Patent ID: 9464521
Filing Date: 2016-10-11
CPC Classification: E21B

Claim Text:
1. A fluid pressure pulse generating apparatus for downhole drilling comprising a fluid pressure pulse generator and a pulser assembly, the pulser assembly comprising: (a) a pulser assembly housing; (b) a motor and a driveshaft enclosed by the pulser assembly housing, the driveshaft extending from the motor out of the pulser assembly housing and coupling with the fluid pressure pulse generator; (c) a seal surrounding a portion of the driveshaft and configured to seal against the driveshaft to prevent drilling fluid from entering the pulser assembly housing and lubrication liquid from leaving the pulser assembly housing when the fluid pressure pulse generating apparatus is positioned downhole; and (d) a pressure compensation device enclosed by the pulser assembly housing and comprising a pressure compensation mechanism providing a fluid barrier between the lubricating liquid on a first side of the pressure compensation mechanism and the drilling fluid on an opposed second side of the pressure compensation mechanism when the fluid pressure pulse generating apparatus is positioned downhole, the pressure compensation mechanism configured to allow pressure equalization between the lubrication liquid on the first side and the drilling fluid on the second side of the pressure compensation mechanism, wherein the pulser assembly housing comprises an interior wall with a plurality of primary apertures therethrough and an exterior wall with a plurality of secondary apertures therethrough, the exterior wall overlying the interior wall, and the primary apertures and the secondary apertures being in fluid communication with the pressure compensation mechanism such that the drilling fluid flows through the primary and secondary apertures and contacts the second side of the pressure compensation mechanism when the fluid pressure pulse generating apparatus is positioned downhole.