Equinor sought to address multiple challenges while drilling an appraisal carbon capture well in 318 m of water to a TD of 1,870 m. The operator needed precise rock velocity data and seismic responses to establish a reliable well-to-seismic tie and to calibrate sonic logs and seismic velocity models.
Achieving these objectives was critical for ensuring robust formation evaluation. However, traditional VSP surveys using geophones are prone to lengthy operational times exceeding 9 hours and are susceptible to weather related downtime, which hamper efficiency and increase operational risks.
In line with its commitment to enhancing operational efficiency, improving safety, and reducing its carbon footprint, the operator sought an innovative solution to overcome these challenges. By adopting the Optiq TuffLine™ torque-balanced fiber-optic wireline conveyance system, featuring fiber-optic distributed acoustic sensing (DAS) technology, the operator aimed to significantly reduce survey time while meeting its technical and environmental objectives.
By adopting the Optiq TuffLine™ torque-balanced fiber-optic wireline conveyance system, featuring fiber-optic distributed acoustic sensing (DAS) technology, the operator aimed to significantly reduce survey time while meeting its technical and environmental objectives.
To optimize VSP density and operational efficiency, SLB deployed an integrated suite of advanced technologies. The CMR-Plus™ combinable magnetic resonance tool, PressureXpress™ reservoir pressure-while-logging service, and Litho Scanner™ high‑definition spectroscopy service were operated in tandem and conveyed using the Optiq TuffLine conveyance system.
This innovative fiber-optic cable, featuring a safe working load of 18 klbf, combined with the latest-generation ONYX™ quantitative DAS interrogator, delivered high-quality DAS data in both the open and cased sections of the vertical well, enabling accurate measurement of seismic velocities and the formations reflectivity response.
A triple G-gun rig source was autotuned within 0.5 ms using the TRISOR™ acoustic source control system. The ONYX DAS laser interrogator parameters were carefully optimized to enhance the signal-to-noise ratio across the seismic bandwidth, including a gauge length of 11 m, pulse frequency of 10 kHz, and pulse width of 4 m.
Additionally, the second single-mode fiber available was simultaneously recorded using a gauge length of 5 m, further improving efficiency by simultaneously recording two independent DAS datasets.
Optiq, Optiq Tuffline, VSI, CMR-Plus, Litho Scanner, PressureXpress, and TRISOR are SLB marks. ONYX technology co-developed by SLB and Sintela.
