Metal felt and brush structures as sealing elements in metal-metal mud motors

Abstract

A mud motor and a drill string having the mud motor. The mud motor includes a stator and a rotor. A lining between the stator and the rotor includes fibers forming a fiber pattern. The lining is a coating of at least one of a lobed inner surface of the stator and a lobed outer surface of the rotor.

What is claimed is: 
     
         1 . A mud motor, comprising:
 a stator;   a rotor; and   a lining between the stator and the rotor, the lining including fibers forming a fiber pattern.   
     
     
         2 . The mud motor of  claim 1 , wherein the lining is a coating of at least one of a lobed inner surface of the stator and a lobed outer surface of the rotor. 
     
     
         3 . The mud motor of  claim 2 , wherein the lining is adhered by at least one of: (i) an adhesive; (ii) a sintering process; (iii) a soldering process; (iv) a welding process; and (v) a brazing process. 
     
     
         4 . The mud motor of  claim 1 , wherein the fiber pattern further comprises one of: (i) a felt pattern; (ii) a web pattern; (iii) a mesh pattern; and (iv) a brush pattern. 
     
     
         5 . The mud motor of  claim 1 , wherein a material of the fibers includes at least one of: (i) nickel; (ii) nickel alloy; (iii) stainless steel; (iv) low alloy steel; (v) copper; (vi) copper alloy; (vii) carbon fiber; (viii) glass fiber; and (ix) polymeric fiber. 
     
     
         6 . The mud motor of  claim 1 , wherein the fiber pattern includes a gap between the fibers. 
     
     
         7 . The mud motor of  claim 6 , further comprising a secondary material in the gap, the secondary material being at least one of: (i) polytetrafluoroethylene (PTFE); (ii) polyether ether ketone (PEEK); (iii) a polymer; and (iv) an elastomer. 
     
     
         8 . The mud motor of  claim 6 , wherein the gap is unfilled. 
     
     
         9 . The mud motor of  claim 1 , wherein the mud motor is configured to operate at temperatures higher than 150 C for more than 40 circulation hours. 
     
     
         10 . A method for manufacturing a mud motor, the method comprising:
 forming a mud motor comprising a stator and a rotor; and   disposing a lining between the stator and the rotor, the lining including fibers forming a fiber pattern.   
     
     
         11 . The method of  claim 10 , wherein the lining disposed between the stator and the rotor by coating at least one of a lobed inner surface of the stator and a lobed outer surface of the rotor with the lining. 
     
     
         12 . The method of  claim 11 , further comprising adhering the lining by at least one of: (i) an adhesive; (ii) a sintering process; (iii) a soldering process; (iv) a welding process; and (v) a brazing process. 
     
     
         13 . The method of  claim 10 , wherein the fiber pattern further comprises one of: (i) a felt pattern; (ii) a web pattern; (iii) a mesh pattern; and (iv) a brush pattern. 
     
     
         14 . The method of  claim 10 , wherein a material of the fibers include at least one of: (i) nickel; (ii) nickel alloy; (iii) stainless steel; (iv) low alloy steel; (v) copper; (vi) copper alloy; (vii) carbon fiber; (viii) glass fiber; and (ix) polymeric fiber. 
     
     
         15 . The method of  claim 10 , wherein the fiber pattern includes one or more gaps between the fibers. 
     
     
         16 . The method of  claim 15 , wherein the gaps are filled with a secondary material, wherein the secondary material is at least one of: (i) PTFE (polytetrafluoroethylene); (ii) PEEK (polyether ether ketone); (iii) a polymer; and (iv) an elastomer. 
     
     
         17 . The method of  claim 15 , wherein the one or more gaps are unfilled. 
     
     
         18 . The method of  claim 10 , wherein the mud motor is configured to operate at temperatures higher than 150 C for more than 40 circulation hours.