Gulf of Mexico Sees World’s First Permanent Subsea Distributed Acoustic Sensing System
Fiber-optic technology company Silixa announced the installation, validation, and borehole seismic acquisition from a permanently installed fiber-optic distributed acoustic sensing system on BP’s Atlantis Phase 3 subsea field development.
Fiber-optic technology company Silixa announced the installation, validation, and borehole seismic acquisition from a permanently installed fiber-optic distributed acoustic sensing (DAS) system—the Carina Subsea 4D system—on BP’s Atlantis Phase 3 subsea field development in the Gulf of Mexico.
The Atlantis Phase 3 development involves a new subsea production system with eight new wells tied into the current Atlantis platform, 150 miles south of New Orleans. The engineered fiber-optic system enables high-definition seismic data acquisition along the entire subsea wellbore. The Carina Subsea system has been installed in two wells, and installation is continuing over the rest of the field. A zero-offset DAS vertical seismic profiling was acquired to validate coupling and signal-to-noise characteristics and showed excellent data quality. Subsequent production noise recordings showed little effect despite ongoing significant production.
The system is the world’s first permanent in-well seismic acquisition system for subsea wells. It can operate independently or provide complementary data to ocean bottom node surveys. It is especially effective for reservoirs that are traditionally difficult to image using surface seismic such as presalt reservoirs or those beneath gas clouds.
Silixa says its system delivers improved signal-to-noise ratio compared with DAS systems using standard fibers. It features Constellation fiber engineered with brighter backscatter centers along its length to capture and reflect more light back to the interrogator without introducing significant loss to the forward-propagating laser pulses. This makes this new technology ideal for subsea tieback applications where high optical losses from subsea connectors have previously prevented DAS deployment. A further advantage is that it does not require complex electronics to be placed on the seafloor.
“Until now, subsea fields had to rely on sparse data acquisition due to the risk and cost of acquisition,” said Garth Naldrett, Silixa’s chief product officer. “Bringing our engineered distributed fiber-optic sensing technology to subsea wells and allowing the same data acquisition we have already enabled on land and platform wells will have a tremendous impact on the industry.”