Using distributed temperature sensing (DTS) technology in acid gas injection design

Optical Sensing of CO2 Geological Storage Using Distributed Fiber-Optic Sensor: From Laboratory to Field-Scale Demonstrations

“…Although some fluctuations occurred at 5 m depth (i.e., surface) from the wellhead throughout the CO 2 injection process, which were mainly due to the difference between the temperature during the day and night, the shift in the Rayleigh frequency remained almost constant from the level of the groundwater (at approximately 5 m depth) to a depth of 50 m during CO 2 injection, as illustrated in Figure 8. This indicated that there is no obvious influence on the temperature field near the surface when CO 2 is injected at a depth of around 278 m. 54,55 Thus, it can be concluded that when the temperature of the shallow groundwater was elevated within a CCS site region, there is no doubt that this phenomenon could not have arisen simply because of CO 2 injection. 56 Considering that no significant effect was observed on the temperature in the fiber cable, the vertical strain (Δε z ) and radial strain (Δε r ) at the injection wellbore calculated, respectively, using Yamauchi's method below are given by 57…”

Monitoring cold water injections for reservoir characterization using a permanent fiber optic installation in a geothermal production well in the Southern German Molasse Basin

“…Above A, which is at 2820 m MD, heating is uniform, indicating mainly conductive heat transfer (Ali et al 2013). From A to B there is slow heating, suggesting that most of the injected cold water infiltrated within this zone.…”

“…5) can be estimated. At zones with high permeability (hydraulically active zones), the vertical moving thermal front should change in terms of velocity and a slowdown should be noticeable (Ali et al 2013). In Fig.…”

“…Further down in the reservoir section, no vertical movement is evident in the DTS profiles, indicating that the injected water was lost above, or that fluid flow velocities were below the detection limit of the DTS analysis. Ali et al (2013) also used fluid velocity analysis when they monitored DTS during an injection of water to the carbonatic reservoir of a test well in the south-west of the USA. Similarly to the Schäftlarntraße well considered in our study, the major feed zone they investigated was a highly permeable karstic zone.…”

“…DTS profiles show that the same zone took the injected cold After 24 h of injection, the section from 3500 m MD to TD was the only one unaffected by the cold water injection. As the temperature recovers towards the undisturbed equilibrium, the transient temperature distribution gives evidence of hydraulically active zones (Henninges et al 2005;Ali et al 2013).…”