阅读说明：本技术 封堵裂缝的封堵剂及其封堵方法 (Plugging agent for plugging cracks and plugging method thereof ) 是由 罗强 唐可 原风刚 白雷 李明 向小玲 李凯 王凤清 袁恩来 孟亚玲 曹强 于 2018-06-22 设计创作，主要内容包括：本发明提供了一种封堵裂缝的封堵剂及其封堵方法。该封堵剂包括第一组分和第二组分。第一组分包括第一反应型高聚物、聚合单体、交联剂、引发剂；第二组分包括非可溶性固体颗粒和聚合物溶液。采用上述封堵剂不仅能够实现对油藏裂缝的有效封堵,同时有机凝胶-颗粒的立体网络封堵体系的形成还使得其具有较高的封堵强度和耐冲刷性能。此外由于第一组分和第二组分在注入前具有良好的注入性,因而采用本申请提供的上述封堵剂不仅具有良好的封堵性能,同时还具有优异的注入性。(The invention provides a plugging agent for plugging cracks and a plugging method thereof. The blocking agent includes a first component and a second component. The first component comprises a first reactive polymer, a polymerization monomer, a cross-linking agent and an initiator; the second component includes non-soluble solid particles and a polymer solution. By adopting the plugging agent, not only can the effective plugging of oil reservoir cracks be realized, but also the formation of a three-dimensional network plugging system of organogel-particles enables the plugging agent to have higher plugging strength and flushing resistance. In addition, the first component and the second component have good injectability before injection, so that the plugging agent provided by the application has good plugging performance and excellent injectability.)

1. A plugging agent for plugging a fracture, the plugging agent comprising:

a first component, wherein the first component comprises a first reactive polymer, a polymerization monomer, a cross-linking agent and an initiator; and

a second component comprising non-soluble solid particles, a second reactive polymer, and water.

2. The plugging agent of claim 1, wherein the first component comprises, in parts by weight: 0.1-0.3 part of the first reactive polymer, 5-10 parts of the polymerized monomer, 0.005-0.03 part of the crosslinking agent and 0.1-1.0 part of the initiator.

3. The plugging agent of claim 1 or 2, wherein the second component comprises 0.1 to 1 part by weight of the insoluble solid particles and 0.1 to 0.3 part by weight of the second reactive polymer.

4. The plugging agent of claim 3, wherein the non-soluble solid particles are selected from perlite and/or rubber particles.

5. The plugging agent according to claim 3, wherein the total weight of the first reactive polymer and the second reactive polymer is represented as A, and the weight ratio of the insoluble solid particles, A and the polymerized monomer is 0.2-1.0: 0.1-0.3: 5-8; preferably 0.5:0.2: 6.

6. The plugging agent according to any one of claims 1 to 3, further comprising a third component which is a mixed solution of a third reactive polymer and water.

7. The plugging agent of claim 6, wherein the first reactive polymer, the second reactive polymer and the third inverse polymerThe reactive high polymers are respectively and independently selected from the group consisting of self-adhesive average molecular weight of 2 x 10⁷～3.5×10⁷And the degree of hydrolysis is 20-30% of anionic polyacrylamide.

8. The blocking agent according to claim 1 or 2, characterized in that the polymerized monomers are acrylamide and/or acrylic acid;

preferably, the cross-linking agent is N, N-dimethyl bisacrylamide;

preferably, the initiator is selected from one or more of the group consisting of ammonium persulfate, potassium persulfate, and sodium persulfate.

9. The plugging agent of claim 1, further comprising added water.

10. A method of plugging with the plugging agent of any one of claims 1 to 9, comprising:

s1, injecting a second component into the fracture of the stratum to be plugged, wherein the second component comprises insoluble solid particles, a second reactive polymer and water;

and S2, injecting a first component into the fracture of the stratum, wherein the first component comprises a first reaction type high polymer, a polymerization monomer, a cross-linking agent and an initiator.

11. The method as claimed in claim 10, wherein after the step S2, the method further comprises a step S3: injecting a third component into the fractures of the formation, the third component being a mixed solution of a third reactive polymer and water;

preferably, after the step S3, the method further includes a step S4: injecting additional water into fractures of the formation.

Technical Field

The invention relates to the field of oil reservoir exploitation, in particular to a plugging agent for plugging a crack and a plugging method thereof.

Background

In the development process of an oil field, the development of a fractured reservoir faces serious water channeling or agent channeling (such as polymer channeling, surfactant channeling, jelly channeling and the like), so that water injection, ineffective circulation of polymer or surfactant and development effect are seriously influenced, and the recovery rate of the oil field is influenced.

In order to solve the problem of channeling of fractured reservoirs, polymer jelly, inorganic gel, particles or a composite system is mostly adopted for plugging at present. The prior document provides a plugging method in which a super absorbent resin is carried by jelly and a subsequently injected propyl system is used as a sealing slug. Inorganic gels (e.g., cement) have good blocking properties but poor injectability. The process of plugging by adopting the particles has the problems that the plugging agent cannot be injected or the plugging effect is poor although the plugging agent can be injected. When the propyl coagulation system is used as jelly to carry high water absorption resin for sealing, the irreversible pollution of the medium-low permeability reservoir can be caused due to the low viscosity of the propyl coagulation system. Therefore, the plugging method is difficult to realize deep plugging of the crack.

To achieve effective plugging of cracks, the injectability and strong plugging performance of the formulation need to be met. In order to solve the problem of deep plugging of a fractured channeling channel, a deep plugging formula suitable for a fracture type and an injection process are needed to be provided.

Disclosure of Invention

The invention mainly aims to provide a plugging agent for plugging cracks and a plugging method thereof, and aims to solve the problem that the existing plugging agent cannot have good plugging property and good injection property at the same time.

In order to achieve the above object, an aspect of the present invention provides a plugging agent for plugging a crack, the plugging agent comprising: a first component and a second component. The first component comprises a first reactive polymer, a polymerization monomer, a cross-linking agent and an initiator; and the second component comprises non-soluble solid particles, a second reactive polymer and water.

Further, the first component comprises the following components in parts by weight: 0.1-0.3 part of first reaction type high polymer, 5-10 parts of polymerized monomer, 0.005-0.03 part of cross-linking agent and 0.1-1.0 part of initiator.

Further, the second component comprises 0.1-1 part of non-soluble solid particles and 0.1-0.3 part of second reaction type high polymer in parts by weight.

Further, the non-soluble solid particles are selected from perlite and/or rubber particles; preferably, the solution comprises the second reactive polymer and water.

Further, the total weight of the first reactive polymer and the second reactive polymer is denoted as A, and the weight ratio of the insoluble solid particles, A and the polymerized monomer is 0.2-1.0: 0.1-0.3: 5-8.

Further, the blocking agent also comprises a third component which is a mixed solution of a third reaction type high polymer and water.

Further, the first, second and third reactive polymers are each independently selected from the group consisting of a polymer having a self-adhesive average molecular weight of 2X 10⁷～3.5×10⁷And the degree of hydrolysis is 20-30% of anionic polyacrylamide.

Further, the polymerized monomer is acrylamide and/or acrylic acid; preferably, the crosslinking agent is N, N-dimethyl bisacrylamide; preferably, the initiator is selected from one or more of the group consisting of ammonium persulfate, potassium persulfate, and sodium persulfate.

Further, the blocking agent also comprises external water.

The application also provides a method for plugging by using the plugging agent, which comprises the following steps:

s1, injecting a second component into the fracture of the stratum to be plugged, wherein the second component comprises insoluble solid particles, a second reaction type polymer and water;

and S2, injecting a first component into the fracture of the stratum, wherein the first component comprises a first reaction type polymer, a polymerization monomer, a cross-linking agent and an initiator.

Further, after the step S2, the method further includes a step S3: injecting a third component into the cracks of the stratum, wherein the third component is a mixed solution of a third reaction type high polymer and water; preferably, after step S3, the method further comprises step S4: additional water is injected into the fractures of the formation.

By applying the technical scheme of the invention, the first reactive polymer and the polymerized monomer in the plugging agent can generate graft polymerization reaction under the action of an initiator and the temperature of the oil reservoir to form a high-molecular organic polymer (organogel), and the high-molecular organic polymer and the polymerized monomer are crosslinked to form a network structure under the action of a crosslinking agent, so that the effective filling of cracks can be realized. Meanwhile, after the insoluble solid particles are dispersed in the solvent to form the second component, the second component is injected into the crack to be plugged, and the second component can play a role in supporting the skeleton. The two are matched for use to form an organic polymer which can wrap the insoluble solid particles, and further form an organogel-particle three-dimensional network plugging system in the crack. Compared with the existing plugging agent, the plugging agent can be used for effectively plugging oil reservoir cracks, and meanwhile, the organogel-particle three-dimensional network plugging system has higher plugging strength and flushing resistance. In addition, the first component and the second component have good injectability before injection, so that the plugging agent provided by the application has good plugging performance and excellent injectability.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail with reference to examples.

As described in the background art, the conventional plugging agent has a problem that it cannot achieve both good plugging property and good injection property. In order to solve the technical problems, the invention provides a plugging agent, which comprises a first component and a second component, wherein the first component comprises a first reactive polymer, a polymerized monomer, a cross-linking agent and an initiator; and the second component comprises non-soluble solid particles and a solvent.

In the oil reservoir plugging process, the first reactive polymer and the polymerized monomer in the plugging agent can generate graft polymerization reaction under the action of an initiator and the oil reservoir temperature to form a high-molecular organic polymer (organogel), and the high-molecular organic polymer and the organogel are crosslinked to form a network structure under the action of a crosslinking agent, so that effective filling of cracks can be realized. Meanwhile, after the insoluble solid particles are dispersed in the solvent to form the second component, the second component is injected into the crack to be plugged, and the second component can play a role in supporting the skeleton. The two are matched for use to form an organic polymer which can wrap the insoluble solid particles, and further form an organogel-particle three-dimensional network plugging system in the crack. Compared with the existing plugging agent, the plugging agent can be used for effectively plugging oil reservoir cracks, and meanwhile, the organogel-particle three-dimensional network plugging system has higher plugging strength and flushing resistance. In addition, the first component and the second component have good injectability before injection, so that the plugging agent provided by the application has good plugging performance and excellent injectability.

Preferably, the plugging agent and the injection process are suitable for plugging a crack type strong channeling channel, and have good control effect on water channeling, channeling collection, gel channeling and the like of a crack type oil reservoir. The method has wide application prospect in water flooding, polymer flooding, composite flooding, deep profile control and flooding technologies and other applications of oil reservoirs with crack type strong channeling characteristics.

The plugging agent provided by the application not only has good higher plugging strength and flushing resistance, but also has good injectability. In a preferred embodiment, the first component comprises, in parts by weight: 0.1-0.3 part of first reaction type high polymer, 5-8 parts of polymerized monomer, 0.005-0.03 part of cross-linking agent and 0.1-1.0 part of initiator. The weight ratio of the components in the first component includes, but is not limited to, the above range, and it is preferable to limit it within the above range to further improve the blocking strength and the flushing resistance of the above blocking agent.

In a preferred embodiment, the second component comprises 0.1 to 1 part by weight of the insoluble solid particles and 0.1 to 0.3 part by weight of the second reactive polymer.

Preferably, the non-soluble solid particles are selected from perlite and/or rubber particles. The perlite and the rubber particles have better compressive strength, and are beneficial to further improving the plugging strength and the scouring resistance of the plugging agent.

In a preferred embodiment, the total weight of the first reactive polymer and the second reactive polymer is represented as A, and the weight ratio of the insoluble solid particles, A and the polymerized monomer is 0.2 to 1.0:0.1 to 0.3:5 to 8. The weight ratio of the insoluble solid particles, the total weight of the first reactive polymer and the second reactive polymer, and the polymerized monomers includes, but is not limited to, the above range, and it is preferable to further improve the plugging effect by limiting the weight ratio to the above range. More preferably, the weight ratio of the insoluble solid particles, a and polymerized monomer is 0.5:0.2: 6.

In a preferred embodiment, the blocking agent further comprises a third component, and the third component is a mixed solution of the third reactive polymer and water. The third component is added, so that the previously injected component can be transferred to the deep part of the oil reservoir, and the plugging depth of the oil reservoir can be improved.

The weight of the first component, the second component, the third component and water in the plugging agent provided by the application all adopt the same dimension.

In a preferred embodiment, the first, second and third reactive polymers are each independently selected from the group consisting of polymers having a self-adhesive average molecular weight of 2X 10⁷～3.5×10⁷And the degree of hydrolysis is 20-30% of anionic polyacrylamide.

The first reactive polymer, the second reactive polymer and the third reactive polymer provided herein may be the same or different in kind. The anionic polyacrylamide is selected as the required reactive high polymer, so that the plugging agent has the advantages of selectively entering cracks, dilution resistance, controllable polymerization time and the like.

After the first component, the second component and the third component are injected, additional water is injected to clean a pipeline used when the plugging agent is injected. The water injection amount can be increased or decreased according to the actual condition.

The weight of the first component, the second component, the third component and water in the plugging agent provided by the application all adopt the same dimension.

The polymerizable monomer in the first component may be selected from those conventionally used in the art. In a preferred embodiment, the polymerized monomers include, but are not limited to, acrylamide and/or acrylic acid. The polymerized monomers belong to acrylamide polymerized monomers, which is favorable for further improving the blocking strength and the flushing resistance of the blocking agent.

The crosslinking agent used in the blocking agent may be selected from those commonly used in the art. Preferably, the crosslinking agent includes, but is not limited to, N-dimethylacrylamide.

The initiator used in the blocking agent may be any initiator commonly used in the art. In a preferred embodiment, the initiator includes, but is not limited to, one or more of the group consisting of ammonium persulfate, potassium persulfate, and sodium persulfate. The initiators have low initiation activity and low cost, so the selection of the initiators is beneficial to reducing the plugging cost.

For better understanding of the present application, in another aspect, the present application further provides a method for plugging with the plugging agent, the method comprising:

s1, injecting a second component into the fracture of the stratum to be plugged, wherein the second component comprises insoluble solid particles, a second reaction type polymer and water;

and S2, injecting a first component into the fracture of the stratum, wherein the first component comprises a first reaction type polymer, a polymerization monomer, a cross-linking agent and an initiator.

Compared with the existing plugging agent, the plugging agent can be used for effectively plugging oil reservoir cracks, and meanwhile, the organogel-particle three-dimensional network plugging system has higher plugging strength and flushing resistance. Due to the good injectability of the first component and the second component before injection, the plugging agent provided by the application has good plugging performance and excellent injectability. The plugging method is simple and has a good plugging effect.

Preferably, after step S2, the method further comprises step S3: injecting a third component into the cracks of the stratum, wherein the third component is a mixed solution of a third reaction type high polymer and water; the third component is added, so that the previously injected component can be transferred to the deep part of the oil reservoir, and the plugging depth of the oil reservoir can be improved.

Preferably, after step S3, the method further comprises step S4: additional water is injected into the fractures of the formation. Additional water is injected to clean the tubing used in the sealant injection. The water injection amount can be increased or decreased according to the actual condition.

The present invention is described in further detail below with reference to specific examples, which are not to be construed as limiting the scope of the invention as claimed.