Abstract: Evaluation of injection profile for multi⁃layer reservoirs is vitally important for successful water injection development and effective reservoir management. It can be achieved by using distributed temperature sensing (DTS) technology, which provides reservoir information with high measuring frequency, low cost, and low risk to environment and personnel. However, conventional DTS inversion model depends heavily on steady temperature data. To improve the evaluation accuracy and efficiency, this paper proposes an injection profile log evaluation method based on DTS and using wellbore temperature recovery data. First of all, according to the multi⁃field coupling theory and numerical simulation, a temperature field model for injection well in multi⁃layer reservoirs was constructed to analyze the temperature varia⁃ tion in wellbore and reservoirs under different injection conditions and shut⁃in time. Then, an injection profile evaluation model based on the characteristic temperature recovery index was established to invert the water absorption of each layer using temperature recovery data. Moreover, the proposed model of injection profile log evaluation using wellbore temperature recovery data was validated through numerical simulation. Finally, the model was applied to the data measured by DTS and production logging tool (PLT) in two water injection wells. The application results are found consistent with the isotope interpretation, with the errors mostly below 15%, verifying the reliability and practicability of the model. The study provides theoretical support for optimizing water⁃injection development and reservoir dynamic monitoring.

Key words: distributed temperature sensing, wellbore temperature recovery, reservoir, injection profile, temperature field model, numerical simulation, log evaluation