Powder metal gripping elements for settable downhole tools having slips

Abstract

A settable downhole tool with millable powder metal slips having a case hardened edge and a soft core.

1 . A settable downhole tool comprising:
 a mandrel; and   a slip located about the mandrel for engaging a casing and holding the tool to the casing;   wherein the slip is comprised of one or more slip bodies and multiple gripping elements, the slip body or slip bodies holding the gripping elements;   at least some of the gripping elements are comprised of compacted powdered metal and have an outer layer and a core, the outer layer for engaging the casing and being case hardened to hardness in the range of 70-97 HR 15 N (superficial Rockwell); and the core supporting the outer layer and having hardness in the range of 12-60 HRB (Rockwell); and   wherein the tool, after being set in the casing, may be milled out of the casing in less time than needed to mill out a similar tool in which of the similar tool's gripping elements are carbide.   
     
     
         2 . The tool of  claim 1  wherein the hardness of the core is in the range of 17-50 HRB. 
     
     
         3 . The tool of  claim 2  wherein the hardness of the core is in the range of 17-40 HRB. 
     
     
         4 . The tool of  claim 1  wherein the compacted powdered metal is iron with up to 0.3% by weight carbon before the outer layer is hardened. 
     
     
         5 . The tool of  claim 1  wherein the compacted powdered metal is iron with up to 0.1% by weight carbon before the outer layer is hardened. 
     
     
         6 . The tool of  claim 1  wherein the outer layer is hardened by a process which leaves the hardness of the middle of the core materially unaffected. 
     
     
         7 . The tool of  claim 6  wherein the outer layer is hardened by a process which produces a gripping element having graduated hardness, the hardness of succeeding gripping element layers being inversely correlated to each layer's distance from the outer layer, the core being the softest portion of the gripping element. 
     
     
         8 . The tool of  claim 6  wherein the outer layer is case hardened by a nitriding, carbonitriding or carburizing process which leaves the hardness of the middle of the core materially unaffected. 
     
     
         9 . The tool of  claim 1  wherein the hardness of the outer layer is in the range of 75-90 HR 15 N. 
     
     
         10 . The tool of  claim 1  wherein the hardness of the outer layer is in the range of 75-90 HR 15 N. 
     
     
         11 . The tool of  claim 1  wherein the gripping element is comprised of MPIF/ASTM F-0000. 
     
     
         12 . The tool of  claim 1 , wherein at least some of the gripping elements are wickers having a hardened outer layer, wherein the outer layer is case hardened by a nitriding, carbonitriding or carburizing process which leaves the core materially unaffected. 
     
     
         13 . The tool of  claim 1 , wherein at least some of the gripping elements are inserts having a hardened outer layer, wherein the outer layer is case hardened by a nitriding, carbonitriding or carburizing process which leaves the core materially unaffected. 
     
     
         14 . The tool of  claim 1 , wherein the tool may be milled out of the casing in 50% or less time than needed to mill out a similar tool in which of the similar tool's gripping elements are carbide. 
     
     
         15 . The tool of  claim 1  wherein, upon milling the tool out of the casing, the largest 10% of the cuttings produced by the milling are at least 30% smaller than the largest 10% of the cuttings produced by milling out a similar tool with carbide inserts under similar conditions. 
     
     
         16 . A settable downhole tool comprising:
 a mandrel; and   a slip located about the mandrel for engaging a casing and holding the tool to the casing;   wherein the slip is comprised of one or more slip bodies and multiple gripping elements, the slip bodies holding the gripping elements;   at least some of the gripping elements are:
 made from compacted powdered iron having up to 0.3% by weight carbon, and have an outer layer and a core, 
 the outer layer is for engaging the casing and has been case hardened by nitriding, carbonitriding, or carburizing to be harder than the core and has a hardness in the range of 70-97 HR 15 N (superficial Rockwell); and 
 the core is for supporting the outer layer against the casing, and has hardness in the range of 12-60 HRB (Rockwell); and 
   wherein the tool, after being set in the casing, may be milled out of the casing in 50% or less time than needed to mill out a similar tool in which of the similar tool's gripping elements are carbide.   
     
     
         17 . A method of making the settable downhole tool of  claim 15  comprising:
 providing a mandrel; 
 providing a slip for being located about the mandrel for engaging a casing and holding the tool to the casing; wherein the slip is comprised of one or more slip bodies and multiple gripping elements, namely, wickers or inserts, the slip bodies holding the gripping elements; 
 providing at least some gripping elements manufactured from a single material; namely compacted powdered iron with up to 0.3% by weight carbon, and have an outer layer and a core, the outer layer being for engaging the casing and has been hardened by nitriding, carbonitriding or carburizing to be harder than the core and have hardness in the range of 70-97 HR 15 N (superficial Rockwell); and the core is held by a slip body, is for supporting the outer layer against the casing, and has hardness in the range of 12-60 HRB (Rockwell); 
 wherein the gripping element is hardened by a process which produces a gripping element having graduated hardness, the hardness of succeeding gripping element layers being inversely correlated to each layer's distance from the outer layer, the core being the softest portion of the gripping element; and 
 assembling the mandrel, slip and gripping elements to make a tool which may be milled out of the casing in 50% or less time than needed to mill out a similar tool in which of the similar tool's gripping elements are carbide. 
 
     
     
         18 . A settable downhole tool comprising:
 a mandrel; and   a slip located about the mandrel for engaging a casing and holding the tool to the casing;   wherein the slip is comprised of a unitary body having multiple gripping elements on the slips outer surface; wherein:
 the slip is made from compacted powdered iron having up to 0.3% by weight carbon, and has an outer layer and a core, 
 the outer layer is for engaging the casing and has been case hardened by nitriding, carbonitriding or carburizing to be harder than the core and has a hardness in the range of 70-97 HR 15 N (superficial Rockwell); 
 the core is for supporting the outer layer against the casing and has hardness in the range of 12-60 HRB (Rockwell); and
 the slip has one or more relatively thin sections which extend from the upper end of the slip to the lower end of the slip for preferentially breaking at the thin sections as the slip is expanded when the tool is set in the casing. 
 
   
     
     
         19 . A settable downhole tool comprising:
 a mandrel;   gripping element;   a packing element;
 wherein the slip comprises a gripping element comprising compacted powdered metal having a core and an outer layer, wherein the core has a hardness in the range of 12-60 HRB (Rockwell) and is a softer material than the harder outer layer. 
   
     
     
         20 . The downhole tool of  claim 19 , wherein the slip includes a slip body and wherein the gripping element comprises multiple powder metal buttons engaging the slip body. 
     
     
         21 . The downhole tool of  claim 20 , wherein at least some of the buttons are cylindrical, with a length of between 0.25″ and 0.375″ and a diameter of between 0.350″ and 0.400.″ 
     
     
         22 . The downhole tool of  claim 20 , wherein the powdered metal buttons are low or no carbon iron. 
     
     
         23 . The downhole tool of  claim 20 , wherein the harder outer layer is carbonitrided. 
     
     
         24 . The downhole tool of  claim 20 , wherein the harder outer layer has a hardness in the range of 70-97 HR15N (superficial Rockwell). 
     
     
         25 . The downhole tool of  claim 20 , wherein at least one of the slip body, packing element, cone or mandrel is made, at least partly, from a material degradable in a downhole fluid. 
     
     
         26 . The downhole tool of  claim 20 , wherein at least one of the slip body, packing element, cone or mandrel is made, at least partly, from a millable material. 
     
     
         27 . The downhole tool of  claim 20 , wherein at least one of the slip body, packing element, cone or mandrel is made, at least partly, from a millable non-metallic material comprising a composite material. 
     
     
         28 . The downhole tool of  claim 20 , wherein the harder outer layer is between 0.005″ and 0.040″ thick. 
     
     
         29 . The downhole tool of  claim 20 , wherein the core has a hardness in the range of 12-60 HRB (Rockwell). 
     
     
         30 . The downhole tool of  claim 19 , wherein the slip includes a slip body and wherein the gripping element comprises a multiplicity of powder metal wicker pads. 
     
     
         31 . The downhole tool of  claim 30 , wherein the powdered metal wicker pads are low or no carbon iron. 
     
     
         32 . The downhole tool of  claim 30 , wherein the harder outer layer is carbonitrided. 
     
     
         33 . The downhole tool of  claim 30 , wherein the harder outer layer has a hardness in the range of 70-97 HR15N (superficial Rockwell). 
     
     
         34 . The downhole tool of  claim 30 , wherein at least one of the slip body, packing element, cone or mandrel is made, at least partly, from a material degradable in a downhole fluid. 
     
     
         35 . The downhole tool of  claim 30 , wherein at least one of the slip body, packing element, cone or mandrel is made, at least partly, from a millable material. 
     
     
         36 . The downhole tool of  claim 30 , wherein at least one of the slip body, packing element, cone or mandrel is made, at least partly, from a millable non-metallic material comprising a composite material. 
     
     
         37 . The downhole tool of  claim 30 , wherein the harder outer layer is between 0.005″ and 0.040″ thick. 
     
     
         38 . The downhole tool of  claim 29 , wherein the wicker pad has arms for engaging the slip body. 
     
     
         39 . The downhole tool of  claim 29 , wherein the wicker pad has dovetail side walls for engaging the slip body. 
     
     
         40 . The downhole tool of  claim 30 , wherein the core has a hardness in the range of 12-60 HRB (Rockwell). 
     
     
         41 . The downhole tool of  claim 19 , wherein the gripping element is a powder metal wicker. 
     
     
         42 . The downhole tool of  claim 41  wherein the powdered metal wicker is low or no carbon iron. 
     
     
         43 . The downhole tool of  claim 41 , wherein the harder outer layer is carbonitrided or borized 
     
     
         44 . The downhole tool of  claim 41 , wherein the harder outer layer has a hardness in the range of 70-97 HR15N (superficial Rockwell). 
     
     
         45 . The downhole tool of  claim 41 , wherein at least one of the slip body, packing element, cone or mandrel is made, at least partly, from a material degradable in a downhole fluid. 
     
     
         46 . The downhole tool of  claim 41 , wherein at least one of the slip body, packing element, cone or mandrel is made, at least partly, from a millable material. 
     
     
         47 . The downhole tool of  claim 41 , wherein at least one of the slip body, packing element, cone or mandrel is made, at least partly, from a millable non-metallic material comprising a composite material. 
     
     
         48 . The downhole tool of  claim 41 , wherein the harder outer layer is between 0.005″ and 0.040″ thick. 
     
     
         49 . The downhole tool of  claim 41 , wherein the core has a hardness in the range of 12-60 HRB (Rockwell). 
     
     
         50 . A slip for a downhole tool, the slip comprising:
 a gripping element comprising compacted powder metal, the gripping element having a hard outer layer for gripping a tubing and core supporting the outer layer and having hardness in the range of 12-60 HRB (Rockwell).   
     
     
         51 . The slip of  claim 50 , wherein the gripping element is a powder metal button and the slip includes a slip body. 
     
     
         52 . The slip of  claim 50 , wherein the gripping element is a powder metal wicker pad and the slip includes a slip body. 
     
     
         53 . The slip of  claim 50 , wherein the gripping element is a powder metal wicker. 
     
     
         54 . The slip of  claim 51 , wherein the powdered metal buttons are low or no carbon iron. 
     
     
         55 . The slip of  claim 51 , wherein the harder outer layer is carbonitrided. 
     
     
         56 . The slip of  claim 51 , wherein the harder outer layer has a hardness in the range of 70-97 HR15N (superficial Rockwell). 
     
     
         57 . The slip of  claim 52 , wherein the powdered metal buttons are low or no carbon iron. 
     
     
         58 . The slip of  claim 52 , wherein the harder outer layer is carbonitrided. 
     
     
         59 . The slip of  claim 52 , wherein the harder outer layer has a hardness in the range of 70-97 HR15N (superficial Rockwell). 
     
     
         60 . The slip of  claim 53 , wherein the powdered metal buttons are low or no carbon iron. 
     
     
         61 . The slip of  claim 53 , wherein the harder outer layer is carbonitrided. 
     
     
         62 . The slip of  claim 53 , wherein the harder outer layer has a hardness in the range of 70-97 HR15N (superficial Rockwell).