The assignee ranking for this dataset covers 100 companies, and it is heavily front-loaded: the leading filer holds 764 of the 1,381 records in scope, and the top five together hold 1,106 records, or 80.1% of the field. By the tenth-ranked company the count has fallen to 19 records, so beyond the leadership block the field is a long tail of companies with only a handful of filings each. This concentration means most of the well-known bridging-particle and wellbore-strengthening claim space is already occupied by a small number of oilfield service majors.

Filings peaked at 49 in 2017 and have eased since, with the 2021-to-2024 window running from 21 down to 14, a -33% change over that span. However, patent publication typically lags filing by around 18 months, so the last one to two years of any filing trend are always undercounted at the time of measurement. Treat the recent-year numbers as provisional and the 2021-2024 comparison as the more reliable read on direction.

Two IPC classes cover the great majority of filings: C09K, materials for miscellaneous applications, appears in 76.0% of the 1,381 records, and E21B, earth and rock drilling, appears in 60.2%. Because most filings claim both a sealing material and a drilling or treatment method, these two shares overlap heavily rather than being separate camps. Smaller classes such as cement chemistry (C04B), testing methods (G01N) and various polymer chemistries each cover under 5% of records and represent comparatively thinner claim territory.