Methods for removing metals and cations thereof from oil-based fluids

Abstract

An effective amount of a hydrazine complexing agent and/or a non-hydrazine complexing agent may be added to an oil-based fluid having at least one metal. The complexing agent may form an insoluble metal complex with the metal(s). The metal(s) may be or include, but are not limited to zinc metal, nickel metal, iron metal, cations thereof, and combinations thereof. The insoluble metal complex may be or include, but is not limited to a zinc complex, a nickel complex, an iron complex, and combinations thereof. The insoluble metal complex may be removed from the oil-based fluid where the metal may be separated from the insoluble metal complex.

What is claimed is: 
     
         1 . A method for removing metals from an oil-based fluid comprising:
 adding an effective amount of hydrazine to an oil-based fluid to form an insoluble metal complex selected from the group consisting of a zinc hydrazine complex, a nickel hydrazine complex, an iron hydrazine complex, and combinations thereof; wherein the oil-based fluid comprises at least one metal selected from the group consisting of zinc metal, nickel metal, iron metal, cations thereof, and combinations thereof.   
     
     
         2 . The method of  claim 1  wherein the effective amount of the hydrazine ranges from about 10 wt % to about 50 wt %. 
     
     
         3 . The method of  claim 1  wherein a molar ratio of hydrazine to the at least one metal ranges from about one to about three moles of hydrazine to about one mole of the at least one metal. 
     
     
         4 . The method of  claim 1  further comprising physically removing the insoluble metal complex from the oil-based fluid. 
     
     
         5 . The method of  claim 4 , wherein the physically removing the insoluble metal complex occurs by a process selected from the group consisting of filtering, centrifugation, settling, and combinations thereof. 
     
     
         6 . The method of  claim 4  further comprising subjecting the oil-based fluid comprising the insoluble metal complex to flocculation and/or coagulation prior to removing the insoluble metal complex. 
     
     
         7 . The method of  claim 6 , wherein an additive selected from the group consisting of nonionic, cationic, amphoteric, and anionic polymers; lime; alum; ferric sulfate; and
 mixtures thereof is added to the oil-based fluid in an amount effective to assist the flocculation/coagulation.   
     
     
         8 . The method of  claim 1  wherein the insoluble metal complex is reusable. 
     
     
         9 . The method of  claim 1 , wherein the oil-based fluid is selected from the group consisting of crude oil, a refinery fluid, a production fluid, and combinations thereof. 
     
     
         10 . The method of  claim 1 , wherein the oil-based fluid is selected from the group consisting of a drilling fluid, a completion fluid, a fracturing fluid, a servicing fluid, a stimulation fluid, a treating fluid, and combinations thereof. 
     
     
         11 . The method of  claim 1 , wherein the oil-based fluid further comprises an effective amount of a non-hydrazine complexing agent to form the insoluble metal complex. 
     
     
         12 . A method for removing metals from an oil-based fluid comprising:
 adding an effective amount of a non-hydrazine complexing agent to an oil-based fluid to form an insoluble metal complex selected from the group consisting of a zinc metal complex, a nickel metal complex, an iron metal complex, and combinations thereof; and wherein the oil-based fluid comprises at least one metal selected from the group consisting of zinc metal, nickel metal, iron metal, cations thereof, and combinations thereof; and wherein the non-hydrazine complexing agent is selected from the group consisting of monodentate, bidentate, or poly dentate amine compounds; amino-ether, amino-alcohol, amino-ketone, and phosphorous analogs; and combinations thereof.   
     
     
         13 . The method of  claim 12 , wherein the monodentate, bidentate, or poly dentate amine compounds are selected from the group consisting of ethylenediamine (EDA), diethylenetriamine (DETA), trithethylenetetramine (TETA), tetraethylenepentamine (TEPA), aminoethylethanolamine (AEEA), diethanol amine (DEA), diethyl amine, hexamethyltetraamine, monoethyl amine, poly amines, and mixtures thereof. 
     
     
         14 . The method of  claim 12 , wherein the non-hydrazine complexing agent is immobilized onto a substrate. 
     
     
         15 . The method of  claim 14 , wherein the substrate is selected from the group consisting of nanoparticles, zeolites, polymer chains, solid substrates, nanotubes, and mixtures thereof. 
     
     
         16 . The method of  claim 12 , further comprising physically removing the insoluble metal complex from the oil-based fluid. 
     
     
         17 . The method of  claim 12 , wherein the physically removing the insoluble metal complex occurs by a process selected from the group consisting of filtering, centrifugation, settling, and combinations thereof. 
     
     
         18 . The method of  claim 17  further comprising subjecting the oil-based fluid comprising the insoluble metal complex to flocculation and/or coagulation prior to removing the insoluble metal complex.