Downhole fluid pressure pulse generator

Abstract

A fluid pressure pulse generator forms part of a tubing string for use in a wellbore. The generator includes a tubular stator and a tubular rotor disposed for rotation within the stator to periodically align rotor transverse openings with stator transverse openings to permit fluid communication from a rotor longitudinal bore to a stator outer surface. The rotor is disposed longitudinally between bearing members to define a pair of end gaps sized for creation of end fluid film bearings. The stator inner surface defines a plurality of longitudinally extending grooves. The rotor transverse openings are adapted to direct fluid away from the rotor longitudinal bore in a direction having a tangential component in respect to the rotor longitudinal bore, and into the grooves. The stator transverse openings are adapted to direct away from the stator outer surface in at least six different directions.

1 . A fluid pressure pulse generator for forming part of a tubing string for use in a wellbore, the fluid pressure pulse generator comprising:
 (a) a pair of longitudinally spaced apart annular bearing members, wherein each of the bearing members comprises an annular bearing surface, and defines a bearing member opening for fluid communication with the tubing string; and   (b) a tubular stator and a tubular rotor disposed for rotation within the stator to periodically align at least one rotor transverse opening with at least one stator transverse opening to permit fluid communication from a rotor longitudinal bore to a stator outer surface;   (c) wherein the rotor is disposed longitudinally between the bearing members with the rotor longitudinal bore in fluid communication with the bearing member openings, and wherein rotor longitudinal ends and the bearing surfaces define therebetween a pair of end gaps in fluid communication with the bearing member openings and sized for creation of end fluid film bearings.   
     
     
         2 . The fluid pressure pulse generator of  claim 1 , further comprising a pair of crossover subs adapted for connecting the stator to the tubing string, and wherein each bearing member is disposed longitudinally between and in abutting relationship with one of the subs and one of the stator longitudinal ends. 
     
     
         3 . The fluid pressure pulse generator of  claim 1 , further comprising a pair of longitudinally spaced apart annular bushings, wherein each bushing is disposed in an annular space defined between a stator inner surface and a rotor outer surface, and wherein the rotor outer surface and bushing inner surfaces define therebetween a pair of inner annular gaps in fluid communication with the bearing member openings and sized for creation of inner annular fluid film bearings. 
     
     
         4 . The fluid pressure pulse generator of  claim 1 , wherein the stator inner surface and bushing outer surfaces define therebetween outer annular gaps in fluid communication with the bearing member openings and sized for creation of outer annular fluid film bearings. 
     
     
         5 . The fluid pressure pulse generator of  claim 3 , wherein the end gaps extend between bushing longitudinal ends and the bearing surfaces. 
     
     
         6 . A fluid pressure pulse generator for forming part of a tubing string for use in a wellbore, the fluid pressure pulse generator comprising:
 (a) a tubular stator defining at least one stator transverse opening, and comprising a stator inner surface defining a plurality of longitudinally extending grooves; and   (b) a tubular rotor defining at least one rotor transverse opening adapted to direct fluid away from a rotor longitudinal bore in a direction having a tangential component in respect to the rotor longitudinal bore, wherein the rotor is disposed for rotation within the stator to periodically align the at least one rotor transverse opening with the at least one stator transverse opening to permit fluid communication from the rotor longitudinal bore to an outer surface of the stator, followed sequentially by alignment of the at least one rotor transverse opening with the grooves.   
     
     
         7 . A fluid pressure pulse generator for forming part of a tubing string for use in a wellbore, the fluid pressure pulse generator comprising a tubular stator and a tubular rotor disposed for rotation within the stator to periodically align at least one rotor transverse opening with at least six stator transverse openings to permit fluid communication from a rotor longitudinal bore to a stator outer surface, wherein the at least six stator transverse openings are adapted to direct away from the stator outer surface in at least six different directions. 
     
     
         8 . The fluid pressure pulse generator  claim 7 , wherein the at least one rotor transverse openings comprises at least one pair of rotor transverse openings, wherein the pair of transverse openings are positioned on the rotor such that rotation of the rotor within the stator aligns the pair of rotor transverse openings simultaneously with a pair of the at least six stator transverse openings. 
     
     
         9 . The fluid pressure pulse generator of  claim 7 , wherein each of the stator transverse openings has a different longitudinal position on the stator.