A composite oil displacement composition, its preparation method and application
Patent Information
- Application Number
- CN202211266994.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-10-17
- Publication Date
- 2026-09-25
- Estimated Expiration
- 2042-10-17
AI Technical Summary
就聚合物型表面活性剂而言，目前仍然存在分子量受共聚单体影响太大，增粘能力不足，界面活性较表活剂体系差别大等问题
[0075](1)本发明利用孤对电子与空轨道的配位耦合和氢键耦合同时作用，形成了一个稳定的环状结构，进而实现了相互作用的强化，克服了地下运移中两相分离的现象；
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of oil displacement agents, particularly oil displacement agents for tertiary oil recovery, and especially to composite oil displacement compositions, their preparation methods and applications. Background Technology
[0002] Acrylamide polymers are widely used in major oilfields both domestically and internationally as important chemical agents in tertiary oil recovery. Their primary function is to increase the viscosity of the displaced phase by enhancing the viscosity of the aqueous phase, thereby improving the mobility ratio and increasing oil recovery. Another important class of oil displacement agents are small-molecule surfactants, which can effectively reduce the interfacial tension between oil and water, increase capillary number, and thus improve oil washing efficiency.
[0003] Both of these types of chemical agents have been widely used in tertiary oil recovery. To further maximize their effectiveness, composite flooding was proposed and promoted. Composite flooding systems can simultaneously expand the swept volume and improve oil washing efficiency, thus further enhancing oil recovery. However, the full potential of composite flooding has not been realized because surfactants and polymers experience different flow resistances, resulting in different propulsion speeds. Consequently, they gradually separate during underground migration, failing to achieve the desired composite flooding effect in deep formations.
[0004] To address this issue, extensive research has been conducted on polymeric surfactants and viscoelastic surfactants. However, polymeric surfactants still face challenges such as molecular weight being significantly influenced by comonomers, insufficient thickening ability, and substantial differences in interfacial activity compared to surfactant systems. Furthermore, some studies have shown that polymeric surfactants are simply polymer macromolecules modified with a small amount of hydrophobic chains, possessing almost no interfacial activity and thus failing to effectively function as multi-functional oil displacement agents.
[0005] The technical problem to be solved by this invention is how to achieve an oil displacement system with a large molecular weight and strong interfacial activity. Summary of the Invention
[0006] To overcome the problems existing in the prior art, this invention provides a composite oil displacement composition, its preparation method, and its application. The composite oil displacement composition comprises a polymer and an amine oxide-type surfactant. Specifically, this invention introduces a phenylboronic acid structure with empty orbitals into the polymer chain. The boron atoms have empty orbitals that can bind to the lone pairs of electrons on the amine oxide. Simultaneously, hydrogen bonding between the hydroxyl or amide groups on the polymer molecular chain and the hydroxyl groups on the amine oxide further enhances the interaction between the polymer and the surfactant, thereby achieving an enhanced surface-active polymer system. In this way, by strengthening the interaction between the polymer and the surfactant, they can move synchronously during underground migration, overcoming phase separation and maximizing the effect of the composite oil displacement.
[0007] One of the objectives of this invention is to provide a composite composition for oil displacement, comprising a polymer and an amine oxide surfactant, wherein the polymer comprises a main chain and a plurality of side chains, the side chains comprising amide side chains and boron-containing side chains.
[0008] This invention introduces boron atoms with empty orbitals into the polymer chain. These boron atoms possess empty orbitals that can bind to the lone pairs of electrons on amine oxides. Furthermore, the interaction between the polymer and surfactant is enhanced through hydrogen bonding between the carboxyl or amide groups on the polymer chain and the hydroxyl groups on the amine oxide, thus achieving an enhanced composite flooding composition. By strengthening the interaction between the polymer and surfactant, they can migrate synchronously underground, overcoming phase separation and maximizing the effectiveness of the composite flooding. Therefore, it solves the problem of weak interaction between traditional anionic polymers and surfactants.
[0009] In a preferred embodiment, the structure of the amide side chain is shown in formula (I), and the boron-containing side chain is a phenylboronic acid side chain. Preferably, the structure of the phenylboronic acid side chain is shown in formula (II).
[0010]
[0011] In equation (II): m = 0 or 1; R1 is selected from -(R') a -C(=O)-O-、-(R') a -C(=O)NH- or -(R') a -C(=O)-, R' is selected from alkylene, arylene or arylene, a=0 or 1; R2 is selected from hydrogen, alkyl, aryl or aryl, and repeated R2 may be the same or different.
[0012] In a preferred embodiment, in formula (II), R1 is selected from -(R'). a -C(=O)-O-、-(R') a -C(=O)NH- or -(R') a -C(=O)-, R' is selected from C1~C20 alkylene, C6~C20 arylene or C7~C20 arylene, a=0 or 1; R2 is selected from hydrogen, C1~C20 alkyl, C6~C20 aryl or C7~C20 aralkyl, and repeated R2 may be the same or different.
[0013] In a further preferred embodiment, in formula (II), R1 is selected from -(R'). a -C(=O)-O-、-(R') a -C(=O)NH- or -(R') a-C(=O)-, R' is selected from C1~C10 alkylene, C6~C12 arylene or C7~C15 arylene, a=0 or 1; R2 is selected from hydrogen, C1~C10 alkyl, C6~C12 aryl or C7~C15 aralkyl, and repeated R2 may be the same or different.
[0014] In a further preferred embodiment, in formula (II), R1 is selected from -(R'). a -C(=O)-O-、-(R') a -C(=O)NH- or -(R') a -C(=O)-, R' is selected from C1~C5 alkylene, phenylene or C7~C10 phenylene alkylene, a=0 or 1; R2 is selected from hydrogen, C1~C5 alkyl, phenyl or C7~C10 phenyl alkyl, and repeated R2 may be the same or different.
[0015] For example, in formula (II), R1 is selected from -C(=O)-NH-, m=0 or 1; for example, in formula (II), R' is selected from methylene, ethylene, propylene, butylene, pentylene, phenylene, benzylene or phenylethylene.
[0016] Most preferably, the phenylboronic acid side chain is selected from one of amide-4-phenylboronic acid, amide-3-phenylboronic acid, 4-phenylboronic acid, and 3-phenylboronic acid.
[0017] In a preferred embodiment, the side chains of the polymer further include: optional carboxylic acid side chains, optional sulfonate side chains, and optional pyrrolidone side chains.
[0018] In a further preferred embodiment, the structures of the carboxylic acid side chain, the sulfonate side chain, and the pyrrolidone side chain are as shown in formulas (III), (IV), and (V), respectively:
[0019]
[0020] In formula (IV): R5 and R6 are each independently selected from hydrogen, alkyl, aryl, or aralkyl; R3 is selected from -(R”). r -C(=O)O-、-(R”) r -C(=O)NH- or -(R”) r -C(=O)-, R” is selected from alkylene, arylene or arylene, r=0 or 1; R4 is selected from alkylene, arylene or arylene; in formula (V), R7 is selected from alkylene, arylene or arylene, q=0 or 1.
[0021] In a preferred embodiment, in formula (IV): R5 and R6 are each independently selected from hydrogen, C1-C20 alkyl, C6-C20 aryl, or C7-C20 aralkyl; R3 is selected from -(R”). r -C(=O)O-、-(R”) r -C(=O)NH- or -(R”) r -C(=O)-, R” is selected from C1~C20 alkylene, C6~C20 arylene or C7~C20 arylene, r=0 or 1; R4 is selected from C1~C20 alkylene, C6~C20 arylene or C7~C20 arylene.
[0022] In a further preferred embodiment, in formula (IV): R5 and R6 are each independently selected from hydrogen, C1-C10 alkyl, C6-C12 aryl or C7-C15 aralkyl, and R3 is selected from -(R”). r -C(=O)-O-、-(R”) r -C(=O)-NH- or -(R”) r -C(=O)-, R” is selected from alkylene of C1~C10, arylene of C6~C12 or arylene of C7~C15, r=0 or 1, R4 is selected from alkylene of C1~C10, arylene of C6~C12 or arylene of C7~C15.
[0023] In a further preferred embodiment, in formula (IV): R5 and R6 are each independently selected from hydrogen, C1-C5 alkyl, phenyl, or C7-C10 phenylalkyl, and R3 is selected from -(R”). r -C(=O)-O-、-(R”) r -C(=O)-NH- or -(R”) r -C(=O)-, R” is selected from C1~C5 alkylene, phenylene or C7~C10 phenylene alkylene, r=0 or 1, R4 is selected from C1~C5 alkylene, phenylene or C7~C10 phenylene alkylene.
[0024] Wherein, the alkyl group of C1 to C5 is methyl, ethyl, propyl, butyl, or pentyl, and the alkyl group of C7 to C10 is benzyl, phenethyl, phenylpropyl, or phenylbutyl; the alkylene group of C1 to C5 is methylene, ethylene, propylene, butylene, or pentylene, and the alkylene group of C7 to C10 is benzylene, phenylethylene, phenylpropylene, or phenylbutylene.
[0025] In a preferred embodiment, in formula (V), R7 is selected from C1-C20 alkylene, C6-C20 arylene, or C7-C20 arylene, and q = 0 or 1.
[0026] In a further preferred embodiment, in formula (V), R7 is selected from C1-C10 alkylene, C6-C12 arylene, or C7-C15 arylene, and q = 0 or 1.
[0027] In a further preferred embodiment, in formula (V), R7 is selected from C1 to C5 alkylene, phenylene, or C7 to C10 phenylene alkylene, and q = 0 or 1.
[0028] In formula (V), the alkyl group of C1 to C5 can be methyl, ethyl, propyl, butyl or pentyl, and the phenylene alkyl group of C7 to C10 can be phenylenemethyl, phenyleneethyl or phenylenepropyl.
[0029] In a preferred embodiment, based on 100 parts by weight of the polymer, the structural unit containing the amide side chain is 15 to 40 parts by weight, and / or the structural unit containing the phenylboronic acid side chain is 15 to 35 parts by weight, and / or the structural unit containing the carboxylic acid side chain is 0 to 45 parts by weight, and / or the structural unit containing the sulfonate side chain is 0 to 15 parts by weight, and / or the structural unit containing the pyrrolidone side chain is 0 to 15 parts by weight.
[0030] For example, based on 100 parts by weight of the polymer, the structural unit containing the amide side chain is 15, 20, 25, 30, 35 or 40 parts by weight, and / or the structural unit containing the phenylboronic acid side chain is 15, 20, 25, 30 or 35 parts by weight, and / or the structural unit containing the carboxylic acid side chain is 0, 5, 15, 20, 25, 30, 35, 40 or 45 parts by weight, and / or the structural unit containing the sulfonate side chain is 0, 5, 10 or 15 parts by weight, and / or the structural unit containing the pyrrolidone side chain is 0, 5, 10 or 15 parts by weight.
[0031] In a further preferred embodiment, based on 100 parts by weight of the polymer, the structural unit containing the amide side chain is 25-35 parts by weight, and / or the structural unit containing the phenylboronic acid side chain is 20-28 parts by weight, and / or the structural unit containing the carboxylic acid side chain is 0-43 parts by weight, and / or the structural unit containing the sulfonate side chain is 0-9 parts by weight, and / or the structural unit containing the pyrrolidone side chain is 0-9 parts by weight. Preferably, the content of the carboxylic acid side chain, sulfonate side chain, and pyrrolidone side chain is not 0.
[0032] In a preferred embodiment, the amine oxide surfactant is selected from amine oxide surfactants containing hydroxyl or carboxyl groups, for example, amine oxide surfactants containing hydroxyl groups.
[0033] Among them, amine oxide surfactants are a type of weak cationic amphoteric surfactants that are very soluble in water. Because of their weak cationic nature, they are not selected in traditional sandstone reservoir oil displacement agents, mainly due to the problem of their electrostatic adsorption with sandstone reservoirs.
[0034] This invention creatively combines an amine oxide surfactant with the polymer described in this invention to obtain a high-performance composite oil displacement composition that overcomes the phenomenon of two-phase separation during underground migration and can be used for tertiary oil recovery.
[0035] In a further preferred embodiment, the amine oxide surfactant is selected from at least one of the surfactants shown in formula (VI):
[0036]
[0037] In equation (VI), R 10 R8 and R9 are each independently selected from alkylene, arylene, or arylalkylene groups selected from C3-C40, and A and B are each independently selected from hydrogen, hydroxyl, or carboxyl groups, with at least one of A and B being a hydroxyl or carboxyl group.
[0038] Preferably, in formula (VI), R 10 R8 and R9 are each independently selected from C5-C28 hydrocarbon groups (e.g., alkyl), C3-C40 alkylamide groups, and C1-C4 alkylene groups; R8 and R9 are each independently selected from C1-C5 alkylene groups, phenyl groups, or C7-C10 phenylene groups; A and B are each independently selected from hydrogen or hydroxyl groups, and at least one of A and B is a hydroxyl group.
[0039] In formula (VI), the hydrocarbon groups of C5-C28 are hydrocarbon groups of C5, C10, C15, C20, C25 or C28, the alkylene groups of C1-C5 are methylene, ethylene, propylene, butylene or pentylene, and the alkylene groups of C7-C10 are phenylenemethyl, phenyleneethyl or phenylenepropyl.
[0040] In a further preferred embodiment, the amine oxide surfactant is selected from at least one of the surfactants shown in formula (VIA):
[0041]
[0042] Among them, R 10 It has the same definition as equation (VI).
[0043] For example, the amine oxide surfactant is selected from at least one of dodecyl dihydroxyethyl amine oxide, hexadecyl dihydroxyethyl amine oxide, octadecyl dihydroxyethyl amine oxide, dodecylamidopropyl dihydroxyethyl amine oxide, hexadecylamidopropyl dihydroxyethyl amine oxide, and octadecylamidopropyl dihydroxyethyl amine oxide.
[0044] In a preferred embodiment, the molar ratio of the boron-containing side chain in the polymer to the amine oxide surfactant is (0.9–1.2):1, for example, 0.9:1, 0.92:1, 0.95:1, 0.98:1, 1:1, 1.02:1, 1.05:1, 1.08:1, 1.1:1, 1.12:1, 1.14:1, 1.16:1, 1.18:1, or 1.2:1.
[0045] In this invention, the empty orbitals of boron atoms in the polymer can bind with the lone pairs of electrons in the amine oxide surfactant. Simultaneously, the carboxyl or amide groups on the polymer molecular chain can form hydrogen bonds with the hydroxyl groups on the amine oxide surfactant. Thus, the coordination coupling of lone pairs of electrons and empty orbitals, along with hydrogen bonding, work together to form a stable ring structure between the amine oxide surfactant and the polymer molecular chain (as shown in the structural formula below). This strengthens the interaction between the amine oxide surfactant and the polymer, thereby solving the separation problem during its underground migration.
[0046]
[0047] A second objective of this invention is to provide a method for preparing a composite oil displacement composition, preferably used to prepare the composite oil displacement composition described in one objective of this invention. The preparation method includes: mixing the polymer and the amine oxide surfactant to obtain the composite oil displacement composition.
[0048] In a preferred embodiment, the molar ratio of the boron-containing side chain in the polymer to the amine oxide surfactant is (0.9–1.2):1.
[0049] In a preferred embodiment, the preparation of the polymer comprises: polymerizing raw materials, including monomers, to obtain the polymer, wherein the monomers include acrylamide monomers, boron-containing monomers, optionally acrylic monomers, optionally sulfonate monomers, and optionally pyrrolidone monomers. In a further preferred embodiment, based on 100 parts by weight of all monomers, the amount of the acrylamide monomer is 15 to 40 parts by weight, and / or the amount of the boron-containing monomer is 15 to 35 parts by weight, and / or the amount of the acrylic monomer is 0 to 45 parts by weight, and / or the amount of the sulfonate monomer is 0 to 15 parts by weight, and / or the amount of the pyrrolidone monomer is 0 to 15 parts by weight.
[0050] In a further preferred embodiment, based on 100 parts by weight of all monomers, the amount of the acrylamide monomer is 25 to 35 parts by weight, and / or the amount of the boron-containing monomer is 20 to 28 parts by weight, and / or the amount of the acrylic acid monomer is 0 to 43 parts by weight, and / or the amount of the sulfonate monomer is 0 to 9 parts by weight, and / or the amount of the pyrrolidone monomer is 0 to 9 parts by weight.
[0051] In this invention, the acrylamide monomer is a monomer containing a side chain as shown in formula (I), the boron-containing monomer is a monomer containing a side chain as shown in formula (II), the acrylic monomer is a monomer containing a side chain as shown in formula (III), the sulfonate monomer is a monomer containing a side chain as shown in formula (IV), and the pyrrolidone monomer is a monomer containing a side chain as shown in formula (V).
[0052] Preferably, the acrylamide monomer, the boron-containing monomer, the acrylic acid monomer, the sulfonate monomer, and the pyrrolidone monomer are each selected from at least one of the compounds shown in formulas (i) to (v):
[0053]
[0054] In equations (i) to (v), R1 to R7, m, n, and q have the same definitions as in equations (i) to (v); R 1 ~R 15 Each of the components is independently selected from hydrogen, C1-C15 alkyl groups, or C6-C10 aryl groups, preferably from hydrogen or C1-C10 alkyl groups, and more preferably from hydrogen or C1-C5 alkyl groups.
[0055] In a preferred embodiment, the raw materials further include an initiator, a solvent, a chelating agent, and a cosolvent.
[0056] In a further preferred embodiment, based on a total of 100 parts by weight of all monomers, the amount of the initiator is 0.001 to 0.004 parts by weight, and / or the amount of the solvent is 120 to 220 parts by weight, and / or the amount of the chelating agent is 0.002 to 0.01 parts by weight, and / or the amount of the co-solvent is 0.05 to 0.5 parts by weight.
[0057] In a preferred embodiment, the initiator is selected from a combination of redox initiators, co-reducing agents, and high-temperature free radical initiators.
[0058] In a further preferred embodiment, the redox initiator and the high-temperature free radical initiator of the present invention are any redox initiator and any free radical initiator disclosed in the prior art, preferably but not limited to the following limitations: the redox initiator includes an oxidant and a reductant, wherein the oxidant is selected from at least one of potassium persulfate, sodium persulfate, hydrogen peroxide, potassium bromate, and tert-butyl hydroperoxide, and the reductant is selected from at least one of ferrous ammonium sulfate, sodium bisulfite, sodium thiosulfate, sodium dithionite, sodium metabisulfite, and sodium formaldehyde sulfoxylate; and / or, the high-temperature free radical initiator is selected from at least one of azobisisobutyronitrile, azobisisoheptanenitrile, azobisisobutylamidine hydrochloride, 2,2'-azo[2-(2-imidazolin-2-yl)propane] dihydrochloride, and 4,4'-azobis(4-cyanopentanoic acid).
[0059] In a further preferred embodiment, based on a total of 100 parts by weight of all monomers, the amount of the oxidant is 0.00015 to 0.0004 parts by weight, preferably 0.0002 to 0.00035 parts by weight, the amount of the reducing agent is 0.00017 to 0.0005 parts by weight, preferably 0.00025 to 0.00040 parts by weight, and the amount of the high-temperature free radical initiator is 0.0005 to 0.005 parts by weight, preferably 0.001 to 0.0025 parts by weight.
[0060] In a preferred embodiment, the raw materials used in preparing the polymer further include a reducing agent; preferably, the amount of the reducing agent is 0.05 to 0.2 parts by weight, more preferably 0.07 to 0.15 parts by weight; more preferably, the reducing agent is dimethylaminoacetonitrile.
[0061] In a preferred embodiment, the solvent is water, such as deionized water.
[0062] In a preferred embodiment, the chelating agent is selected from at least one of the following: disodium ethylenediaminetetraacetate, pentasodium diethylenetriaminepentaacetate, sodium polyphosphate (e.g., sodium tripolyphosphate), nitric acid triacetate, N-hydroxyethyl ethylamine triacetate, ethylene glycol-bis-(B-aminoethyl ether)-N,N-tetraacetic acid, aminotrimethylene phosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, and aminotrimethylenephosphonic acid.
[0063] In a preferred embodiment, the co-solvent is selected from one of urea, sodium formate, sodium hypophosphite, mercaptoacetic acid, and dodecyl mercaptan.
[0064] In a preferred embodiment, the preparation of the polymer includes:
[0065] (1) The monomer raw material, the reducing agent, the solvent, the chelating agent, and the co-solvent are mixed and the pH value is adjusted to between 6.0 and 8.0 (e.g., 6.0, 6.5, 7.0, 7.5, 8.0) to obtain a dispersion;
[0066] (2) The temperature of the dispersion is controlled to be between -10°C and 5°C (preferably between -5°C and 0°C);
[0067] (3) Introduce a protective gas (e.g., for 1 hour), stir, add an aqueous solution containing an initiator (preferably the oxidant, the reducing agent, or the high-temperature free radical initiator), stop introducing the protective gas when the viscosity of the system increases, and seal until the reaction is complete (i.e., the system is heated to the highest temperature); optionally granulate, dry, and pulverize to obtain the polymer.
[0068] Preferably, the protective gas is selected from nitrogen and / or argon.
[0069] A third objective of this invention is to provide a composite oil displacement agent, comprising a composite oil displacement composition and a dispersion, wherein the composite oil displacement composition is selected from the composite oil displacement composition described in one objective of this invention or the composite oil displacement composition obtained by the preparation method described in another objective of this invention.
[0070] In a preferred embodiment, the dispersion is selected from water, simulated formation brine, or actual formation brine.
[0071] In a preferred embodiment, the polymer (preferably polymer powder) is first dispersed (preferably dissolved) in a dispersion, and then the amine oxide surfactant is added under stirring, preferably stirred until it is uniformly dissolved, to obtain the composite oil displacement agent.
[0072] The fourth objective of this invention is to provide the application of the composite oil displacement composition described in the first objective of this invention, the composite oil displacement composition obtained by the preparation method described in the second objective of this invention, or the composite oil displacement agent described in the third objective of this invention in tertiary oil recovery.
[0073] The endpoints and any values of the ranges disclosed in this invention are not limited to the precise ranges or values; these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In the following, various technical solutions can, in principle, be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.
[0074] Compared with the prior art, the present invention has the following beneficial effects:
[0075] (1) This invention utilizes the coordination coupling of lone pair electrons and empty orbitals and hydrogen bonding coupling to form a stable ring structure, thereby strengthening the interaction and overcoming the phenomenon of two-phase separation during underground migration.
[0076] (2) The composite oil displacement composition of the present invention, when used at a dosage of 1500 ppm, after injecting 0.3 PV into brine of 32868 mg / L (1000 ppm each of calcium and magnesium ions), increases the recovery rate of crude oil after water flooding by more than 29%.
[0077] (3) The composite oil displacement composition of the present invention is injected into a sand-filled pipe (permeability 1000mD, diameter 2.5cm, length 1m) with 2PV solution, and the produced fluid is collected at the outlet, wherein the polymer concentration retention rate is greater than 90% and the surfactant concentration retention rate is greater than 88%. Detailed Implementation
[0078] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.
[0079] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.
[0080] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.
[0081] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.
[0082] In the examples and comparative examples, the retention rates of the two components were calculated as shown in equation (1):
[0083]
[0084]
Example 1
[0085] Prepare a homogeneous solution from the following ingredients:
[0086]
[0087]
[0088] Adjust the pH of the above solution to 8-8.2 with sodium hydroxide solution, and cool the solution to 0-5℃. Pour the cooled solution into a thermos and purge with nitrogen for 1 hour. Then, add solutions of 0.0001g potassium bromate, 0.00012g sodium bisulfite, and 0.0005g azobisisobutylamidine hydrochloride dissolved in 1g of water, respectively. Continue purging with nitrogen until the system becomes viscous. Seal and store until the heating is finished. Discharge, granulate, dry, and pulverize to obtain polymer powder 1.
[0089] In a 32868 mg / L brine solution (1000 ppm each of calcium and magnesium ions), the above polymer powder 1 was prepared at a concentration of 1500 ppm. After stirring and dissolving evenly, 526 ppm of dodecyl dihydroxyethylamine oxide was added and stirred evenly to obtain composite oil displacement agent 1.
[0090] Oil displacement experiments were conducted using the composite oil displacement agent 1, with crude oil from Zhongyuan Oilfield Ming 16 as the simulated oil. A sand-packed tube (permeability 1000 mD, diameter 2.5 cm, length 1 m) was used, with an injection volume of 0.3 PV. The experimental temperature was 75℃. Water flooding was performed until the water cut reached 98%, then polymer slugs were injected. Subsequent water flooding continued until the water cut reached 100%. The enhanced oil recovery data after water flooding are shown in Table 1. Two PV of the above solution were injected into the sand-packed tube (permeability 1000 mD, diameter 2.5 cm, length 1 m), and the produced fluid from the outlet was collected. The concentrations of polymers and surfactants were analyzed, and their retention rates were calculated, as shown in Table 1.
[0091]
Example 2
[0092] Prepare a homogeneous solution from the following ingredients:
[0093]
[0094]
[0095] Adjust the pH of the above solution to 8-8.2 with sodium hydroxide solution, and cool the solution to 0-5℃. Pour the cooled solution into a thermos and purge with nitrogen for 1 hour. Then, add 0.00012g of sodium persulfate, 0.00014g of sodium formaldehyde sulfoxylate, and 0.00075g of 2,2'-azo[2-(2-imidazolin-2-yl)propane] dihydrochloride, dissolved in 1g of water respectively. Purge with nitrogen until the system becomes viscous. Seal and store until the heating is finished. Discharge, granulate, dry, and pulverize to obtain polymer powder 2.
[0096] In a 32868 mg / L brine solution (1000 ppm each of calcium and magnesium ions), the above polymer powder 2 was prepared at a concentration of 1500 ppm. After stirring and dissolving evenly, 720 ppm of hexadecyl dihydroxyethylamine oxide was added and stirred evenly to obtain composite oil displacement agent 2.
[0097] Oil displacement experiments were conducted using the composite oil displacement agent 2, with crude oil from Ming 16 in Zhongyuan Oilfield as the simulated oil. A sand-packed tube (permeability 1000 mD, diameter 2.5 cm, length 1 m) was used, with an injection volume of 0.3 PV. The experimental temperature was 75℃. Water flooding was performed until the water cut reached 98%, then polymer slugs were injected. Subsequent water flooding continued until the water cut reached 100%. The enhanced oil recovery data after water flooding are shown in Table 1. Two PV of the above solution were injected into the sand-packed tube (permeability 1000 mD, diameter 2.5 cm, length 1 m), and the produced fluid from the outlet was collected. The concentrations of polymers and surfactants were analyzed, and their retention rates were calculated, as shown in Table 1.
[0098]
Example 3
[0099] Prepare a homogeneous solution from the following ingredients:
[0100]
[0101]
[0102] Adjust the pH of the above solution to 8-8.2 with sodium hydroxide solution, and cool the solution to 0-5℃. Pour the cooled solution into a thermos and purge with nitrogen for 1 hour. Then, add solutions of 0.00008g hydrogen peroxide, 0.0001g ferrous ammonium sulfate, and 0.0006g 4,4'-azobis(4-cyanopentanoic acid) dissolved in 1g of water, respectively. Continue purging with nitrogen until the system becomes viscous. Seal and store until the heating is finished. Discharge, granulate, dry, and pulverize to obtain polymer powder 3.
[0103] In a 32868 mg / L brine solution (1000 ppm each of calcium and magnesium ions), the above polymer powder 3 was prepared at a concentration of 1500 ppm. After stirring and dissolving evenly, 780 ppm of octadecyl dihydroxyethylamine oxide was added and stirred evenly to obtain composite oil displacement agent 3.
[0104] Oil displacement experiments were conducted using the composite oil displacement agent 3. Crude oil from Ming 16 in Zhongyuan Oilfield was used as the simulated oil. A sand-packed tube (permeability 1000 mD, diameter 2.5 cm, length 1 m) was used, with an injection volume of 0.3 PV. The experimental temperature was 75℃. Water flooding was performed until the water cut reached 98%, then polymer slugs were injected. Subsequent water flooding continued until the water cut reached 100%. The enhanced oil recovery data after water flooding are shown in Table 1. Two PV of the above solution were injected into the sand-packed tube (permeability 1000 mD, diameter 2.5 cm, length 1 m). The produced fluid from the outlet was collected, and the concentrations of polymer and surfactant substances were analyzed. The retention rates were calculated and are shown in Table 1.
[0105]
Example 4
[0106] Prepare a homogeneous solution from the following ingredients:
[0107]
[0108]
[0109] Adjust the pH of the above solution to 8-8.2 with sodium hydroxide solution, and cool the solution to 0-5℃. Pour the cooled solution into a thermos and purge with nitrogen for 1 hour. Then, add solutions of 0.0001g hydrogen peroxide, 0.00012g ferrous ammonium sulfate, and 0.0007g 4,4'-azobis(4-cyanopentanoic acid) dissolved in 1g of water, respectively. Continue purging with nitrogen until the system becomes viscous. Seal and store until the heating is finished. Discharge, granulate, dry, and pulverize to obtain polymer powder 4.
[0110] In a 32868 mg / L brine solution (1000 ppm each of calcium and magnesium ions), the above polymer powder 4 was prepared at a concentration of 1500 ppm. After stirring and dissolving evenly, 720 ppm of dodecylamidopropyl dihydroxyethylamine oxide was added and stirred evenly to obtain composite oil displacement agent 4.
[0111] Oil displacement experiments were conducted using the composite oil displacement agent 4, with crude oil from Ming 16 in Zhongyuan Oilfield as the simulated oil. A sand-packed tube (permeability 1000 mD, diameter 2.5 cm, length 1 m) was used, with an injection volume of 0.3 PV. The experimental temperature was 75℃. Water flooding was performed until the water cut reached 98%, then polymer slugs were injected. Subsequent water flooding continued until the water cut reached 100%. The enhanced oil recovery data after water flooding are shown in Table 1. Two PV of the above solution were injected into the sand-packed tube (permeability 1000 mD, diameter 2.5 cm, length 1 m), and the produced fluid from the outlet was collected and analyzed. The concentrations of polymer and surfactant substances were calculated, and their respective retention rates are shown in Table 1.
[0112]
Comparative Example 1
[0113] Prepare a homogeneous solution from the following ingredients:
[0114]
[0115]
[0116] Adjust the pH of the above solution to 8-8.2 with sodium hydroxide solution, and cool the solution to 0-5℃. Pour the cooled solution into a thermos and purge with nitrogen for 1 hour. Then, add solutions of 0.0001g potassium bromate, 0.00012g sodium bisulfite, and 0.0005g azobisisobutylamidine hydrochloride dissolved in 1g of water, respectively. Continue purging with nitrogen until the system becomes viscous. Seal and store until the heating is finished. Discharge, granulate, dry, and pulverize to obtain polymer powder D1.
[0117] In a 32868 mg / L brine solution (1000 ppm each of calcium and magnesium ions), the above polymer powder D1 was prepared with a concentration of 1500 ppm. After stirring and dissolving evenly, 526 ppm of dodecyl dihydroxyethylamine oxide was added and stirred evenly to obtain the composite oil displacement agent D1.
[0118] Oil displacement experiments were conducted using the composite oil displacement agent D1. Crude oil from Ming 16 in Zhongyuan Oilfield was used as the simulated oil. A sand-packed tube (permeability 1000 mD, diameter 2.5 cm, length 1 m) was used, with an injection volume of 0.3 PV. The experimental temperature was 75℃. Water flooding was carried out until the water cut reached 98%, then polymer slugs were injected. After completion, subsequent water flooding continued until the water cut reached 100%. The enhanced oil recovery data after water flooding are shown in Table 1. 2 PV of the above solution was injected into the sand-packed tube (permeability 1000 mD, diameter 2.5 cm, length 1 m), and the produced fluid at the outlet was collected. The concentrations of polymer and surfactant substances were analyzed, and their respective retention rates were calculated, as shown in Table 1.
[0119] [Comparative Example 2]
[0120] Prepare a homogeneous solution from the following ingredients:
[0121]
[0122]
[0123] Adjust the pH of the above solution to 8-8.2 with sodium hydroxide solution, and cool the solution to 0-5℃. Pour the cooled solution into a thermos and purge with nitrogen for 1 hour. Then, add 0.00012g of sodium persulfate, 0.00014g of sodium formaldehyde sulfoxylate, and 0.00075g of 2,2'-azo[2-(2-imidazolin-2-yl)propane] dihydrochloride, dissolved in 1g of water respectively. Continue purging with nitrogen until the system becomes viscous. Seal and store until the heating is finished. Discharge, granulate, dry, and pulverize to obtain polymer powder D2.
[0124] In a 32868 mg / L brine solution (1000 ppm each of calcium and magnesium ions), the above-mentioned polymer powder D2 was prepared with a concentration of 1500 ppm. After stirring and dissolving evenly, 720 ppm of hexadecyl dihydroxyethylamine oxide was added and stirred evenly to obtain the composite oil displacement agent D2.
[0125] Oil displacement experiments were conducted using the composite oil displacement agent D2. Crude oil from Ming 16 in Zhongyuan Oilfield was used as the simulated oil. Sand-packed tubing (permeability 1000 mD, diameter 2.5 cm, length 1 m) was used, with an injection volume of 0.3 PV. The experimental temperature was 75℃. Water flooding was carried out until the water cut reached 98%, then polymer slugs were injected. After completion, subsequent water flooding continued until the water cut reached 100%. The enhanced oil recovery data after water flooding are shown in Table 1.
[0126] 2PV of the above solution was injected into a sand-filled pipe (permeability 1000mD, diameter 2.5cm, length 1m), the produced fluid at the outlet was collected and the concentrations of polymer and surfactant substances were analyzed, and the retention rates were calculated as shown in Table 1.
[0127] [Comparative Example 3]
[0128] The process of Example 1 was repeated, except that an equimolar amount of sodium dodecyl sulfonate was used to replace the dodecyl dihydroxyethylamine oxide, while other conditions remained unchanged, to obtain the composite oil displacement agent D3.
[0129] Oil displacement experiments were conducted using the composite oil displacement agent D3. Crude oil from Ming 16 in Zhongyuan Oilfield was used as the simulated oil. A sand-packed tube (permeability 1000 mD, diameter 2.5 cm, length 1 m) was used, with an injection volume of 0.3 PV. The experimental temperature was 75℃. Water flooding was carried out until the water cut reached 98%, then polymer slugs were injected. After completion, subsequent water flooding continued until the water cut reached 100%. The enhanced oil recovery data after water flooding are shown in Table 1. 2 PV of the above solution was injected into the sand-packed tube (permeability 1000 mD, diameter 2.5 cm, length 1 m), and the produced fluid from the outlet was collected. The concentrations of polymers and surfactants were analyzed, and their respective retention rates were calculated, as shown in Table 1.
[0130] [Comparative Example 4]
[0131] In a 32868 mg / L brine solution (1000 ppm each of calcium and magnesium ions), the above polymer powder 1 was prepared with a concentration of 2026 ppm and stirred evenly to obtain composite oil displacement agent D4.
[0132] Oil displacement experiments were conducted using the composite oil displacement agent D4. Crude oil from Ming 16 in Zhongyuan Oilfield was used as the simulated oil. Sand-packed tubing (permeability 1000 mD, diameter 2.5 cm, length 1 m) was used, with an injection volume of 0.3 PV. The experimental temperature was 75℃. Water flooding was carried out until the water cut reached 98%, then polymer slugs were injected. After completion, subsequent water flooding continued until the water cut reached 100%. The enhanced oil recovery data after water flooding are shown in Table 1.
[0133] [Comparative Example 5]
[0134] In a saline solution with a concentration of 32868 mg / L (1000 ppm each of calcium and magnesium ions), 2026 ppm of dodecyl dihydroxyethylamine oxide was added and stirred until homogeneous to obtain the composite oil displacement agent D5.
[0135] Oil displacement experiments were conducted using the composite oil displacement agent D5. Crude oil from Ming 16 in Zhongyuan Oilfield was used as the simulated oil. Sand-packed tubing (permeability 1000 mD, diameter 2.5 cm, length 1 m) was used, with an injection volume of 0.3 PV. The experimental temperature was 75℃. Water flooding was carried out until the water cut reached 98%, then polymer slugs were injected. After completion, subsequent water flooding continued until the water cut reached 100%. The enhanced oil recovery data after water flooding are shown in Table 1.
[0136] Table 1
[0137]
[0138]
[0139] Table 1 shows the test results for different embodiments and comparative examples. It is clear that:
[0140] (1) Compared with the comparative examples, the recovery rate of crude oil after water flooding in Examples 1 to 4 of the present invention is significantly improved. This is precisely because the product obtained by the present invention can simultaneously expand the swept volume and improve the oil washing efficiency during the oil displacement process.
[0141] (2) As can be seen from the concentration retention rates of the polymer and surfactant components in the examples, the system involved in this invention is integrated and can move synchronously, so the concentration retention rates are both high. In contrast, the comparative system shows a significant difference in retention rates due to the smaller interaction force between the two components.
[0142] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.
Claims
1. A composite composition for oil displacement, comprising a polymer and an amine oxide surfactant, wherein the molar ratio of boron-containing side chains in the polymer to the amine oxide surfactant is (0.9~1.2):1; wherein, The polymer comprises a main chain and multiple side chains, the side chains including amide side chains and boron-containing side chains; the structure of the amide side chain is shown in formula (I), and the boron-containing side chain is a phenylboronic acid side chain, the structure of which is shown in formula (II). In equation (II), R1 is selected from -(R'). a -C(=O)-O-、-(R') a -C(=O)NH- or -(R') a -C(=O)-, R' is selected from C1~C10 alkylene groups. a =0 or 1; R2 is selected from hydrogen; The amine oxide surfactant is selected from at least one of the surfactants shown in formula (VI): In equation (VI), R 10 R8 and R9 are each independently selected from C1 to C5 alkylene groups, and A and B are each independently selected from hydrogen or hydroxyl groups, with at least one of A and B being a hydroxyl group.
2. The composite composition for oil displacement according to claim 1, characterized in that, The side chains of the polymer further include: optional carboxylic acid side chains, optional sulfonate side chains, and optional pyrrolidone side chains.
3. The composite composition for oil displacement according to claim 2, characterized in that, The structures of the carboxylic acid side chain, the sulfonate side chain, and the pyrrolidone side chain are shown in formulas (III), (IV), and (V), respectively: In formula (IV): R5 and R6 are each independently selected from hydrogen, alkyl, aryl, or aralkyl; R3 is selected from -(R''). r -C(=O)O-、-(R'') r -C(=O)NH- or -(R'') r -C(=O)-, R'' is selected from alkylene, arylene or arylene, r=0 or 1; R4 is selected from alkylene, arylene or arylene; in formula (V), R7 is selected from alkylene, arylene or arylene, q=0 or 1.
4. The composite composition for oil displacement according to claim 2, characterized in that, In formula (IV): R5 and R6 are each independently selected from hydrogen, C1-C20 alkyl, C6-C20 aryl, or C7-C20 aralkyl; R3 is selected from -(R''). r -C(=O)O-、-(R'') r -C(=O)NH- or -(R'') r -C(=O)-, R'' is selected from C1~C20 alkylene, C6~C20 arylene or C7~C20 arylene, r=0 or 1; R4 is selected from C1~C20 alkylene, C6~C20 arylene or C7~C20 arylene.
5. The composite composition for oil displacement according to claim 2, characterized in that, In formula (IV): R5 and R6 are each independently selected from hydrogen, C1-C10 alkyl, C6-C12 aryl or C7-C15 aralkyl, and R3 is selected from -(R''). r -C(=O)-O-、-(R'') r -C(=O)-NH- or -(R'') r -C(=O)-, R'' is selected from C1~C10 alkylene, C6~C12 arylene or C7~C15 arylene, r=0 or 1, R4 is selected from C1~C10 alkylene, C6~C12 arylene or C7~C15 arylene.
6. The composite composition for oil displacement according to claim 2, characterized in that, In formula (V), R7 is selected from C1~C20 alkylene, C6~C20 arylene or C7~C20 arylene, and q=0 or 1.
7. The composite composition for oil displacement according to claim 2, characterized in that, In formula (V), R7 is selected from C1~C10 alkylene, C6~C12 arylene or C7~C15 arylene, and q=0 or 1.
8. The composite composition for oil displacement according to claim 2, characterized in that, Based on the polymer being 100 parts by weight, the structural unit containing the amide side chain is 15-40 parts by weight, and / or the structural unit containing the phenylboronic acid side chain is 15-35 parts by weight, and / or the structural unit containing the carboxylic acid side chain is 0-45 parts by weight, and / or the structural unit containing the sulfonate side chain is 0-15 parts by weight, and / or the structural unit containing the pyrrolidone side chain is 0-15 parts by weight.
9. The composite composition for oil displacement according to claim 2, characterized in that, Based on 100 parts by weight of the polymer, the structural unit containing the amide side chain is 25-35 parts by weight, and / or the structural unit containing the phenylboronic acid side chain is 20-28 parts by weight, and / or the structural unit containing the carboxylic acid side chain is 0-43 parts by weight, and / or the structural unit containing the sulfonate side chain is 0-9 parts by weight, and / or the structural unit containing the pyrrolidone side chain is 0-9 parts by weight.
10. A method for preparing a composite oil displacement composition, used to prepare the composite oil displacement composition according to any one of claims 1 to 9, the preparation method comprising: The polymer and the amine oxide surfactant are mixed to obtain the composite composition for oil displacement.
11. The preparation method according to claim 10, characterized in that, The preparation of the polymer includes: polymerizing raw materials, including monomers, to obtain the polymer, wherein the monomers include acrylamide monomers, boron-containing monomers, optional acrylic monomers, optional sulfonate monomers, and optional pyrrolidone monomers.
12. The preparation method according to claim 10, characterized in that, The molar ratio of the boron-containing side chain in the polymer to the amine oxide surfactant is (0.9~1.2):
1.
13. The preparation method according to any one of claims 10 to 12, characterized in that, The raw materials further include initiators, solvents, chelating agents, co-solvents, and co-reducing agents.
14. The preparation method according to claim 13, characterized in that, The initiator is selected from a combination of redox initiators and high-temperature free radical initiators; and / or, the solvent is water; and / or, the chelating agent is selected from at least one of disodium ethylenediaminetetraacetate, pentasodium diethylenetriaminepentaacetate, sodium polyphosphate, nitrilotriacetic acid, N-hydroxyethylethylaminetriacetic acid, ethylene glycol-bis-(B-aminoethyl ether)-N,N-tetraacetic acid, aminotrimethylenephosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, and aminotrimethylenephosphonic acid; and / or, the co-solvent is selected from one of urea, sodium formate, sodium hypophosphite, mercaptoacetic acid, and dodecyl mercaptan; and / or, the co-reducing agent is dimethylaminoacetonitrile.
15. The preparation method according to claim 13, characterized in that, Based on a total monomer content of 100 parts by weight, the amount of the initiator is 0.001 to 0.004 parts by weight, and / or the amount of the solvent is 120 to 220 parts by weight, and / or the amount of the chelating agent is 0.002 to 0.01 parts by weight, and / or the amount of the co-solvent is 0.05 to 0.5 parts by weight, and / or the amount of the co-reducing agent is 0.05 to 0.2 parts by weight.
16. A composite oil displacement agent comprising a composite oil displacement composition and a dispersion, wherein the composite oil displacement composition is selected from the composite oil displacement compositions of any one of claims 1 to 9 or the composite oil displacement compositions obtained by the preparation method of any one of claims 10 to 15.
17. The composite oil displacement agent according to claim 16, characterized in that, The dispersion is selected from water, simulated formation brine, or actual formation brine.
18. The application of the composite oil displacement composition according to any one of claims 1 to 9, the composite oil displacement composition obtained by the preparation method according to any one of claims 10 to 15, or the composite oil displacement agent according to any one of claims 16 to 17 in tertiary oil recovery.