Galvanically-active in situ formed particles for controlled rate dissolving magnesium alloy

Abstract

A dissolvable magnesium alloy can be used for components of a downhole tool. The dissolvable magnesium alloy can be dissolved completely and controlled at a dissolving rate so as to be compatible with downhole operations, including hydraulic fracturing operations. The alloy includes nickel at 0.04-0.4% by weight and the balance of magnesium. The alloy is dissolvable in KCl at 2.1% by weight and 95° C. with a dissolving rate in a range of 10-100 mg/cm2/hr, yield strength in a range of 18-37 ksi, ultimate tensile strength in a range of 29-47 ksi, and elongation in a range of 8-40%.

We claim: 
     
         1 . A dissolvable magnesium composite that at least partially forms a ball, a frac ball, a tube, a plug or other tool component that is to be used in a well drilling or completion operation, said dissolvable magnesium composite includes in situ precipitate, said dissolvable magnesium composite comprising a mixture of magnesium or a magnesium alloy and an additive material, said magnesium composite includes greater than about 60 wt. % magnesium, said in situ precipitate includes said additive material, said additive material includes one or more metal materials selected from the group consisting of:
 a) nickel, wherein said nickel constitutes about 0.04-0.4 wt. % of said dissolvable magnesium composite, and   b) copper, wherein said copper constitutes about 0.1-10 wt. % of said dissolvable magnesium composite,   said dissolvable magnesium composite has a dissolution rate of at least 10 mg/cm 2 /hr. in 2.1 wt. % KCl water mixture at 93° C.   
     
     
         2 . The dissolvable alloy of  claim 1 , wherein said dissolvable magnesium composite has yield strength in a range of from about 25 to about 37 ksi. 
     
     
         3 . The dissolvable alloy of  claim 1 , wherein said dissolvable magnesium composite has ultimate tensile strength in a range of from about 35 to about 45 ksi. 
     
     
         4 . The dissolvable alloy of  claim 1 , wherein said dissolvable magnesium composite has an elongation in a range of from about 10 to about 19%. 
     
     
         5 . The dissolvable alloy of  claim 1 , wherein said magnesium alloy comprises greater than 60 wt. % magnesium and no more than 10 wt. % aluminum, and one or more metals selected from the group consisting of 0.5-10 wt. % aluminum, 0.1-2 wt. % zinc, and 0.15-2 wt. % manganese. 
     
     
         6 . The dissolvable alloy of  claim 1 , wherein said magnesium alloy comprises greater than 60 wt. % magnesium and no more than 10 wt. % aluminum, and one or more metals selected from the group consisting of 0.5-10 wt. % gadolinium, 0.1-6 wt. % yttrium, and 0.15-12 wt. % lithium. 
     
     
         7 . The dissolvable alloy of  claim 1 , wherein said additive material includes nickel, said nickel constitutes 0.15-0.4 wt. % of said dissolvable magnesium composite. 
     
     
         8 . A dissolvable magnesium cast composite comprising a mixture of magnesium or a magnesium alloy and an additive material, said additive material includes one or more metals selected from the group consisting of a) copper wherein said copper constitutes at least 0.01 wt. % of said dissolvable magnesium cast composite, and b) nickel wherein said nickel constitutes at least 0.01 wt. % of said dissolvable magnesium cast composite, said magnesium composite includes in situ precipitate, said in situ precipitate includes said additive material, a plurality of particles of said in situ precipitate having a size of no more than 50 μm, said magnesium composite has a dissolution rate of at least 5 mg/cm 2 /hr. in 3 wt. % KCl water mixture at 90° C. 
     
     
         9 . The dissolvable alloy of  claim 8 , wherein said dissolvable magnesium composite has yield strength in a range of from about 25 to about 37 ksi. 
     
     
         10 . The dissolvable alloy of  claim 8 , wherein said dissolvable magnesium composite has ultimate tensile strength in a range of from about 35 to about 45 ksi. 
     
     
         11 . The dissolvable alloy of  claim 8 , wherein said dissolvable magnesium composite has an elongation in a range of from about 10 to about 19%. 
     
     
         12 . The dissolvable alloy of  claim 8 , wherein said magnesium alloy comprises greater than 50 wt. % magnesium and no more than 10 wt. % aluminum, and one or more metals selected from the group consisting of 0.5-10 wt. % aluminum, 0.1-2 wt. % zinc, and 0.15-2 wt. % manganese. 
     
     
         13 . The dissolvable alloy of  claim 8 , wherein said magnesium alloy comprises greater than 60 wt. % magnesium and no more than 10 wt. % aluminum, and one or more metals selected from the group consisting of 0.5-10 wt. % gadolinium, 0.1-6 wt. % yttrium, and 0.15-12 wt. % lithium. 
     
     
         14 . The dissolvable alloy of  claim 8 , wherein said additive material includes nickel, said nickel constitutes 0.15-0.4 wt. % of said dissolvable magnesium composite. 
     
     
         15 . A dissolvable magnesium cast composite comprising a mixture of magnesium or a magnesium alloy and an additive material, said additive material includes a) nickel wherein said nickel constitutes 0.01-0.4 wt. % of said dissolvable magnesium cast composite, said dissolvable magnesium cast composite includes in situ precipitate, said in situ precipitate includes said additive material, said dissolvable magnesium cast composite has a dissolution rate of at least 75 mg/cm 2 /hr. in 3 wt. % KCl water mixture at 90° C. 
     
     
         16 . The dissolvable alloy of  claim 15 , wherein said dissolvable magnesium composite has yield strength in a range of from about 25 to about 37 ksi. 
     
     
         17 . The dissolvable alloy of  claim 15 , wherein said dissolvable magnesium composite has ultimate tensile strength in a range of from about 35 to about 45 ksi. 
     
     
         18 . The dissolvable alloy of  claim 15 , wherein said dissolvable magnesium composite has an elongation in a range of from about 10 to about 19%. 
     
     
         19 . The dissolvable alloy of  claim 15 , wherein said magnesium alloy comprises greater than 50 wt. % magnesium and no more than 10 wt. % aluminum, and one or more metals selected from the group consisting of 0.5-10 wt. % aluminum, 0.1-2 wt. % zinc, and 0.15-2 wt. % manganese. 
     
     
         20 . The dissolvable alloy of  claim 15 , wherein said magnesium alloy comprises greater than 50 wt. % magnesium and no more than 10 wt. % aluminum, and one or more metals selected from the group consisting of 0.5-10 wt. % gadolinium, 0.1-6 wt. % yttrium, and 0.15-12 wt. % lithium.