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CN-121991305-A - Profile control agent and preparation method and application thereof

CN121991305ACN 121991305 ACN121991305 ACN 121991305ACN-121991305-A

Abstract

The invention relates to the field of oil field development and recovery, and discloses a profile control agent and a preparation method and application thereof. The profile control agent comprises a modified nano silicon dioxide inner core and hair chains grafted on the surface of the inner core, wherein the hair chains comprise a structural unit A shown in a formula (I), a structural unit B shown in a formula (II) and a blocking group, the inner core comprises a surface modification group shown in a formula (III), the molar ratio of the structural unit A to the structural unit B is 1 (0.5-1.8), the number average molecular weight of the hair chains is 5000-20000g/mol, the blocking group is halogen, and the weight ratio of the inner core to the hair chains is 1 (25-65). The profile control agent does not depend on the matching property with the pore throat size in an oil reservoir, can be self-adapted to pore throat space and form effective plugging areas in pore throats with different sizes, has excellent plugging effect, and greatly improves the adaptability of the profile control agent to the oil reservoir.

Inventors

  • ZHU YINGTING
  • LV JING
  • WEI FALIN
  • LI MANTIAN
  • SONG TAO
  • ZHANG QUN
  • DING BIN
  • TIAN HUI
  • ZHANG SONG
  • Xin Huazhi

Assignees

  • 中国石油天然气股份有限公司

Dates

Publication Date
20260508
Application Date
20241106

Claims (12)

  1. 1. The profile control agent is characterized by comprising a modified nano silicon dioxide core and hair chains grafted on the surface of the modified nano silicon dioxide core; wherein the hair chain comprises a structural unit A shown in a formula (I), a structural unit B shown in a formula (II) and a terminal group; Wherein R 1 、R 2 、R 3 is independently selected from-H or C 1 -C 3 alkyl, R 4 、R 5 、R 6 is independently selected from-H or C 1 -C 3 alkyl, R 7 is Or C 1 -C 4 alkyl, wherein n is an integer from 1 to 3; the mol ratio of the structural unit A to the structural unit B is 1 (0.5-1.8); The number average molecular weight of the hair chain is 5000-20000g/mol; The end sealing group is-X, wherein X is halogen; the modified nano silicon dioxide inner core has a surface modification group shown in a formula (III), Wherein, represents the connection position of the surface modifying group and the nano silicon dioxide, Represents the attachment position of the surface modifying group to the hair chain; The weight ratio of the nano modified silicon dioxide kernel to the hair chain is 1 (25-65).
  2. 2. The profile control agent of claim 1, wherein each R 1 、R 2 、R 3 is independently selected from-H or C 1 -C 2 alkyl; And/or R 4 、R 5 、R 6 is each independently selected from-H or C 1 -C 2 alkyl, R 7 is Or C 1 -C 2 alkyl, wherein n is an integer from 1 to 2.
  3. 3. The profile control agent according to claim 1 or 2, wherein the molar ratio of structural unit A to structural unit B is 1 (0.6-1.2); and/or the number average molecular weight of the hair strand is 8000-15000g/mol.
  4. 4. The profile control agent of claim 1 or 2, wherein the end capping group is-Br.
  5. 5. The profile control agent according to claim 1 or 2, wherein the weight ratio of the nano modified silica core to the hair chain is 1 (30-45).
  6. 6. The preparation method of the profile control agent is characterized by comprising the following steps: (1) In the presence of a first solvent, carrying out a first reaction on nano silicon dioxide particles and a silane coupling agent to obtain modified nano silicon dioxide; (2) In the presence of a second solvent and an auxiliary agent, carrying out a second reaction on the modified nano silicon dioxide and the monomers A 'and B', and then carrying out post-treatment on the obtained product to obtain a profile control agent; wherein the monomer A 'is a monomer with a structure shown in a formula (IV), the monomer B' is a monomer with a structure shown in a formula (V), Wherein R 1 、R 2 、R 3 is independently selected from-H or C 1 -C 3 alkyl, R 4 、R 5 、R 6 is independently selected from-H or C 1 -C 3 alkyl, R 7 is Or C 1 -C 4 alkyl, wherein n is an integer from 1 to 3; The silane coupling agent is selected from 2-bromo-2-methylpropanoic acid (3-trimethoxysilyl) propyl ester and/or 2-bromo-2-methylpropanoic acid 3- (triethoxysilyl) propyl ester; The weight ratio of the modified nano silicon dioxide to the monomer A 'to the monomer B' is 1 (10-15) to 20-50.
  7. 7. The method of claim 6, wherein in step (1), the nanosilica has a particle size of 10-30nm; And/or the first solvent is selected from alkylbenzene and/or alcohol solvents, preferably toluene.
  8. 8. The method according to claim 6 or 7, wherein in the step (1), the weight ratio of the nano silica particles to the silane coupling agent is 1 (0.5 to 1.2); And/or the conditions of the first reaction comprise a temperature of 90-120 ℃ and a time of 12-24h.
  9. 9. The process according to claim 6 or 7, wherein in step (2), the second solvent is selected from at least one of tetrahydrofuran, dimethyl sulfoxide and N, N-dimethylformamide, preferably tetrahydrofuran; and/or, the auxiliary agent comprises pentamethyldiethylenetriamine, copper bromide and L-ascorbic acid.
  10. 10. The method according to claim 9, wherein in the step (2), the weight ratio of the modified nano-silica to the pentamethyldiethylenetriamine to the copper bromide to the L-ascorbic acid is 1 (0.35-0.55): 0.05-0.1): 0.25-0.85; And/or the conditions of the second reaction comprise that the reaction is carried out under a protective atmosphere, the pH value is 1-5, the temperature is 60-90 ℃, and the time is 2-8h.
  11. 11.A profile control agent obtainable by the process of any one of claims 6 to 10.
  12. 12. Use of the profile control agent of any one of claims 1-5 and 11 in reservoir development.

Description

Profile control agent and preparation method and application thereof Technical Field The invention relates to the field of oil field development and recovery, in particular to a profile control agent and a preparation method and application thereof. Background The water injection development is a main development mode of oil reservoirs in China, but dominant channels are formed in a reservoir in the later period of water injection, injected water is in ineffective circulation in the reservoir, the water content of produced liquid is high, the oil reservoirs enter a high-water-content development stage, and the oil reservoir utilization degree is difficult to be further and greatly improved. Chemical profile control is an effective technical means for regulating and controlling the dominant seepage channel of the oil reservoir, and has good effect in oilfield application. In the chemical profile control agent, compared with other types of profile control agents, the polymer microsphere has the advantages of good injectability, strong deep migration capacity, good shearing resistance and the like, the profile control agent enters a reservoir in a smaller size, absorbs water to expand and gradually increases the volume in the reservoir, and after the volume size reaches a certain value, the pore throat of the stratum can be plugged in a bridging, blocking and other modes, so that the seepage resistance of the subsequent water flow in the original dominant seepage channel is obviously improved, the liquid flow is promoted to be diverted into a low seepage area which is not swept by the water flow, and the water driving wave efficiency and the oil reservoir crude oil utilization degree are further improved. The plugging effect of the polymer microsphere on the reservoir is very dependent on the matching relation between the microsphere size and the pore throat size of the reservoir, however, the pore throat size distribution in the reservoir is generally wider, a large number of pore channels with different seepage capacities are contained, the size of a single microsphere product is single, the fine matching with the pore throat of the reservoir is difficult to be satisfied, and the outstanding problems of microsphere channeling, low plugging rate and the like occur in the application process. To solve the above-mentioned drawbacks of polymer microspheres, some researchers have proposed microsphere multiparticulate agglomeration techniques. For example, CN109111904A discloses a profile control agent for heterocharge polymer nano-microspheres, which is prepared from the following components, by mass, 20-49% of an oil-soluble solvent, 40-71% of a water phase and 9-17% of a surfactant, wherein the water phase comprises, by mass, 10-70% of a cationic monomer and an anionic monomer, 0.001-1.00% of a cross-linking agent, and the balance water. The profile control agent is applied to a stratum, and is expanded when being contacted with water, so that surface charges are rearranged on the outer surfaces of microspheres, electrostatic attraction between microspheres with different charges is enough to overcome copolymerization and sedimentation of van der Waals repulsive force, and further a dominant water flow channel in the stratum is blocked, and the application permeability range of the nano microsphere profile control agent is enlarged from about 0.1 mu m 2 to 3 mu m 2. In addition, as disclosed in CN108315003A, a polyacrylamide microsphere deep profile control agent comprises, by weight, a) 0.05-0.5 part of a polymer microsphere emulsion, b) 0.1-1 part of a surfactant for oil displacement, and c) 0-99.85 parts of water, wherein the polymer microsphere in the polymer microsphere emulsion has a core-shell structure, the core is a crosslinked polymer gel microsphere containing an ionic monomer structural unit, and the shell is a crosslinked polymer gel containing an ionic monomer structural unit with different or same electrical property as the ionic monomer structural unit in the core. The microsphere deep profile control agent can be used for field application of deep profile control, water shutoff, oil displacement and the like of medium and high permeability oil reservoirs for improving recovery ratio. The above scheme can effectively promote the plugging property of polymer microsphere, but still can not thoroughly solve the problem that microsphere and reservoir pore throat size can not be effectively matched, and the microsphere profile control agent is difficult to form a plug when the particle size is too small, and is difficult to inject into the deep part of the reservoir when the particle size is too large. Disclosure of Invention Aiming at the problems that the conventional microsphere profile control agent is difficult to effectively match with the pore throat size in an oil reservoir, so that the microsphere profile control agent is difficult to form a plug when the particle size is too small and is di