Fluid loss control agents for viscoelastic surfactant fluids

Abstract

Alkaline earth metal compounds may be fluid loss control agents for viscoelastic surfactant (VES) fluids used for well completion or stimulation in hydrocarbon recovery operations. The VES fluid may further include proppant or gravel, if it is intended for use as a fracturing fluid or a gravel packing fluid, although such uses do not require that the fluid contain proppant or gravel. The fluid loss control agents may include, but not be limited to, oxides and hydroxides of alkaline earth metal, and in one case magnesium oxide where the particle size of the magnesium oxide is between 1 nanometer to 0.4 millimeter. The fluid loss agent appears to associate with the VES micelles and together form a novel pseudo-filter cake crosslinked-like viscous fluid layer that limits further VES fluid flow into the porous media. The fluid loss control agent solid particles may be added along with VES fluids.

1 . A method for treating a subterranean formation comprising:
 injecting an aqueous viscoelastic surfactant treating fluid through a wellbore and to the subterranean formation, where the aqueous viscoelastic treating fluid comprises:
 an aqueous base fluid; 
 a viscoelastic surfactant (VES) gelling agent; and 
 an amount of a fluid loss control agent effective to improve the fluid loss of the aqueous viscoelastic treating fluid as compared with an identical fluid absent the fluid loss control agent, where the fluid loss control agent is selected from the group consisting of
 alkaline earth metal oxides or hydroxides selected from the group consisting of oxides or hydroxides of magnesium, calcium, strontium, barium and mixtures thereof; 
 transition metal oxides or hydroxides selected from the group consisting of oxides or hydroxides of vanadium, molybdenum, manganese, iron, cobalt, nickel, palladium, copper, zinc, titanium and mixtures thereof; 
 transition metal hydroxides selected from the group consisting of aluminum, zirconium, tin, antimony and mixtures thereof; and 
 combinations thereof, 
 
 where the fluid loss control agent has a size ranging from about 1 nanometer to about 5 microns; and 
   treating the subterranean formation.   
   
   
       2 . The method of  claim 1  where the aqueous base fluid is brine. 
   
   
       3 . The method of  claim 1  where the effective amount of the fluid loss control agent ranges from about 2 to about 200 pptg (about 0.2 to about 24 kg/m 3 ) based on the aqueous viscoelastic treating fluid. 
   
   
       4 . The method of  claim 1  where the agent has a size ranging from about 1 nanometer to about 1 micron. 
   
   
       5 . The method of  claim 1  where treating the subterranean formation is selected from the group consisting of:
 fracturing the formation under effective pressure where the aqueous viscoelastic treating fluid further comprises a proppant;   packing the formation with gravel where the aqueous viscoelastic treating fluid further comprises gravel;   stimulating the formation where the aqueous viscoelastic treating fluid further comprises a stimulating agent;   completing a well; and   controlling fluid loss where the aqueous viscoelastic treating fluid further comprises a salt or easily removed solid; and mixtures thereof.   
   
   
       6 . The method of  claim 1  where for a period of time during the method the fluid is exposed to a temperature of from about 70° F. to about 400° F. (about 21 to about 204° C.). 
   
   
       7 . A method for treating a subterranean formation comprising:
 injecting an aqueous viscoelastic surfactant treating fluid through a wellbore and to the subterranean formation, where the aqueous viscoelastic treating fluid comprises:
 an aqueous brine base fluid; 
 a viscoelastic surfactant (VES) gelling agent; and
 from about 2 to about 200 pptg (about 0.2 to about 24 kg/m 3 ) based on the aqueous viscoelastic treating fluid of a fluid loss control agent selected from the group consisting of
 alkaline earth metal oxides or hydroxides selected from the group consisting of oxides or hydroxides of magnesium, calcium, strontium, barium and mixtures thereof; 
 transition metal oxides or hydroxides selected from the group consisting of oxides or hydroxides of vanadium, molybdenum, manganese, iron, cobalt, nickel, palladium, copper, zinc, titanium and mixtures thereof; 
 transition metal hydroxides selected from the group consisting of aluminum, zirconium, tin, antimony and mixtures thereof; and 
 combinations thereof, 
 
 where the fluid loss control agent has a size ranging from about 1 nanometer to about 0.4 millimeter; and 
 
 treating the subterranean formation. 
   
   
   
       8 . The method of  claim 7  where the fluid loss control agent is magnesium oxide. 
   
   
       9 . The method of  claim 7  where for a period of time during the method the fluid is exposed to a temperature of about 70° F. to about 400° F. 
   
   
       10 . The method of  claim 7  where treating the subterranean formation is selected from the group consisting of:
 fracturing the formation under effective pressure where the aqueous viscoelastic treating fluid further comprises a proppant;   packing the formation with gravel where the aqueous viscoelastic treating fluid further comprises gravel;   stimulating the formation where the aqueous viscoelastic treating fluid further comprises a stimulating agent;   completing a well; and   controlling fluid loss where the aqueous viscoelastic treating fluid further comprises a salt or easily removed solid; and mixtures thereof.   
   
   
       11 . A method for treating a subterranean formation comprising:
 injecting an aqueous viscoelastic surfactant treating fluid through a wellbore and to the subterranean formation, where the aqueous viscoelastic treating fluid comprises:
 an aqueous base fluid; 
 a viscoelastic surfactant (VES) gelling agent; and 
 an amount of a fluid loss control agent effective to improve the fluid loss of the aqueous viscoelastic treating fluid as compared with an identical fluid absent the fluid loss control agent, where the fluid loss control agent is selected from the group consisting of
 alkaline earth metal oxides or hydroxides selected from the group consisting of oxides or hydroxides of magnesium, calcium, strontium, barium and mixtures thereof; 
 transition metal oxides or hydroxides selected from the group consisting of oxides or hydroxides of vanadium, molybdenum, manganese, iron, cobalt, nickel, palladium, copper, zinc, titanium and mixtures thereof; 
 transition metal hydroxides selected from the group consisting of aluminum, zirconium, tin, antimony and mixtures thereof; and 
 combinations thereof, 
 
 where the fluid loss control agent has a size ranging from about 1 nanometer to about 1 micron; and 
   treating the subterranean formation in a manner selected from the group consisting of:
 fracturing the formation under effective pressure where the aqueous viscoelastic treating fluid further comprises a proppant; 
 packing the formation with gravel where the aqueous viscoelastic treating fluid further comprises gravel; 
 stimulating the formation where the aqueous viscoelastic treating fluid further comprises a stimulating agent; 
 completing a well; and 
 controlling fluid loss where the aqueous viscoelastic treating fluid further comprises a salt or easily removed solid; and mixtures thereof. 
   
   
   
       12 . The method of  claim 11  where the aqueous base fluid is brine. 
   
   
       13 . The method of  claim 11  where the effective amount of the fluid loss control agent ranges from about 2 to about 200 pptg (about 0.2 to about 24 kg/m 3 ) based on the aqueous viscoelastic treating fluid. 
   
   
       14 . The method of  claim 11  where for a period of time during the method the fluid is exposed to a temperature of from about 70° F. to about 400° F. (about 21 to about 204° C.).