Drilling fluid recovery

Abstract

A method for recovering drilling fluid from a mixture containing drilling fluid and other components, the mixture resulting from a wellbore operation including the pumping of drilling fluid, the method including producing a mixture of flocculant with a spent drilling fluid mixture containing drilling fluid and contaminants, heating the mixture, and separating drilling fluid from the mixture. This Abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims, 37 CFR 1.72(b).

1 . A method for recovering drilling fluid from a mixture containing drilling fluid and other components, the mixture resulting from a wellbore operation including the pumping of drilling fluid, the method comprising
 producing a mixture of flocculant with a spent drilling fluid, the spent drilling fluid containing drilling fluid and contaminants,   heating the mixture, and   separating drilling fluid from the mixture.   
   
   
       2 . The method of  claim 1  wherein the heating is effected by injecting steam into the mixture. 
   
   
       3 . The method of  claim 1  wherein the mixture is in a flow conduit and the steam is injected into the mixture within the flow conduit. 
   
   
       4 . The method of  claim 2  wherein the mixture is in a pressure vessel and the steam is injected into the mixture within the pressure vessel. 
   
   
       5 . The method of  claim 2  wherein the mixture is heated to a temperature between 160° F. and 705° F. 
   
   
       6 . The method of  claim 1  wherein the mixture is produced in a mixing apparatus, the mixing apparatus comprising a high speed mixer, the method further comprising
 producing the mixture in the high speed mixer.   
   
   
       7 . The method of  claim 1  in which no emulsifier is added to the mixture. 
   
   
       8 . The method of  claim 1  wherein the flocculant is in a combination of flocculant and water, the flocculant present at between 0.00125% and 0.5% of the total volume of the combination. 
   
   
       9 . The method of  claim 8  wherein the flocculant is present as 0.0025% of the total volume of the combination. 
   
   
       10 . The method of  claim 8  wherein the water is present by volume between 5% to 20%. 
   
   
       11 . The method of  claim 1  wherein the spent drilling fluid is pumped from an active rig mud system, the method further comprising
 feeding separated drilling fluid back to the active rig mud system.   
   
   
       12 . The method of  claim 1  wherein the separating is effected with centrifuge apparatus. 
   
   
       13 . The method of  claim 12  wherein the centrifuge apparatus produces a stream of recovered drilling fluid in which the ratio by volume of drilling fluid to water is at least 90 to 10. 
   
   
       14 . The method of  claim 1  further comprising
 emulsion testing separated drilling fluid to determine if it is acceptable for re-use.   
   
   
       15 . The method of  claim 1  wherein the contaminants include solids, the method further comprising
 processing separated drilling fluid to remove solids with a largest dimension between 3 microns and 30 microns.   
   
   
       16 . The method of  claim 1  further comprising
 feeding the heated mixture to a tank in which solids in the mixture settle out and are removed before the separating step.   
   
   
       17 . The method of  claim 1  in which drilling fluid is continuously separated from the mixture. 
   
   
       18 . A method for recovering drilling fluid from a mixture containing drilling fluid and other components, the mixture resulting from a wellbore operation including the pumping of drilling fluid, the method comprising
 producing a mixture of flocculant with a spent drilling fluid, the spent drilling fluid containing drilling fluid and contaminants,   heating the mixture,   separating drilling fluid from the mixture,   wherein the heating is effected by injecting steam into the mixture,   wherein the mixture is heated to a temperature between 160° F. and 705° F.,   wherein the mixture is produced in a mixing apparatus, the mixing apparatus comprising a high speed mixer, the method further comprising
 producing the mixture in the high speed mixer, 
   wherein no emulsifier is added to the mixture,   wherein the flocculant is in a combination of flocculant and water, the flocculant present at between 0.00125% and 0.5% of the total volume of the combination,   wherein the water is present by volume between 5% to 20%,   wherein the separating is effected with centrifuge apparatus,   wherein the centrifuge apparatus produces a stream of recovered drilling fluid in which the ratio by volume of drilling fluid to water is at least 90 to 10, and   wherein drilling fluid is continuously separated from the mixture.   
   
   
       19 . A system for recovering drilling fluid from a spent drilling fluid mixture, the spent drilling fluid mixture including drilling fluid and contaminants, the system comprising
 a tank apparatus for mixing water and flocculant to produce a water-flocculant mixture,   a mixing apparatus for receiving and mixing the water-flocculant mixture with spent drilling fluid to produce a drilling fluid mixture,   heating apparatus for receiving and heating the drilling fluid mixture to produce a heated drilling fluid mixture, and   separation apparatus for receiving the heated drilling fluid mixture and for separating drilling fluid from the drilling fluid mixture.   
   
   
       20 . A method for wellbore operations comprising
 pumping drilling fluid with an active rig mud system into and from a wellbore,   pumping spent drilling fluid from the wellbore with the active rig mud system to a mixer,   pumping a water-flocculant mixture to the mixer,   mixing with the mixer the spent drilling fluid and the water-flocculant mixture producing a primary mixture,   heating the primary mixture,   feeding heated primary mixture to separation apparatus,   with the separation apparatus producing re-usable drilling fluid separated from the primary mixture, and   feeding the separated re-usable drilling fluid back to the active rig and system for re-use.