Permeability, Skin, and Inflow-Profile Estimation From Production-Logging-Tool Temperature Traces

Abstract

Summary Temperature traces from multiple rates are used to estimate the production-inflow profile and layer permeability and skin by use of a transient coupled reservoir/wellbore model. Production-logging-tool (PLT) temperature traces from two rates show heating of approximately 6–11°F above the geothermal because of the Joule-Thomson expansion of the reservoir oil. Production is single-phase oil from a high-pressure oil reservoir. Nonlinear regression was used to automatically adjust the layer permeability and skin values until the observation temperature traces from both rates were matched. History matching the temperature data provides a quantitative estimate of the skin and permeability within each contributing layer; this cannot be obtained from conventional pressure-transient analysis, which, unless for highly specialized cases, provides only a single value of permeability and skin. The production-inflow profile is then constructed by use of the history-matched layer permeability and skin values. In addition to the wellbore-temperature profiles, temperature and pressure profiles within the reservoir will be shown that illustrate the relative effect of the reservoir permeability and skin on the wellbore-temperature responses. The approach in this paper is different from many of the previous studies in the literature, in which only a single temperature trace is history matched and often under the assumption of steady-state conditions. Furthermore, no studies were found in which multiple temperature traces were matched by use of a transient model in which the temperature data were field data as opposed to synthetic data. Information on the coupled reservoir/wellbore model and the optimizer will be provided.