For the safe and sustainable use of deep geothermal wells, construction must proceed as intended. An integer well ensures that all fluids within the borehole are always under control. One of the most critical steps is the cementing of the casings. Despite extensive experience in the petroleum industry, challenges with well integrity are a worldwide phenomenon. One reason could be that conventional measurement methods can only verify the success of cementing once the cement job has been completed. In contrast, distributed fiber optic sensing methods can monitor the entire cementing process along the entire drilling path.
This data set contains the results of the Distributed Temperature Sensing (DTS) and the derived product "vibrational energy" of a Distributed Dynamic Strain Sensing (DDSS or DAS) of the whole cementing process. We collected this data during the primary cementing of an injection well's 874m surface casing at the geothermal site Schäftlarnstr, Munich. We measured the cement placement and 24 hours of the early hydration.
We obtained the data with a fiber optic cable permanently deployed behind the casing. The cable contained Multi-Mode fibers (for DTS) and Single-Mode fibers (for DAS). Table 1 in the data description document shows the units used and the key parameters of our measurement.
In the first step, we allocated each channel to its depth in the borehole. We used a cold spray (for DTS) and a tap test (for DAS) to locate the entry to the borehole. To obtain the vibrational energy of the DAS data, we summarized the raw dynamic strain with a Root Mean Square (RMS) in a window of 60 seconds. We calculated the vibrational energy for a wide range of different frequency ranges (Butterworth bandpass). The data are provided in csv formats and further explained in the data description document.
Acknowledgement:
GFK-Monitor is funded by the Federal Ministry for Economic Affairs and Climate Action via the Project Management Jülich (PTJ) (funding code: 03EE4036, project duration: July 1, 2022 - June 30, 2025). The fiber optic infrastructure was provided by GAB (Geothermie Allianz Bayern): Funded by: Bayerisches Staatsministerium für Wissenschaft und Kunst (Hauptgebäude: Salvatorstraße 2, 80333 München).
The data set contains conventional- as well as distributed fiber-optic logging data recorded during the drilling of Well RN-34, located in the Reykjanes geothermal filed, Iceland. Published as well is part of the source code used to produce the data based figures in the SPE Journal paper Raab et al., 2019. For detailed information regarding the measurement geometry, timing of the measurements, and applied processing steps the reader is referred to corresponding publication. The accompanying data description file is explaining the file structure and contents in detail.Licence statement:This data set and part of the source code is available under the Creative Commons Attribution 4.0 International License (CC BY 4.0), excluding the conventional logging data owned by HS Orka.The conventional logging data is contained in the \data\logs directory. As mandated by HS Orka, all data files contained in this directory are released under the Attribution-NonCommercial-NoDerivatives 4.0 International licence (CC BY-NC-ND 4.0).Part of the source code, i.e the old and new segy header structure (Line 1166 to 1314 in the WellFunc.py module), is adopted from the Obspy source code. The Obspy source code is released under the GNU Lesser General Public License (LGPL) v3.0. This code section remains under the LGPL v3.0 Licence. A copy of the LGP Licence is included as a separate text file.