Drilling Motor Bearing Assembly

Abstract

A drilling motor bearing assembly having a longitudinal axis with an outer upper tubular housing threadedly connected to a lower outer tubular housing. The outer upper tubular housing is threadedly engaged to the stator of a power section of a downhole drilling motor assembly. A mandrel having a central bore is threadedly connected to a bearing sub that is threadedly connected to a longitudinally extending rotatable drive shaft so that the mandrel rotates upon rotation of the drive shaft. A lower rotor bearing is connected to the mandrel. A stationary stator bearing is fixed to the lower outer tubular housing at a desired predetermined position so that that the lower rotor bearing rotates with the mandrel relative to the fixed stationary stator bearing. The fixed location of the stator bearing dictates the axial location of the component parts of the bearing assembly.

1 . A drilling motor bearing assembly comprising:
 a. an outer upper tubular housing threadedly connected to a lower outer tubular housing;   b. a mandrel having a central bore, said mandrel threadedly connected to a bearing sub, said bearing sub having an upper end threadedly connected to a longitudinally extending rotatable drive shaft whereby said mandrel rotates upon rotation of said rotatable drive shaft;   c. a lower rotor bearing connected to said mandrel, said lower rotor bearing having an upper rotor bearing face;   d. a stationary stator bearing positioned at a predetermined position to said lower outer tubular housing, said stationary stator bearing having a lower stator bearing face;   e. a threaded section on said upper tubular housing threadedly engageable to the stator of a power section of a downhole drilling motor assembly; and   f. wherein no preloading mechanism is provided.   
     
     
         2 . The drilling motor bearing assembly recited in  claim 1  wherein:
 a. said lower stator bearing face on said stationary stator bearing is engageable with said upper rotor bearing face of said lower rotor bearing; and 
 b. wherein said lower rotor bearing rotates with said mandrel relative to said stationary stator bearing. 
 
     
     
         3 . The drilling motor bearing assembly recited in  claim 2  wherein said stationary stator bearing is constrained from rotation and from axial movement relative to said lower outer tubular housing. 
     
     
         4 . The drilling motor bearing assembly recited in  claim 3  wherein said lower stator bearing face on said stationary stator is comprised of a hard or super hard material. 
     
     
         5 . The drilling motor bearing assembly recited in  claim 4  wherein said upper rotor bearing face on said lower rotor bearing is comprised of a hard or superhard material 
     
     
         6 . The drilling motor bearing assembly recited in  claim 5  further comprising a workstring connected to said power section of said downhole drilling motor assembly with said threaded section on said outer upper tubular housing threadedly engaged to said stator of said power section of said downhole drilling motor assembly. 
     
     
         7 . The drilling motor bearing assembly recited in  claim 6  wherein said hard or superhard material of said stator upper bearing face of said stationary stator and wherein said hard or superhard material of said upper rotor bearing face of said lower rotor bearing are selected from the group comprised of carbide, polycrystalline diamond PDC/PCD, or ceramics. 
     
     
         8 . The drilling motor bearing assembly recited in  claim 6  wherein said stationary stator bearing is integral with said lower outer tubular housing. 
     
     
         9 . A drilling motor bearing assembly, said drilling motor bearing assembly having component parts comprising:
 a. an outer upper tubular housing threadedly connected to a lower outer tubular housing along a longitudinal axis;   b. a mandrel having a central bore, said mandrel threadedly connected to a bearing sub, said bearing sub having an upper end threadedly connected to a longitudinally extending rotatable drive shaft whereby said mandrel rotates upon rotation of said rotatable drive shaft;   c. a lower rotor bearing connected to said mandrel;   d. a stationary stator bearing fixed to said lower outer tubular housing at a desired predetermined axial position within said lower outer tubular housing wherein said stationary stator bearing is constrained from rotation and from axial movement relative to said lower outer tubular housing;   e. a threaded section on said upper tubular housing threadedly engageable to the stator of a power section of a downhole drilling motor assembly; and   f. wherein no preloading mechanism is provided   
     
     
         10 . The drilling motor bearing assembly recited in  claim 9  wherein said lower rotor bearing rotates with said mandrel relative to said fixed stationary stator bearing. 
     
     
         11 . The drilling motor bearing assembly recited in  claim 10  wherein said predetermined location of said stationary stator bearing dictates the axial location of said component parts of said drilling motor bearing assembly along said longitudinal axis. 
     
     
         12 . The drilling motor bearing assembly recited in  claim 11  wherein said desired predetermined axial position of said stationary stator bearing within said lower outer tubular housing predetermines the tolerances, gaps, and spacing between said component parts of said drilling motor bearing assembly. 
     
     
         13 . The drilling motor bearing assembly recited in  claim 12  wherein said lower outer tubular housing is integral with said stationary stator bearing. 
     
     
         14 . The drilling motor bearing assembly recited in  claim 13  wherein said driveshaft is an integral component of said bearing sub. 
     
     
         15 . The drilling motor bearing assembly recited in  claim 14  further comprising a workstring connected to a power section of said downhole drilling motor assembly, said power section having a stator and a rotor, said threaded section on said outer upper tubular housing threadedly engaged to said stator of said power section. 
     
     
         16 . The drilling motor bearing assembly recited in  claim 14  wherein said desired predetermined axial position of said stationary stator bearing allows said drilling motor bearing assembly to be assembled only one way. 
     
     
         17 . A downhole drilling motor assembly comprising:
 a. workstring;   b. a power section having a rotor connected to a longitudinally extending rotatable driveshaft; and   c. a bearing assembly, said bearing assembly having:
 i. a longitudinally extending outer upper tubular housing threadedly connected to a longitudinally extending lower outer tubular housing along a longitudinal axis; 
 ii. a mandrel having a central bore, said mandrel threadedly connected to a bearing sub, said bearing sub having an upper end threadedly connected to a longitudinally extending rotatable drive shaft whereby said mandrel rotates about said longitudinal axis of said lower tubular housing upon rotation of said rotatable drive shaft; 
 iii. a lower rotor bearing connected to said mandrel; 
 iv. a stationary stator bearing integral with said lower outer tubular housing at a desired predetermined axial position, said stationary stator bearing constrained from rotation and axial movement relative to said lower outer tubular housing; 
 v. a threaded section on said upper tubular housing threadedly engageable to said stator of said power section; 
 vi. wherein said lower rotor bearing of said bearing assembly rotates with said mandrel relative to said fixed stationary stator bearing about said longitudinal axis of said lower tubular housing; and 
 vii. wherein no preloading mechanism is provided. 
   
     
     
         18 . The downhole drilling motor assembly recited in  claim 17  wherein said desired predetermined axial position of said stationary stator bearing within said lower tubular housing of said bearing assembly predetermines the axial location of the component parts of said bearing assembly along said longitudinal axis and predetermines the tolerances, gaps, and spacing between said component parts of said bearing assembly. 
     
     
         19 . The downhole drilling motor assembly recited in  claim 18  wherein said stationary stator bearing of said bearing assembly has a lower stator bearing face engageable with an upper rotor bearing face on said lower rotor bearing and wherein said lower stator bearing face and said upper rotor bearing face of said bearing assembly are comprised of hard or super hard material selected from the group comprised of carbide, polycrystalline diamond PDC/PCD, or ceramics. 
     
     
         20 . The downhole drilling motor assembly recited in  claim 19  wherein said driveshaft is an integral component of said bearing sub. 
     
     
         21 . A method for assembly of a downhole drilling motor bearing comprising the steps of:
 a. providing a bearing assembly having component parts comprising:
 i. a longitudinally extending outer upper tubular housing threadedly connected to a longitudinally extending lower outer tubular housing along a longitudinal axis; 
 ii. a mandrel having a central bore; 
 iii. a lower rotor bearing connected to said mandrel; 
 iv. a stationary stator bearing integral with said lower outer tubular housing at a desired predetermined axial position, said stationary stator bearing constrained from rotation and axial movement relative to said lower outer tubular housing; 
 v. a threaded section on said stationary stator; 
 vi. a threaded section on said upper tubular housing; 
   b. threadedly engaging said threaded section on said stationary stator with said threaded section of said power section without compression whereby said lower rotor bearing of said bearing assembly rotates with said mandrel relative to said fixed stationary stator bearing about said longitudinal axis of said lower tubular housing; and   c. wherein no preloading mechanism is provided.   
     
     
         22 . The method for assembly of a downhole drilling motor bearing recited in  claim 21  wherein said step of providing said bearing assembly includes fixing said stationary stator bearing of said bearing assembly at a desired predetermined location within said lower tubular housing of said bearing assembly thereby predetermining the tolerances, gaps, and spacing between said component parts of said bearing assembly. 
     
     
         23 . The method for assembly of a downhole drilling motor bearing recited in  claim 22  comprising the additional steps of:
 a. providing a workstring having a power section, said power section having a rotor connected to a longitudinally extending rotatable driveshaft; and 
 b. providing a bearing sub; 
 c. connecting said bearing sub to said mandrel of said bearing assembly, 
 d. connecting said bearing sub to said longitudinally extending rotatable drive shaft whereby said mandrel of said bearing assembly rotates about said longitudinal axis of said lower tubular housing of said bearing assembly upon rotation of said rotatable drive shaft. 
 
     
     
         24 . The method for assembly of a downhole drilling motor bearing recited in  claim 23  wherein said stationary stator bearing of said bearing assembly has a lower stator bearing face engageable with an upper rotor bearing face on said lower rotor bearing and wherein said lower stator bearing face and said upper rotor bearing face are comprised of hard or super hard material selected from the group comprised of carbide, polycrystalline diamond PDC/PCD, or ceramics. 
     
     
         25 . The method for assembly of a downhole drilling motor bearing recited in  claim 24  wherein said driveshaft is an integral component of said bearing sub.