Joint wireline DAS-seismometer deployment in an abandoned well: lessons and insights

We report preliminary results from a first-of-its-kind academic wireline deployment of a joint DAS-seismometer in an abandoned well. We designed a custom-made 1.5 km-long cable that includes both optical fibers and copper wires, and attached a seismometer at its bottom. The apparatus was lowered to a depth of approximately 750m in a vertical borehole, abandoned and plugged about 40 years ago. We also deployed broad-band seismometers near the wellhead. We show data from an active vertical seismic profiling (VSP) experiment in which we also had surface geophones, low-frequency DAS, and earthquake monitoring from the nearby Dead Sea Fault, including comparisons to surface stations. Coupling is obtained from the fluid filling the borehole below a depth of approximately 380 m. Despite very strong tube waves in the upper sections of the well and complicated phase behavior in the deeper parts, we were able to obtain useful data.