Fiber Optic 4C Seabed Cable For Permanent Reservoir Monitoring

Recent advances in fiber optic sensing technology have provided the oilfield service industry with a new tool for fiber optic reservoir monitoring. A fiber optic 4-Component (4C) permanent seabed cable has been successfully demonstrated in the Gulf of Mexico. At SEG 2004 Maas et al [1] discussed a seabed optical cable for seismic applications, advances in the cable design and optical sensors, including a 3-axis optical accelerometer. Further work has now turned this system into a practical tool for 4C permanent reservoir monitoring, and the cable design and performance of the new system are reviewed. An 800 m cable with 4C sensor stations located every 50 m was tested along side a 4C cable with conventional electrical sensors. While the cable tested was limited in size, we have demonstrated the optical systems capabilities beyond 3000 m depth and with channel counts in excess of 2000 over 12 km in the lab. Data collected from the field tests have proven the prototype optical system meets the performance required of the deepwater permanent reservoir monitoring.