Ion-bridged salt-tolerant polymer thickening agent as well as preparation method and application thereof

Abstract

The invention discloses an ion bridging salt-tolerant polymer thickening agent as well as a preparation method and application thereof, belongs to the technical field of preparation of polymer thickening agents, and aims to solve the technical problems that fracturing fluid which is just prepared before a cross-linking agent is injected is too high in viscosity and difficult to inject. The preparation method comprises the following steps: mixing maleic anhydride and initiators azodiisobutyronitrile and dimethylformamide, then adding acrylamide for reaction, and after the reaction is completed, carrying out reduced pressure distillation to remove a solvent, thereby obtaining the ion-bridged salt-tolerant polymer thickening agent. Before the ion bridging salt-tolerant polymer thickening agent is injected into a stratum with sand, maleic anhydride is partially hydrolyzed, intramolecular winding is caused by the disadvantage of the distance between molecules, the viscosity is reduced, and injection is convenient; meanwhile, the stratum water contains divalent ions such as Ca < 2 + > and Mg < 2 + >, metal ions are captured through ortho-position carboxyl, complexing, bridging and crosslinking are carried out, the rigidity of a molecular main chain is increased, and the side effect of the metal ions is reduced. The temperature resistance and the salt resistance of the thickening agent can be obviously improved.

Description

technical field

[0001] The invention belongs to the technical field of polymer thickener preparation, and in particular relates to an ion bridging salt-tolerant polymer thickener and its preparation method and application. Background technique

[0002] Water-based fracturing fluid is currently the most widely used fracturing fluid system, which uses water as a dispersant, thickener, crosslinking agent, gel breaker, drainage aid, clay stabilizer, bactericide and temporary plugging agent Additives such as soluble in water or dispersed in water, the system is mostly in the form of cross-linked gel. Thickeners and crosslinking agents are the most important additives in fracturing. In practice, the high temperature of the formation and metal ions will reduce the viscosity of the fracturing fluid system, and the crosslinking agent used in the fracturing system can make the fracturing fluid It has a certain temperature and salt resistance, but the use of various cross-linking agen...

Examples

Embodiment 1

[0041] A preparation method of ion bridging salt-tolerant polymer thickener, comprising the following steps:

[0042] With 98.06g (1mol) maleic anhydride, 1.69g initiator azobisisobutyronitrile (1wt% of the mass sum of maleic anhydride and acrylamide) and 507.42 dimethylformamide (maleic anhydride quality and acrylamide 3 times of the sum of the masses) mixed, stirred continuously and heated to 80°C, added 71.08g (1mol) of acrylamide to react for 5h, after the reaction was complete, the solvent was distilled off under reduced pressure to obtain an ion bridging salt-tolerant polymer thickener, measured The obtained thickener molecular weight is 4827255, n=28540.

[0043] Dilute the obtained ion bridging salt-tolerant polymer thickener to 1.0wt% to carry sand, inject it into the bottom layer, and simulate the formation Ca 2+ , Mg 2+ Under the action of divalent ions, complexation, bridging and crosslinking are realized.

Embodiment 2

[0045] A preparation method of ion bridging salt-tolerant polymer thickener, comprising the following steps:

[0046] With 98.06g (1mol) maleic anhydride, 2.54g initiator azobisisobutyronitrile (1.5wt% of the mass sum of maleic anhydride and acrylamide) and 507.42 dimethylformamide (maleic anhydride quality and propylene 3 times the sum of the mass of amides) mixed, stirred continuously and heated to 75°C, added 71.08g (1mol) of acrylamide to react for 3h, after the reaction was complete, the solvent was distilled off under reduced pressure to obtain an ion bridging salt-tolerant polymer thickener. The measured molecular weight of the thickener is 3589150, n=21220.

[0047] Dilute the obtained ion bridging salt-tolerant polymer thickener to 0.8wt% sand-carrying agent, inject it into the bottom layer, and simulate the formation Ca 2+ , Mg 2+ Under the action of divalent ions, complexation, bridging and crosslinking are realized.

Embodiment 3

[0049] A preparation method of ion bridging salt-tolerant polymer thickener, comprising the following steps:

[0050] With 98.06g (1mol) maleic anhydride, 3.38g initiator azobisisobutyronitrile (2wt% of the mass sum of maleic anhydride and acrylamide) and 507.42 dimethylformamide (maleic anhydride quality and acrylamide 3 times of the sum of the masses) mixed, stirred continuously and heated to 80°C, added 71.08g (1mol) of acrylamide to react for 5h, after the reaction was complete, the solvent was distilled off under reduced pressure to obtain an ion bridging salt-tolerant polymer thickener, measured The obtained thickener molecular weight is 2650423, n=15670.

[0051] Dilute the obtained ion bridging salt-tolerant polymer thickener to 1.0wt% to carry sand, inject it into the bottom layer, and simulate the formation Ca 2+ , Mg 2+ Under the action of divalent ions, complexation, bridging and crosslinking are realized.

technical field

[0001] The invention belongs to the technical field of polymer thickener preparation, and in particular relates to an ion bridging salt-tolerant polymer thickener and its preparation method and application. Background technique

[0002] Water-based fracturing fluid is currently the most widely used fracturing fluid system, which uses water as a dispersant, thickener, crosslinking agent, gel breaker, drainage aid, clay stabilizer, bactericide and temporary plugging agent Additives such as soluble in water or dispersed in water, the system is mostly in the form of cross-linked gel. Thickeners and crosslinking agents are the most important additives in fracturing. In practice, the high temperature of the formation and metal ions will reduce the viscosity of the fracturing fluid system, and the crosslinking agent used in the fracturing system can make the fracturing fluid It has a certain temperature and salt resistance, but the use of various cross-linking agen...

Examples

Embodiment 1

[0041] A preparation method of ion bridging salt-tolerant polymer thickener, comprising the following steps:

[0042] With 98.06g (1mol) maleic anhydride, 1.69g initiator azobisisobutyronitrile (1wt% of the mass sum of maleic anhydride and acrylamide) and 507.42 dimethylformamide (maleic anhydride quality and acrylamide 3 times of the sum of the masses) mixed, stirred continuously and heated to 80°C, added 71.08g (1mol) of acrylamide to react for 5h, after the reaction was complete, the solvent was distilled off under reduced pressure to obtain an ion bridging salt-tolerant polymer thickener, measured The obtained thickener molecular weight is 4827255, n=28540.

[0043] Dilute the obtained ion bridging salt-tolerant polymer thickener to 1.0wt% to carry sand, inject it into the bottom layer, and simulate the formation Ca 2+ , Mg 2+ Under the action of divalent ions, complexation, bridging and crosslinking are realized.

Embodiment 2

[0045] A preparation method of ion bridging salt-tolerant polymer thickener, comprising the following steps:

[0046] With 98.06g (1mol) maleic anhydride, 2.54g initiator azobisisobutyronitrile (1.5wt% of the mass sum of maleic anhydride and acrylamide) and 507.42 dimethylformamide (maleic anhydride quality and propylene 3 times the sum of the mass of amides) mixed, stirred continuously and heated to 75°C, added 71.08g (1mol) of acrylamide to react for 3h, after the reaction was complete, the solvent was distilled off under reduced pressure to obtain an ion bridging salt-tolerant polymer thickener. The measured molecular weight of the thickener is 3589150, n=21220.

[0047] Dilute the obtained ion bridging salt-tolerant polymer thickener to 0.8wt% sand-carrying agent, inject it into the bottom layer, and simulate the formation Ca 2+ , Mg 2+ Under the action of divalent ions, complexation, bridging and crosslinking are realized.

Embodiment 3

[0049] A preparation method of ion bridging salt-tolerant polymer thickener, comprising the following steps:

[0050] With 98.06g (1mol) maleic anhydride, 3.38g initiator azobisisobutyronitrile (2wt% of the mass sum of maleic anhydride and acrylamide) and 507.42 dimethylformamide (maleic anhydride quality and acrylamide 3 times of the sum of the masses) mixed, stirred continuously and heated to 80°C, added 71.08g (1mol) of acrylamide to react for 5h, after the reaction was complete, the solvent was distilled off under reduced pressure to obtain an ion bridging salt-tolerant polymer thickener, measured The obtained thickener molecular weight is 2650423, n=15670.

[0051] Dilute the obtained ion bridging salt-tolerant polymer thickener to 1.0wt% to carry sand, inject it into the bottom layer, and simulate the formation Ca 2+ , Mg 2+ Under the action of divalent ions, complexation, bridging and crosslinking are realized.

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