FRICTION REDUCERS, FRACTURING FLUID COMPOSITIONS AND USES THEREOF
FIELD OF THE INVENTION
The invention relates to friction reducers, fracturing fluid compositions and methods for treating subterranean formations. BACKGROUND OF THE INVENTION
Galactomannan gums have many industrial uses, such as the use in food and beverages as a thickener, stabilizer, suspension and binding agent, in explosives, and in oil and gas fields as part of fracturing fluid and as a crosslinkable polymer to carry proppants. Similarly, polyacrylamides also have various uses such as water treatment, flocculants, absorbents, thickening agents, oil and gas fields for secondary oil recovery and as a proppant carrier and friction reducer.
In oil well operations, a fracturing fluid is pumped into the well bore under high pressure to fracture the rock formations surrounding it. The pressure is then relieved, allowing the oil to seep through the fractures into the well bore where it is pumped to the surface. It is desirable to have the thickening agent degrade because degradation should decrease the viscosity to near the levels it would be at without the thickening agent. This is desirable because, when the viscosity of the fracturing fluid is high, oil will not flow easily into the fractures of the formation and will remain in the fissured spaces. A good thickening agent, therefore, yields a high viscosity at a low concentration, reduces friction pressure, is inexpensive, and degrades once it has carried the sand particles into the fractures. Preferably, it should also not leave insoluble precipitates or residues when it is degraded, as these precipitates or residues tend to plug the formations. The amount of oil which can be obtained from a well depends to a great extent upon how extensively the rock formations can be fractured. This, in turn, depends upon the degree of pressure that is applied to the rock. Due to friction between the fracturing fluid and the pipe or rock and within the fracturing fluid itself because of turbulent flow, a significant amount of energy may be lost as the fluid travels from the earth’s surface to the formation, and considerably less pressure may be actually applied to the rock than was originally applied at the top of the well. This problem is minimized by adding a friction reducer to the fracturing fluid.
A good friction reducer should cause a large decrease in friction when used in small concentrations, be inexpensive, have shear, temperature, and pressure stability, work at all or most total dissolved solids (TDS) and not leave deposits which plug the formation.
There remains a need in the art for good friction reducers that would satisfy these characteristics and for fracturing fluid compositions containing these friction reducers.
SUMMARY OF THE INVENTION
In one embodiment, the invention provides a fracturing fluid comprising: an aqueous base fluid, a dry blend or a liquid slurry; a friction reducer, wherein the friction reducer is a blend of natural gum and partially hydrolyzed polyacrylamide (PHPA) having a molecular weight between 300,000 and 30,000,000. The fracturing fluid contains natural gum and polyacrylamide in a ratio of 5:1 to 1: 0.01 by weight.
What about a particle size of natural gum and polyacrylamide?
We are using commercially available guar gum and PHPA’s
How are we making this blend?
We are mixing guar gum and PHPA and blending them using motor and pistol in the laboratory.
If we can avoid using dry powders with a particle size below 500 µm, this would avoid any potential FTO issues with Univar’s PCT (if it ever issues as US patent).
These dry powders are available to us commercially below 500 microns only
In one embodiment, the concentration of the polyacrylamide in the fracturing fluid is…1-20%
In one embodiment, the fracturing fluid of the invention has a viscosity of from 1 cP to 10 cP; and more preferably from 2 cP to 4 cP.
In one embodiment, the concentration of the friction reducer is about 0.1% or less by weight of the fracturing fluid.
In one preferred embodiment, the natural gum and polyacrylamide are provided in a ratio of about 5:1 to about 1: 0.01 by weight relative to the friction reducer.
In one embodiment, the natural gum is galactomannan gum.
In one preferred embodiment, the polyacrylamide is partially hydrolyzed polyacrylamide (PHPA).
In another preferred embodiment, fresh water comprises 99.95% weight of the total weight of the aqueous base fluid.
In one embodiment, the aqueous base fluid is a brine comprising one or more dissolved inorganic salts in a total concentration between 0.1 and 20 weight percent of the total weight of the aqueous base fluid.
In another embodiment, the inorganic salt comprises one or more monovalent or divalent cations.
In one embodiment, at least a portion of the aqueous base fluid is flowback water.
In another embodiment, the aqueous base fluid comprises fresh fracturing fluid recycled fracturing fluid, flowback fracturing fluid or back-produced fracturing fluid, or combinations thereof.
In one preferred embodiment, the friction reducer comprises a locust bean gum.
In another preferred embodiment, the friction reducer comprises a karaya gum.
In another preferred embodiment, the friction reducer comprises a cassia tora gum.
In one embodiment, the friction reducer comprises a cellulose polymer.
In one embodiment, the friction reducer comprises a starch polymer.
In another embodiment, the friction reducer comprises a combination of guar gum, guar gum derivatives, locust bean gum, karaya gum, cassia tora, carrageenan gum, xanthan gum, starch, cellulose or any natural gum.
In another embodiment, the friction reducer comprises copolymers of acrylamides.
In another embodiment, the friction reducer comprises acrylic acids.
In another embodiment, the friction reducer comprises acrylic acids salts.
In another embodiment, the friction reducer comprises a combination of PHPA, copolymers of acrylamides, acrylic acid and its salts.
In another embodiment, the divalent cations comprise calcium cations.
In one preferred embodiment, the divalent cations comprise magnesium cations.
In another preferred embodiment, the divalent cations comprise both calcium cations and magnesium cations.
In one preferred embodiment, the monovalent cations comprise sodium cations.
In another preferred embodiment, the monovalent cations comprise potassium cations.
In another preferred embodiment, the monovalent cations comprise both sodium cations and potassium cations.
In one embodiment, the friction reducer can act as hybrid fracturing fluid and eliminate the need to use two products for different stages of fracturing.
In one embodiment, the friction reducer can also be used for carrying proppants from 20 mesh to 100 mesh.
In one embodiment, the friction reducer can also be crosslinked with boron and other group 4 metals likes zirconium, titanium and hafnium.
In another embodiment, the friction reducer can be used without any additional crosslinkers. Thus, in one embodiment, the fracturing fluid of the invention does not include any additional cross-linker (because there is no need to use other cross-linkers due to the advantages of the provided synergistic blend).
In one embodiment, the friction reducer is biodegradable.
In one embodiment, the friction reducer is breakable with strong oxidizers.
In one embodiment, the friction reducer is slurriable in mineral oil and other non-sheen forming oils and solvents.
Please list the specific blends, including all of the ingredients (not internal abbreviations) and preferred concentrations/amounts (ranges are fine).
Simple blends were made using mortar and pistol in the lab at room temperature. As seen in example 1, we mixed 70% guar gum and 30% partially hydrolyzed polyacrylamide blend and the results were noted, the economics didn’t look good even though the results were promising. In example two we experimented with different concentrations of guar gum to PHPA. We decided to stay within the range 99% -90% guar gum and 1%-10% PHPA for all our future experiments. Example 3 was using guar gum and CMHPG and blending with PHPA and in example 4 we tested for variations from different suppliers of PHPA.
EXAMPLES
Preparation of Natural Gum/Polyacrylamide Blends
Experimental Conditions
Please describe how the blends were actually prepared. Please explain all of the abbreviations.
Example 1 To a 500ml blender jar add 250 ml DIW and 1.2gms of guar gum or friction reducer or modified friction reducer for 0.5% solution and 0.6gms for 0.25% solution was slowly added and mixed at 1100rpm for 2.5 minutes at room temperature.
Here viscosities were compared between regular guar gum and regular anionic PHPA and between mixtures of guar gum and polyacrylamides. A 70% guar gum and 30% anionic PHPA mixture was blended and compared.
Table 1 1 2 3 4 5 6
Hydration Time 0.5% 0.25% 0.5% 0.25% 0.5% 0.25%
MFR-211 MFR-211 FR FR Guar Gum Guar Gum
3 min 43 16 20 11 39 12
30 min 52 20 45 17 44 14
pH 7.6 7.73 7.72 7.78 7.61 7.69
Example 2 To a 500ml blender jar add 250 ml DIW and 1.2gms of guar gum or modified friction reducer, for 0.5% solution and 0.6gms for 0.25% solution was slowly added and mixed at 1100rpm for 2.5 minutes at room temperature.
Here hydration viscosities were compared between regular guar gum and between mixtures of guar gum and polyacrylamides. From 100%-70% guar gum and 5%-30% anionic polyacrylamide mixture was blended and compared.
Table 2 Hydration Time 0.25% 0.25% 0.25% 0.25% 0.25% 0.25% 0.25% 0.5% 0.125%
Guar Gum MFR-210 (5%) MFR-210 (10%) MFR-210 (15%) MFR-210 (20%) MFR-210 (25%) MFR-210 (30%) MFR-210 (5%) MFR-210 (10%)
3 min 8.4 10.3 11.9 13.1 14.5 15.5 16.9 34.5 5.6
30 min 10.1 12.6 14.2 16.7 18.7 20.5 22.1 41 7.2
Example 3
To a 500ml blender jar add 250 ml DIW and guar gum or modified friction reducer blend, 0.6gms for 0.25% solution
and 0.3gms for 0.125% solution and 0.15gms for 0.0625% solution was slowly added and mixed at 1100rpm for 2.5
minutes at room temperature.
Here viscosities were compared between guar gum and derivatized guar gum and between mixtures of guar gum and polyacrylamides. From 90.1% guar gum and 9.9% anionic polyacrylamide mixture was blended and compared. These
samples were sent to third party lab to run friction loop test.
Table 3
1 2 3 4 5 6
Hydration Time 0.063% 0.13% 0.25% 0.06% 0.13% 0.25%
GG GG GG MFR-210 MFR-210 MFR-210
3 min 2.1 3.9 12.4 3.2 6.7 15
30 min 2.3 4.7 14.5 3.5 8.2 16.5
1 2 3 4 5 6
0.063% 0.13% 0.25% 0.06% 0.13% 0.25%
Hydration Time CMHPG CMHPG CMHPG MFR-212 MFR-212 MFR-212
3 min 2.9 6 11.5 4.3 9.2 16
30 min 3.9 6 13.3 4.7 9.2 16
Example 4
To a 500ml blender jar add 250 ml DIW and guar gum and anionic PHPA from different vendors were blended for 0.25%, 0.125% and 0.0625% solution and mixed at 1100rpm for 2.5 minutes.
Table 4
FR1+GG1 1 2 3 4 5 6
0.63% 0.13% 0.25% 0.06% 0.13% 0.25%
FR-Vendor1
GG GG GG MFR-210 MFR-210 MFR-210
3 min 1.9 3.7 8.9 2.5 4.9 11.9
30 min 2 4.5 11.1 3 6.4 14.2
FR2+GG1 1 2 3 4 5 6
0.063% 0.13% 0.25% 0.06% 0.13% 0.25%
FR-Vendor 2 GG GG GG MFR-210 MFR-210 MFR-210
3 min 1.9 3.7 8.9 2.9 5.6 15.5
30 min 2 4.5 11.1 3.1 7 18.8
FR3+GG1 1 2 3 4 5 6
0.063% 0.13% 0.25% 0.06% 0.13% 0.25%
FR- Vendor 3 GG GG GG MFR-210 MFR-210 MFR-210
3 min 1.9 3.7 8.9 2.9 5.8 17.2
30 min 2 4.5 11.1 3 7.2 19.2
Example 2
Testing of Natural Gum/Polyacrylamide Blends
Experiments falling under this would probably include “Performance of SHI Guar Gums in HTW”; Performance of Guar Products in HTW and 200K Brine
Experimental Conditions
Please describe how the tests were done. Please explain all of the abbreviations.
Experimental Results
Please describe the results with reference to Tables and Figures as necessary. Please explain what the experiment has demonstrated.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a
Figure 1
Figure 1 shows better friction reduction performance at lower concentration 0.125% of different grades compared to 0.25% of the modified friction reducer (MFR) and at that same concentration the friction reduction doesn’t change when fresh water is replaced with 7% potassium chloride.
FIG. 2 is a
Figure 2
Figure 2 shows better friction reduction performance at lower concentration of 0.0625% solution from 0.25% solution to 0.125% solution and the friction reduction doesn’t change when fresh water is replaced with 7% potassium chloride.
FIG. 3 is a
Figure 3
Figure 3 shows better friction reduction performance at lower concentration of 0.0625% solution and 0.0325% solution compared to 0.125% and 0.25% solution and the friction reduction doesn’t change when fresh water is replaced with 7% potassium chloride and 150K synthetic brine
FIG. 4 is a
Figure 4
Figure 4 shows premium friction reduction performance at lower concentration of 0.0625% solution of MFR from different vendors and at that same concentration the friction reduction doesn’t change when fresh water is replaced with 231K Brine
Additives
GG Guar Gum
CMHPG Carboxy Methyl Hydroxy Propyl Guar
SHI-057PB Anionic PHPA Dry (FR)
HTW Houston Tap water
DIW Deionized water
KCl Potassium Chloride
PAM Polyacrylamide
PHPA Partially hydrolyzed polyacrylamides
MFR-210 Modified Friction Reducer with guar gum
MFR-212 Modified Friction Reducer with CMHPG
DETAILED DESCRIPTION OF THE INVENTION
The invention is directed to a surprising and unexpected discovery that a blend of natural gum and polyacrylamide having a molecular weight between 300,000 and 30,000,000 can serve as an effective friction reducer at a very low concentration of less than 0.1% (when this blend is used in a combination with an aqueous base fluid, a dry blend, or a liquid slurry) or as a thickening agent when used at higher concentrations of greater than 0.2%.
The polyacrylamides currently used as friction reducers are essentially linear homopolymers. In contrast, the synergetic blend of the present invention is a mixture of mainly a natural gum (a carbohydrate with soluble fiber) with small amounts of (1-20% and preferably 1-10%) partially hydrolyzed polyacrylamides. One of the key advantages of the friction reducers of the present invention is that when they are utilized as friction reducers, they provide more viscous aqueous solutions than conventional friction reducers while maintaining the friction reducing properties. Therefore, the synergetic blends of the present invention are more economically utilizable as friction reducers than conventional linear galactomannans and homo polyacrylamides because they provide the desired solution properties at lower concentrations, such as 0.1% or less by weight of the fracturing fluid.
The synergistic blends of the present invention effectively reduce friction in all Total Dissolved Solids (TDS) brines. Utilizing friction reducers of the present invention allows to avoid the need for separate friction reducers for fresh water, mid brine, high brine, cationic liquid friction reducer, or high viscosity liquid friction reducer.
At higher concentrations of greater than 0.2%, this blend is effective as a thickening agent. The synergistic blend of the present invention has improved shear and temperature stability, is easily degradable, and does not leave in soluble residues when degraded.
Accordingly, in one embodiment, the invention provides a fracturing fluid comprising: an aqueous base fluid, a dry blend or a liquid slurry; a friction reducer, wherein the friction reducer is a blend of natural gum and polyacrylamide having a molecular weight between 300,000 and 30,000,000.
The term “natural gum” refers to polysaccharides of natural origin, capable of causing a large increase in a solution’s viscosity, even at small concentrations. This term includes, but is not limited to, galactomannan gums.
What about a particle size of natural gum and PAM? (same comment as above) Commercially available product have been used for blending.
In one embodiment, the concentration of the polyacrylamide in the fracturing fluid is 1-10%
In one embodiment, the fracturing fluid of the invention has a viscosity of from 1 cP to 10 cP; and more preferably from 2 cP to 4 cP.
In one embodiment, the concentration of the friction reducer is about 0.1% or less by weight of the fracturing fluid.
In one preferred embodiment, the natural gum and polyacrylamide are provided in a ratio of about 5:1 to about 1: 0.01 by weight relative to the friction reducer.
In one embodiment, the natural gum is galactomannan gum.
In one preferred embodiment, the polyacrylamide is partially hydrolyzed polyacrylamide (PHPA).
In another preferred embodiment, fresh water comprises 99.95% weight of the total weight of the aqueous base fluid.
In one embodiment, the aqueous base fluid is a brine comprising one or more dissolved inorganic salts in a total concentration between 0.1 and 20 weight percent of the total weight of the aqueous base fluid.
In another embodiment, the inorganic salt comprises one or more monovalent or divalent cations.
In one embodiment, at least a portion of the aqueous base fluid is flowback water.
In another embodiment, the aqueous base fluid comprises fresh fracturing fluid recycled fracturing fluid, flowback fracturing fluid or back-produced fracturing fluid, or combinations thereof.
In one preferred embodiment, the friction reducer comprises a locust bean gum.
In another preferred embodiment, the friction reducer comprises a karaya gum.
In another preferred embodiment, the friction reducer comprises a cassia tora gum.
In one embodiment, the friction reducer comprises a cellulose polymer.
In one embodiment, the friction reducer comprises a starch polymer.
In another embodiment, the friction reducer comprises a combination of guar gum, guar gum derivatives, locust bean gum, karaya gum, starch, cellulose or any natural gum.
In another embodiment, the friction reducer comprises copolymers of acrylamides.
In another embodiment, the friction reducer comprises acrylic acids.
In another embodiment, the friction reducer comprises acrylic acids salts.
In another embodiment, the friction reducer comprises a combination of PHPA, copolymers of acrylamides, acrylic acid and its salts.
In another embodiment, the divalent cations comprise calcium cations.
In one preferred embodiment, the divalent cations comprise magnesium cations.
In another preferred embodiment, the divalent cations comprise both calcium cations and magnesium cations.
In one preferred embodiment, the monovalent cations comprise sodium cations.
In another preferred embodiment, the monovalent cations comprise potassium cations.
In another preferred embodiment, the monovalent cations comprise both sodium cations and potassium cations.
In one embodiment, the friction reducer can act as hybrid fracturing fluid and eliminate the use of two products for different stages of fracturing.
In one embodiment, the friction reducer can also be used for carrying proppants from 20 mesh to 100 mesh
In one embodiment, the friction reducer can also be crosslinked with boron and other group 4 metals likes zirconium, titanium and hafnium.
In another embodiment, the friction reducer can be used without any additional crosslinkers. Thus, in one embodiment, the fracturing fluid of the invention does not include any additional cross-linker (because there is no need to use other cross-linkers due to the advantages of the provided synergistic blend).
In one embodiment, the friction reducer is biodegradable.
In one embodiment, the friction reducer is breakable with strong oxidizers and enzymes.
In one embodiment, the friction reducer is slurriable in mineral oil and other non-sheen forming oils and solvents.
The fracturing fluid of the invention may also contain other conventional additives common to the well service industry, including but not limited to, corrosion inhibitors, surfactants, demulsifying agents, scale inhibitors, asphaltene inhibitors, paraffin inhibitors, gas hydrate inhibitors, dispersants, oxygen scavengers, biocides and the like.
Suitable surfactants may act as surface active agents and function as emulsifiers, dispersants, foamers or defoamers. In some embodiments of the invention, the surfactant is an anionic surfactant. Examples of suitable anionic surfactants include, but are not limited to, anionic surfactants such as alkyl carboxylates, alkyl ether carboxylates, alkyl sulfates, alkyl ether sulfates, alkyl sulfonates, alpha olefin sulfonates, alkyl phosphates and alkyl ether phosphates. Examples of suitable anionic surfactants also include, but are not limited to, cationic surfactants such as alkyl amines, alkyl diamines, alkyl ether amines, alkyl quaternary ammonium, dialkyl quaternary ammonium and ester quarternary ammonium compounds. Examples of suitable ionic surfactants also include, but are not limited to, surfactants that are usually regarded as zwitterionic surfactants and in some cases as amphoteric surfactants such as alkyl betaines, alkyl amido betaines, alkyl imidazolines, alkyl amine oxides and alkyl quarternary ammonium carboxylates.
The following are some of the examples of the friction reducer blends of the invention:
Fracturing fluids of the invention, may be prepared, for example as follows:
Please provide a brief description how a skilled artisan could go about preparing a fracturing fluid of the invention, i.e. what is combined with what, in what sequence, etc.
Hydraulic fracturing is an unconventional drilling method used due to increasing scarcity of retrieving oil and gas using conventional methods. It allows to drill down, drill horizontally and fracturing happens, which enables oil and gas to be flowing from tight reservoirs. The general practice for treatments of reservoirs applies a sequence of pumping events where millions of gallons of water based fracturing fluids mixed with proppants and other chemicals are pumped in a controlled environment above fracture pressure. Proppants such as sand or ceramic beads are usually added to hold the fractures open after treatment is complete. The chemical additives account for only 0.5% -2% of the total fluid, the rest is water. The chemicals include and not limited to thickening agents like friction reducers, guar gum and its derivatives, crosslinkers, scale inhibitors, corrosion inhibitors, biocides, surfactants, acids, oxygen scavengers, breakers and clay control.
The main fluids currently used for fracturing are water based friction reducing additives called slick water. This allows the fracturing additives to be pumped to the target zone at reduced pressure and higher rate. However the choice of additives varies with water quality source, site specific needs of the target formation and including company preferences along with the design engineer.
Hereinafter, the present invention will be further illustrated with reference to the following examples. However, these examples are only provided for illustrate purpose, but not to limit the scope of the present invention.
Experimental Results
Example 3
Measuring Viscosity of Natural Gum/Polyacrylamide Blends
The data you sent me includes several Viscosity vs Time @250F graphs. These experiments need to be explained here.
Several crosslink test were done to see if the guar gum properties were intact in the invention modified friction reducer.
Experimental Conditions
Please describe how the tests were done. Please explain all of the abbreviations.
Were there any experiments done with comparison versus conventional friction reducers? Such experiments, showing superior results versus Comparative Examples would be very helpful.
Additives Concentration Units Test Number
Guar Gum 0.05-0.5 % Test1
MFR-210 0.05-0.5 % Test2
Oxygen Scavenger 0-0.5 % Test 1 ; 2
Crosslinker Boron 0.01-0.1 % Test 1 ; 2
Temperature 100-400 F Test 1 ; 2
Clay Control 0.01-10 % Test 1 ; 2
Buffer 0.01-0.1 % Test 1 ; 2
Biocide 0.01-0.1 % Test 1 ; 2
Scale Inhibitor 0.01-0.1 % Test 1 ; 2
Flow back Additive 0.01-0.1 % Test 1 ; 2
Test 1 was done using guar gum 0.375% solution at 250F and crosslinking with a delayed borate crosslinker, using 0.25% oxygen scavenger sodium thiosulfate.
Test 2 was done using MFR-210 0.375% solution at 250F and crosslinking with a delayed borate crosslinker, using 0.25% oxygen scavenger sodium thiosulfate.
Experimental Results
Please describe the results with reference to Tables and Figures as necessary. Please explain what the experiment has demonstrated.
Please describe how this experiment was done. Please explain all of the abbreviations.
Experimental Results
Please describe the results with reference to Tables and Figures as necessary. Please explain what the experiment has demonstrated.
Additives Concentration Units Test Number
MFR-212 0.05-0.5 % Test 3
Sodium bicarbonate 0.01-0.1 % Test 3
Crosslinker Zirconium 0.01-0.1 % Test 3
Buffer 0.01-0.1 % Test 3
Oxygen Scavenger 0-0.5% % Test 3
Test 3 was done using MFR-212 0.375% solution at 250F and crosslinking with zirconium based crosslinker, using 0.25% oxygen scavenger sodium thiosulfate.
Test 4 was done using MFR-210 0.25% solution in 5% KCl at 200F and crosslinking with delayed boron based crosslinker.
Example 4
Using Natural Gum/Polyacrylamide Blends to Carry Proppants
The experiment where “MFR” was used to carry proppants need to be explained here.
Experimental Conditions
Previous Art:
Patent Number 3,658,734 April 25 1972Kelco
Publication Number 0157356A1 June 21 2012Frac Tech Services LLC
WO Application20162001445A1 DEC 12 2017Univar USA Inc.
The MFR can be used to carry proppants.
A sand settling test was conducted , using different combinations of guar to PHPA for a
0.24% solution to determine the fluids capability to carry sand and how concentration/viscosity
changes affected this ability. This test was performed at a 3rd party lab to see how well MFR fluids are able to transport sand.
Sand 100 mesh was added at 3 ppa (pounds of proppant added) to 0.125% and 0.24% polymer fluids.
A video as well as pictures were taken to see how sand falls in each solution. The slower the sand
Accumulates in the cylinder, the better is the sand carrying capacity of the fracturing fluid.
A 50 ml cylinder was used.
Another sand settling test was conducted , using different combinations of guar to PHPA for a
20ppt (0.24%) solution to determine the fluids capability to carry sand and how
concentration/viscosity changes affected this ability. Sand (20/40) mesh was added at 10 ppa (pounds of proppant added) to 0.24% polymer fluids. The mixtures were shaken to homogenize
the slurry and were then allowed to settle. Sand volumes accumulated at the bottom of the cylinder were measured over time approximately seven minutes. A 50ml measuring cylinder was used Figure 5 below shows the results. There was some delay in settling as ratio of Guar to PHPA increased (0%-30%. By the end of seven
minutes all the sand settled in every cylinder. This static test study is insufficient to determine the
actual concentrations required during fracturing operations due to the friction while transporting the
sand As settling is fast, we need to prepare ourselves during pump shut down, flushing and flow
back is necessary to avoid screening out.
The third party lab has performed some dynamic proppant carrying test which can be provided to
customers upon request. MFR-210 is the SHI preferred formulation in terms of value and
performance.
Figure 5
Figure 6
Figure 7
Figure 8
Pictures showing complete sand settling in seven minutesThe MFR is Slurriable: Test 5
The slurry had the following composition
250gms Chemicals Lab1-144A Mineral Oil 130 organophilic clay 3.75 Surfactant 1.25 MFR 115 Please use overhead mixtures Neat slurry viscosity cps ;250cps sludge 1 week 0% Settling one Day ;1% Settling one week ;2% Specific Gravity 1.05+/-0.02 Hydrate gel 5mls/500gms DIW with 2% KCl at 2000rpm mix for 2 minutes 3 min viscosity 36-40 41 10 min viscosity 40-44 44 60 min viscosity 42-46 47 pH ‘7-8 7.52 Images from Google
Acrylic Acid Copolymer
Xanthan gum 1XanxthX
cationic guar gum 1What is claimed is:
1. A fracturing fluid comprising: an aqueous base fluid, a dry blend or a liquid slurry; a friction reducer, wherein the friction reducer is a blend of natural gum and polyacrylamide having a molecular weight between 300,000 and 30,000,000.
2.The fracturing fluid of claim 1, wherein the concentration of the friction reducer is about 0.1% or less by weight of the fracturing fluid.3.The fracturing fluid of claim 1, wherein the natural gum and polyacrylamide is provided in a ratio of about 1:5 to about 1: 0.01 by weight relative to the friction reducer. 4. The fracturing fluid of claim 3, wherein the natural gum is galactomannan gum.
5. The fracturing fluid of claim 3, wherein the polyacrylamide is partially hydrolyzed polyacrylamide (PHPA).
6. The fracturing fluid of claim 1, wherein the aqueous base fluid is fresh water 99.9 weight percent of the total weight of the aqueous base fluid.
7. The fracturing fluid of claim 1, wherein the aqueous base fluid is a brine comprising one or more dissolved inorganic salts in a total concentration between 0.1 and 20 weight percent of the total weight of the aqueous base fluid. 8. The fracturing fluid of claim 7, wherein inorganic salt comprises one or more monovalent or divalent cations. 9. The fracturing fluid of claim 1, wherein at least a portion of the aqueous base fluid is flowback water. 10. The fracturing fluid of claim 1, wherein the aqueous base fluid comprises fresh fracturing fluid recycled fracturing fluid, flowback fracturing fluid or back-produced fracturing fluid, or combinations thereof. 11. The fracturing fluid of claim 1, wherein the friction reducer comprises a locust bean gum.12.The fracturing fluid of claim 1, wherein the friction reducer comprises a karaya gum.
13.The fracturing fluid of claim 1, wherein the friction reducer comprises a cassia tora gum.
14. The fracturing fluid of claim 1, wherein the friction reducer comprises a cellulose polymer
15. The fracturing fluid of claim 1, wherein the friction reducer comprises a starch polymer
16. The fracturing fluid of claim 1, wherein the friction reducer comprises a combination of guar gum, guar gum derivatives, locust bean gum, karaya gum, cassia tora, starch, cellulose or any natural gum 17. The fracturing fluid of claim 1, wherein the friction reducer comprises copolymers of acrylamides.
18. The fracturing fluid of claim 1, wherein the friction reducer comprises acrylic acids.
19. The fracturing fluid of claim 1, wherein the friction reducer comprises acrylic acids salts.
20. The fracturing fluid of claim 1, wherein the friction reducer comprises a combination of PHPA, copolymers of acrylamides, acrylic acid and its salts. 21. The fracturing fluid of claim 8, where the divalent cations comprise calcium cations. 22. The fracturing fluid of claim 8, wherein the divalent cations comprise magnesium cations. 22. The fracturing fluid of claim 8, wherein the divalent cations comprise both calcium cations and magnesium cations. 24. The fracturing fluid of claim 8, wherein the monovalent cations comprise sodium cations. 25. The fracturing fluid of claim 8, wherein the monovalent cations comprise potassium cations. 26. The fracturing fluid of claim 8, wherein the monovalent cations comprise both sodium cations and potassium cations.
27. The fracturing fluid of claim 1, wherein the friction reducer is used for carrying proppants from 20 mesh to 100 mesh.
28. The fracturing fluid of claim 1, wherein the friction reducer is crosslinked with boron and other group 4 metals likes zirconium, titanium and hafnium.
29. The fracturing fluid of claim 1, wherein the friction reducer is biodegradable.
30. The fracturing fluid of claim 1, wherein the friction reducer is breakable with strong oxidizers and enzymes.
31. The fracturing fluid of claim 1, wherein the friction reducer is slurriable in mineral oil and other non-sheen forming oils and solvents.
ABSTRACT
Friction reducers, fracturing fluid compositions and methods for treating subterranean formations, wherein friction reducer is a blend of natural gum and polyacrylamide having a molecular weight between 300,000 and 30,000,000.
A composition and method for treating a fracturing fluid comprising of fresh water to high Total Dissolved Solids (TDS) brine. 1. A blend of galactomannan gums or any natural gums and partially hydrolyzed polyacrylamides or other copolymers which upon hydration enhances viscosities of galactomannan gums 2. A blend of guar gum or its derivatives and partially hydrolyzed polyacrylamides (PHPA) or other copolymers which reduces friction in excess of the additive friction reduction of the components. 3. A blend of guar gum and partially hydrolyzed polyacrylamides which upon hydration exhibits friction reduction at all TDS brines in excess of the additive friction reduction of the components at low concentration (1ppt to 5ppt). A method is disclosed for reducing friction in the formation by dissolving a unique synergetic blend of polysaccharides, which can include galactomannan gums and its derivatives, locust bean gum and karaya gum, cassia tora, starch and cellulose with a small amount of partially hydrolyzed polyacrylamide (PHPA) and other copolymers of acrylamides, acrylic acid and its salts. Since this composition is a simple blend, galactomannan gum properties are not destroyed, it is biodegradable, slurriable, breakable, crosslinkable and carries proppant as known from prior art.
