Producing hydrocarbon from deep water assets is extremely challenging and expensive. A good estimate of rates from multiple pay zones is essential for well monitoring, surveillance, and workover decisions. Such information can be gleaned from flowing fluid pressure and temperature; deep-water wells are often well instrumented that offers such data on a continuous basis. In this study, we present a model that estimates zonal flow contributions based on energy and momentum balances. Kinetic and heat energy coming from the reservoir fluid to the production tubing is accounted for in the model. The momentum balance takes into account differing flow profile in both laminar and turbulent flows.
In addition, we used a recently developed analytical expression to calculate the effect of Joule-Thompson expansion on sandface fluid temperature to obtain an accurate estimate of the sandface temperature from reservoir temperature. The model developed can be applied to any reservoir with multiple pay zones and is especially useful for deep-water assets where production logging is practically impossible. We used available field data for multiphase flow to validate the model. Additionally, we verified the model using data generated by the model with randomly added inaccuracy to estimate rates and error bounds. Finally, we performed a sensitivity analysis on the various parameters in the model for a better understanding of the model.
