The increasing deployment of distributed temperature and pressure measuring devices in intelligent well completions is providing the means to monitor the inflow profiles of wells without any well intervention. If the profiles of pressure and/or temperature are affected by the inflow profiles of the various phases being produced, it is possible to estimate these flow profiles by inverting the measured temperature and pressure profiles. This inversion process is particularly challenging for horizontal wells because the pressure drop along the well is usually small, and temperature changes, caused primarily by Joule-Thomson effects, are also small.
This paper presents an inversion method that interprets distributed temperature and pressure data to obtain flow rate profiles along horizontal wells. The inversion method, which is based on the Levenberg-Marquardt algorithm, is applied to minimize the differences between the measured profiles and the profiles calculated from a forward model of the well and reservoir flow system.
We present synthetic and field examples in this paper to illustrate how to use the inversion model to interpret the flow profile of a horizontal well. The synthetic examples show that even with single-phase oil production, the inflow profile can be estimated in many cases with the inversion method developed. The method is even more robust when water or gas is produced along discrete intervals in an oil production well because of the unique temperature signature of water or gas production. We applied the inversion method to temperature and pressure profiles measured with production logs in a North Sea horizontal oil producing well. The method successfully inverted pressure and temperature profiles and the profiles of oil and water flow rates determined compared well with the flowmeter derived profiles.