The downhole temperature measurements have become a powerful tool for fracture diagnosis. Multiphase flow is common in fractured horizontal wells, and its effects on temperature behavior are noteworthy. To interpret downhole temperature measurement quantitatively, we need an integrated flow and thermal model to handle multiphase flow with reasonable computational efficiency while maintaining maximum accuracy that can be achieved. This study presents the multiphase black-oil thermal and flow model and shows its applications on temperature interpretation.
The integrated multiphase black-oil thermal and flow model can simulate the transient temperature behavior during the injection of the hydraulic fracturing, shut-in, and the production. The model simulates reservoir flow (pressure and velocity) and thermal (temperature) for a multi-stage hydraulic fractured horizontal well. Previously developed wellbore model for two-phase flow is adopted in this study. The reservoir model solves the mass balance, Darcy's law and energy balance in three dimensions. We assume that the oil and water components are immiscible, and the gas component is only soluble in oil but not in water. The reservoir model and wellbore model are coupled interactively through boundary conditions to each other.
The multiphase black-oil thermal/flow model is validated against the compositional model. The results show the consistency between these two models, and the multiphase black-oil thermal/flow model significantly reduces the computational time. This study gives guidance on when and how to apply this black-oil thermal model to fulfill its full advantages. This work proposes a modified inversion workflow particularly for liquid production based on the previous study and presents a field example of implementing this developed thermal model to interpret temperature data to flow rate profile for a multistage fractured horizontal well with the multiphase flow. The results reveal this multiphase black-oil thermal model is efficient and can be used to interpret temperature measurements for multiphase flow quantitatively with reasonable assumptions.