Abstract:
The present disclosure relates to a crosslinking composition for use in crosslinking an aqueous suspension of guar, for use as a well treatment fluid and/or proppant carrier fluid for natural gas extraction. The present crosslinking composition is an aqueous suspension of hydroboracite. The composition may also comprise varying amounts of borax, canola oil, xanthan, glycerol, and/or NaOH. The composition may be selected to effect a desired delay in the crosslinking reaction in order to customize the viscosity and reaction time to the method of use, thereby maximizing proppant delivery while minimizing pump pressure.

Description:
BACKGROUND 
       [0001]    Hydraulic fracturing (also called hydrofracturing, hydrofracking, fracking or fraccing) is a well-stimulation technique in which rock is fractured by a pressurized liquid. The process involves the high-pressure injection of fracking fluid (such as water containing proppants suspended with the aid of thickening agents) into a wellbore to create cracks in the deep-rock formations through which natural gas, petroleum, and brine will flow more freely. When the hydraulic pressure is removed from the well, proppants hold the fractures open. 
         [0002]    Proppants are solid materials in the form of small grains, such as sand or ceramic particulates, that are introduced into fracking formations in order to prevent small fractures in the earth from collapsing during or following a fracturing treatment. Proppants are often delivered to fractures using carrier fluids. Higher viscosity carrier fluids carry proppants more effectively, but that viscosity also creates friction pressure within the pumps that pump the carrier fluid into the formation. 
         [0003]    Guar is a botanically sourced substance that is commonly used as a thickening agent in proppant carrier fluids. Also called guaran or guar gum, guar is a galactomannan made from the ground endosperm of guar beans. Crosslinking hydrated guar suspensions, or suspensions of various guar derivatives, can create a gel fluid with relatively high viscosity. Higher viscosity fluids can carry higher concentrations of proppant, thereby enhancing the proppant delivery effectiveness of the system and enabling increased fracture width. Higher viscosity fluids also result in reduced fluid loss, which assists in increasing fracture length. 
       SUMMARY 
       [0004]    The presently disclosed composition comprises a crosslinking agent that is useful in crosslinking guar proppant carrier fluids. Crosslinked proppant carrier fluids that contain the presently disclosed composition are well suited for mixture on the fly and are useful in delivering proppant to a wellbore shortly after the crosslinking agent and the guar proppant fluid are mixed. The presently disclosed crosslinking composition is an aqueous suspension that contains a balance between hydroboracite and borax that can be optimized for the timing of a particular mixing and well delivery system. In one preferred embodiment, the balance between hydroboracite and borax consists of approximately equal parts hydroboracite and borax. The presently disclosed composition preferably further comprises a lightweight oil such as canola oil, a thickening or stabilizing agent such as xanthan or a similar rheology modifier, and a polyol such as glycerol (also called glycerine or glycerin). Alternately, the crosslinking composition can comprise NaOH (also called lye or caustic soda) or similar alkali for pH regulation. 
         [0005]    A preferred embodiment of the presently disclosed crosslinking comprises an aqueous suspension of approximately 10-20% hydroboracite, 1-12% borax, 0.15-0.18% xanthan, and 15-20% glycerol. An alternative embodiment further comprises 0.10-0.15% canola oil. A further preferred embodiment comprises approximately 10-12% hydroboracite and 10-12% borax. In general, as the balance between hydroboracite and borax favors hydroboracite, the rate at which the composition crosslinks guar will decrease. Likewise, as the balance favors borax, the rate at which the composition crosslinks guar or HPG will increase. The composition can be balanced to accommodate instant crosslinking, or crosslinking of any desired delay. 
         [0006]    The presently disclosed composition is suited for crosslinking guar-based proppant carrier fluids. One crosslinkable/crosslinked proppant carrier fluid consistent with the present disclosure comprises an aqueous suspension of guar and a crosslinking agent that consists of approximately 10-20% hydroboracite, approximately 1-12% borax, and approximately 1-12% glycerol in water. This crosslinkable/crosslinked proppant carrier fluid may further comprise up to 1% canola oil and/or up to 1% xanthan present in the crosslinking agent. 
         [0007]    The presently disclosed composition is further suited for use in methods of balancing and mixing proppant carrier fluids such that the timing of the crosslinking reaction is customized for the timing of the mixing and pumping process that delivers the crosslinkable/crosslinked proppant fluid to the fractures in a wellbore. One method of crosslinking a proppant carrier fluid consistent with the present disclosure comprises mixing the presently disclosed crosslinking composition with an aqueous suspension of guar in a just-in-time fashion as the proppant carrier fluid is introduced into a wellbore. The balance between the amount of hydroboracite and the amount of borax in the crosslinking composition can delay the attainment of maximum viscosity in the proppant solution 0-120 minutes after the crosslinking composition is mixed with the aqueous suspension of guar, depending on the desired timeframe for pumping and delivery of the fluid to the fracture in the wellbore. A preferred delay is typically up to about 40 minutes. 
         [0008]    As such, the presently disclosed composition provides for a novel method of optimizing a delay with which a crosslinkable proppant fluid reaches a desired viscosity. That novel method involves adjusting the balance between the amount of hydroboracite and the amount of borax in the crosslinking composition according to the respective rates of borate ion release in hydroboracite and borax such that the delay corresponds to the expected time delay between mixing the crosslinking composition with the guar-based crosslinkable substrate and delivering the resulting crosslinkable proppant fluid to the wellbore fracture. 
         [0009]    It should be noted that because the presently disclosed composition crosslinks a crosslinkable substrate such (as guar-based suspensions) gradually, or in a delayed fashion, the proppant fluid that results from mixing the crosslinking composition with the substrate can be described as both crosslinkable and crosslinked at most times during the processes described herein. At all times after the crosslinking reaction begins (which is virtually instantly upon mixing the crosslinking composition with the guar-based fluid substrate), the proppant fluid is crosslinked to some extent. At all times before the crosslinking reaction has ceased (which may be indefinitely, may continue to the point of over-crosslinking, or may be until a crosslink breaker is employed), the proppant fluid is crosslinkable to some extent. As such, the proppant fluid is referred to as crosslinkable, or crosslinked, or both interchangeably, in different instances throughout the present disclosure, depending on the context. Such descriptions are not intended to limit the proppant fluid or other formulations containing the presently described crosslinking agent to a particular state of progress with respect to the crosslinking reaction. 
         [0010]    It should also be noted that many of the formulations described herein refer to specific ingredients that are exemplary or preferential, for example canola oil, glycerin, and xanthan. One of skill in the art would appreciate that there are countless oils, polyols, and rheology modifiers that are equivalent to the specific ingredients recited and that could be substituted as indicated in the detailed descriptions that follow. 
     
    
     DETAILED DESCRIPTION 
       [0011]    The present composition is a crosslinking agent for use in crosslinking a guar-based proppant fluid. The present composition is designed to crosslink guar at a controlled rate, and is particularly suited to applications where the crosslinking agent and the guar-based proppant fluid are mixed on-site at the well formation shortly before the mixture is introduced into the hydraulic fracture. The crosslinking rate of the fluid mixture can thus be customized according to how much time is expected to elapse between when the crosslinking agent and the proppant fluid are mixed, and when the resulting mixture arrives at its intended destination within the hydraulic fracture. An objective of the present composition is therefore to maintain a relatively lower viscosity in the proppant during the earlier stages of the proppant delivery, in order to minimize the friction pressure associated with pumping a viscous fluid into a well formation, while maximizing the benefits of a fully-crosslinked and therefore relatively highly viscous fluid at the later stages of proppant delivery, when the viscosity of the fluid accommodates increased proppant suspension and reduced fluid loss within the fractures. 
         [0012]    The present composition comprises water, hydroboracite, and borax. Hydroboracite is a compound that releases borate ions relatively slowly when suspended in aqueous solutions such as proppant fluids under the conditions typically associated with fracking formations. Borax is a compound that releases borate ions relatively quickly when suspended in aqueous solutions like proppant fluids under the conditions typically associated with fracking formations. By customizing the balance between the amount of borax and the amount of hydroboracite in the present composition, one of skill in the art can customize the resulting crosslinking reaction to fit the needs of any particular hydraulic fracturing operation. The inventors have determined that many hydraulic fracturing systems will be desirably served by providing approximately equal amounts of borax and hydroboracite in the present composition. 
         [0013]    Alternate embodiments that deviate from this balance include differing the relative amounts of hydroboracite or borax, or including other known sources of borate ions that have different rates of borate ion release. For instance, each of the borate compounds ulexite, colemanite, probertite, nobleite, gowerite, frolovite, meyerhofferite, inyoite, priceite, tertschite, ginorite, and inderborite release borate ions at different rates. By accounting for the rate of ion release of the source of the borate ion, one of skill in the art could optimize a reaction rate using the concepts and methods disclosed herein to mix and balance different borate ion sources to support a desired reaction speed. The inventors have found that hydroboracite balanced with borax is one way to provide a well-timed crosslinking reaction for most on-the-fly well delivery applications. 
         [0014]    In preferred embodiments, the present composition further comprises canola oil (or a similar lightweight oil), xanthan (or a similar thickening agent), and/or glycerol (or a similar polyol). Canola oil improves the dispersion of the hydroboracite powder in the aqueous diluent. Xanthan slightly increases the viscosity of the present composition (prior to mixing it with a guar-based proppant fluid) which helps to suspend the hydroboracite. Glycerol also modifies the viscosity of the present composition and enhances the performance of the present composition (and any proppant fluid into which it is mixed) at temperatures that are on the lower end of what would be expected in hydraulic fracturing environments. 
         [0015]    In one preferred embodiment, the present composition consists of: 
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 water 
                 58.36% 
               
               
                   
                 hydroboracite 
                 11.37% 
               
               
                   
                 borax 
                 11.37% 
               
               
                   
                 canola oil 
                  0.13% 
               
               
                   
                 xanthan 
                  0.16% 
               
               
                   
                 glycerol (99%) 
                 18.61% 
               
               
                   
                   
               
             
          
         
       
     
         [0016]    This embodiment typically provides a cross-link delay of 1 to 5 minutes in guar gels depending on the temperature conditions of the environment in which it is used. In general, carrier fluid pH effects delay time, and modification of the pH of the carrier fluid provides yet another way to control the crosslink time. The pH of the carrier fluid also influences the stability of the gel at the higher end of the temperature range. 
         [0017]    Guar gels crosslinked with the present composition are stable from 80° F. to 325° F. The 1 to 5 minute delay associated with the embodiment detailed above occurs at a pH of about 9 to 12. This embodiment provides a stable, aqueous-based, delayed borate crosslinker that yields high quality viscous guar gels upon delivery. One advantage of this embodiment is that it provides a stable, aqueous-based, delayed borate crosslinker without the use of ulexite, colemanite, or other sources of borate ions, and without the need for crosslink modifying agents or other external means for regulating the crosslink reaction. By avoiding the use of boron sources such as ulexite, and avoiding the need for crosslink modifying or regulating agents, this embodiment of the present composition provides increased delay capabilities, increased customization of reaction rate, simplified customization calculations, and lower cost. 
         [0018]    The present composition is well-suited for uses in which it is mixed with the proppant carrier fluid continuously and delivered to the well formation on the fly during the treatment at 1-3 GPT (L/m3). On-the-fly delivery involves mixing the proppant carrier fluid and the crosslinking composition on site and pumping the resulting fluid into the well formation in a just-in-time or continuous fashion, as opposed to mixing the proppant carrier and crosslinking composition off site or in advance and storing or transporting the resulting fluid before pumping it into the wellbore. 
         [0019]    One of skill in the art will fully appreciate how to determine the optimum concentration of the crosslinking composition within the proppant fluid to suit the desired application. The present composition can also be used with gel breakers. One of skill in the art will appreciate how to determine the optimal gel breaker concentration and identify the type of gel breaker to use for the desired fluid properties. 
         [0020]    Preferred embodiments of the present composition have a specific gravity at 68° F. of about 1.11-1.16. Preferred embodiments have a freezing point of about 11° F. 
         [0021]    Additional exemplary embodiments, and their respective viscosities are provided in the following examples. 
       Example 1 
       [0022]    The table below shows the formulation (first table) and corresponding viscosity delay at 160° F. (second table) for example embodiments 1-6. Measurements for embodiment 1 were taken using a F 50 Unit 2 rheometer, and measurements for embodiments 2-6 were taken using an F 50 Unit 1 rheometer. 
         [0023]    Formulation: 
         [0000]    
       
         
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
               
               
                   
                   
                   
                   
                   
                 x-Linker 
                   
               
               
                   
                   
                   
                   
                   
                 loading, 
                 CrossLink 
               
               
                   
                 Water 
                 HB 
                 Borax 
                 Glycerol 
                 gpt 
                 pH 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1 
                 58.36% 
                 11.37% 
                 11.37% 
                 18.61% 
                 1 
                 11.01 
               
               
                 2 
                 67.34% 
                 11.37% 
                 11.37% 
                  9.63% 
                 1.5 
                 11.09 
               
               
                 3 
                 71.82% 
                 15.00% 
                  7.74% 
                  5.16% 
                 1.5 
                 10.85 
               
               
                 4 
                 74.37% 
                 13.82% 
                  6.91% 
                  4.61% 
                 1.5 
                 11.01 
               
               
                 5 
                 78.08% 
                 17.08% 
                  4.55% 
                  0.00% 
                 1 
                 11.3 
               
               
                 6 
                 58.36% 
                 19.37% 
                  0.00% 
                 18.61% 
                 1.5 
                 11.26 
               
               
                   
               
             
          
         
       
     
         [0024]    Viscosity (in cP) Over Time (in Minutes): 
         [0000]    
       
         
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                   
               
               
                   
                 1.5 
                 2 
                 2.5 
                 3 
                 3.5 
                 4 
                 5 
                 10 
                 20 
                 25 
                 30 
                 35 
                 40 
                 50 
                 60 
                 90 
                 120 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1 
                 71 
                 80 
                 100 
                 110 
                 131 
                 151 
                 186 
                 201 
                 178 
                 171 
                 182 
                 199 
                 218 
                 232 
                 240 
                 249 
                 257 
               
               
                 2 
                 45 
                 119 
                 155 
                 164 
                 201 
                 206 
                 196 
                 209 
                 301 
                 313 
                 318 
                 330 
                 331 
                 342 
                 342 
                 345 
                 340 
               
               
                 3 
                 10 
                 14 
                 30 
                 50 
                 72 
                 88 
                 138 
                 150 
                 213 
                 240 
                 250 
                 267 
                 289 
                 310 
                 318 
                 338 
                 341 
               
               
                 4 
                 24 
                 27 
                 36 
                 53 
                 70 
                 93 
                 134 
                 164 
                 211 
                 230 
                 250 
                 266 
                 280 
                 295 
                 300 
                 312 
                 342 
               
               
                 5 
                 10 
                 9 
                 8 
                 9 
                 8 
                 7 
                 6 
                 6 
                 Fail 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 6 
                 54 
                 51 
                 51 
                 51 
                 50 
                 50 
                 50 
                 49 
                 48 
                 50 
                 53 
                 61 
                 63 
                 102 
                 150 
                 196 
                 212 
               
               
                   
               
             
          
         
       
     
       Example 2 
       [0025]    The table below shows the formulation (first table) and corresponding viscosity delay at 200° F. (second table) for example embodiments 7-11. Measurements for embodiments 7-11 were taken using an F50 Unit 2 rheometer. 
         [0026]    Formulation: 
         [0000]    
       
         
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
               
               
                   
                   
                   
                   
                   
                 x-Linker 
                   
               
               
                   
                   
                   
                   
                   
                 loading, 
                 CrossLink  
               
               
                   
                 Water 
                 HB 
                 Borax 
                 Glycerol 
                 gpt 
                 pH 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                  7 
                 58.36% 
                 11.37% 
                 11.37% 
                 18.61% 
                 1.5 
                 11.26 
               
               
                  8 
                 67.34% 
                 11.37% 
                 11.37% 
                  9.63% 
                 1.5 
                 11.23 
               
               
                  9 
                 71.82% 
                 15.00% 
                  7.74% 
                  5.16% 
                 1.5 
                 11.32 
               
               
                 10 
                 74.37% 
                 13.82% 
                  6.91% 
                  4.61% 
                 1.5 
                 11.4 
               
               
                 11 
                 78.08% 
                 17.08% 
                  4.55% 
                  0.00% 
                 1.5 
                 11.5 
               
               
                   
               
             
          
         
       
     
         [0027]    Viscosity (in cP) Over Time (in Minutes): 
         [0000]    
       
         
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                   
               
               
                   
                 1.5 
                 2 
                 2.5 
                 3 
                 3.5 
                 4 
                 5 
                 10 
                 20 
                 25 
                 30 
                 35 
                 40 
                 50 
                 60 
                 90 
                 120 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 7 
                 77 
                 95 
                 126 
                 175 
                 202 
                 237 
                 234 
                 250 
                 255 
                 267 
                 260 
                 264 
                 260 
                 262 
                 259 
                 232 
                 204 
               
               
                 8 
                 30 
                 35 
                 61 
                 106 
                 137 
                 172 
                 191 
                 220 
                 181 
                 191 
                 178 
                 173 
                 176 
                 174 
                 170 
                 154 
                 134 
               
               
                 9 
                 25 
                 23 
                 24 
                 30 
                 45 
                 67 
                 100 
                 112 
                 128 
                 137 
                 123 
                 121 
                 130 
                 133 
                 132 
                 128 
                 119 
               
               
                 10 
                 17 
                 27 
                 40 
                 53 
                 68 
                 85 
                 110 
                 84 
                 83 
                 89 
                 65 
                 76 
                 94 
                 97 
                 97 
                 77 
                 59 
               
               
                 11 
                 24 
                 23 
                 21 
                 20 
                 20 
                 21 
                 20 
                 20 
                 Fail 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                   
               
             
          
         
       
     
       Example 3 
       [0028]    In an alternate embodiment, the present composition further comprises NaOH. NaOH modifies the pH under which the crosslinking reaction takes place, thus moderating the rate at which hydroboracite releases borate ions. The rate at which hydroboracite releases borate ions, in turn, further influences the rate at which the crosslinking reaction progresses. 
       Formulation 12: 
       [0029]      
         [0000]    
       
         
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                   
               
               
                   
                   
                   
                 Lab 
                 Lab 
                 Lab 
                   
                   
                   
               
               
                   
                   
                 Sp. 
                 Blend 
                 Blend 
                 Blend 
                 % by 
                 Volume 
                 Volume 
               
               
                 Component 
                 State 
                 Gravity 
                 gms 
                 ml 
                 lbs 
                 Gallon 
                 gals 
                 lbs. 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Water 
                 Liquid 
                 1 
                  45.58% 
                 2161.54 
                 4.7653065 
                  57% 
                 0.570930541 
                 4.7653065 
               
               
                 Hydroboracite 
                 Solid 
                 2.2 
                  11.05% 
                 238.19 
                 1.1552575 
                  6% 
                 0.062914182 
                 1.155257499 
               
               
                 Borax 
                 Liquid 
                 1.73 
                  11.41% 
                 312.77 
                 1.19289485 
                  8% 
                 0.08261302 
                 1.192894848 
               
               
                 Canola Oil 
                 Liquid 
                 0.916 
                  0.13% 
                 6.73 
                 0.01359126 
                  0% 
                 0.001777693 
                 0.013591265 
               
               
                 Xanthan 
                 Solid 
                 1.49 
                  0.16% 
                 5.09 
                 0.01672771 
                  0% 
                 0.001345063 
                 0.01672771 
               
               
                 Glycerol 99% 
                 Liquid 
                 1.26 
                  11.84% 
                 445.63 
                 1.23785057 
                  12% 
                 0.117703699 
                 1.23785057 
               
               
                 NaOH 50% 
                 Liquid 
                 1.529 
                  19.83% 
                 615.04 
                 2.07319061 
                  16% 
                 0.162451671 
                 2.073190608 
               
               
                 Total 
                   
                   
                 100.00% 
                 3785.00 
                 10.4456077 
                 100% 
                 0.999735869 
                 10.44560771 
               
               
                 Theoretical 
                   
                   
                   
                   
                 1.25292098 
                   
                   
                   
               
               
                 Specific 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Gravity 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Desired 
                   
                   
                   
                   
                 1 
                   
                   
                   
               
               
                 Volume in 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 gallons: 
               
               
                   
               
             
          
         
       
     
       Example 4 
     Formulation 1 at 200° F. Measured with Fann 50 Unit 2 Rheometer in DI Water, with Polymer Loading 20 ppt, 1.5 gpt Formulation 1, Poolystim CS 1 gpt 
       [0030]    Formulation 13: Formulation 1 without Canola Oil 
         [0000]    
       
         
               
               
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                   
               
             
             
               
                 Linear  
                   
                 pH 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
             
          
           
               
                 Gel Visc 
                 Linear 
                 Adjust 20 
                 CrossLink 
                 Viscosity (in cP) over time 
               
             
          
           
               
                 (cP) 
                 Gel pH 
                 (gpt) 
                 pH 
                 1 min 
                 1.5 min 
                 2 min 
                 2.5 min 
                 3 min 
                 3.5 min 
                 4 min 
                 5 min 
                 10 min 
               
               
                   
               
               
                 15 
                 7.6 
                 1 
                 11.6 
                 52 
                 69 
                 83 
                 90 
                 87 
                 87 
                 84 
                 85 
                 121 
               
               
                 15 
                 7.6 
                 1 
                 11.6 
                 32 
                 38 
                 50 
                 56 
                 69 
                 70 
                 77 
                 74 
                 104 
               
               
                 15 
                 7.6 
                 0.5 
                 10.86 
                 175 
                 163 
                 155 
                 146 
                 136 
                 122 
                 112 
                 106 
                 88 
               
               
                   
               
               
                   
                   
                   
                   
                 20 min 
                 25 min 
                 30 min 
                 35 min 
                 40 min 
                 50 min 
                 60 min 
                 90 min 
                 120 min 
               
               
                   
               
               
                   
                   
                   
                   
                 79 
                 100 
                 95 
                 98 
                 95 
                 97 
                   
                   
                   
               
               
                   
                   
                   
                   
                 76 
                 95 
                 83 
                 80 
                 86 
                 83 
                   
                   
                   
               
               
                   
                   
                   
                   
                 34 
                 29 
                 22 
               
               
                   
               
             
          
         
       
     
       As Compared to Formulation 1: 
       [0031]      
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
             
           
               
                   
               
             
             
               
                 Linear 
                   
                   
                   
                   
               
             
          
           
               
                 Gel  
                   
                 PfP pH 
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
             
          
           
               
                 Visc 
                 Linear 
                 Adjust 20 
                 CrossLink 
                 Viscosity (in cP) over time 
               
             
          
           
               
                 (cP) 
                 Gel pH 
                 (gpt) 
                 pH 
                 1 min 
                 1.5 min 
                 2 min 
                 2.5 min 
                 3 min 
                 3.5 min 
                 4 min 
                 5 min 
               
               
                   
               
               
                 15.4 
                 7.1 
                 1 
                 11.26 
                 70 
                 77 
                 95 
                 126 
                 175 
                 202 
                 237 
                 234 
               
               
                 15.4 
                 7.1 
                 1 
                 11.3 
                 68 
                 70 
                 80 
                 100 
                 140 
                 149 
                 190 
                 210 
               
               
                 15.4 
                 7.1 
                 1 
                 11.08 
                 67 
                 69 
                 93 
                 100 
                 100 
                 112 
                 123 
                 199 
               
               
                   
               
             
          
           
               
                 10 min 
                 20 min 
                 25 min 
                 30 min 
                 35 min 
                 40 min 
                 50 min 
                 60 min 
                 90 min 
                 120 min 
               
               
                   
               
               
                 250 
                 255 
                 267 
                 260 
                 264 
                 260 
                 262 
                 259 
                 232 
                 204 
               
               
                 167 
                 230 
                 265 
                 261 
                 242 
                 255 
                 266 
                 260 
                 260 
                 202 
               
               
                 281 
                 293 
                 296 
                 258 
                 261 
                 282 
                 274 
                 270 
                 250 
                 216 
               
               
                   
               
             
          
         
       
     
       Example 5 
       [0032]      
         [0000]    
       
         
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                   
               
               
                   
                   
                   
                 Linear 
                   
                   
                   
                   
                   
                 Cross- 
                   
               
               
                   
                   
                 Slurry 
                 Gel 
                 Linear 
                 Polystim 
                 PfP pH 
                 Polystim 
                   
                 Linker 
                 Cross- 
               
               
                 Con- 
                   
                 Load-ing 
                 Visc 
                 Gel 
                 CS 
                 Adjust 20 
                 HTS 
                 Formu- 
                 loading 
                 Link 
               
               
                 dition 
                 (° F.) 
                 (gpt) 
                 (cP) 
                 pH 
                 (gpt) 
                 (gpt) 
                 (gpt) 
                 lation 
                 (gpt) 
                 pH 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 A 
                 270 
                 35 
                 37 
                 7.2 
                 1 
                 2.8 
                 4 
                 1 
                 2.5 
                 12.21 
               
               
                 B 
                 280 
                 40 
                 46 
                 7.4 
                 1 
                 2.8 
                 4 
                 1 
                 2.5 
                 12.01 
               
               
                 C 
                 300 
                 40 
                 46 
                 7.5 
                 1 
                 3 
                 4 
                 1 
                 3 
                 12.1 
               
               
                 D 
                 300 
                 40 
                 46 
                 7.5 
                 1 
                 3.75 
                 5 
                 1 
                 3 
                 12.1 
               
               
                   
               
             
          
         
       
     
       Crosslinked Gel Viscosity in cP Over Time: 
       [0033]      
         [0000]    
       
         
               
               
               
               
               
               
               
               
               
             
           
               
                   
               
             
             
               
                 Condition 
                 1.5 min 
                 2 min 
                 2.5 min 
                 3 min 
                 3.5 min 
                 4 min 
                 5 min 
                 10 min 
               
               
                   
               
               
                 A 
                 136 
                 195 
                 387 
                 496 
                 560 
                 581 
                 541 
                 548 
               
               
                 B 
                 231 
                 407 
                 740 
                 880 
                 862 
                 719 
                 674 
                 781 
               
               
                 C 
                 203 
                 244 
                 392 
                 589 
                 714 
                 782 
                 751 
                 982 
               
               
                 D 
                 216 
                 393 
                 674 
                 792 
                 797 
                 752 
                 586 
                 781 
               
               
                   
               
               
                 Condition 
                 20 min 
                 30 min 
                 35 min 
                 40 min 
                 50 min 
                 60 min 
                 90 min 
                 120 min 
               
               
                   
               
               
                 A 
                 257 
                 379 
                 369 
                 404 
                 368 
                 360 
                 272 
                 204 
               
               
                 B 
                 659 
                 946 
                 827 
                 826 
                 763 
                 648 
                 479 
                 274 
               
               
                 C 
                 342 
                 179 
                 175 
                 160 
                 132 
                 111 
                 84 
                 72 
               
               
                 D 
                 320 
                 170 
                 362 
                 206 
                 156 
                 145 
                 86 
                 70 
               
               
                   
               
             
          
         
       
     
       Example 6 
     Formulation 1 
     Table Top Crosslinking at Various pH Gel Formulation: 20 ppt PolyFrac Plus M-4.0+1 gpt PolyStim (CS)+See table below Linear Gel Viscosity: 15.4 cP---&gt;Gel pH: 7.20 
       [0034]      
         [0000]    
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
               
             
             
               
                 x-linked gel 
                 9.25 
                 9.54 
                 9.92 
                 10.50 
                 11.2 
               
               
                 pH 
               
             
          
           
               
                 pH Adjust 20 
                 0.12 
                 gpt 
                 0.16 
                 gpt 
                 0.2 
                 gpt 
                 0.4 
                 gpt 
                 0.8 gpt 
               
             
          
           
               
                 Gel pH 
                 10.3  
                 10.5  
                 10.7  
                 11.05 
                 11.5 
               
             
          
           
               
                 Vortex 
                 7 
                 sec 
                 11 
                 sec 
                 11 
                 sec 
                 24 
                 sec 
                 1 min 28 sec 
               
               
                 Closure 
               
               
                 Crown 
                 10 
                 sec 
                 14 
                 sec 
                 15 
                 sec 
                 29 
                 sec 
                 1 min 50 sec 
               
             
          
           
               
                 Lip 
                 Instant 
                 Instant 
                 Instant 
                 41 
                 sec 
                 2 min 11 sec 
               
               
                   
               
             
          
         
       
     
       Example 7 
     Crosslinking Formulations 1 and 6 at Varying Temperatures 
       [0035]      
         [0000]    
       
         
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                   
               
             
             
               
                 Test 
                   
                 pH 
                   
                   
                 1.5 min 
                 2 min 
                 2.5 min 
                 3 min 
                 4 min 
               
               
                 Temp 
                 Formu- 
                 Adjust 20 
                 Crosslinker 
                 Crosslink 
                 Viscocity 
                 Viscocity 
                 Viscocity 
                 Viscocity 
                 Viscocity 
               
               
                 (° F.) 
                 lation 
                 (gpt) 
                 (gpt) 
                 pH 
                 (cP) 
                 (cP) 
                 (cP) 
                 (cP) 
                 (cP) 
               
               
                   
               
               
                 200 
                 1 
                 0.6 
                 2 
                 10.52 
                 225 
                 240 
                 239 
                 236 
                 213 
               
               
                 160 F. 
                 1 
                 0.6 
                 1.5 
                 11.09 
                 45 
                 119 
                 155 
                 164 
                 206 
               
               
                 200 
                 1 
                 1 
                 1.5 
                 11.26 
                 77 
                 95 
                 126 
                 175 
                 237 
               
               
                 160 F. 
                 1 
                 1 
                 1 
                 11.44 
                 39 
                 49 
                 62 
                 71 
                 104 
               
               
                 160 
                 1 
                 1 
                 1 
                 11.03 
                 53 
                 50 
                 51 
                 57 
                 81 
               
               
                 160 
                 6 
                 1 
                 1.5 
                 11.26 
                 54 
                 51 
                 51 
                 51 
                 50 
               
               
                 160 
                 6 
                 0.16 
                 1.5 
                 9.7 
                 54 
                 51 
                 51 
                 51 
                 50 
               
               
                   
               
             
          
           
               
                   
                 Test 
                 5 min 
                 10 min 
                 20 min 
                 30 min 
                 35 min 
                 40 min 
                 60 min 
                 90 min 
                 120 min 
               
               
                 Formu- 
                 Temp 
                 Viscocity 
                 Viscocity  
                 Viscocity 
                 Viscocity 
                 Viscocity 
                 Viscocity 
                 Viscocity 
                 Viscocity 
                 Viscocity 
               
               
                 lation 
                 (° F.) 
                 (cP) 
                 (cP) 
                 (cP) 
                 (cP) 
                 (cP) 
                 (cP) 
                 (cP) 
                 (cP) 
                 (cP) 
               
               
                   
               
               
                 1 
                 200 
                 187 
                 278 
                 285 
                 225 
                 241 
                 246 
                 236 
                 212 
                 211 
               
               
                 1 
                 160 F. 
                 196 
                 209 
                 301 
                 318 
                 331 
                 342 
                 342 
                 345 
                 340 
               
               
                 1 
                 200 
                 234 
                 250 
                 255 
                 260 
                 264 
                 260 
                 259 
                 232 
                 204 
               
               
                 1 
                 160 F. 
                 130 
                 164 
                 213 
                 246 
                 251 
                 262 
                 264 
                 273 
                 275 
               
               
                 1 
                 160 
                 110 
                 173 
                 210 
                 235 
                 220 
                 217 
                 231 
                 243 
                 245 
               
               
                 6 
                 160 
                 50 
                 50 
                 48 
                 61 
                 63 
                 102 
                 150 
                 196 
                 212 
               
               
                 6 
                 160 
                 49 
                 50 
                 48 
                 53 
                 61 
                 75 
                 125 
                 216 
                 210 
               
               
                   
               
             
          
         
       
     
       Example 8 
     Gel Formulation: PolyFrac Plus+1 gpt PolyStim (CS)+2.0 gpt Hydroboracite x-Linker+See Table Below Linear Gel pH: 7.20 
       [0036]      
         [0000]    
       
         
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                   
               
             
             
               
                   
                 Cross-linked Gel Viscosity, cP @ 100 sec-1 over time in minutes 
               
             
          
           
               
                 Condition 
                 1.5 
                 2.0 
                 2.5 
                 3.0 
                 3.5 
                 4.0 
                 5.0 
                 10 
                 20 
                 30 
                 40 
                 50 
                 60 
                 90 
                 120 
               
               
                   
               
               
                 E 
                 96 
                 120 
                 129 
                 140 
                 147 
                 166 
                 200 
                 241 
                 212 
                 178 
                 145 
                 128 
                 130 
                 133 
                 103 
               
               
                 F 
                 594 
                 601 
                 605 
                 617 
                 604 
                 583 
                 556 
                 469 
                 310 
                 213 
                 148 
                 108 
                 126 
                 146 
                 147 
               
               
                 G 
                 45 
                 119 
                 155 
                 164 
                 201 
                 206 
                 196 
                 209 
                 301 
                 318 
                 331 
                 342 
                 342 
                 345 
                 340 
               
               
                 H 
                 39 
                 49 
                 62 
                 71 
                 90 
                 104 
                 130 
                 164 
                 213 
                 246 
                 251 
                 262 
                 264 
                 273 
                 275 
               
               
                 I 
                 225 
                 240 
                 239 
                 236 
                 223 
                 213 
                 187 
                 278 
                 285 
                 225 
                 241 
                 246 
                 236 
                 212 
                 211 
               
               
                   
               
             
          
           
               
                   
                 Test 
                   
                   
                 pH 
                   
                   
                 X-linker 
                   
               
               
                   
                 Temp 
                 Gel 
                 Hydration 
                 Adjust20, 
                 HTS,  
                   
                 Loading, 
                 X-linked 
               
               
                 Condition 
                 (° F.) 
                 loading 
                 Visc, cP 
                 gpt 
                 gpt 
                 Formulation 
                 gpt 
                 gel pH 
               
               
                   
               
               
                 E 
                  80 F. 
                 20# 
                 15.4 
                 0.4 
                 0 
                 1 
                 1.5 
                 10.61 
               
               
                 F 
                  80 F. 
                 20# 
                 15.4 
                 0.6 
                 0 
                 1 
                 2.0 
                 10.2 
               
               
                 G 
                 160 F. 
                 20# 
                 15.2 
                 0.6 
                 0 
                 1 
                 1.5 
                 11.09 
               
               
                 H 
                 160 F. 
                 20# 
                 15.2 
                 1 
                 0 
                 1 
                 1.0 
                 11.44 
               
               
                 I 
                 200 
                 20# 
                 15.4 
                 0.6 
                 0 
                 1 
                 2.0 
                 10.52 
               
               
                   
               
             
          
         
       
     
       Example 9 
     Formulations 1-12 with Canola Oil and Xanthan 
       [0037]      
         [0000]    
       
         
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                   
               
             
             
               
                   
                   
                 50% 
                   
                   
                   
                 Canola 
                   
                   
               
               
                   
                   
                 NaOH 
                   
                   
                   
                 Oil  
                 Xanthan 
                   
               
               
                 Form. # 
                 Water 
                 % 
                 Glycerol 
                 HB 
                 Borax 
                 % 
                 % 
                 Total 
               
               
                   
               
               
                  1 
                 58.36% 
                   
                 18.61% 
                 11.37% 
                 11.37% 
                 0.13% 
                 0.16% 
                 100.00% 
               
               
                  2 
                 67.34% 
                   
                  9.63% 
                 11.37% 
                 11.37% 
                 0.13% 
                 0.16% 
                 100.00% 
               
               
                  3 
                 71.82% 
                   
                  5.16% 
                 15.00% 
                  7.74% 
                 0.13% 
                 0.16% 
                 100.01% 
               
               
                  4 
                 74.37% 
                   
                  4.61% 
                 13.82% 
                  6.91% 
                 0.13% 
                 0.16% 
                 100.00% 
               
               
                  5 
                 78.08% 
                   
                  0.00% 
                 17.08% 
                  4.55% 
                 0.13% 
                 0.16% 
                 100.00% 
               
               
                  6 
                 58.36% 
                   
                 18.61% 
                 22.74% 
                  0.00% 
                 0.13% 
                 0.16% 
                 100.00% 
               
               
                  7 
                 29.72% 
                 17.42% 
                 30.84% 
                 22.02% 
                   
                   
                   
                 100.00% 
               
               
                  8 
                 32.56% 
                 19.83% 
                 35.09% 
                 12.52% 
                   
                   
                   
                 100.00% 
               
               
                  9 
                 50.10% 
                 19.83% 
                 17.55% 
                 12.52% 
                   
                   
                   
                 100.00% 
               
               
                 10 
                 65.18% 
                   
                 11.80% 
                 11.37% 
                 11.37% 
                 0.13% 
                 0.16% 
                 100.01% 
               
               
                 11 
                 45.42% 
                 19.76% 
                 11.80% 
                 11.37% 
                 11.37% 
                 0.13% 
                 0.16% 
                 100.01% 
               
               
                 12 
                 52.03% 
                 17.97% 
                 10.73% 
                 19.03% 
                   
                 0.12% 
                 0.12% 
                 100.00% 
               
               
                   
               
             
          
           
               
                   
                   
                 50% 
                   
                   
                   
                 Canola 
                   
               
               
                   
                 Water  
                 NaOH  
                 Glycerol, 
                 HB  
                 Borax 
                 Oil,  
                 Xanthan 
               
               
                   
                 % 
                 % 
                 % 
                 % 
                 % 
                 % 
                 % 
               
               
                   
               
               
                 All 
                 29-79% 
                 17-20% 
                 0-36% 
                 10-23% 
                 0-12% 
                 0-0.13% 
                 0-0.16% 
               
               
                 formulation 
                   
                   
                   
                   
                   
                   
                   
               
               
                 Range 
               
               
                   
               
             
          
         
       
     
         [0038]    The embodiments disclosed above are various species of the larger genus that is the presently disclosed composition, and methods of making and using that composition that collectively constitute the present disclosure. From this disclosure one of skill in the art can appreciate the relationships among borate ion sources, crosslink reactions, time, an temperature and will be able to readily extrapolate other desired reaction times and the borate ion source balances for achieving those reaction times through routine optimization. One of skill in the art would readily appreciate that further optimization of the formulation of the presently disclosed composition, the proppant fluid into which it is mixed, and the fracking systems and methods in which it is used can vary without departing from the scope of the present disclosure.