This paper presents how joint DAS and DTS logging on a permanently deployed fiber optic system allows us to sense changes in production distribution along a horizontal well. Utilizing the permanent array, we were also able to assess the interaction with offset wells. This assessment was anchored utilizing both DAS and permanent downhole gauges at various times in the life of the wells. Our project is located within the prolific Permian Basin where our well is instrumented with permanent downhole P/T gauges as well as one permanent fiber optic cable for both DAS and DTS monitoring. The logging program was designed to allow for both the production logging via DAS and DTS, as well as for the interference monitoring of three offsetting wells. We utilized advanced and unique data processing workflows integrating various DAS derivatives including acoustic spectral noise logging, slow strain transient thermal plumes, and speed of sound propagations with DTS thermal modelling. Interference analysis was performed via activity tables, displaying the activation and deactivation of clusters, under the changing states of the offset wells. From these high-resolution datasets, we were able to quantify the two-phase gas and water allocations along the wellbore. The results from the production allocation highlight the strongest water and gas contributing stages. The project was repeated three months later allowing for a comparison of the production allocations along the well. Stages that were initially highly productive remained through time. Water production appeared homogeneously distributed along the wellbore. The interference analysis highlighted changes in cluster level activity during different interference states. We also recognized possible crossflow or wellbore storage effects within the wellbore. Leveraging the advanced technology discussed here allows for understanding of the dynamics of downhole conditions within the wellbore. DAS slow strain differential analysis was also performed to detect small local strain changes, highlighting near wellbore effects likely related to the prior stimulation. The assessment of the production along the wellbore as well as interactions between wells provides an understanding of the variability of inter-well connections and reservoir characteristics. These data and their analysis can then be utilized for optimizing future completions and well performance which help define the well spacing across the development program and leasehold.
Repeat DAS and DTS Production Logs on a Permanent Fiber Optic Cable for Evaluating Production Changes and Interference with Offset Wells
Mahue, Veronique, Jimenez, Erick, Dawson, Peter, Trujillo, Kirk, and Robert Hull. "Repeat DAS and DTS Production Logs on a Permanent Fiber Optic Cable for Evaluating Production Changes and Interference with Offset Wells." Paper presented at the SPE/AAPG/SEG Unconventional Resources Technology Conference, Houston, Texas, USA, June 2022. doi: https://doi.org/10.15530/urtec-2022-3725993
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