Patent ID: 9528370
Filing Date: 2016-12-27
CPC Classification: E21B

Claim Text:
1. A fluid pressure pulse generating apparatus for downhole drilling comprising: (a) a fluid pressure pulse generator comprising a stator and a rotor which rotates relative to the stator to create fluid pressure pulses in drilling fluid flowing through the fluid pressure pulse generator; (b) a pulser assembly longitudinally adjacent the fluid pressure pulse generator and comprising a pulser assembly housing that houses a motor and a driveshaft extending from the motor out of the pulser assembly housing and coupling with the rotor; and (c) a primary seal surrounding a portion of the driveshaft and configured 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, wherein there is a fluid flow channel between adjacent surfaces of the pulser assembly and the rotor and the fluid flow channel defines at least a portion of a flow path for the drilling fluid which flows from external the pulser assembly to the primary seal when the fluid pressure pulse generating apparatus is positioned downhole, and wherein the entrance to the fluid flow channel is downhole relative to the primary seal and the adjacent surfaces of the pulser assembly and the rotor are configured such that the fluid flow channel comprises a tortuous flow path.