Phase transition material fluid and proppant formed therefrom

Abstract

Provided are a phase transition material fluid and a proppant formed therefrom, wherein the components for preparing the phase transition material fluid comprise in percentages by mass: a supramolecular building block 10 to 60 wt %, a supramolecular functional unit 20 to 50 wt %, a dispersant 0.1 to 2 wt %, an inorganic co-builder 0.1 to 1 wt %, an initiator 0.1 to 1 wt %, the balance being a solvent. The supramolecular building block comprises a melamine-based substance and/or a triazine-based substance; the supramolecular functional unit comprises a dicyclopentadiene resin; and the dispersant includes a hydroxyl-bearing polysaccharide substance and a surfactant. After the phase transition material fluid enters the reservoir, it may form a solid substance to prop the fracture under the action of supramolecular chemistry and physics.

Claims

1. A phase transition material fluid, wherein the components for preparing the phase transition material fluid comprise in percentages by mass: a supramolecular building block 10 to 60 wt %, a supramolecular functional unit 20 to 50 wt %, a dispersant 0.1 to 2 wt %, an inorganic co-builder 0.1 to 1 wt %, an initiator 0.1 to 1 wt %, the balance being a solvent; the supramolecular building block comprises a melamine-based substance and/or a triazine-based substance; the supramolecular functional unit comprises a dicyclopentadiene resin; and the dispersant includes a hydroxyl-bearing polysaccharide substance and a surfactant.

2. The phase transition material fluid according to claim 1, wherein the components for preparing the phase transition material fluid comprise in percentages by mass: the supramolecular building block 30 to 40 wt %, the supramolecular functional unit 20 to 30 wt %, the dispersant 0.5 to 1 wt %, the inorganic co-builder 0.5 to 1 wt %, the initiator 0.5 to 1 wt %, the balance being the solvent.

3. The phase transition material fluid according to claim 1, wherein the melamine-based substance includes melamine, alkenyl-substituted melamine, or esterified melamine.

4. The phase transition material fluid according to claim 1, wherein the triazine-based substance comprises triazine or alkenyl-substituted triazine.

5. The phase transition material fluid according to claim 1, wherein the supramolecular building block further comprises a building aid; the building aid comprises one or more of 1,4-butanediol diacrylate, N,N-methylene bisacrylamide and triallyl isocyanurate.

6. The phase transition material fluid according to claim 1, wherein the hydroxyl-bearing polysaccharide substance comprises one or more of hydroxypropyl methylcellulose, polyvinyl alcohol, hydroxymethyl cellulose, ethyl cellulose, and sucrose fatty acid ester.

7. The phase transition material fluid according to claim 1, wherein the surfactant comprises an anionic surfactant or a nonionic surfactant.

8. The phase transition material fluid according to claim 1, wherein the inorganic co-builder includes sodium bicarbonate, or a composition of calcium chloride and phosphoric acid.

9. The phase transition material fluid according to claim 1, wherein the initiator comprises a peroxide initiator.

10. The phase transition material fluid according to claim 1, wherein the solvent comprises benzene-based solvents.

11. The phase transition material fluid according to claim 1, wherein the components for preparing the phase transition material fluid further comprise a pore-forming agent 0.2-5 wt %; the pore-forming agent comprises a pore-forming agent of generating gas by heating and/or a pore-forming agent of hot melt discharge.

12. A proppant, which is a solid product formed after phase transition of the phase transition material fluid according to claim 1.

13. The phase transition material fluid according to claim 3, wherein the alkenyl-substituted melamine comprises propenyl-substituted melamine; and the esterified melamine comprises triallyl 1,3,5-cyanurate.

14. The phase transition material fluid according to claim 3, wherein the propenyl-substituted melamine has a substitution degree of 2 to 3.

15. The phase transition material fluid according to claim 4, wherein the alkenyl-substituted triazine comprises propenyl-substituted triazine.

16. The phase transition material fluid according to claim 15, wherein the propenyl-substituted triazine has a substitution degree of 2 to 3.

17. The phase transition material fluid according to claim 7, wherein the anionic surfactant comprises an alkyl sulfate surfactant, an alkyl sulfonate surfactant or an alkylbenzene sulfonate surfactant, and the nonionic surfactant comprises a polyether surfactant.

18. The phase transition material fluid according to claim 9, wherein the peroxide initiator is one or more of dibenzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, dicumyl peroxide, di-tert-butyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxypivalate, diisopropyl peroxydi-carbonate, dicyclohexyl peroxydi-carbonate and diethylhexyl peroxydi-carbonate.

19. The phase transition material fluid according to claim 10, wherein the benzene-based solvents is one or more of styrene, divinyl benzene, xylene and toluene.

20. The phase transition material fluid according to claim 11, wherein the pore-forming agent of generating gas by heating includes azobisisobutyronitrile or ammonium bicarbonate; the pore-forming agent of hot melt discharge comprises one or more of solid paraffin, dodecanol and heptane.

Description

DETAILED DESCRIPTION

(1) In order to more clearly understand the technical features, the objects and the beneficial effects of the present invention, the technical solutions of the present invention will now be described in details below, which should not be construed as limiting the implementable scope of the present invention.

Example 1

(2) This Example provides a phase transition material fluid using a melamine-based substance as the supramolecular building block, and a corresponding proppant.

(3) Two phase transition material fluids HPP.sub.1 and HPP.sub.2 were prepared as follows, respectively.

(4) HPP.sub.1: Xylene 50 g was firstly weighed, and then melamine 40 g, dicyclopentadiene resin 30 g, hydroxypropyl methylcellulose 0.5 g, sodium dodecyl sulfate 0.5 g, phosphoric acid 0.5 g, calcium chloride 0.5 g, and dibenzoyl peroxide 1 g were added therein. All of them were placed in a flask, and stirred evenly at room temperature, to complete the preparation of the phase transition material fluid HPP.sub.1.

(5) HPP.sub.2: Xylene 50 g was firstly weighed, and then 2,4-diamino-6-diallylamino-1,3,5-triazine 40 g, dicyclopentadiene resin 30 g, hydroxypropyl methylcellulose 0.5 g, sodium dodecyl sulfate 0.5 g, phosphoric acid 0.5 g, calcium chloride 0.5 g, and dibenzoyl peroxide 1 g were added therein. All of them were placed in a flask, and stirred evenly at room temperature, to complete the preparation of the phase transition material fluid HPP.sub.2.

(6) The proppant was prepared as follows.

(7) The obtained phase transition material fluid each was placed in an oil bath at constant temperature. HPP.sub.1 was heated to 90° C. and reacted for 1 hour, and formed a bead-like, bulk solid, that is proppant, designated as H.sub.1. HPP.sub.2 was heated to 90° C. and reacted for 0.7 hour, and formed a bead-like, bulk solid, that is, proppant, designated as H.sub.2. It can be seen that the above two phase transition material fluids can realize the transition from liquid to solid, and therefore can be used for phase inversion fracturing.

(8) The above-mentioned proppants H.sub.1 and H.sub.2 were subjected to performance tests, and the test data were shown in Table 1.

(9) TABLE-US-00001 TABLE 1 Performance test data of proppant Breakage rate (%) Bulk density True density Pressure Pressure Pressure Sample g/cm.sup.3 g/cm.sup.3 52 MPa 86 MPa 96 MPa H.sub.1 0.49 1.03 ≤0.32 ≤9.5 ≤22 H.sub.2 0.53 1.04 ≤0.3 ≤8.9 ≤18

(10) Comparing HPP.sub.1 with HPP.sub.2, the use of allyl-substituted melamine shortens the time for the material fluid to form the proppant in comparison with the use of melamine. The breakage rate of H.sub.2 is lower than that of H.sub.1 under the same pressure, indicating that H.sub.2 has better toughness than H.sub.1.

Example 2

(11) This Example provides a phase transition material fluid comprising a pore-forming agent and a corresponding proppant.

(12) Three phase transition material fluids HPP.sub.3, HPP.sub.4 and HPP.sub.5 were prepared as follows, respectively.

(13) HPP.sub.3: Xylene 50 g was firstly weighed, and then propenyl-substituted triazine 40 g, dicyclopentadiene resin 30 g, polyvinyl alcohol 0.7 g, sodium dodecyl sulfonate 0.3 g, phosphoric acid 0.5 g, calcium chloride 0.5 g, dibenzoyl peroxide 1 g, and ammonium bicarbonate 5 g were added therein in this order. All of them were placed in a flask and stirred evenly at room temperature to complete the preparation of the underground phase transition material fluid HPP.sub.3.

(14) HPP.sub.4: Xylene 50 g was firstly weighed, and then propenyl-substituted melamine 40 g, dicyclopentadiene resin 30 g, hydroxypropyl methylcellulose 0.5 g, sodium dodecyl sulphonate 0.5 g, sodium bicarbonate 1 g, di-tert-butyl peroxide 1 g and 5 g of paraffin wax were added therein in this order. All of them were placed in a flask and stirred evenly at room temperature to complete the preparation of the underground phase transition material fluid HPP.sub.4.

(15) HPP.sub.5: Xylene 50 g was firstly weighed, and then melamine 40 g, dicyclopentadiene resin 30 g, polyvinyl alcohol 0.5 g, nonylphenol polyoxyethylene ether 0.5 g, sodium bicarbonate 1 g, dibenzoyl peroxide 1 g, and dodecanol 5 g were added therein in this order. All of them were placed in a flask and stirred evenly at room temperature to complete the preparation of the underground phase transition material HPP.sub.5.

(16) The proppant was prepared as follows.

(17) The obtained phase transition material fluid each was placed in an oil bath at a constant temperature. HPP.sub.3 was heated to 100° C. and reacted for 0.5 hour, and formed a bead-like, bulk solid, that is, proppant, designated as H.sub.3. HPP.sub.4 was heated to 100° C. and reacted for 0.5 hour, and formed a bead-like, bulk solid, that is, proppant, designated as H.sub.4. HPP.sub.5 was heated to 100° C. and reacted for 0.7 hour, and formed a bead-like, bulk solid, that is, proppant, designated as H.sub.5. It can be seen that the above three phase transition material fluids can realize the transition from liquid to solid, and therefore can be used for phase inversion fracturing.

(18) Among them, the propenyl-substituted triazine used in this Example was specifically prepared by the following steps.

(19) In a 250 mL three-necked flask, 4.6 g (25 mmol) of cyanuric chloride was added and dissolved with 15 mL of toluene; it was cooled to 0° C., and then 2.9-5.1 g (50 mmol-87.5 mmol) of propenyl alcohol was added dropwise over 1-3 h. Then it was gradually heated to 80° C. and continued to react for 2 h. It was cooled to room temperature, and filtered to collect the precipitate. 3.0 g of NaOH and 150 mL of dichloromethane were added, and heated until NaOH was completely dissolved, and then heated under reflux for 30 min. It was filtered to collect the filtrate. The solvent was evaporated to dryness, and the crude product was washed with dichloromethane/toluene (1:5, V/V) mixture to give the propenyl-substituted triazine having a substitution degree of 2-3.

(20) The propenyl-substituted melamine used in this Example was specifically prepared by the following steps.

(21) In a 250 mL three-necked flask, 3.2 g (25 mmol) of melamine was added, and dissolved with 30 mL N-methylpyrrolidone; then 6.9-12.1 g (50 mmol-87.5 mmol) of potassium carbonate was added, and heated to 60° C.; 6.0-10.6 g (50 mmol-87.5 mmol) of bromopropene was added dropwise over 1-3 h. Then it was gradually heated to 70° C. and continued to react for 2 h. It was cooled to room temperature, and filtered to collect the filtrate. The solvent was concentrated, and the crude product was washed with diethyl ether/methanol (3:1, V/V) mixture to give the propenyl-substituted melamine having a substitution degree of 2-3.

(22) The above-mentioned proppants H.sub.3, H.sub.4 and H.sub.5 were subjected to performance test. The test data were shown in Table 2.

(23) TABLE-US-00002 TABLE 2 Performance test data of proppants Breakage rate (%) Bulk density True density Pressure Pressure Pressure Sample g/cm.sup.3 g/cm.sup.3 52 MPa 86 MPa 96 MPa H.sub.3 0.43 1.03 ≤0.33 ≤9.5 ≤23 H.sub.4 0.41 1.03 ≤0.33 ≤9.5 ≤23 H.sub.5 0.44 1.04 ≤0.35 ≤10 ≤25

(24) Comparing HPP.sub.3, HPP.sub.4, and HPP.sub.5, the use of allyl-substituted melamine shortens the time for the material fluid to form the proppant in comparison with the use of melamine. Since the proppants H.sub.3, H.sub.4, and H.sub.5 have a porous structure, their bulk density is significantly smaller than that of H.sub.1 and H.sub.2. The breakage rate of H.sub.2 is lower than that of H.sub.1 under the same pressure, indicating that H.sub.2 has better toughness than H.sub.1.

(25) The proppants H.sub.1 and H.sub.2 produced in Example 1 and H.sub.3, H.sub.4, and H.sub.5 produced in this Example were subjected to permeability test. The specific process is as follows.

(26) The proppants H.sub.1, H.sub.2, H.sub.3, H.sub.4, and H.sub.5 were sieved to give solid particles of 40-60 mesh, and the sieved solid particles were pressed into small cores having a length of 8 cm and a diameter of 2.54 cm with with a core machine under 10 MPa. The small cores were placed in a core flow experimental device to measure its gas permeability. The test results were: K.sub.H1=483 mD, K.sub.H2=426 mD, K.sub.H3=617 mD, K.sub.H4=633 mD, K.sub.H5=675 mD. From the test data of five samples, it can be seen that the generation of pores can greatly increase the permeability of the proppants.

Example 3

(27) This Example provides a phase transition material fluid using a melamine-based substance as the supramolecular building block, and a corresponding proppant.

(28) Two phase transition material fluids HPP.sub.6 and HPP.sub.7 were prepared as follows, respectively.

(29) HPP.sub.6: Xylene 45 g was firstly weighed, and then melamine 12 g, dicyclopentadiene resin 60 g, hydroxypropyl methylcellulose 0.5 g, sodium dodecyl sulfate 0.5 g, phosphoric acid 0.5 g, calcium chloride 0.5 g, and dibenzoyl peroxide 1 g were added therein. All of them were placed in a flask and stirred evenly at room temperature to complete the preparation of the phase transition material HPP.sub.6.

(30) HPP.sub.7: Xylene 20 g was firstly weighed, and then melamine 60 g, dicyclopentadiene resin 20 g, hydroxypropyl methylcellulose 0.5 g, sodium dodecyl sulfate 0.5 g, phosphoric acid 0.5 g, calcium chloride 0.5 g, and dibenzoyl peroxide 1 g were added therein. All of them were placed in a flask and stirred evenly at room temperature to complete the preparation of the phase transition material fluid HPP.sub.7.

(31) The proppant was prepared as follows.

(32) The obtained phase transition material fluid each was placed in an oil bath at constant temperature. HPP.sub.6 was heated to 90° C. and reacted for 1.5 hours, and formed a bead-like, bulk solid, that is, proppant, designated as H.sub.6. HPP.sub.7 was heated to 90° C. and reacted for 0.6 hour, and formed a bead-like, bulk solid, that is, proppant, designated as H.sub.7. It can be seen that the above two phase transition material fluids can realize the transition from liquid to solid, and therefore can be used for phase inversion fracturing.

(33) The above-mentioned proppants H.sub.6 and H.sub.7 were subjected to performance test, and the test data were shown in Table 3.

(34) TABLE-US-00003 TABLE 3 Performance test data of proppants Breakage rate (%) Bulk density True density Pressure Pressure Pressure Sample g/cm.sup.3 g/cm.sup.3 52 MPa 86 MPa 96 MPa H.sub.6 0.51 1.03 ≤3.6 ≤13.9 ≤31 H.sub.7 0.54 1.04 ≤0.28 ≤7.3 ≤15

(35) Comparing HPP.sub.6 and HPP.sub.7, due to the difference in the main component content, the formation time has a certain difference, and the shape of the formed proppants is different. Meanwhile, due to the difference in the content, the breakage of the material under pressure is somewhat different.