Bionics-based efficiently transported and packed proppant and preparation method thereof

Abstract

The present invention relates to a bionics-based efficiently transported and packed proppant and preparation method thereof, comprising enhanced fracturing fluid and biomimetic dandelion proppant; the mass ratio of the enhanced fracturing fluid and the biomimetic dandelion is: 1-2:100-400; the 100 pbw of enhanced fracturing fluid includes 0.1-1 pbw of drag reducing agent, 0.01-0.1 pbw of cleanup additive, 0.2-0.8 pbw of clay stabilizer, 0.01-0.05 pbw of bactericide, 0.01-0.2 pbw of nanoparticle enhancer, and water; the biomimetic dandelion proppant consists of modified proppant and modified fiber, and the mass ratio between the modified proppant and the modified fiber is 99-99.9:0.1-1.

Claims

1. A bionics-based efficiently transported and packed proppant, comprising enhanced fracturing fluid and biomimetic dandelion proppant, wherein the mass ratio of the enhanced fracturing fluid and the biomimetic dandelion proppant is: 1-2:100-400; The 100 pbw of enhanced fracturing fluid includes 0.1-1 pbw of drag reducing agent, 0.01-0.1 pbw of cleanup additive, 0.2-0.8 pbw of clay stabilizer, 0.01-0.05 pbw of bactericide, 0.01-0.2 pbw of nanoparticle enhancer, and water; The biomimetic dandelion proppant consists of modified proppant and modified fiber, and the mass ratio between the modified proppant and the modified fiber is 99-99.9:0.1-1.

2. The bionics-based efficiently transported and packed proppant according to claim 1, wherein the nanoparticle enhancer is nanoparticle, which is modified as follows: a modifier is sprayed on the surface of the nanoparticle, and then nanoparticle are kept at 50° C. for 20-30 min and dried at 105° C. to obtain the modified nanoparticle; The nanoparticle are prepared with one, two or more of nanosilicon dioxide.

3. The bionics-based efficiently transported and packed proppant according to claim 2, wherein the modifier is prepared with one, two or more of cocamidopropyl hydroxysulfobetaine, and/or lauramidopropyl betaine.

4. The bionics-based efficiently transported and packed proppant according to claim 1, wherein the proppant is modified as follows: Step 1-1: Clean the proppant, dry it at 105° C., and then cool down to room temperature; Step 1-2: Sock the proppant prepared in Step 1-1 in a proppant treating agent at 50° C. for 10-30 min; Step 1-3: Filter out the proppant, dry it at 50° C., heat it up to 105° C. for 10-30 min to obtain a modified proppant.

5. The bionics-based efficiently transported and packed proppant according to claim 1, wherein the fibers are modified as follows: Step 2-1: Clean the fibers and dry them at 105° C.; Step 2-2: Put the fibers prepared in Step 2-1 in an acidic solution with a temperature of 40-90° C., and soak and ultrasonically oscillate it for 30-40 min; Step 2-3: Filter out the fibers and dry them at 105° C.; Step 2-4: Soak the dried fibers in a solution of nitrogen-containing silane coupling agent for 5-10 min, filter them out and dry in the shade at 70-80° C. to obtain a modified fibers.

6. The bionics-based efficiently transported and packed proppant according to claim 4, wherein the proppant treating agent includes 70 pbw of organic solvent, 1-5 pbw of poly-methyltriethoxysilane, 1-20 pbw of silane coupling agent, 0.1-3 pbw of titanate, and 0.5 to 2 pbw of silicone resin.

7. The bionics-based efficiently transported and packed proppant according to claim 1, wherein the drag reducing agent is polyacrylamide polymer; the clay stabilizer is prepared with potassium chloride; the cleanup additive is alkyl glycoside nonionic surfactant; the bactericide is dodecyl dimethyl benzyl ammonium chloride; the water is seawater, freshwater, or no water is contained.

8. The bionics-based efficiently transported and packed proppant according to claim 6, wherein the proppant is prepared with quartz sand, with a particle size of 20-140 mesh; the organic solvent is prepared with one, two or more of alcohol; the silane coupling agent is N-(B-aminoethyl)-γ-aminopropytrimethoxysilane; the titanate is titanium tetrabutoxide.

9. The bionics-based efficiently transported and packed proppant according to claim 5, wherein the fibers are mineral fiber, with a length of 1-20 mm; the acidic solution is diluted hydrochloric acid; the silane coupling agent is N-(B-aminoethyl)-γ-aminopropytrimethoxysilane.

10. A preparation method for the bionics-based efficiently transported and packed proppant according to claim 1, wherein the proppant can be obtained by completely mixing the enhanced fracturing fluid and the biomimetic dandelion proppant in proportion to their weight.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a principle diagram of the seawater-based enhanced fracturing fluid carrying the biomimetic, dandelion proppant in the present invention.

(2) FIG. 2 is a schematic diagram of the proppant placement effect of the seawater-based enhanced fracturing fluid carrying the biomimetic dandelion proppant Embodiment 1 of the present invention.

(3) FIG. 3 is a schematic diagram of the proppant placement effect of the seawater-based enhanced fracturing fluid carrying the conventional ceramsite in Embodiment 2 of the present invention.

(4) FIG. 4 is a schematic diagram of the proppant placement effect of the seawater-based enhanced fracturing fluid with medium viscosity carrying the biomimetic dandelion proppant in Embodiment 3 of the present invention.

(5) FIG. 5 is a schematic diagram of the proppant placement effect of the seawater-based enhanced fracturing fluid carrying the biomimetic dandelion proppant with a small particle size in Embodiment 4 of the present invention.

(6) FIG. 6 is a schematic diagram of the grafting mode of the biomimetic proppant in the present invention.

(7) FIG. 7 is a SEM image of the modified proppant obtained in Embodiment 1 of the present invention.

(8) FIG. 8 is a schematic XRD pattern of the modified proppant and the untreated proppant obtained in Embodiment 1 of the present invention.

(9) FIG. 9 is a schematic diagram of the ATR-FTIR comparison between the modified proppant obtained in Embodiment 1 of the present invention and the untreated proppant.

(10) FIG. 10 is a schematic diagram of the ATR-FTIR. comparison between the modified fiber obtained in Embodiment 1 of the present invention and the untreated fiber.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(11) The present invention is further described with reference to the drawings and embodiments.

(12) A bionics-based efficiently transported and packed proppant comprising enhanced fracturing fluid and biomimetic dandelion proppant, wherein the mass ratio of the enhanced fracturing fluid and the biomimetic dandelion is: 1-2:100-400;

(13) The 100 pbw of enhanced fracturing fluid includes 0.1-1 pbw of drag reducing agent, 0.01-0.1 pbw of cleanup additive, 0.2-0.8 pbw of clay stabilizer, 0.01-0.05 pbw of bactericide, 0.01-0.2 pbw of nanoparticle enhancer, and water; the nanoparticle enhancer is nanoparticle, which is modified as follows:

(14) The modifier is sprayed on the surface of the nanoparticle, and then nanoparticle are kept at 50° C. for 20-30 min and dried at 105° C. to obtain the modified nanoparticle;

(15) The nanoparticle arc prepared with one, two or more of nanosilicon dioxide, nanometer titania and nano zirconia in any proportion. the modifier is prepared with one, two or more of cocamidopropyl hydroxysulfobetaine, lauramidopropyl betaine, dodecyl polyglucoside and sodium alpha-olefin sulfonate in any proportion.

(16) The drag reducing agent is polyacrylamide polymer; the day stabilizer is prepared with one, two or more of potassium chloride, ammonium chloride and dodecyl trimethyl ammonium chloride in any proportion; the cleanup additive is one of alkyl glycoside nonionic surfactant and nonionic surfactant; the bactericide is dodecyl dimethyl benzyl ammonium chloride; the water is prepared with one, two or more of seawater, freshwater, flowback liquid and high-salinity water, or no water is contained,

(17) The biomimetic dandelion proppant consists of modified proppant and modified fiber, and the mass ratio between the modified proppant and the modified fiber is 99-99.9:0.1-1.

(18) The proppant is modified as follows:

(19) Step 1-1; Clean the proppant, dry it at 105° C., and then cool down to room temperature;

(20) Step 1-2: Sock the proppant prepared in Step 1-1 in a proppant treating agent at 50° C. for 10-30 min;

(21) Step 1-3: Filter out the proppant, dry it at 50° C. heat it up to 105° C. for 10-30 min to obtain the desired modified proppant.

(22) The proppant treating agent includes 70 pbw of organic solvent, 1-5 pbw of poly-methyltriethoxysilane, 1-20 pbw of silane coupling agent, 0.1-3 pbw of titanate, and 0.5 to 2 pbw of silicone resin.

(23) The proppant is prepared with one, two or more of quartz sand, ceramsite and steel slag in any proportion, with a particle size of 20-140 mesh; the organic solvent is prepared with one, two or more of alcohol, ethanol, isopropyl alcohol, tart butyl alcohol, normal butanol, water, glacial acetic acid, ethyl acetate, benzene, toluene and xylene in any proportion; the silane coupling agent is prepared with one, two or more of N-(B-aminoethyl)-γ-aminopropytrimethoxysilane, N-(β-aminoethyl)-γ-aminopropytriethoxysilane, 3-(methacryloyloxy)propyltrimethoxysiane, N-aminoethyl-3-aminopropylmethyldimethoxysilane and bis(3-trimethoxysilylpropyl)amine in any proportion; the titanate is prepared with one, two or more of titanium tetrabutoxide, tetraisopropyl titanate and tetraethyl titanate in any proportion.

(24) The fibers are modified as follows:

(25) Step 2-1: Clean the fibers and dry them at 105° C.;

(26) Step 2-2: Put the fibers prepared in Step 2-1 in an acidic solution with a temperature of 40-90° C., and soak and ultrasonically oscillate it for 30-40 min;

(27) Step 2-3: Filter out the fibers and dry them at 105° C.;

(28) Step 2-4: Soak the dried fibers in a solution of nitrogen-containing silane coupling agent for 5-10 min, filter them out and dry in the shade at 70-80° C. to obtain the desired modified fibers.

(29) The fibers are prepared with one, two or more of mineral fiber, polyester fiber, polyamide fiber, polyvinyl alcohol fiber, polyacrylonitrile polypropylene fiber, polyvinyl chloride fiber, viscose fiber, acetate fiber, cupro fiber, cellulose fiber and basalt fiber in any proportion, with a length of 1-20 mm; the acid solution is prepared with one, two or more of diluted hydrochloric acid, diluted sulfuric acid, acetic acid, formic acid, propionic acid, chromic acid, organic sulfonic acid, organic boric acid and organic phosphoric acid in any proportion: the silane coupling agent is prepared with one, two or more of N-(B-aminoethyl)-γ-aminopropytrimethoxysilane, N-(β-aminoethyl)-γ-aminopropytriethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, N-aminoethyl-3-aminopropylmethyldimethoxysilane and bis(3-trimethoxysilylpropyl)amine in any proportion.

(30) The desired proppant can be obtained by completely mixing the enhanced fracturing fluid and the biomimetic: dandelion proppant in proportion to their weight.

(31) Embodiment 1

(32) A bionics-based efficiently transported and packed proppant comprising enhanced fracturing fluid and biomimetic dandelion proppant, wherein the mass ratio of the enhanced fracturing fluid and the biomimetic dandelion is: 1-2:100-400;

(33) The enhanced fracturing fluid is seawater-based fracturing fluid, and 100 pbw of seawater-based fracturing fluid includes 0.1 pbw of polyacrylamide polymer, 0.01 pbw of alkyl glycoside nonionic surfactant, 0.2 pbw of ammonium chloride, 0.01 pbw of dodecyl dimethyl benzyl ammonium chloride, 0.05 pbw of nanosilicon dioxide, and artificial seawater. The nanoparticle enhancer is nanoparticle, which is modified as follows.

(34) The cocamidopropyl hydroxysulfobetaine solution is sprayed on the surface of the nanoparticle, and then the nanoparticle are placed at a constant temperature of 50° C. for 20 min, and then dried at 105° C. to obtain the nanoparticle enhancer.

(35) The treated nanoparticle are added to the enhanced fracturing fluid and anionic polymers are grafted on the fracturing fluid surface to dissociate negatively charged groups during fracturing, making the entire fracturing fluid system frill of free negative charges. The fracturing systems respectively with and without modified nanoparticle are tested by a Zeta potential meter. The results are shown in Table 1. From the table, it can be seen that Zeta potential in the enhanced fracturing fluid system is significantly greater than that in the conventional fracturing fluid system, which indicates that the fracturing fluid system with biomimetic proppant has negative charges.

(36) TABLE-US-00001 TABLE 1 Comparison of Zeta Potential between Enhanced Fracturing Fluid System and Conventional Fracturing Fluid System SD/N 1114-5 1114-11 Description Conventional Fracturing fluid system fracturing fluid with biomimetic system proppant Zeta potential −10.39 −18.54 coefficient

(37) The biomimetic dandelion proppant consists of modified proppant and modified fiber, and the mass ratio between the modified proppant and the modified fiber is 99-99.9:0.1-1.

(38) The modified proppant is treated ceramsite with a particle size of 20-40 mesh, consisting of 70 pbw of tert butanol, 1 pbw of poly-methyltriethoxysilane, 10 pbw of 3-(methacryloyloxy) propyl trimethoxysilane, 0.5 pbw of titanate coupling agent and 1 pbw of silicone resin.

(39) The proppant is modified as follows.

(40) Step 1-1: Clean the proppant to remove surface impurities usually with deionized water, dry it at 105° C., and cool down to room temperature;

(41) Step 1-2: Soak the proppant prepared in Step 1-1 in a proppant treating agent at 50° C. for 30 min;

(42) Step 1-3: Filter out the proppant, dry it at 50° C. and beat it up to 105° C. for 30 min to obtain the desired modified proppant. After the above treatment, the interaction between the proppant and the fibers is improved.

(43) The fibers are modified fibers which are treated with polyvinyl alcohol, with a length of 9 mm,

(44) The fibers are modified as follows.

(45) Step 2-1: Put the fibers into a plasma cleaning agent for 5 to 10 min, and dry them at 105° C.;

(46) Step 2-2: Put the fibers prepared in Step 2-1 in a chromic add solution with a temperature of 40-90° C., and soak and ultrasonically oscillate it for 30-40 min;

(47) Step 2-3: Filter out the fibers and dry them at 105° C.;

(48) Step 2-4: Soak the dried fibers in an ethanol solution containing N-aminoethyl-(dimethoxyimethylsilyl) propylamine for 10 min, filter them out and dry in the shade at 70° C. to obtain the desired modified fibers,

(49) Then, completely mix the enhanced fracturing fluid and the biomimetic dandelion proppant in proportion to their weight to obtain the desired proppant.

(50) The SEM image of the modified proppant obtained in this embodiment is shown in FIG. 7, from which it can be seen that the surface of the proppant after surface treatment is obviously gelatinized, indication that the treated proppant is covered with a layer of membrane that changes the surface properties of the proppant. The XRD pattern of the modified proppant obtained in this embodiment and the XRD pattern of the untreated proppant are shown in FIG. 8. As can be seen from the diagram, the peaks at 28.60°, 34.12°, 43.18°, 58.74°, 66.58° and 73.66° in the untreated proppant are significantly weaker or disappear compared to the treated proppant, indicating that the polymer is successfully coated on the surface of the proppant.

(51) The diagram of ATR-FTIR comparison between the modified proppant Obtained in this embodiment and the untreated proppant is shown in FIG. 9. The figure shows that the conventional proppant has a stretching vibration absorption peak for the Si-O bond at 1,001 cm.sup.−1 and a stretching vibration absorption peak for the water molecules adsorbed on the proppant surface at 1,424 cm.sup.−1 The modified proppant has significantly more peaks at 3,436 cm.sup.−1, 2,925 cm.sup.−1, 2,857 cm.sup.−1 and 1,636 cm.sup.−1 than the untreated proppant, with the peak at 3,436 cm.sup.−1 attributed to a stretching vibration absorption peak of the zwitterionic polymer, the peaks at 2925 cm.sup.−1 and 2857 cm.sup.−1 attributed to another stretching vibration absorption peak of the zwitterionic polymer and the peak at 1,636 cm.sup.−1 attributed to the C=O stretching vibration absorption peak of the zwitterionic polymer. This Shows that the zwitterionic polymer is successfully coated on the surface of the proppant and that the modified proppant is capable to dissociate negatively and positively charged groups.

(52) The modified fibers in this embodiment are grafted with cationic polymers on their surface and when they come into contact with water or fracturing fluid, the grafted cationic polymers on their surface dissociate from the positively charged groups, resulting in a positively charged surface On the modified fibers. The modified fibers are characterized by ATR-FTIR and the results are shown in FIG. 10. It is clear from FIG. 10 that compared to the untreated fibers, the grafted fibers show new peaks at 3,296 cm.sup.−1. The peak is significantly enhanced at 2,916 cm.sup.−1 and 2,852 cm.sup.−1, and a new peak appears at 1,638 cm.sup.−1. From these results it can be inferred that the modified fiber snake are successfully grafted with: cationic polymers and results in a change in the surface properties of the fiber.

(53) The reagent ratio for the artificial seawater in this embodiment is shown in Table 2.

(54) TABLE-US-00002 TABLE 2 Reagent Ratio for the Artificial Seawater Name Reagent name Proportion, g/L Artificial seawater NaCl 24.53 MgCl.sub.2 5.2 NaSO.sub.4 4.09 CaCl.sub.2 1.16 KCl 0.695 NaHCO.sub.3 0.201 KBr 0.101

(55) The efficiency of the enhanced fracturing fluid carrying the biomimetic dandelion proppant obtained from this embodiment i s evaluated as follows,

(56) 1. Assemble and test the dynamic proppant-carrying evaluation device, add enhanced seawater-based fracturing fluid to the mixing barrel and start stirring;

(57) 2. Open the perforation channel and turn on the injection pump, inject 0.5 L of seawater-based fracturing fluid (prepad fluid), and then close the perforation channel;

(58) 3. Add the biomimetic dandelion proppant to the mixing barrel in the order of fiber first and then proppant, and open the perforation channel and the fracture outlet valve after the proppant is evenly mixed, and observe the experimental results. The dynamic experimental results of the enhanced seawater-based fracturing fluid carrying the biomimetic dandelion proppant are shown in FIG. 2.

(59) Embodiment 2

(60) The steps are as in Embodiment 1, except that 100 pbw of seawater-based fracturing fluid includes 0.1 pbw of polyacrylamide polymer, 0.01 pbw of alkyl glycoside nonionic surfactant, 0.2 pbw of ammonium chloride, 0.01 pbw of dodecyl dimethyl benzyl ammonium chloride, and artificial seawater.

(61) Equal amounts of conventional ceramsite proppant and polyvinyl alcohol fibers are weighed as in Embodiment 1, with a fiber length of 9 mm; the efficiency of proppant carrying is evaluated as in Embodiment 1, and the results are shown in FIG. 3.

(62) Embodiment 3

(63) The steps are as in Embodiment 1, except that the polyacrylamide polymer in the seawater-based fracturing fluid is adjusted to 1 pbw, the viscosity of the fracturing fluid is changed, and the rest remain unchanged. Dynamic experiment is conducted on the enhanced seawater-based fracturing fluid carrying the biomimetic dandelion proppant, with its results shown in FIG. 4.

(64) Embodiment 4

(65) The steps are as in Embodiment 1, except that the particle size of the modified ceramsite is 70/140, that is, the particle size of the proppant is changed, and the rest remains unchanged. Dynamic experiment is conducted on the enhanced seawater-based fracturing fluid carrying the biomimetic dandelion proppant, with its results shown in FIG. 5.

(66) The enhanced fracturing fluid, proppant and fibers treated in the present invention can interact to make the fibers and the proppant bond with each other, and the enhanced nanoparticle in the fracturing fluid can further enhance the bonding between fibers and proppant; the fibers arc etched on the surface by the acidic solution, while the ultrasonic oscillation makes the molecular chains in the fibers loosen and creep to limn pores, and the acidic solution can enter the pores and thither etch the surface of the fibers, and partially remain on the surface of the fibers; thus the roughness and specific surface area of the treated fiber surface are greatly increased; which is therefore more conducive to the interaction with the treated proppant and the fibers; moreover, as some polar bonds remain on the fiber, it is also conducive to the formation of chemical bonds, such as hydrogen bond, between the fiber and the treated proppant, thus further enhancing their interaction.

(67) The specific principle is shown in FIG. 6. The proppant covered with zwitterionic polymer is mixed with the fiber grafted with cationic polymer and the fracturing fluid with anionic polymer. There are three electrostatic attraction based on positive and negative charges in the solution at the same time, including the Coulomb force between the groups in the proppant and the groups in the fibers, the Coulomb force between the groups in the fracturing fluid and the groups in the fibers, and the Coulomb force between the groups in the proppant and the groups in the fracturing fluid. These three types of electrostatic attraction make it possible for any two of fiber, propellant and fracturing fluid to be mutually attracted to each other to establish a new coupling system. In addition, the existence of some polar bonds on the fibers also facilitates the formation of chemical bonds, such as hydrogen bond, between the fibers and the treated proppant, which further enhances their interaction, allowing the groups to be held tightly together and not affected by external physical or chemical factors, resulting in the grafting pattern shown in FIG. 6.