Filing in this field is concentrated among a small number of oilfield service majors, with the top five assignees together accounting for 75.8% of the 322 records in scope. The single leading assignee holds 90 records, well ahead of the fifth-ranked holder at 21. Below the top ten, which together hold 93.2% of records, a long tail of smaller filers each contribute a handful of records or fewer, so the practical competitive set for freedom-to-operate checks is small.

No — filing volume peaked at 32 records in 2019 and has fallen sharply since, down to 1 record in 2024, a 94% decline from the 16 filed in 2021. That 2024 figure is the most recent year that can be treated as a complete data point, since publication typically lags filing by around 18 months and 2025-2026 counts will still rise as pending applications publish. The pattern points to a field where foundational claim space is largely staked out rather than one still in early growth.

The search combines downhole optical fibre hardware terms with backscatter and interrogation method terms, so it captures patents describing both the physical fibre deployment and the sensing technique used to read it. By IPC class, 60.9% of the 322 records sit in E21B (earth and rock drilling), 32.0% in G01V (geophysics and surveying) and 20.5% in G02B (optical elements and systems), with smaller shares in vibration sensing, temperature measurement, material analysis and transmission classes. Because records can carry multiple classes, these figures overlap rather than sum to 100%.