Simultaneous acquisition of distributed acoustic sensing VSP with multi-mode and single-mode fiber optic cables and 3-component geophones at the Aquistore CO₂ storage site

Abstract

A dynamite 3D VSP survey, a Vibrator 2D VSP survey and related calibration surveys at the Aquistore CO 2 storage site in Saskatchewan served as a technology test for distributed acoustic sensing (DAS). DAS data was acquired as a vertical seismic profile (VSP) on two codeployed fibers, one single-mode (SM) and one multi-mode (MM), simultaneously with a 60-level 3-component wireline geophone array. A 2D grid of explosive shots, used for baseline 4D surface seismic, provided 3D-VSP data from all sensors, while vibrator sources were used for a single 2D VSP line. The DAS fibers were cemented in place on the outside of the well casing during the original well completion and extend to a depth of ~2.8 km. Good quality data was acquired by all systems with comparable SM and MM VSP results. DAS data converted to particle velocity and geophone data have comparable responses. Both explosive and vibroseis source types give good quality DAS data with expected improvement from two versus one vibroseis source. We observe variable coherent borehole noise attributed to variable cement quality. Good quality and comparable migrated images are obtained from DAS and geophone data. Following these tests, we conclude DAS 3D VSP is a viable candidate for time-lapse monitoring.

Application of Distributed Acoustic Sensing in Geophysics Exploration: Comparative Review of Single-Mode and Multi-Mode Fiber Optic Cables

“…Furthermore, as the underlying technology, SMF optic cable presents enhanced robustness compared to conventional geophones. This robustness mitigates the potential hazards of deploying mechanical and electrical components within a well [51]. This makes SMF an excellent tool for replacing geophones, providing subsurface properties, in addition to having been used widely in various subsurface applications.…”

Feasibility of time-lapse VSP monitoring at the Aquistore CO2 storage site using a distributed acoustic sensing system

“…The success of an initial test of DAS recording at the Aquistore site in May, 2013 (Daley et al, 2014) led to the execution of an expanded pre-injection baseline 3D VSP in November 2013. This survey was recorded with both a downhole geophone array and with DAS systems connected to single-mode and multimode fibers in the observation well, allowing direct comparisons to be made between the 3 VSP data sets.…”

A field experiment of walkaway distributed acoustic sensing vertical seismic profile in a deep and deviated onshore well in Japan using a fibre optic cable deployed inside coiled tubing

“…Another DAS‐VSP field experiment was performed at the Aquistore CCS site in Saskatchewan, Canada, in November 2011 by the same research group (Daley et al . ). The aquifer formation in the field lies at a depth of approximately 3.2 km.…”

“…On the other hand, tubewave noise with a high amplitude also exists in the shot gather, thus necessitating appropriate data processing for further analysis. Another DAS-VSP field experiment was performed at the Aquistore CCS site in Saskatchewan, Canada, in November 2011 by the same research group (Daley et al 2014). The aquifer formation in the field lies at a depth of approximately 3.2 km.…”