Methods of generating magnetic particles in a subterranean environment

Abstract

The subject disclosure relates to methods of generating magnetic particles in a wellbore. More particularly, the subject disclosure relates to a fluid system which comprises two or more fluids which react chemically to generate magnetic particles in a wellbore.

1 . A method of generating magnetic particles in a wellbore comprising:
 introducing a fluid system into the wellbore comprising a first fluid and a second fluid; and   reacting chemically the first fluid and the second fluid in the wellbore to form a plurality of magnetic particles.   
     
     
         2 . The method of  claim 1  wherein the plurality of magnetic particles are magnetically attracted to one another in response to exposure to a magnetic field. 
     
     
         3 . The method of  claim 1  wherein the first fluid comprises one or a plurality of irons salts. 
     
     
         4 . The method of  claim 3  wherein the one or the plurality of iron salts comprises at least an iron (II) salt and an iron (III) salt. 
     
     
         5 . The method of  claim 3  wherein the iron (II) salt is selected from the group consisting of:
 iron (II) chloride tetrahydrate, iron (II) sulfate heptahydrate, iron (II) sulfate hydrate, iron (II) oxalate dehydrate, and combinations thereof. 
 
     
     
         6 . The method of  claim 3  wherein the iron (III) salt is selected from the group consisting of:
 iron (III) chloride hexahydrate, iron (III) nitrate nonahydrate, ion (III) sulfate hydrate; iron (III) oxalate hexahydrate, and combinations thereof. 
 
     
     
         7 . The method of  claim 1  wherein the plurality of magnetic particles are iron oxide particles. 
     
     
         8 . The method of  claim 7  wherein the iron oxide particles are magnetite or maghemite. 
     
     
         9 . The method of  claim 1  wherein the second fluid comprises hydroxide ions. 
     
     
         10 . The method of  claim 9  wherein the hydroxide ions are selected from the group consisting of:
 sodium hydroxide, potassium hydroxide, barium hydroxide, strontium hydroxide, calcium hydroxide, lithium hydroxide, rubidium hydroxide, caesium hydroxide or ammonium hydroxide and combinations thereof. 
 
     
     
         11 . The method of  claim 1  wherein the second fluid is a cement slurry. 
     
     
         12 . The method of  claim 1  wherein the first and the second fluid are non-magnetic. 
     
     
         13 . The method of  claim 1  wherein a dispersion of the plurality of particles is sufficient for at least one use selected from the group consisting of: downhole sensing or downhole flow control. 
     
     
         14 . The method of  claim 1  wherein the plurality of particles are used in a downhole valve. 
     
     
         15 . The method of  claim 1  wherein the plurality of particles are formed by co-precipitation. 
     
     
         16 . The method of  claim 1  further comprising detecting the plurality of particles with a sensor in a well logging tool. 
     
     
         17 . A process for producing a plurality of magnetic particles comprising:
 introducing a fluid system into a wellbore comprising a first fluid and a second fluid;   reacting chemically the first fluid and the second fluid in the wellbore; and   co-precipitating a plurality of magnetic particles from said chemical reaction.