Distributed Acoustic Sensing (DAS) and Distributed Temperature Sensing (DTS) measurements are technologies which are adding some benefits in the aim to replace or complete traditional logging measurements like noise logging tools (NLT) or production logging tools (PLT). The aim of well integrity interventions using distributed fiber optic sensing (DFOS) is to significantly reduce the duration and the cost of these operations, and to provide additional information in comparison to traditional logging tool. The combination of DAS and DTS can offer both qualitative and quantitative information regarding fluid dynamics in the context of well integrity investigation, as the flow characteristics (intensity of turbulences).
In this study, we will investigate different failure patterns occurring on the well completion, as the production tubing or packers. On the first hand, we will see that the combination of DAS and DTS provides complementary information regarding leaks characterization. On the other hand, we will investigate the monitoring of temperature gradient (DTGS for Distributed Temperature Gradient Sensing) using DAS by the integration of low frequency acoustic signal (< 1 Hz).