Vertical seismic profiling using fiber optic sensing systems: first results of new technology implementation

UDK: 550.834:681.7.068

DOI: 10.24887/0028-2448-2026-4-18-22

Key words: fiber optic sensing systems for vertical seismic profiling (VSP) and offset vertical seismic profiling (offset VSP), fiber optic distributed sensor, processing and interpretation of VSP/offset VSP data using high-definition seismic (HDS) technology, signal-to-noise ratio, correlation coefficient, reflection, subsurface contour map

Authors: D.V. Garaev (TatNIPIneft, RF, Almetyevsk); А.А. Tabakov (GEOVERS LLC, RF, Saint Petersburg); Yu.А. Stepchenkov (GEOVERS LLC, RF, Saint Petersburg); V.N. Ferentsi (GEOVERS LLC, RF, Saint Petersburg); О.М. Ilmukov (TATNEFT PJSC, RF, Almetyevsk); E.R. Asadullin (TatNIPIneft, RF, Almetyevsk); B.F. Аkhmetov (TatNIPIneft, RF, Almetyevsk); V.А. Soldatova (TatNIPIneft, RF, Almetyevsk)

Nowadays, fiber optic sensing systems are not widely used in Russia for vertical seismic profiling (VSP) and offset vertical seismic profiling (offset VSP) due to insufficient study of fiber optics capabilities. TATNEFT PJSC successfully completed offset vertical profiling in three wells using fiber optic systems. At the same time, vertical seismic profiling was performed in the same wells based on the conventional technology using electrodynamic receivers. During the well interventions, the following benefits were confirmed from using fiber optic sensing systems to record seismic wave fields in the wells based on the results of tying the obtained data to well logging and land seismic survey data: high speed of operations due to simultaneous recording along the entire wellbore with one seismic excitation at the array station; obtaining high-quality VSP survey data matching the data from SK6-823 logging tool. A number of problems were identified: a signal-to-noise ratio and a correlation coefficient are higher for offset VSP data obtained with the SK6-823 tool than that obtained with the fiber optic sensing system; the fiber optic sensing system performance reduces rapidly with the growing distance between a seismic source point and a well due to basic limitations of a uniform linear array related to its directivity parameters; a relatively high inherent noise level. Despite differences in the medium seismic response between a distributed sensor and geophones, the prospects of using fiber optic systems for VSP/ offset VSP are promising provided that their key drawbacks are eliminated.

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