances in data-gathering techniques and instrumentation continue to this day. At the same time, our understanding of the mechanics of gas/liquid and liquid/liquid flows in conduits of various orientations, as discussed in Chapter 4, has also matured over the years. Despite these advances, integration of mechanistic models with sensor responses has lagged behind. For instance, a holdup model may be used, but without an explicit usage of the flow pattern map associated with it. We also observe that the traditional approach of station-based analysis, dealing with a few data points, often does not explain anomalous flow behavior. Stated differently, one wonders whether a certain sensor response is induced by the complex flow behavior, poor sensor resolution, logging speed, or a combination thereof.