Abstract

Optimum fluid placement is crucial for a successful acid stimulation treatment, especially in thick, highly heterogeneous carbonate formations with multiple zones and/or extensive productive intervals. A variety of diversion methods are applied in acidizing treatments to evenly place acid along the well, but the effectiveness of these diversion methods is generally only inferred from the rate and pressure behavior during the treatment, and is not known with any certainty. Recently, distributed temperature sensing technology has enabled us to observe dynamic temperature profiles along the wellbore during and immediately following an acid treatment. This technology allows us to monitor and evaluate treatments and diversion methods in real-time from captured sequence of temperature profiles at different times during and after acid injection.

We presented a mathematical model in previous papers to simulate the temperature behavior in the formation and along the wellbore, during and shortly after an acid treatment (Tan, 2009 and 2011). An inversion procedure was also included to interpret the acid distribution profile from the measured temperature data in a hypothetical example. In this paper, we apply our model to a field case. The well is a gas producers and was stimulated with acid treatments. The temperature data was measured with DTS tool during shut-in period, and shortly after each stage of the treatments. The model is used to quantify the acid distribution with the temperature data to evaluate the efficiency of acid treatments. We have focused on diagnosing the volume of acid placed in each zone with the shut-in temperature data. Results indicate that the model is applicable in the field operation for acid profiling and is helpful to evaluate and optimize acid treatments.

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