Two-Phase Liquid Production Allocation in Multilayer Producing Wells Using Temperature Measurements

This work presents a methodology of allocating oil rate and associated water cut to each individual layer using temperature measurements and total surface production of oil and water. This paper consists of two parts. In part one; an analytical forward model is proposed for wellbore temperature response under two-phase production in a multilayer geometry, using a nodal representation of the well. This model accounts for the formation geothermal gradient, steady-state oil-water flow in the wellbore, friction loss and Joule-Thomson effect in the wellbore, contrast in the thermal and physical properties of oil and water, wellbore heat losses due to unsteady heat conduction in the earth, and the mixing of the fluid streams of contrasting temperature. The second part shows the application of the above solution by applying inversion techniques on temperature data coupled with forward model to allocate water and oil influx from producing layers. The inversion result is verified using a variety of commingled flow problems including a field case of a deviated well producing an oil-water mixture from two active completions. Inversion results seem to be robust within +/-15% provided the temperature contrast between the commingled layers is at least one order of magnitude greater than the resolution of the temperature measurements (e.g., 4°C contrast for 0.1°C resolution) Key words: Oil rate; Temperature measurement; Nodal representation; Inversion techniques