Easily degradable plugging agent and preparation method thereof

文档序号：758195 发布日期：2021-04-06 浏览：24次中文

阅读说明：本技术 一种易降解封堵剂及其制备方法 (Easily degradable plugging agent and preparation method thereof ) 是由孔拥华李新来于 2020-12-15 设计创作，主要内容包括：本申请涉及封堵剂制造的技术领域,具体公开了一种易降解封堵剂及其制备方法,易降解封堵剂主要由以下重量份的原料制得：聚丙烯酰胺80-120份,丙烯酸30-50份,多糖15-30份,碱0.5-3份,交联剂0.5-3份,氧化剂3-5份,尿素1-3份,聚合引发剂1-2份,膨润土160-200份,粘胶纤维0.5-2份,分散剂0.2-0.8份,水280-350份。该易降解封堵剂具有封堵率高、降解速度快的优点。(The application relates to the technical field of blocking agent manufacturing, and particularly discloses an easily degradable blocking agent and a preparation method thereof, wherein the easily degradable blocking agent is mainly prepared from the following raw materials in parts by weight: 80-120 parts of polyacrylamide, 30-50 parts of acrylic acid, 15-30 parts of polysaccharide, 0.5-3 parts of alkali, 0.5-3 parts of cross-linking agent, 3-5 parts of oxidant, 1-3 parts of urea, 1-2 parts of polymerization initiator, 200 parts of bentonite 160-ion-doped material, 0.5-2 parts of viscose fiber, 0.2-0.8 part of dispersant and 350 parts of water 280-ion-doped material. The easily degradable plugging agent has the advantages of high plugging rate and high degradation speed.)

1. An easily degradable plugging agent is characterized by being mainly prepared from the following raw materials in parts by weight: 80-120 parts of polyacrylamide, 30-50 parts of acrylic acid, 15-30 parts of polysaccharide, 0.5-3 parts of alkali, 0.5-3 parts of cross-linking agent, 3-5 parts of oxidant, 1-3 parts of urea, 1-2 parts of polymerization initiator, 200 parts of bentonite 160-ion-doped material, 0.5-2 parts of viscose fiber, 0.2-0.8 part of dispersant and 350 parts of water 280-ion-doped material.

2. The degradable blocking agent of claim 1 wherein the polysaccharide is comprised of one or more of methylcellulose, ethylcellulose, and starch.

3. The degradable blocking agent of claim 1 wherein the base is sodium hydroxide.

4. The degradable sealant according to claim 1, wherein the polymerization initiator is potassium persulfate.

5. The degradable blocking agent of claim 1 wherein the crosslinking agent is N, N' -methylenebisacrylamide.

6. The easily degradable blocking agent according to claim 1, wherein said viscose fiber is ultra fine denier viscose fiber with denier less than 0.55dtex and length of 0.5-2 mm.

7. The degradable blocking agent of claim 1 wherein the dispersant is sodium methylene bis naphthalene sulfonate.

8. The degradable blocking agent of claim 1 wherein the oxidizing agent is sodium hypochlorite.

9. A method for preparing a readily degradable blocking agent according to any one of claims 1 to 8, comprising the steps of:

step 1: polysaccharide, alkali, oxidant and part of water are mixed evenly to oxidize polysaccharide completely to prepare modified material;

step 2: uniformly mixing polyacrylamide, acrylic acid, a polymerization initiator, a cross-linking agent, urea, a modified material and the rest water, adjusting the pH to 4.5-6.5, and reacting at the temperature of 45-60 ℃ for 3-5h to prepare a gel material;

and step 3: the bentonite, the dispersant, the viscose and the gel material are mixed evenly to prepare the easily degradable plugging agent.

10. The method for preparing the easily degradable plugging agent according to claim 9, wherein in step 3, the viscose fiber is subjected to electron beam irradiation treatment before being mixed, wherein the irradiation time is 5-8min, and the irradiation dose is 30-50 kGy.

Technical Field

The application relates to the technical field of blocking agent manufacturing, in particular to an easily degradable blocking agent and a preparation method thereof.

Background

The plugging agent is widely applied to the field of oil exploitation at present, and is divided into a plurality of types according to different environments of oil field application, wherein the polyacrylamide gel plugging agent has strong controllability, simple construction method and good adaptability, can enter a water outlet layer and a high permeable layer preferentially, can be suitable for low-permeability sandstone oil reservoirs, and has good plugging effect when being used for plugging water and profile control of the oil reservoirs with cracks and large water flow channels.

After the gel formed by the polyamide gel blocking agent forms physical blockage in the pores of the bottom layer, the bonding force between the gel and the inner wall of the pore channel is strong, so that the gel is difficult to degrade and block, and the subsequent operation is influenced.

In order to solve the problems, the chinese patent with application publication number CN103013052A discloses a degradable underground plugging material, which is composed of a component a and a component B, wherein: the component A comprises epoxy resin, a toughening agent, a diluent, a coupling agent and a filler; the component B comprises a curing agent and a composite accelerator; there is also a soluble or degradable substance A in the A component or a soluble or degradable substance B in the B component. The degradable underground plugging material has non-selective adhesive property and strength, can be partially dissolved automatically after being used for a certain period (18-24 months), and is beneficial to environmental protection, but the degradable underground plugging material has long degradation time when being used and can not be plugged in time.

Disclosure of Invention

In order to solve the problem that the degradable plugging material is long in degradation time, the application provides an easily degradable plugging agent and a preparation method thereof.

In a first aspect, the easily degradable plugging agent provided by the application adopts the following technical scheme:

an easily degradable plugging agent is mainly prepared from the following raw materials in parts by weight: 80-120 parts of polyacrylamide, 30-50 parts of acrylic acid, 15-30 parts of polysaccharide, 0.5-3 parts of alkali, 0.5-3 parts of cross-linking agent, 3-5 parts of oxidant, 1-3 parts of urea, 1-2 parts of polymerization initiator, 200 parts of bentonite 160-ion-doped material, 0.5-2 parts of viscose fiber, 0.2-0.8 part of dispersant and 350 parts of water 280-ion-doped material.

By adopting the technical scheme, the polysaccharide reacts with the oxidant to enhance the reaction activity of polysaccharide molecules, and then the polysaccharide molecules and polyacrylamide are subjected to graft copolymerization under the catalysis of a polymerization initiator to form a gel material with a space network structure; bentonite and viscose are added into the gel material to further perfect a space network structure, enhance the plugging performance of the gel material and effectively plug the pore channels at the bottom layer; after a short time, the polysaccharide and the viscose fiber are spontaneously degraded, so that the space network structure in the gel material is dissociated and disintegrated, and pore channels at the bottom layer are unblocked.

Preferably, the polysaccharide is composed of one or more of methylcellulose, ethylcellulose and starch.

By adopting the technical scheme, a large number of hydroxyl groups are arranged on the anhydroglucose units on the methyl cellulose, the ethyl cellulose and the starch molecules, and after being activated by an oxidant, the hydroxyl groups can perform nucleophilic reaction with active amino groups in amide groups on side chains of polyacrylamide molecules and are grafted and copolymerized to form a spatial network structure.

Preferably, the base is sodium hydroxide.

By adopting the technical scheme, the sodium hydroxide improves the reactivity of the polysaccharide, opens the macromolecular chain segment of the polysaccharide, disperses the macromolecular chain segment into single monomer molecules and increases the number of free radicals on the molecular chain of the polysaccharide.

Preferably, the polymerization initiator is potassium persulfate.

By adopting the technical scheme, the potassium persulfate can initiate the polymerization reaction of the modified material and the polyacrylamide at a lower temperature (-10-30 ℃).

Preferably, the crosslinking agent is N, N' -methylenebisacrylamide.

Through the technical scheme, N, N '-methylene bisacrylamide can perform free radical reaction with hydroxyl on polysaccharide, is crosslinked and grafted, reinforces a space network structure, hydrolyzes part of N, N' -methylene bisacrylamide into acrylic acid, increases the concentration of the acrylic acid in a system, improves the matching property of the acrylic acid and polyacrylamide, enables the reaction to proceed in the positive direction, and increases the reactivity of the polyacrylamide.

Preferably, the viscose fiber is superfine denier viscose fiber, the denier is less than 0.55dtex, and the length is 0.5-2 mm.

By adopting the technical scheme, the superfine denier viscose fiber has the advantages of fine fiber diameter and good dispersibility, and the superfine denier viscose fiber with the length of 0.5-2mm is not easy to agglomerate in a gel material and can be dispersed more uniformly.

Preferably, the dispersant is sodium methylene dinaphthalene sulfonate.

By adopting the technical scheme, the methylene dinaphthalene sodium sulfonate has excellent diffusibility and the effect of maintaining the stability of a gel system, and has better affinity to the polyamide copolymer.

Preferably, the oxidant is sodium hypochlorite.

By adopting the technical scheme, the sodium hypochlorite can oxidize C6 hydroxyl on the anhydroglucose ring of the polysaccharide into aldehyde group or carboxyl more easily, so that the anhydroglucose ring is opened, and the polymerization reaction speed is increased.

In a second aspect, the preparation method of the easily degradable plugging agent provided by the application adopts the following technical scheme:

the preparation method of the easily degradable plugging agent comprises the following steps:

step 1: polysaccharide, alkali, oxidant and part of water are mixed evenly and the polysaccharide is oxidized completely to prepare modified material;

and step 3: the bentonite, the dispersant, the viscose and the gel material are uniformly mixed to prepare the easily degradable plugging agent.

By adopting the technical scheme, the oxidant, the polyacrylamide, the acrylic acid, the polymerization initiator and the cross-linking agent are separately mixed, so that the oxidant is prevented from influencing the cross-linking reaction of the gel material, and the influence of alkali on the pH value range of the cross-linking reaction is also avoided; the viscose fiber is easy to degrade under the acidic condition, and the degradation speed of the plugging agent is accelerated.

Preferably, in step 3, the viscose fibers are degraded by electron beam radiation before being mixed, the irradiation time is 5-8min, and the irradiation dose is 30-50 kGy.

By adopting the technical scheme, the crystallization area of the viscose fiber degraded by electron beam radiation is damaged, the water absorption of the viscose fiber is increased, and the degradation speed is higher.

In summary, the present application has the following beneficial effects:

1. because the gel material with the space network structure is formed by graft copolymerization of the modified material and the polyacrylamide, the gel material has good plugging effect and short-time degradation and plugging removal effect; viscose and bentonite are added into the gel material, and the bentonite has good thickening property and suspension stability and can improve the stability of the gel material; the viscose fiber plays a role of a bridge frame, further strengthens the space net structure of the gel material and enhances the blocking effect of the easily degradable blocking agent;

2. viscose fiber in this application degrades through electron beam irradiation, reduces the occupation of area ratio in viscose fiber crystallization district, and increase viscose fiber's hydroscopicity makes viscose fiber's dispersion degree in gel material higher to it is faster to make viscose fiber degradation speed, and then has improved the unblock speed of easy degradation plugging agent.

Detailed Description

The present application will be described in further detail with reference to examples.

The polysaccharide in the application is composed of one or more of methyl cellulose, ethyl cellulose and starch, preferably methyl cellulose; in the application, the viscose fiber is degraded by electron beam radiation, the irradiation time is 5-8min, the irradiation dose is 30-50kGy, the preferable irradiation time is 6min, and the irradiation dose is 40 kGy.

The molecular weight of the polyacrylamide in the application is 800-1600 ten thousand, and the molecular weight of the polyacrylamide in the embodiment is preferably 1000 ten thousand.

In the examples of the present application, each portion was 1 kg.

The bentonite in the application is sodium bentonite, the swelling index is 15, the water absorption is 200-400% (2h), and the water absorption is preferably 300%.

In the preparation method of the easily degradable plugging agent, the polysaccharide, the alkali, the oxidant and part of water are uniformly mixed, namely the polysaccharide, the alkali and the part of water are mixed and stirred for 10-30min, the stirring speed is 800rpm, and the preferred stirring time is 15 min; then adding an oxidant and oxidizing for 20min under continuous stirring to prepare the modified material, wherein the stirring speed is 1000 rpm.

The preparation method of the easily degradable plugging agent comprises the steps of mixing polyacrylamide, acrylic acid, a polymerization initiator, a cross-linking agent, urea, a modification material and residual water uniformly, stirring the polyacrylamide, the acrylic acid, the polymerization initiator, the cross-linking agent, the modification material and the residual water for 20min at the stirring speed of 1000rpm, adding the urea and then mixing for 5-15min, wherein the step of adding the urea and then mixing for 5-15min is to add the urea and then stir for 5-10min at the stirring speed of 600rpm, and preferably to stir for 8 min.

In the preparation method of the easily degradable plugging agent, polyacrylamide, acrylic acid, potassium persulfate, N' -methylene bisacrylamide, urea, a modified material and the residual water are uniformly mixed, and then the pH is adjusted to 4.5-6.5, namely the pH is adjusted to 5, and hydrochloric acid is preferably adopted to adjust the pH in the preparation method.

In the preparation method of the easily degradable plugging agent, the bentonite, the sodium methylene dinaphthalene sulfonate, the viscose and the gel material are uniformly mixed, namely the bentonite, the sodium methylene dinaphthalene sulfonate, the viscose and the gel material are mixed and stirred for 5-8min, the stirring speed is 1200rpm, and the preferred stirring time is 6 mm.

Example 1

The easily degradable plugging agent is mainly prepared from the following raw materials in parts by weight: 80 parts of polyacrylamide, 30 parts of acrylic acid, 15 parts of polysaccharide, 0.5 part of alkali, 0.5 part of a cross-linking agent, 3 parts of an oxidant, 2 parts of urea, 300 parts of water, 1.5 parts of a polymerization initiator, 180 parts of bentonite, 0.5 part of viscose and 0.2 part of a dispersing agent; the cross-linking agent is N, N' -methylene bisacrylamide; the viscose fiber is superfine denier viscose fiber, the denier is 0.2dtex, and the length is 1 mm; the dispersant is sodium methylene dinaphthalene sulfonate; the oxidant is sodium hypochlorite, and the polymerization initiator is potassium persulfate; the alkali is sodium hydroxide; the polysaccharide is methylcellulose.

The preparation method of the easily degradable plugging agent comprises the following steps:

step 1: mixing methylcellulose and sodium hydroxide, stirring with part of water for 15min at the stirring speed of 800rpm, adding an oxidant, and oxidizing for 20min under continuous stirring to obtain a modified material at the stirring speed of 1000 rpm;

step 2: mixing and stirring polyacrylamide, acrylic acid, potassium persulfate, N' -methylene bisacrylamide, a modified material and the residual water for 20min at the stirring speed of 1000rpm, then adding urea, mixing and stirring for 8min at the rotation speed of 600rpm, then adjusting the pH value to 5, and reacting at the temperature of 50 ℃ for 4h to obtain a gel material;

and step 3: performing electron beam radiation degradation on the superfine denier viscose fibers, wherein the irradiation time is 6min, and the irradiation dose is 40 kGy;

and 4, step 4: mixing and stirring bentonite, sodium methylene dinaphthalene sulfonate, superfine denier viscose fiber and the gel material for 6min at the stirring speed of 1200rpm to prepare the easily degradable plugging agent.

Example 2

The easily degradable plugging agent is mainly prepared from the following raw materials in parts by weight: 80 parts of polyacrylamide, 30 parts of acrylic acid, 15 parts of polysaccharide, 0.5 part of alkali, 0.5 part of a cross-linking agent, 3 parts of an oxidant, 2 parts of urea, 300 parts of water, 1.5 parts of a polymerization initiator, 180 parts of bentonite, 1.5 parts of viscose and 0.8 part of a dispersing agent; the cross-linking agent is N, N' -methylene bisacrylamide; the viscose fiber is superfine denier viscose fiber, the denier is 0.2dtex, and the length is 1 mm; the dispersant is sodium methylene dinaphthalene sulfonate; the oxidant is sodium hypochlorite, and the polymerization initiator is potassium persulfate; the alkali is sodium hydroxide; the polysaccharide is methylcellulose.

The preparation method of the easily degradable plugging agent comprises the following steps:

step 1: mixing and stirring methyl cellulose, part of water and sodium hydroxide for 15min at the stirring speed of 800rpm, adding an oxidant, and oxidizing for 20min under continuous stirring to obtain a modified material, wherein the stirring speed is 1000 rpm;

step 2: mixing and stirring polyacrylamide, acrylic acid, potassium persulfate, N' -methylene bisacrylamide, residual water and a modification material for 20min at the stirring speed of 1000rpm, then adding urea, mixing and stirring for 8min at the rotation speed of 600rpm, then adjusting the pH value to 5, and reacting at the temperature of 50 ℃ for 4h to obtain a gel material;

and step 3: performing electron beam radiation degradation on the superfine denier viscose fibers, wherein the irradiation time is 6min, and the irradiation dose is 40 kGy;

and 4, step 4: mixing and stirring bentonite, sodium methylene dinaphthalene sulfonate, superfine denier viscose fiber and the gel material for 6min, wherein the stirring speed is 1200 rpm.

Example 3

The easily degradable plugging agent is mainly prepared from the following raw materials in parts by weight: 80 parts of polyacrylamide, 30 parts of acrylic acid, 15 parts of polysaccharide, 0.5 part of alkali, 0.5 part of cross-linking agent, 3 parts of oxidant, 3 parts of urea, 300 parts of water, 1.5 parts of polymerization initiator and 200 parts of bentonite; 2 parts of viscose and 0.8 part of dispersant; the cross-linking agent is N, N' -methylene bisacrylamide; the viscose fiber is superfine denier viscose fiber, the denier is 0.2dtex, and the length is 1 mm; the dispersant is sodium methylene dinaphthalene sulfonate; the oxidant is sodium hypochlorite, and the polymerization initiator is potassium persulfate; the alkali is sodium hydroxide; the polysaccharide is methylcellulose.

The preparation method of the easily degradable plugging agent comprises the following steps:

and step 3: performing electron beam radiation degradation on the superfine denier viscose fibers, wherein the irradiation time is 6min, and the irradiation dose is 40 kGy;

and 4, step 4: mixing and stirring bentonite, sodium methylene dinaphthalene sulfonate, superfine denier viscose fiber and the gel material for 6min, wherein the stirring speed is 1200 rpm.

Example 4

The easily degradable plugging agent is mainly prepared from the following raw materials in parts by weight: 100 parts of polyacrylamide, 50 parts of acrylic acid, 20 parts of polysaccharide, 2 parts of alkali, 1 part of a cross-linking agent, 5 parts of an oxidant, 2 parts of urea, 300 parts of water, 1.5 parts of a polymerization initiator, 200 parts of bentonite, 1.5 parts of viscose and 0.2 part of a dispersing agent; the cross-linking agent is N, N' -methylene bisacrylamide; the viscose fiber is superfine denier viscose fiber, the denier is 0.2dtex, and the length is 1 mm; the dispersant is sodium methylene dinaphthalene sulfonate; the oxidant is sodium hypochlorite, and the polymerization initiator is potassium persulfate; the alkali is sodium hydroxide; the polysaccharide is methylcellulose.