Deep water completions fracturing fluid compositions

Abstract

It has been discovered that fracturing fluid compositions can be designed for successful deep water completion fracturing fluid operations. These fluids must be pumped relatively long distances from offshore platforms to the reservoir, and they are often subjected to a wide temperature range. Under these conditions, it is necessary to inhibit the formation of gas hydrates in the fracturing fluid compositions, as well as to delay the crosslinking of the gels that are formed to increase the viscosity of the fluids prior to fracturing the formation. Preferably, two different gas hydrate inhibitors are used to ensure placement of a gas hydrate inhibitor in most parts of the operation. In addition, as with all offshore or deep water hydrocarbon recovery operations, it is important that the components of the fracturing fluid compositions be environmentally benign and/or biodegradable.

I claim:  
     
         1 . A fracturing fluid composition comprising: 
 i) water;    ii) at least one hydratable polymer;    iii) at least one crosslinking agent;    iv) at least one additional crosslinking delay agent;    v) at least one breaking agent; and    vi) at least one gas hydrate inhibitor.    
     
     
         2 . The fracturing fluid composition of  claim 1  where the gas hydrate inhibitor is selected from the group consisting of: 
 thermodynamic inhibitors selected from the group consisting of NaCl salt, KCl salt, CaCl 2  salt, MgCl 2  salt, formate brines, polyols, amine glycols, glycol ethers, alcohols, and electrolytes,  
 kinetic and anti-agglomerate inhibitors selected from the group consisting of copolymers, vinyl polymers, polysaccharides, amides, lactams (such as vinylcaptrolactam, polyvinyl lactam), pyrrolidones, acrylates, fatty acid surfactants, alkyl glucosides, alkyl amines, alkyl phosphonates, alkyl sulphonates, hydrocarbon based dispersants, polycarbonates, amino acids, proteins, glycoproteins, amino carboxylic acids, and  
 mixtures thereof.  
 
     
     
         3 . The fracturing fluid composition of  claim 1  further comprising: 
 vii) an additional gas hydrate inhibitor different from v); where one of the gas hydrate inhibitors remains in the aqueous phase and the other gas hydrate inhibitor is a polymer that at least temporarily becomes part of a polymer accumulation.  
 
     
     
         4 . The fracturing fluid composition of  claim 1  where the crosslinking delay agent can function over a temperature range from about 300° to about 30° F. (about 1490 to about −1° C.).  
     
     
         5 . The fracturing fluid composition of  claim 1  where the crosslinking agent iii) and the crosslinking delay agent iv) is a single component.  
     
     
         6 . The fracturing fluid composition of  claim 5  where the single component is selected from the group consisting of slurried borax suspensions, ulexite, colemanite; complexes of borate ion, zirconate ion and/or titanate ion with a polyol selected from the group of sorbitol, mannitol, sodium gluconate, sodium glucoheptonate, glycerol, alpha D-glucose, fructose, ribose, alkyl glucosides, and mixtures thereof.  
     
     
         7 . The fracturing fluid composition of  claim 1  where the hydratable polymer is a polysaccharide.  
     
     
         8 . The fracturing fluid composition of  claim 7  where the hydratable polymer is selected from the group consisting of guar, hydroxypropyl guar, carboxymethylhydroxypropyl guar, or other guar polymer derivatives.  
     
     
         9 . The fracturing fluid composition of  claim 1  further comprising at least one additional component selected from the group consisting of pH buffers; biocides; surfactants; non-emulsifiers; anti-foamers; at least one additional, different breaking agent selected from the group consisting of enzyme breakers, oxidizer breakers and mixtures thereof; scale inhibitors; colorants; clay control agents; gel breaker aids; and mixtures thereof.  
     
     
         10 . The fracturing fluid composition of  claim 1  further comprising: 
 viii) an additional crosslinking delay agent different from iv).  
 
     
     
         11 . The fracturing fluid composition of  claim 1  where the crosslinking agent is selected from the group consisting of titanate ion, zirconate ion, borate ion, and mixtures thereof.  
     
     
         12 . The fracturing fluid composition of  claim 1  where the breaking agent is selected from the group consisting of enzyme breakers, oxidizer breakers, and mixtures thereof.  
     
     
         13 . The fracturing fluid composition of  claim 1  further comprising: 
 from about 10 to about 60 pptg (about 1.2 to about 7.2 kg/m 3 ) of hydratable polymer;  
 from about 0.025 to about 3.0 volume % of crosslinking and delaying agent;  
 from about 0.006 to about 0.5 bw % of crosslinking delay agent;  
 from about 0.1 to about 40.0 pptg (about 0.072 to about 4.8 kg/m 3 ) of breaking agent; and  
 from about 0.006 to about 30 bw % of gas hydrate inhibitor.  
 
     
     
         14 . A method for fracturing a subterranean formation comprising: 
 a. pumping a fracturing fluid composition down a wellbore to a subterranean formation;    b. permitting the fracturing fluid composition to gel;    c. pumping the fracturing fluid composition against the subterranean formation at sufficient rate and pressure to fracture the formation;    d. breaking the fracturing fluid composition gel;    e. subsequently flowing the fracturing fluid composition out of the formation;    where the fracturing fluid composition comprises:    i) water;    ii) at least one hydratable polymer;    iii) at least one crosslinking agent;    iv) at least one crosslinking delay agent;    v) at least one breaking agent; and    vi) at least one gas hydrate inhibitor.    
     
     
         15 . The method of  claim 14  where at least part of the wellbore extends from an offshore platform to a sea floor where the distance from the offshore platform to the sea floor is at least 1,000 feet (304 m), and where the temperature differential over the length of the wellbore from the sea floor to the subterranean formation is at least about 90° F. (50° C.).  
     
     
         16 . The method of  claim 14  where in the fracturing fluid composition the gas hydrate inhibitor is selected from the group consisting of: 
 thermodynamic inhibitors selected from the group consisting of NaCl salt, KCl salt, CaCl 2  salt, MgCl 2  salt, formate brines, polyols, amine glycols, glycol ethers, alcohols, and electrolytes,  
 kinetic and anti-agglomerate inhibitors selected from the group consisting of copolymers, vinyl polymers, polysaccharides, amides, lactams (such as vinylcaptrolactam, polyvinyl lactam), pyrrolidones, acrylates, fatty acid surfactants, alkyl glucosides, alkyl amines, alkyl phosphonates, alkyl sulphonates, hydrocarbon based dispersants, polycarbonates, amino acids, proteins, glycoproteins, amino carboxylic acids, and  
 mixtures thereof.  
 
     
     
         17 . The method of  claim 14  where in the fracturing fluid composition, the composition further comprises: 
 vii) an additional gas hydrate inhibitor different from v); where one of the gas hydrate inhibitors remains in the aqueous phase and the other gas hydrate inhibitor is a polymer that at least temporarily becomes part of a polymer accumulation.  
 
     
     
         18 . The method of  claim 14  where in the fracturing fluid composition the crosslinking delay agent can function over a temperature range from about 350° to about 25° F. (about 177° to about −4.0° C.).  
     
     
         19 . The method of  claim 14  where in the fracturing fluid composition the crosslinking agent iii) and the crosslinking delay agent iv) is a single component.  
     
     
         20 . The method of  claim 19  where in the fracturing fluid composition the single component is selected from the group consisting of slurried borax suspensions, ulexite, colemanite, complexes of borate ion, zirconate ion and/or titanate ion with a polyol selected from the group of sorbitol, mannitol, sodium gluconate, sodium glucoheptonate, glycerol, alpha D-glucose, fructose, ribose, alkyl glucosides, and mixtures thereof.  
     
     
         21 . The method of  claim 14  where in the fracturing fluid composition the hydratable polymer is a polysaccharide.  
     
     
         22 . The method of  claim 21  where the hydratable polymer is selected from the group consisting of a guar, hydroxypropyl guar, carboxymethylhydroxypropyl guar, or other guar polymer derivatives.  
     
     
         23 . The method of  claim 14  where in the fracturing fluid composition the composition further comprises at least one additional component selected from the group consisting of pH buffers; biocides; surfactants; non-emulsifiers; anti-foamers; at least one additional, different breaking agent selected from the group consisting of enzyme breakers, oxidizer breakers, and mixtures thereof; scale inhibitors; colorants; clay control agents; gel breaker aids; and mixtures thereof.  
     
     
         24 . The method of  claim 14  where in the fracturing fluid composition, the composition further comprises: 
 viii) an additional crosslinking delay agent different from iv).  
 
     
     
         25 . The method of  claim 14  where the fracturing fluid further comprising: 
 from about 10 to about 60 pptg (about 1.2 to about 7.2 kg/m 3 ) of hydratable polymer;  
 from about 0.025 to about 3.0 volume % of crosslinking agent;  
 from about 0.006 to about 0.5 bw % of crosslinking delay agent;  
 from about 0.1 to about 40.0 pptg (about 0.072 to about 4.8 kg/m 3 ) of breaking agent; and  
 from about 0.006 to about 30 bw % of gas hydrate inhibitor.  
 
     
     
         26 . A method for fracturing a subterranean formation comprising: 
 a. pumping a fracturing fluid composition down a wellbore to a subterranean formation, where the temperature differential over the length of the wellbore is at least about 90° F. (50° C.);    b. permitting the fracturing fluid composition to gel,    c. pumping the fracturing fluid composition against the subterranean formation at sufficient rate and pressure to fracture the formation;    d. breaking the fracturing fluid composition gel;    e. subsequently flowing the fracturing fluid composition out of the formation;    where the fracturing fluid composition comprises:    i) water;    ii) at least one hydratable polymer;    iii) at least one crosslinking agent, where the crosslinking delay agent can function over a temperature range from about 350° F. to about 25° F. (173° C. to about −4.0° C.);    iv) at least one crosslinking delay agent;    v) at least one breaking agent; and    vi) at least one gas hydrate inhibitor.