Production Logging Acquisition is the most fruitful way to collect information about down hole well behavior. One of the most critical parameters is the definition of the contributing net pay during well test operations in order to reduce the Pressure Transient Analysis uncertainties. Where possible, a PLT string may be run at the end of the well test to provide a down-hole flow profile and a discrete fluid allocation in front of the perforated interval at the different choke conditions. However, these operations in offshore deep-water wells are often not performed because they are risky, time consuming and therefore with high associated costs.
Recently a new temperature tool able to be integrated on perforation guns has been introduced into commercial service. This specific configuration has been successfully tested in a deep water gas well in the Egyptian offshore (Zohr field) in order to map the flowing temperature profile in front of the perforated zone during all the well test periods (perforations, clean-up, main flows and build-up phases).
The acquired temperature profiles versus time were collected in memory mode and interpreted in order to obtain a quantitative down-hole flow profile characterized by a robust agreement with the reservoir petrophysical properties.
Finally, the calculated productive pay was used for well test interpretation, leading to a better understanding of the reservoir behaviour and a more detailed calibration of the 3D reservoir model. Most importantly, the data collected with such application has allowed detailed characterization of the deliverability of the various reservoir zones, in particular the lower permeability intervals.
Understanding fluid movement from the reservoir through the perforated intervals becomes crucial in conventional well management but it is also considered strategic during well test operation in defining the actual producing net pay. This information is not only required for a comprehensive dynamic petrophysical reservoir characterization but can also provide reliable input data for a more robust pressure transient analysis.