Dissolvable, protective covering for downhole tool components

Abstract

A downhole tool can include: an inner mandrel; at least one component, wherein a portion of the at least one component moves in a direction radially away from the inner mandrel when the downhole tool is set; and a protective covering, wherein the protective covering comprises a dissolvable material, and wherein the protective covering partially surrounds an outer diameter of the at least one component when the downhole tool is run-in. The downhole tool can be introduced into a wellbore. The protective covering can dissolve via chemical reactions of metals, metal alloys, or metal oxides, or by melting of a thermoplastic. The downhole tool can be set after the protective covering has dissolved. The tool can be a packer assembly, bridge plug, frac pack plug, or liner hangers. The at least one component of the downhole tool can be a sealing element, a collet, a split wedge, or a slip.

What is claimed is: 
     
         1 . A downhole tool comprising:
 an inner mandrel;   at least one component, wherein a portion of the at least one component moves in a direction radially away from the inner mandrel when the downhole tool is set; and   a protective covering, wherein the protective covering comprises a dissolvable material, and wherein the protective covering partially surrounds an outer diameter of the at least one component when the downhole tool is run-in.   
     
     
         2 . The downhole tool according to  claim 1 , wherein the downhole tool is selected from a packer assembly, a bridge plug, liner hangers, or a frac pack plug. 
     
     
         3 . The downhole tool according to  claim 1 , wherein the at least one component is selected from a sealing element, a collet, a split wedge, or a slip. 
     
     
         4 . The downhole tool according to  claim 1 , wherein the protective covering completely surrounds the entire outer diameter of the at least one component. 
     
     
         5 . The downhole tool according to  claim 1 , wherein one protective covering completely surrounds a two or more components. 
     
     
         6 . The downhole tool according to  claim 1 , wherein the dissolvable material comprises a metal, a metal alloy, or a metal oxide. 
     
     
         7 . The downhole tool according to  claim 6 , wherein the metal or metal alloy chemically reacts with water to form a metal oxide, and wherein the metal oxide chemically reacts with water to hydrolyze and form a metal hydroxide. 
     
     
         8 . The downhole tool according to  claim 7 , wherein the metal hydroxide is insoluble in a basic solution, and wherein the metal hydroxide chemically reacts with an acidic solution to form an ionic compound of the metal cation from the metal hydroxide and the anion from the acid plus water. 
     
     
         9 . The downhole tool according to  claim 6 , wherein the metal or metal alloy chemically reacts with water to form a metal oxide, and wherein the metal oxide chemically reacts with an acidic solution to form a salt of the metal oxide and water. 
     
     
         10 . The downhole tool according to  claim 6 , wherein the metal, the metal of the metal alloy, or the metal of the metal oxide are selected from an alkaline earth metal, a transition metal, or a post-transition metal. 
     
     
         11 . The downhole tool according to  claim 10 , wherein the alkaline earth metal is selected from magnesium or calcium, the transition metal is selected from iron, cobalt, nickel, zinc, copper, or tungsten, and the post-transition metal is aluminum. 
     
     
         12 . The downhole tool according to  claim 1 , wherein the protective covering dissolves via galvanic corrosion in the presence of an electrolyte, wherein the protective covering comprises a first metal and a second metal, and wherein the first metal is an anode and the second metal is a cathode. 
     
     
         13 . The downhole tool according to  claim 1 , wherein the protective covering comprises a thermoplastic, and wherein the thermoplastic dissolves at a temperature greater than or equal to the melting point of the thermoplastic. 
     
     
         14 . The downhole tool according to  claim 1 , wherein the protective covering has a length in a range within 10% to 150% of a length of the at least one component. 
     
     
         15 . A method of introducing a downhole tool into a wellbore comprising:
 (A) positioning the downhole tool at a desired location within the wellbore, wherein the downhole tool comprises:
 an inner mandrel; 
 at least one component; and 
 a protective covering, wherein the protective covering comprises a dissolvable material, and wherein the protective covering partially surrounds an outer diameter of the at least one component while the downhole tool is being positioned at the desired location within the wellbore; 
   (B) causing or allowing the protective covering to dissolve; and   (C) setting the downhole tool at the desired location within the wellbore after the protective covering has dissolved, wherein a portion of the at least one component moves in a direction radially away from the inner mandrel during setting.   
     
     
         16 . The method according to  claim 15 , wherein:
 the dissolvable material comprises a metal, a metal alloy, or a metal oxide, and wherein the protective sleeve dissolves via a chemical reaction of the metal, the metal alloy, or the metal oxide with water or an acidic solution; or   the protective covering dissolves via galvanic corrosion in the presence of an electrolyte, wherein the protective covering comprises a first metal and a second metal, and wherein the first metal is an anode and the second metal is a cathode; or   the dissolvable material comprises a thermoplastic, and wherein the thermoplastic dissolves at a temperature greater than or equal to the melting point of the thermoplastic.   
     
     
         17 . The method according to  claim 16 , wherein the downhole tool is run into the wellbore in a first fluid, and wherein the first fluid is selected such that the first fluid dissolves less than 15% of the protective covering and the protective covering maintains structural integrity. 
     
     
         18 . The method according to  claim 17 , further comprising introducing a second fluid into the wellbore after the downhole tool has reached the desired location within the wellbore, and wherein the second fluid is selected such that the second fluid dissolves more than 15% of the protective covering. 
     
     
         19 . The method according to  claim 17 , wherein the first fluid dissolves more than 15% of the protective covering after the downhole tool has reached the desired location within the wellbore. 
     
     
         20 . The method according to  claim 15 , wherein the protective covering dissolves in a time in the range of 20% to 200% greater than the time to position the downhole tool at the desired location within the wellbore.