Silixa introduced its cable mapping service, a cost-effective, low-risk solution for mapping the orientation of downhole optical sensing cables in order to avoid cable damage during perforation. Fiber-optic cables (FOCs) installed on the outside of completion casing are at risk of being damaged during perforation. To avoid damaging the FOC, the perforation charges are oriented away from the FOC. In order to achieve this, the orientation of the FOC must be determined when the installation is complete. The Cable Orientation Beacon (COB) is an autonomous downhole sensor that is installed adjacent to the FOC under a standard midjoint clamp. Unlike traditional sensors that use wireline electromagnetic or ultrasonic tools inside the casing to detect the presence of the cable on the outside of casing, Silixa’s COB measures its own orientation using an internal sensor, then transmits those data to the FOC by an acoustic signal. The acoustic signal is read at surface and translated back to an orientation in the form of an angular position around the outside of the casing relative to the high side of the borehole. Use of the COB reduces overall costs by eliminating the need for tractored wireline services.