Distributed acoustic sensing (DAS) and other distributed strain sensing techniques have demonstrated their value in the monitoring of the hydraulic fracturing of treatment wells from nearby observation wells. Key to the interpretation of the obtained signals is a knowledge of how the strain changes measured along the optical fiber are related to the strain changes along the monitored wellbore. Ideally, these changes should be the same but slippage between the cable and the wellbore does occur. A theoretical model describing the conditions under which slippage occurs has proven useful for the understanding of field data. This model will be described and examples provided for both crosswell strain and microseismic monitoring. The examples will include results using permanent cables, wireline-conveyed optical fiber, and disposable fiber.
Michel LeBlanc is a chief scientific advisor within the Sensor Physics group at Halliburton and team lead for DAS deployment technology. He has a PhD in Aerospace Science and Engineering from the University of Toronto where his research was in the integration of fiber optic sensors within composite material structures. His first job outside of academia was at the Naval Research Laboratory (NRL) in the Fiber Optic Smart Structures group led by Dr. Alan Kersey. He is co-author of “Fiber Grating Sensors,” a 1997 Journal of Lightwave Technology paper that has now over 4880 citations. His interaction with Halliburton and the Oil and Gas Industry started in 1999 while he was at NRL and restarted in a formal way when Halliburton acquired the downhole fiber-based pressure gauge business of Davidson Instruments, a start-up company where Michel was a lead scientist. Within Halliburton, Michel expanded his work in applied physics to include work on accelerometers, downhole fluid sampling, densitometers and DAS technology. He is currently involved in expanding the capabilities and accuracy of downhole strain-based sensing technology.