CN112011321A

CN112011321A - Self-adaptive deformation composite temporary plugging agent and preparation method thereof

Info

Publication number: CN112011321A
Application number: CN202010883928.4A
Authority: CN
Inventors: 黄维捷; 计扬; 毛彦鹏
Original assignee: Pujing Chemical Industry SHA Co Ltd
Current assignee: Hainan Pujing Environmental Protection Technology Co ltd
Priority date: 2020-08-28
Filing date: 2020-08-28
Publication date: 2020-12-01

Abstract

The invention relates to a self-adaptive deformation composite temporary plugging agent and a preparation method thereof, wherein the self-adaptive deformation composite temporary plugging agent comprises a flexible container and a temporary plugging agent filled in the flexible container, the flexible container is prepared from a material containing water-soluble resin or/and degradable resin, and the temporary plugging agent is prepared from a material containing degradable resin or/and water-soluble tree. Compared with the prior art, the composite temporary plugging agent has good flexibility, can generate self-adaptive deformation to a certain degree under the action of the ground pressure so as to generate deformation matched with the cross section of a target crack, and is favorable for quickly stacking and bridging a plugging belt with a stable pressure-bearing effect at the target crack.

Description

Self-adaptive deformation composite temporary plugging agent and preparation method thereof

Technical Field

The invention relates to a temporary plugging agent, in particular to a self-adaptive deformation composite temporary plugging agent and a preparation method thereof.

Background

At present, in the process of exploiting oil and gas fields, temporary blocking diversion fracturing construction is generally needed to improve the permeability of underground reservoirs so as to connect oil and gas reservoirs of low permeability areas. The temporary blocking and steering fracturing construction is that according to the heterogeneity of the plane and the longitudinal direction of a reservoir stratum and the difference of the mining degrees of different areas and layers, temporary blocking materials are added in real time during the fracturing construction, old cracks or sand cracks are temporarily blocked, and the fluid is steered through the change of fracture pressure and fracture extension pressure to form new artificial cracks (hereinafter referred to as new cracks) so as to open new oil and gas seepage channels, so that the reservoir stratum with low mining degree and even un-mining degree is dug to the greatest extent, and the purpose of increasing the production is achieved.

The existing temporary plugging agent is mostly in a granular shape, a fibrous shape or a combination of the granular shape and the fibrous shape, has higher rigidity, and is usually directly mixed with a carrier fluid and then pumped into a stratum when in use. However, in the actual pumping process, the temporary plugging agent in the carrier fluid mostly shows a dispersed and disordered state, and in addition, the self rigidity is high and the fluid is continuously disturbed, so that the temporary plugging agent is difficult to effectively accumulate and bridge in the corresponding crack in a short time to form a plugging belt with a stable pressure-bearing effect. This directly affects the construction effect of temporary plugging diversion fracturing.

Disclosure of Invention

The invention aims to solve the problems and provide a self-adaptive deformation composite temporary plugging agent and a preparation method thereof, so as to solve the problem that the conventional temporary plugging agent is difficult to effectively accumulate and bridge in corresponding cracks in a short time to form a plugging belt with a stable pressure-bearing effect.

The purpose of the invention is realized by the following technical scheme:

according to a first aspect of the present invention, there is provided an adaptive deformation composite temporary plugging agent, comprising a flexible container and a temporary plugging agent filled in the flexible container.

As one embodiment, the flexible container is made from a material comprising a water-soluble resin or/and a degradable resin.

As a preferred embodiment, for the flexible container, the water-soluble resin may be selected from polyvinyl alcohol-based polymers.

In a more preferred embodiment, the vinyl ester used in the production of the polyvinyl alcohol resin may be vinyl acetate or other vinyl esters of fatty acids (e.g., vinyl propionate, vinyl valerate, etc.) with respect to the polyvinyl alcohol polymer.

Further, the polyvinyl alcohol resin can be produced by copolymerizing the vinyl ester with other comonomers (for example, one or more of ethylene, propylene, butene, isobutylene, 4-methyl-1-pentene, 1-hexene, 1-octene and other α -olefins, (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate and other unsaturated carboxylic acids or esters thereof, vinyl trimethoxysilane and other vinyl silane compounds, unsaturated sulfonic acid or salts thereof, alkyl thiol compounds, N-vinyl pyrrolidone and other vinyl pyrrolidones) and hydrolyzing the ester group without impairing the object of the present invention.

As a further preferred embodiment, the water-soluble resin is selected from polyvinyl alcohols having an alcoholysis degree of 86 to 89%.

As a preferred embodiment, for the flexible container, the degradable resin may be selected from polybutylene succinate (PBS for short), polybutylene adipate-terephthalate (PBAT for short), polybutylene succinate-terephthalate (PBST for short), or polybutylene succinate-adipate (PBSA for short).

As a preferred embodiment, in the raw materials for preparing the flexible container, the mass content of the water-soluble resin and/or the degradable resin is 60-90%, and the balance is the processing aid I.

For example, in the raw materials for producing the flexible container, the water-soluble resin and/or the degradable resin is contained in an amount of 60 to 90% by mass, and the balance is the plasticizer.

For example, in the raw materials for preparing the flexible container, the mass content of the water-soluble resin and/or the degradable resin is 60-80%, the mass content of the plasticizer is 15-35%, and the balance is the toughening agent.

For example, in the raw materials for producing the flexible container, the mass content of the water-soluble resin and/or the degradable resin is 60 to 80%, the mass content of the plasticizer is 15 to 35%, and the balance is the filler.

For example, in the raw materials for preparing the flexible container, the mass content of the water-soluble resin and/or the degradable resin is 60-80%, the mass content of the plasticizer is 10-20%, the mass content of the toughening agent is 5-10%, and the balance is filler.

As a preferred embodiment, the processing aid I comprises at least one of a plasticizer, a toughening agent or a filler.

As a further preferred embodiment, the plasticizer may be selected from at least one of glycerol, glycerol trioleate, sorbitol, propylene glycol or 2-methyl-1, 3-propanediol.

As a further preferred embodiment, in case that the flexible container is mainly made of water-soluble resin, the toughening agent may be selected from one or more of polybutylene succinate, polybutylene terephthalate-adipate-butylene glycol, polybutylene succinate-adipate-butylene glycol, or polymethylethylene carbonate, etc.

As a further preferred embodiment, the filler may be selected from talc or mica powder.

As a preferred embodiment, the wall thickness of the flexible container may be 10-100 μm.

As a further preferred embodiment, the flexible container may be a flexible pouch, or other flexible body having a hollow cavity.

As one embodiment, the temporary blocking agent is prepared from a material comprising a degradable resin or/and a water-soluble resin.

It should be noted here that the temporary plugging agent may comprise one or more of the following temporary plugging agents:

the temporary plugging agent mainly comprises a temporary plugging agent made of degradable resin, a temporary plugging agent made of water-soluble resin and a temporary plugging agent made of degradable resin and water-soluble resin.

As a preferred embodiment, the temporary blocking agent comprises degradable elastic temporary blocking pellets.

In a more preferred embodiment, the degradable elastic temporary plugging granule is mainly prepared by taking a polymer containing glycolic acid repeating units and a thermoplastic elastomer as matrix materials and adding a processing aid.

As a more preferred embodiment, the mass ratio of the polymer comprising glycolic acid repeating units to the thermoplastic elastomer is from 1 to 100:10, preferably from 30 to 100: 10.

Further, the polymer comprising glycolic acid repeat units may be selected from glycolic acid homopolymers and/or glycolic acid copolymers.

As a further preferred embodiment, the glycolic acid homopolymer may be selected to have a relative molecular mass of between about 1 and 100 million, preferably between about 5 and 60 million, more preferably between about 10 and 20 million.

In a more preferred embodiment, the glycolic acid copolymer has a proportion of glycolic acid repeating units of 70 wt% or more.

In a more preferred embodiment, the glycolic acid copolymer contains at least one of a hydroxycarboxylic acid unit, a lactone unit, a carbonate unit, and an amide unit in addition to the glycolic acid repeating unit.

As a further preferred embodiment, the other hydroxycarboxylic acid unit may be selected from at least one of a lactic acid unit, a 3-hydroxypropionic acid unit, a 3-hydroxybutyric acid unit, a 4-hydroxybutyric acid unit, or a 6-hydroxyhexanoic acid unit; the lactone units can be selected from at least one of beta-propiolactone units, beta-butyrolactone units, gamma-butyrolactone units or-caprolactone units; the carbonate units are selected from trimethylene carbonate units; the amide unit is selected from at least one of a caprolactam unit or a gamma-butyrolactam unit.

As a further preferred embodiment, the glycolic acid copolymer may be selected to have a relative molecular mass of about 1 to 50 tens of thousands, preferably about 2 to 20 tens of thousands, more preferably about 8 to 15 tens of thousands.

In a preferred embodiment, both of the glycolic acid homopolymer and the glycolic acid copolymer are polymers capped with a capping agent.

Specifically, the capping with the capping agent means that glycolic acid or glycolic acid and other monomers containing hydrolyzable chemical bonds are capped by adding the capping agent at the devolatilization stage at the end of the polymerization reaction.

As a preferred embodiment, the temperature of the devolatilization stage is controlled to be 210-230 ℃, the pressure is controlled to be 500-2000Pa, and the devolatilization time is 10-30 minutes. The thermal degradation of the glycolic acid polymer component in the melt blending stage can be effectively reduced by adopting the glycolic acid polymer subjected to end capping treatment.

The other monomer having a hydrolyzable chemical bond may be selected from at least one of other hydroxycarboxylic acid monomers other than glycolic acid, lactone monomers, carbonate monomers, or amide monomers.

Preferably, the hydroxycarboxylic acid monomer other than glycolic acid is selected from at least one of lactic acid, 3-hydroxypropionic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid or 6-hydroxyhexanoic acid, the lactone monomer is selected from at least one of beta-propiolactone, beta-butyrolactone, gamma-butyrolactone or-caprolactone, the carbonate monomer is selected from trimethylene carbonate, and the amide monomer is selected from at least one of-caprolactam or gamma-butyrolactam.

As a further preferred embodiment, the end-capping agent is added in an amount of 0.1 to 2 wt% based on the theoretical mass of the resulting polymer calculated on the mass of glycolic acid monomer.

The end-capping agent is selected from monomers containing a terminal hydroxyl group, a terminal amine group or a terminal carboxyl group, and may be selected from at least one of ethylene glycol, oxalic acid, carbodiimide, terephthalic acid or benzoic acid, for example.

As a preferred embodiment, the thermoplastic elastomer may be selected from one or two or more of the following: thermoplastic polyester elastomers, thermoplastic polyurethane elastomers, thermoplastic polyamide elastomers.

Further, the thermoplastic polyester elastomer may be selected from an aromatic polyester-aliphatic polyester block copolymer or an aromatic polyester-aliphatic polyether block copolymer.

Still further, the thermoplastic polyester elastomer may be selected from commercially available ones

P30B or P40B.

Further, the thermoplastic polyurethane elastomer is a block copolymer obtained by condensing an isocyanate-based compound and a compound having a hydroxyl group, and may be selected from at least one of a polyether-based thermoplastic polyurethane elastomer or a polyester-based thermoplastic polyurethane elastomer.

Still further, the thermoplastic polyurethane elastomer may be selected from commercially available ones

DP1085A or DP 1485A.

Further, the thermoplastic polyamide elastomer is a block copolymer of a hard segment composed of polyamide and a soft segment composed of polyether and/or polyester, and the hard segment may be selected from, for example, aliphatic polyamide, specifically, nylon 6, nylon 11, and nylon 12, and the soft segment may be selected from, for example, polyether such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol.

Still further, the thermoplastic polyamide elastomer may be selected from commercially available TPAE-10 or TPAE-12.

As a preferred embodiment, the matrix material of the degradable elastic temporary plugging granule can also comprise a water-soluble polymer, and preferably, the water-soluble polymer can be selected from polyvinyl alcohol with alcoholysis degree of 87-89%.

Further, in the matrix material, the mass ratio of the thermoplastic elastomer to the water-soluble polymer is 1-10:1, preferably 4-10:1, and more preferably 8-10: 1.

As a preferred embodiment, the matrix material of the degradable elastic temporary plugging granule further comprises functionalized graphene modified polymer containing glycolic acid repeating units.

Further, the molecular weight of the functionalized graphene modified polymer containing glycolic acid repeating units is not greater than the molecular weight of the unmodified polymer containing glycolic acid repeating units in the matrix material.

Furthermore, the mass ratio of the polymer containing the glycolic acid repeating unit to the functionalized graphene modified polymer containing the glycolic acid repeating unit in the matrix material is 5-10: 1.

Further, in the functionalized graphene modified glycolic acid repeating unit-containing polymer, the amount of the functionalized graphene used is 0.1 to 5 wt% of the theoretical mass of the glycolic acid polymer obtained by calculating the mass of the glycolic acid monomer.

As an embodiment, the functionalized graphene modified polymer containing glycolic acid repeating units is prepared by grafting functionalized graphene to a polymer containing glycolic acid repeating units through a chemical reaction; or

② the functional graphene is directly physically blended with polymers containing glycolic acid repeating units to prepare the functional graphene.

Further, the functionalized graphene is obtained by modifying the surface of graphene with a functional modifier (e.g., an organic amine modifier including an alicyclic amine, such as, but not limited to, one of triethylenetetramine, triethylenediamine, or hexamethylenetetramine).

According to the invention, the functional modifier is adopted to modify the surface of the graphene so as to prepare the functionalized graphene, and the preparation process can be as follows: firstly, preparing graphene oxide by using a Hummers method, then modifying the surface of the graphene oxide by using a functional modifier to prepare functionalized graphene oxide, and finally reducing the functionalized graphene oxide to obtain the functionalized graphene.

Specific processes for preparing functionalized graphene will be illustrated in the detailed description.

The method of the invention can be realized by the following steps, taking the preparation of functionalized graphene modified glycolic acid homopolymer as an example:

step 1): ultrasonically dispersing functionalized graphene in silicone oil, and preparing a silicone oil suspension of the functionalized graphene with the mass fraction of 10-30%;

step 2): adding a silicone oil solution containing a dispersing agent into a stirring reactor, then adding a glycolic acid monomer and a catalyst, starting reaction at the temperature of 135-145 ℃, then carrying out gradient temperature rise (for example, the temperature rise rate can be controlled to be 1-5 ℃/min, the temperature is controlled to rise by 20 ℃ every time, and the constant temperature reaction lasts for 1-2 hours) to 195-205 ℃, then sequentially adding an antioxidant and the functionalized graphene silicone oil suspension prepared in the step 1), then carrying out gradient temperature rise (for example, the temperature rise rate can be controlled to be 1-2 ℃/min, the temperature rises by 5 ℃ every time, and the constant temperature reaction lasts for 1-2 hours) to 230 ℃, and carrying out decompression continuous reaction to remove small molecular substances;

step 3): and after the reaction is finished, controlling the absolute pressure in the stirring reactor to be less than 1kPa, maintaining the temperature of the stirring reactor at 220 ℃ for 1 hour, then discharging, soaking the obtained material with petroleum ether for multiple times to remove silicone oil on the surface, and then drying in vacuum to obtain the functionalized graphene modified glycolic acid homopolymer.

Wherein, the dosage relationship of the glycolic acid monomer and the silicone oil solution in the step 2) is as follows: 1g of glycolic acid monomer per 10-20ml of silicone oil solution; the mass fraction of the dispersing agent in the silicone oil solution is 0.1-1%, the dosage of the catalyst is 0.01-0.2% of the mass of the glycolic acid monomer, and the dosage of the antioxidant is 0.1-2% of the mass of the glycolic acid monomer.

The amount of functionalized graphene used in step 2) is from 0.1 to 5% by weight, based on the mass of glycolic acid monomer, of the theoretical mass of glycolic acid homopolymer obtained.

The silicone oil used in the above step may be commercially available methyl silicone oil; the dispersants used may be commercially available fatty alcohol-polyoxyethylene ethers, for example MOA-3 or MOA-7; the catalyst used may be a metal alkoxide, such as stannous octoate; the antioxidant employed may be a commercially available antioxidant 1076, namely n-octadecyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate.

In the step 2), preferably, glycolic acid monomer is subjected to polymerization reaction under the action of a catalyst, the polymerization reaction is carried out for 2 hours at 140 ℃, the temperature is raised to 160 ℃ for reaction for 2 hours, then the temperature is raised to 180 ℃ for reaction for 2 hours, and the temperature is raised to 200 ℃ for reaction for 1 hour;

after the functionalized graphene silicon oil suspension is added, firstly heating to 210 ℃, reducing the pressure to the gauge pressure of-50 kPa, reacting for 1 hour, then heating to 215 ℃, reducing the pressure to the gauge pressure of-90 kPa, reacting for 1 hour, then heating to 220 ℃, reducing the pressure to the gauge pressure of-101 kPa, and reacting for 1 hour to fully remove the small molecular substances.

In the glycolic acid homopolymer modified by the functionalized graphene prepared by the method of the first step, the glycolic acid homopolymer is a low molecular weight glycolic acid homopolymer, and the relative molecular mass of the glycolic acid homopolymer is not more than 10 ten thousand.

It is noted herein that the relative molecular mass of the glycolic acid polymers of the present invention can be measured by the following method: glycolic acid polymer was dissolved in hexafluoroisopropanol and formulated into a five parts per million solution for measurement using gel permeation chromatography.

For the method of (c), taking the preparation of functionalized graphene modified glycolic acid homopolymer as an example, the functionalized graphene and the glycolic acid homopolymer can be directly physically blended by using a conventional mixer, wherein the charging amount of the functionalized graphene is 0.1-5 wt% of the mass of the glycolic acid homopolymer.

In the above method, the present invention has no special limitation on the blending parameters (e.g., time, temperature, stirring speed, etc.), and the blending technical scheme known to those skilled in the art can be adopted. Meanwhile, the specification and parameters of the mixer are not particularly limited, and the technical scheme known by the technical personnel in the field when the mixer is used for mixing can be adopted.

It should be noted that, for the preparation of the functionalized graphene-modified glycolic acid copolymer, reference may be made to the above-mentioned method, and details are not described herein again.

As a preferred embodiment, the processing aid in the degradable elastomeric temporary blocking pellet may include at least one of an antioxidant, a metal deactivator, a compatibilizer, a plasticizer, a hydrolysis regulator, or a heat stabilizer.

Further, according to the mass of the matrix material in the degradable elastic temporary plugging granule, the addition amount of the antioxidant is 0.5-1.8 wt%, the addition amount of the metal deactivator is 0.05-0.2 wt%, the addition amount of the compatilizer is 0.2-1.0 wt%, the addition amount of the plasticizer is 0.8-2.0 wt%, the addition amount of the hydrolysis regulator is 0.2-0.8 wt%, and the addition amount of the heat stabilizer is 0.6-1.4 wt%.

Still further, the antioxidant may be selected from antioxidants containing a pentaerythritol skeleton, for example, pentaerythritol diisodecyl diphosphite, pentaerythritol phosphate, and the like; the metal deactivator may be selected from commercially available metal deactivators

One or both of MD-1024 or Chel-180 (i.e., N-salicylidene-N-salicyloyl hydrazide); the compatilizer is at least one selected from polymethyl methacrylate peroxide, acrylic acid-acrylamide copolymer or styrene-acrylamide copolymer; the plasticizer is selected from at least one of epoxidized soybean oil or acetyl tributyl citrate; the heat stabilizer is selected from one of calcium stearate soap, calcium oleate soap, brown calcium oleate soap or calcium linoleate soap; the hydrolysis regulator can be selected from one or two of hydrolysis regulation accelerant or hydrolysis regulation inhibitor, wherein the hydrolysis regulation accelerant can be selected from dimethyl oxalate or diethyl oxalate, and the hydrolysis regulation inhibitor can be selected from carbodiimide.

In one embodiment, the temporary plugging agent is formed by mixing temporary plugging granules with different particle size distributions.

According to a second aspect of the present invention, there is provided a method for preparing the adaptive deformation composite temporary plugging agent, comprising the following steps:

step 1): forming a material comprising a water-soluble resin by extrusion blown film, cutting to obtain a film having a suitable shape, and then forming the film or films into a flexible container having a filling opening by crimping, folding, abutting, splicing, or a combination thereof;

step 2): and filling the temporary plugging agent into the flexible container through the filling port, and then carrying out hot-press bonding on the filling port.

The film or films in the films in step 1) may be a single layer film or a multi-layer film bonded by heat and pressure.

Preferably, when the temporary plugging agent is/comprises degradable elastic temporary plugging granules, the temporary plugging agent can be prepared by adopting the following method for the degradable elastic temporary plugging granules:

drying the matrix material at 110 ℃ under 100-.

In order to obtain more excellent plugging effect, degradable elastic temporary plugging granules with different particle sizes can be obtained according to the method, and then the degradable elastic temporary plugging granules with different particle sizes are uniformly mixed according to a certain proportion, so that the degradable elastic temporary plugging granules with proper particle size distribution can be obtained.

In addition, the bulk volume of the degradable elastic temporary plugging granule material can account for 60-95% of the volume of the flexible container (e.g., flexible bag), which can effectively prevent the problem that the flexible container (e.g., flexible bag) is easily broken under the stress caused by over-filling, and certainly, if the volume filling rate of the flexible container (e.g., flexible bag) is too low (e.g., less than 60%), the flexible container (e.g., flexible bag) contains more air, which makes the composite temporary plugging agent have higher buoyancy in the carrier fluid, which is not favorable for fast stacking of the composite temporary plugging agent on one hand, and also easily causes the breakage of the flexible container (e.g., flexible bag) on the other hand.

In practical application, the overall density of the composite temporary plugging agent can be properly changed by adjusting the volume filling rate of a flexible container (such as a flexible bag), so that the composite temporary plugging agent with better floatability can be obtained, and the technical problems that the existing temporary plugging agent is easy to settle due to higher density and is not beneficial to pumping can be effectively solved.

Compared with the prior art, the invention has the following beneficial effects:

1. the self-adaptive deformation composite temporary plugging agent is conveyed to a stratum target area along with downhole fluid, at a target crack (especially a crack with an irregular shape), under the action of stratum pressure and carrier fluid, a flexible container (such as a flexible bag) filled with degradable elastic temporary plugging granules can be subjected to self-adaptive deformation to generate deformation matched with the cross section of the target crack, and the flexible container is taken as a unit, so that plugging belts with stable pressure bearing effect are rapidly stacked and bridged at the target crack in sequence.

2. In the composite temporary plugging agent, the degradable elastic temporary plugging granules in the flexible container (such as a flexible bag) can play a role of elastic support, the flexible container (such as the flexible bag) can be dissolved/degraded before the degradable elastic temporary plugging granules along with the temporary plugging and fracturing construction, a substance with certain viscosity is formed, the substance with certain viscosity can interact with the degradable elastic temporary plugging granules to jointly maintain the pressure bearing stability of the plugging belt under the action of the stratum pressure, and the degradable elastic temporary plugging granules can be basically and completely degraded/dissolved when the intermediate and later stages of the temporary plugging and fracturing construction are reached, and can be discharged out of the stratum along with the flowback fluid.

3. The functional graphene modified glycollic acid polymer can be introduced into a material system of the degradable elastic temporary plugging granule in the composite temporary plugging agent, and a polymer continuous phase in the functional graphene modified glycollic acid polymer can play a role of a compatilizer, so that the functional graphene can be uniformly dispersed in the material of the degradable elastic temporary plugging granule, and the phenomena that the functional graphene is poor in dispersion uniformity in the material of the degradable elastic temporary plugging granule and has adverse effects on the mechanical property and the thermal stability of the material due to the agglomeration of the functional graphene can be effectively prevented.

4. The material system of the degradable elastic temporary plugging granules in the composite temporary plugging agent adopts the glycolic acid polymer subjected to end capping treatment, so that the thermal degradation of the glycolic acid polymer component in the melt blending stage can be effectively reduced.

Drawings

FIG. 1 is a schematic diagram of an adaptive deformable degradable composite temporary plugging agent of the present invention;

FIG. 2 is a schematic view of another adaptively deformable degradable composite temporary plugging agent of the present invention;

FIG. 3 is a schematic structural view of a hard glass tube and a pressure water bath used in the degradation test of the present invention.

Detailed Description

The inventor of the present invention has conducted extensive and intensive studies and found that a temporary plugging agent (e.g., a plurality of degradable elastic temporary plugging granules) is wrapped by a flexible container (e.g., in the form of a flexible bag) to form a flexible container filled with the temporary plugging agent therein, and in the process of applying the flexible container to a downhole temporary plugging fracturing construction, the adaptive deformation composite temporary plugging agent is conveyed with a downhole fluid to a formation target area, and at a target fracture (particularly, a fracture with an irregular shape), under the action of the formation pressure and the downhole fluid, the flexible container (e.g., the flexible bag) filled with the temporary plugging agent can be adaptively deformed to generate a deformation adapted to the cross section of the target fracture, and a plugging strip with stable pressure-bearing effect is rapidly stacked and bridged at the target fracture in sequence by taking the flexible container as a unit; in the process, the degradable elastic temporary plugging aggregate in the flexible container (for example, the flexible bag) can play a role of elastic support, along with the proceeding of temporary plugging fracturing construction, the flexible container (for example, the flexible bag) can be dissolved/degraded before the degradable elastic temporary plugging aggregate, and a substance with certain viscosity is formed, under the action of the stratum pressure, the substance with certain viscosity can mutually act with the degradable elastic temporary plugging aggregate to jointly maintain the pressure bearing stability of the plugging belt, and when the intermediate and later stages of temporary plugging fracturing construction are reached, the degradable elastic temporary plugging aggregate can be basically and completely degraded/dissolved, and can be discharged out of the stratum along with the return discharge liquid.

On the basis of this, the present invention has been completed.

The features mentioned above, or those of the embodiments, may be combined in any combination. All features disclosed in this specification may be combined in any combination, provided that there is no conflict between such features and the combination, and all possible combinations are to be considered within the scope of the present specification. Each feature disclosed in this specification may be replaced by an alternative feature serving the same, equivalent, or similar purpose. Thus, unless expressly stated otherwise, the features disclosed are merely generic examples of equivalent or similar features.

In this context, it should be understood that where an equivalent concentration range is listed or described as being available, it is intended that any and every concentration (including the endpoints) within that range be considered to have been stated. For example, "a range of from 1 to 10" should be understood to mean every and every possible number in succession between about 1 and about 10. Thus, even if specific data points within the range, or even no data points within the range, are explicitly identified or refer to only a few specific points, it is to be understood that any and all data points within the range are to be considered explicitly stated.

Although numerical ranges and parameters setting forth the broad scope of the invention are approximate, the values set forth in the specific examples are presented as precisely as possible. Any numerical value, however, inherently contains certain standard deviations found in their respective testing measurements. As used herein, "about" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a particular value or range. Alternatively, the term "about" means that the actual value falls within the acceptable standard error of the mean, as considered by those skilled in the art. Except in the experimental examples, or where otherwise expressly indicated, it is to be understood that all ranges, amounts, values and percentages herein used (e.g., to describe amounts of materials, length of time, temperature, operating conditions, quantitative ratios, and the like) are to be modified by the word "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained. At the very least, these numerical parameters are to be understood as meaning the number of significant digits recited and the number resulting from applying ordinary carry notation.

Unless defined otherwise herein, the scientific and technical terms used herein have the same meaning as is commonly understood and used by one of ordinary skill in the art. Furthermore, as used herein, the singular tense of a noun, unless otherwise conflicting with context, encompasses the plural form of that noun; the use of plural nouns also covers the singular form of such nouns.

To make the features and effects of the present invention comprehensible to those skilled in the art, general description and definitions are made below with reference to terms and expressions mentioned in the specification and claims. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

The theory or mechanism described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, i.e., the present disclosure may be practiced without limitation to any particular theory or mechanism.

All features defined herein as numerical ranges or percentage ranges, such as values, amounts, levels and concentrations, are for brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to cover and specifically disclose all possible subranges and individual numerical values (including integers and fractions) within the range.

The present invention will be described in detail with reference to specific examples.

The structure diagrams of the self-adaptive deformation degradable composite temporary plugging agent are shown in figures 1 and 2.

The flexible container in the self-adaptive deformation degradable composite temporary plugging agent can be made into different shapes and is not limited to the two forms in the figures 1 and 2.

Examples 1-6 are preparation of Flexible containers (e.g., Flexible pouches)

The preparation method comprises the following specific steps:

1) preparing materials according to the formula in the table 1;

2) the water-soluble resin and the processing aid I are stirred and mixed uniformly at normal temperature, then a film is formed by hot-melt extrusion blow molding through a single-screw extrusion film blowing machine (the existing process conditions are adopted, no special requirements exist), then cutting is carried out to obtain a film with a proper shape, and then the single film or a plurality of films are curled, folded, butted, spliced or combined to form a flexible bag with a filling opening.

The thickness of the prepared flexible bag is controlled to be 10-100 μm.

Examples 1 to 6 flexible pouches 1 to 6 were produced, respectively.

Table 1 examples 1-6 raw material components of flexible pouch and parts by weight thereof

Examples 7-13 preparation of degradable elastomeric temporary blocking pellets

Preparing materials according to the formula shown in the table 2, and preparing degradable elastic temporary plugging granules 1 to degradable elastic temporary plugging granules 7 in examples 7 to 13 respectively.

Table 2 examples 7-13 formulation components for degradable elastomeric temporary blocking pellets

Example 7

The degradable elastic temporary plugging granule is prepared by the following method:

(1) preparing materials according to the following formula (see table 2 specifically);

the mass ratio of the thermoplastic elastomer to the water-soluble polymer in the composite elastomer is 8:1, wherein the thermoplastic elastomer is

P30B, the water-soluble polymer being polyvinyl alcohol, the degree of alcoholysis being 88%.

The polymer containing glycolic acid repeat units employed was a glycolic acid homopolymer having a relative molecular mass of about 18.4 tens of thousands.

The mass ratio of the polymer containing the glycolic acid repeating units to the composite elastomer is 30: 10;

in terms of processing aids, the antioxidant was added in an amount of 0.5 wt%, the metal deactivator in an amount of 0.06 wt%, and the heat stabilizer in an amount of 0.6 wt%, based on the total mass of the polymer containing glycolic acid repeating units and the composite elastomer (as a base material).

(2) Drying and pretreating a polymer containing glycolic acid repeating units and a composite elastomer at 100 ℃, then uniformly mixing, adding the mixture into a double-screw extruder from a main feeding port of the double-screw extruder, then adding a processing aid into the double-screw extruder from a side feeding port of the double-screw extruder, controlling the rotating speed of the double-screw extruder to be 200 revolutions per minute, controlling the plasticizing temperature to be 200 ℃, controlling the blending temperature to be 210 ℃, controlling the extrusion temperature to be 210 ℃, extruding and granulating, and sieving by a screen to control the diameter and the length of a material, thereby preparing the degradable elastic temporary plugging granule.

Example 8

the mass ratio of the thermoplastic elastomer to the water-soluble polymer in the composite elastomer is 10:1, wherein the thermoplastic elastomer is

The DP1085A, the water-soluble polymer was polyvinyl alcohol, and the degree of alcoholysis was 87%.

The polymer containing glycolic acid repeating units was a polyglycolic acid-polylactic acid copolymer having a relative molecular mass of about 15.1 ten thousand, in which the proportion of glycolic acid repeating units was about 70% by weight.

The mass ratio of the polymer containing glycolic acid repeating units to the composite elastomer was 80: 10.

In terms of processing aids, the amount of antioxidant added was 1.8 wt%, the amount of compatibilizer added was 1.0 wt%, the amount of plasticizer added was 1.3 wt%, the amount of hydrolysis modifier added was 0.8 wt%, and the amount of heat stabilizer added was 1.4 wt%, based on the total mass of the polymer containing glycolic acid repeating units and the composite elastomer (as a base material).

(2) Drying and intervening the polymer containing glycolic acid repeating units and the composite elastomer at 110 ℃, then uniformly mixing, adding the mixture into a double-screw extruder from a main feeding port of the double-screw extruder, then adding the processing aid into the double-screw extruder from a side feeding port of the double-screw extruder, controlling the rotating speed of the double-screw extruder at 500 revolutions per minute, controlling the plasticizing temperature at 230 ℃, controlling the blending temperature at 220 ℃, controlling the extrusion temperature at 240 ℃, extruding and granulating, and screening by a screen to control the diameter and the length of the material, thus obtaining the degradable elastic temporary plugging granule.

Example 9

the mass ratio of the thermoplastic elastomer to the water-soluble polymer in the composite elastomer is 9:1, wherein the thermoplastic elastomer is

P40B, the water-soluble polymer being polyvinyl alcohol, the degree of alcoholysis being 89%.

The polymer containing glycolic acid repeating units employed was a glycolic acid homopolymer having a relative molecular mass of about 21.2 million.

The mass ratio of the polymer containing glycolic acid repeating units to the composite elastomer was 60: 10.

In terms of processing aids, the amount of antioxidant added is 0.5 wt%, the amount of metal deactivator added is 0.12 wt%, the amount of compatibilizer added is 0.7 wt%, the amount of plasticizer added is 1 wt%, the amount of hydrolysis regulator added is 0.4 wt%, and the amount of heat stabilizer added is 0.8 wt%, based on the total mass of the polymer containing glycolic acid repeating units and the composite elastomer (as a base material).

(2) Drying and pretreating a polymer containing glycolic acid repeating units and a composite elastomer at 105 ℃, then uniformly mixing, adding the mixture into a double-screw extruder from a main feeding port of the double-screw extruder, then adding a processing aid into the double-screw extruder from a side feeding port of the double-screw extruder, controlling the rotating speed of the double-screw extruder to be 300 revolutions per minute, controlling the plasticizing temperature to be 220 ℃, controlling the blending temperature to be 215 ℃, controlling the extrusion temperature to be 220 ℃, extruding and granulating, and sieving by a screen to control the diameter and the length of a material, thereby preparing the degradable elastic temporary plugging granule.

Example 10

preparing materials according to the following formula (see table 2 specifically);

the mass ratio of the thermoplastic elastomer to the water-soluble polymer in the composite elastomer is 4:1, wherein the thermoplastic elastomer is TPAE-10, the water-soluble polymer is polyvinyl alcohol, and the alcoholysis degree is 87%.

The polymer having glycolic acid repeating units was a polyglycolic acid-polylactic acid copolymer having a relative molecular mass of about 12.6 ten thousand and a glycolic acid repeating unit content of about 85 wt%.

The mass ratio of the polymer containing glycolic acid repeating units to the composite elastomer was 50: 10.

In terms of processing aids, the amount of antioxidant added was 1.2 wt%, the amount of compatibilizer added was 0.5 wt%, the amount of plasticizer added was 0.8 wt%, the amount of hydrolysis modifier added was 0.2 wt%, and the amount of heat stabilizer added was 1.2 wt%, based on the total mass of the polymer containing glycolic acid repeating units and the composite elastomer (as a base material).

The rest is the same as example 9.

Example 11

the mass ratio of the thermoplastic elastomer to the water-soluble polymer in the composite elastomer is 1:1, wherein the thermoplastic elastomer is

DP 1485A (1) the water-soluble polymer is polyvinyl alcohol with an alcoholysis degree of 88%.

The polymer containing glycolic acid repeating units employed was a glycolic acid homopolymer having a relative molecular mass of about 26.3 tens of thousands.

The mass ratio of the polymer containing glycolic acid repeating units to the composite elastomer is 100: 10.

In terms of processing aids, the amount of antioxidant added is 1.2 wt%, the amount of metal deactivator added is 0.1 wt%, the amount of compatibilizer added is 1.0 wt%, the amount of plasticizer added is 1.8 wt%, the amount of hydrolysis regulator added is 0.6 wt%, and the amount of heat stabilizer added is 0.9 wt%, based on the total mass of the polymer containing glycolic acid repeating units and the composite elastomer (as a base material).

The rest is the same as example 9.

Example 12

the mass ratio of the thermoplastic elastomer to the water-soluble polymer in the composite elastomer is 5:1, wherein the thermoplastic elastomer is TPAE-12, the water-soluble polymer is polyvinyl alcohol, and the alcoholysis degree is 88%.

The polymer containing glycolic acid repeating units employed was a glycolic acid homopolymer having a relative molecular mass of about 23.4 million.

The mass ratio of the polymer containing glycolic acid repeating units to the composite elastomer is 5: 10.

In terms of processing aids, the amount of antioxidant added is 1.6 wt%, the amount of metal deactivator added is 0.2 wt%, the amount of compatibilizer added is 0.6 wt%, the amount of plasticizer added is 1.1 wt%, the amount of hydrolysis regulator added is 0.4 wt%, and the amount of heat stabilizer added is 0.9 wt%, based on the total mass of the polymer containing glycolic acid repeating units and the composite elastomer (as a base material).

The rest is the same as example 9.

Example 13

the composite elastomer is a thermoplastic elastomer

P30B.

The mass ratio of the polymer containing glycolic acid repeating units to the composite elastomer was 1: 10.

The rest is the same as example 9.

In the following examples 14 to 16, each of the glycolic acid homopolymer and the glycolic acid copolymer was capped with a capping agent, and degradable elastic temporary plugging pellets 8 to 10 were prepared.

Example 14

The glycolic acid homopolymer of example 9 was end-capped with an end-capping agent, added in an amount of 1 wt% based on the theoretical mass of the polymer obtained based on the mass of glycolic acid monomer, and ethylene glycol was used as the end-capping agent. In the devolatilization stage at the end of the polymerization reaction for synthesizing glycolic acid homopolymer, an end capping agent is added for end capping, the temperature in the devolatilization stage is controlled at 220 ℃, the pressure is controlled at 1000Pa, and the devolatilization time is 20 minutes.

The rest is the same as in example 9.

Example 15

The glycolic acid copolymer of example 10 was end-capped with an end-capping agent, added in an amount of 1.5 wt% based on the theoretical mass of the resulting polymer calculated on the mass of glycolic acid monomer, and the end-capping agent was oxalic acid. In the devolatilization stage at the end of the polymerization reaction for synthesizing the polyglycolic acid-polylactic acid copolymer, an end capping agent is added for end capping, the temperature in the devolatilization stage is controlled to be 210 ℃, the pressure is controlled to be 1500Pa, and the devolatilization time is 10 minutes.

The rest is the same as in example 10.

Example 16

The glycolic acid homopolymer of example 9 was end-capped with an end-capping agent, added in an amount of 1.2 wt% based on the theoretical mass of the resulting polymer calculated on the mass of glycolic acid monomer, and carbodiimide was used as the end-capping agent. In the devolatilization stage at the end of the polymerization reaction for synthesizing glycolic acid homopolymer, an end capping agent is added for end capping, the temperature in the devolatilization stage is controlled at 220 ℃, the pressure is controlled at 1000Pa, and the devolatilization time is 20 minutes.

The rest is the same as in example 9.

The matrix material of the degradable elastic temporary plugging pellets in the following examples 17 to 20, in which the ratio of the mass of the functionalized graphene-modified glycolic acid homopolymer to the mass of the unmodified glycolic acid repeat unit-containing polymer is 1, was incorporated with a functionalized graphene-modified glycolic acid homopolymer to further improve the high-temperature thermal stability of the degradable elastic temporary plugging pellets: 5-10, respectively preparing degradable elastic temporary plugging granules 11-14.

Example 17

Introducing a functionalized graphene-modified glycolic acid homopolymer into the matrix material of the degradable elastic temporary plugging pellet on the basis of example 16, wherein the mass ratio of the functionalized graphene-modified glycolic acid homopolymer to the unmodified polymer containing glycolic acid repeating units is 1: 8.

the rest is the same as in example 16.

In this example, the functionalized graphene-modified glycolic acid homopolymer is specifically prepared by the following steps:

step I): preparation of graphene oxide

Preparing graphene oxide by using a Hummers method: 2g of graphite and 1g of NaNO₃46ml of 98% concentrated sulfuric acid, the mixture was placed in an ice-water bath, stirred for 30 minutes to mix the mixture sufficiently, and 6g of KMnO was weighed₄Adding into the above mixed solution for several times, stirring for 2 hr, transferring into 35 deg.C warm water bath, and stirring for 30 min; slowly adding 92ml of distilled water, controlling the temperature of the reaction liquid to be about 98 ℃ for 15 minutes, and adding a proper amount of 30% H₂O₂Removing excess oxidant, thenThen adding 140ml of distilled water for dilution, filtering while the solution is hot, and washing the solution by using 0.01mol/L HCl, absolute ethyl alcohol and deionized water in sequence until no SO exists in the filtrate₄ ^2-Until the graphite exists, preparing graphite oxide; then ultrasonically dispersing graphite oxide in water to prepare a dispersion liquid of graphene oxide; and (3) drying the dispersion liquid of the graphene oxide in a vacuum drying oven at 60 ℃ for 48 hours to obtain a graphene oxide sample, and storing for later use.

Step II): preparation of functionalized graphene oxide, taking organic amine modifier triethylenetetramine as an example, to prepare functionalized graphene oxide: weighing 200mg of graphene oxide, ultrasonically dispersing in 200ml of DMF (N-N dimethylformamide) for 2.5 hours to obtain a graphene oxide suspension, adding 30g of triethylenetetramine and 5g of dicyclohexylcarbodiimide, ultrasonically treating for 5 minutes, reacting at 120 ℃ for 48 hours, adding 60ml of absolute ethyl alcohol, and standing overnight; and removing the supernatant, filtering the lower precipitate by using a polytetrafluoroethylene membrane, and washing the lower precipitate for multiple times by using absolute ethyl alcohol and deionized water to obtain the functionalized graphene oxide.

Step III): reducing functionalized graphene oxide into functionalized graphene by adopting a reducing agent hydrazine hydrate, and the method comprises the following specific steps: dispersing the washed and undried functionalized graphene oxide in 60ml of absolute ethyl alcohol, performing ultrasonic dispersion for 1 hour to form uniform and stable functionalized graphene oxide dispersion liquid, then adding 1g of hydrazine hydrate, and reducing for 24 hours at 60 ℃; and washing the obtained product to be neutral by using absolute ethyl alcohol and deionized water, and drying the product in a vacuum drying oven at the temperature of 60 ℃ for 48 hours to obtain the functionalized graphene, and storing for later use.

Step IV): the functionalized graphene is prepared by a method of bonding with a glycolic acid homopolymer through a chemical reaction, and is specifically realized through the following steps:

step 1): ultrasonically dispersing the functionalized graphene in silicone oil, and preparing a silicone oil suspension of the functionalized graphene with the mass fraction of 25%;

step 2): adding a silicone oil solution containing a dispersing agent into a stirring reactor, then adding a glycolic acid monomer and a catalyst, carrying out a polymerization reaction on the glycolic acid monomer under the action of the catalyst, reacting at 140 ℃ for 2 hours, heating to 160 ℃ at 2 ℃/min for reacting for 2 hours, heating to 180 ℃ at 2 ℃/min for reacting for 2 hours, heating to 200 ℃ at 2 ℃/min for reacting for 1 hour, sequentially adding an antioxidant and the functionalized graphene silicone oil suspension prepared in the step 1), after the functionalized graphene silicone oil suspension is added, heating to 210 ℃ at 2 ℃/min, decompressing to a gauge pressure of-50 kPa, reacting for 1 hour, heating to 215 ℃ at 1 ℃/min, decompressing to a gauge pressure of-90 kPa, reacting for 1 hour, heating to 220 ℃ at 1 ℃/min, Reducing the pressure to a gauge pressure of-101 kPa, and reacting for 1 hour to fully remove small molecular substances;

Wherein, the dosage relationship of the glycolic acid monomer and the silicone oil solution in the step 2) is as follows: each 15ml of silicone oil solution contains 1g of glycolic acid monomer, the mass fraction of the dispersing agent in the silicone oil solution is 0.5%, the dosage of the catalyst is 0.1% of the mass of the glycolic acid monomer, and the dosage of the antioxidant is 1% of the mass of the glycolic acid monomer.

The amount of functionalized graphene used in step 2) was 3 wt% of the theoretical mass of glycolic acid homopolymer obtained calculated on the mass of glycolic acid monomer.

The silicone oil adopted in the steps is commercially available methyl silicone oil, and the adopted dispersing agent is commercially available fatty alcohol-polyoxyethylene ether MOA-3; the adopted catalyst is metal alkoxy compound stannous octoate; the antioxidant employed was a commercially available antioxidant 1076, n-octadecyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate.

Example 18

Introducing a functionalized graphene-modified glycolic acid homopolymer into the matrix material of the degradable elastic temporary plugging pellet on the basis of example 16, wherein the mass ratio of the functionalized graphene-modified glycolic acid homopolymer to the unmodified polymer containing glycolic acid repeating units is 1: 5.

this example prepared functionalized graphene by the method of preparing functionalized graphene as in example 17, and then physically blended with a glycolic acid homopolymer directly to prepare a functionalized graphene-modified glycolic acid homopolymer, wherein the amount of functionalized graphene was 3 wt% of the mass of glycolic acid homopolymer.

The rest is the same as in example 16.

Example 19

Introducing a functionalized graphene-modified glycolic acid homopolymer into the matrix material of the degradable elastic temporary plugging pellet on the basis of example 16, wherein the mass ratio of the functionalized graphene-modified glycolic acid homopolymer to the unmodified polymer containing glycolic acid repeating units is 1: 10.

the method for producing a functionalized graphene-modified glycolic acid homopolymer of this example was substantially the same as in example 17, and the amount of functionalized graphene used was 5 wt% based on the theoretical mass of the glycolic acid homopolymer obtained based on the mass of glycolic acid monomer.

In this embodiment, the functionalized graphene is prepared by a method of bonding a functionalized graphene with a glycolic acid homopolymer through a chemical reaction, and the method specifically includes the following steps:

step 1): ultrasonically dispersing functionalized graphene in silicone oil, and preparing a silicone oil suspension of the functionalized graphene with the mass fraction of 10%;

step 2): adding a silicone oil solution containing a dispersing agent into a stirring reactor, then adding a glycolic acid monomer and a catalyst, carrying out a polymerization reaction on the glycolic acid monomer under the action of the catalyst, reacting for 1 hour at 135 ℃, heating to 155 ℃ at 5 ℃/min for reacting for 1 hour, heating to 175 ℃ at 5 ℃/min for reacting for 2 hours, heating to 195 ℃ at 5 ℃/min for reacting for 2 hours, sequentially adding an antioxidant and the functionalized graphene silicone oil suspension prepared in the step 1), after the addition of the functionalized graphene silicone oil suspension is finished, heating to 220 ℃ at 2 ℃/min, reducing the pressure to 50kPa at the gauge pressure, reacting for 1 hour, heating to 225 ℃ at 1 ℃/min, reducing the pressure to 90kPa at the gauge pressure, reacting for 1 hour, heating to 230 ℃ at 1 ℃/min, Reducing the pressure to a gauge pressure of-101 kPa, and reacting for 1 hour to fully remove small molecular substances;

The rest is the same as in example 17.

Example 20

Introducing a functionalized graphene-modified glycolic acid homopolymer into the matrix material of the degradable elastic temporary plugging pellet on the basis of example 16, wherein the mass ratio of the functionalized graphene-modified glycolic acid homopolymer to the unmodified polymer containing glycolic acid repeating units is 1: 6.

the process for the preparation of functionalized graphene-modified glycolic acid homopolymer was substantially the same as in example 17, and the amount of functionalized graphene used was 0.1 wt% based on the theoretical mass of glycolic acid homopolymer obtained, calculated on the mass of glycolic acid monomer.

step 1): ultrasonically dispersing functionalized graphene in silicone oil, and preparing a silicone oil suspension of the functionalized graphene with the mass fraction of 30%;

step 2): adding a silicone oil solution containing a dispersing agent into a stirring reactor, then adding a glycolic acid monomer and a catalyst, carrying out a polymerization reaction on the glycolic acid monomer under the action of the catalyst, reacting at 145 ℃ for 1 hour, heating to 165 ℃ at 4 ℃/min for reacting for 1 hour, heating to 185 ℃ at 2 ℃/min for reacting for 2 hours, heating to 205 ℃ at 1 ℃/min for reacting for 2 hours, sequentially adding an antioxidant and the functionalized graphene silicone oil suspension prepared in the step 1), after the addition of the functionalized graphene silicone oil suspension is finished, heating to 220 ℃ at 2 ℃/min, reducing the pressure to 50kPa at the gauge pressure, reacting for 1 hour, heating to 225 ℃ at 2 ℃/min, reducing the pressure to 90kPa at the gauge pressure, reacting for 1 hour, heating to 230 ℃ at 2 ℃/min, Reducing the pressure to a gauge pressure of-101 kPa, and reacting for 1 hour to fully remove small molecular substances;

The rest is the same as in example 17.

The degradable elastic temporary plugging granules 1 to 14 prepared in examples 7 to 20 were filled into the corresponding flexible bags 1 to 6 prepared in examples 1 to 6, and the filling ports were bonded by hot pressing, so that the composite temporary plugging agent of the present invention was prepared, and the specific product list is shown in table 3.

TABLE 3 composite temporary plugging agent

Serial number	Temporary plugging agent	Flexible pouch
			Product 1	Degradable elastic temporary plugging granular material 1	Flexible pouch 1
Product 2	Degradable elastic temporary plugging granular material 2	Flexible pouch 2
			Product 3	Degradable elastic temporary plugging granular material 3	Flexible pouch 3
Product 4	Degradable elastic temporary plugging granular material 4	Flexible pouch 4
			Product 5	Degradable elastic temporary plugging granular material 5	Flexible pouch 5
Product 6	Degradable elastic temporary plugging granular material 6	Flexible pouch 6
			Product 7	Degradable elastic temporary plugging granular material 7	Flexible pouch 3
Product 8	Degradable elastic temporary plugging granular material 8	Flexible pouch 3
			Product 9	Degradable elastic temporary plugging granular material 9	Flexible pouch 4
Product 10	Degradable elastic temporary plugging granule 10	Flexible pouch 3
			Product 11	Degradable elastic temporary plugging granular material 11	Flexible pouch 3
Product 12	Degradable elastic temporary plugging granular material 12	Flexible pouch 3
			Product 13	Degradable elastic temporary plugging granular material 13	Flexible pouch 3
Product 14	Degradable elastic temporary plugging granular material 14	Flexible pouch 3
			Comparative product 1	Temporary plugging agent particle	/
Comparative product 2	Temporary plugging agent particle	Flexible pouch 3
			Comparative product 3	Degradable elastic temporary plugging granular material 3	/
Comparative product 4	Degradable elastic temporary plugging granular material 11	/

Note: 1) in table 3, the particles of the temporary blocking agent in comparative products 1 and 2 were made of only glycolic acid homopolymer (molecular weight about 21.9 ten thousand) and were free of other auxiliaries and components; 2) the product in table 3, the fill rate of the flexible pouch was about 90%.

Test for degradation Properties

The products 1-14 and the comparative products 1-4 were tested for degradation, the specific test method being as follows:

step I): weighing 2 parts by mass of M₀The sample to be tested is placed in a constant-temperature drying oven and dried for 24 hours at the temperature of 60 ℃;

step II): respectively placing 2 parts of dried samples to be detected in hard glass tubes with one open end, respectively adding a proper amount of clear water to completely soak the samples, respectively placing the two hard glass tubes into pressure water bath tanks using the clear water as a heat transfer medium, sealing the pressure water bath tanks, respectively filling nitrogen into the two pressure water bath tanks until the pressure reaches 2.0MPa, controlling the temperature inside the two pressure water bath tanks to be 110 ℃, and respectively marking as S1 and S2;

step III): after 12 hours, taking out the hard glass tube in S1, extracting supernatant to separate residual solid phase, cleaning the separated residual solid phase with distilled water, putting the cleaned residual solid phase into a constant temperature drying oven, drying for 2 hours at 105 ℃, weighing, and recording the weight of the residual solid phase as M₁；

Step IV): after 7 days, taking out the hard glass tube in S2, then extracting supernatant to separate residual solid phase, cleaning the separated residual solid phase with distilled water, placing the cleaned residual solid phase into a constant temperature drying oven, drying for 2 hours at 105 ℃, weighing, and recording the weight of the residual solid phase as M₂；

Step V): calculating the degradation rate R_dThe calculation formula is as follows:

R_dS1＝(M₀-M₁)/M₀×100％；

R_dS2＝(M₀-M₂)/M₀×100％。

it should be noted that, the schematic structural diagram of the rigid glass tube and the pressurized water bath tank (mainly composed of a copper tube and a copper nut) used in the degradation test is shown in fig. 3.

The results of the degradation tests for products 1-14 and comparative products 1-4 according to the degradation test method described above are shown in table 4.

TABLE 4 degradation test results

As can be seen from the degradation test results in table 4, the degradation rates of products 1 to 14 at 110 ℃ over 12 hours are all less than 40%, while the degradation rate over 12 hours of a product (e.g., product 8) comprising the degradable elastic temporary plugging particles made of the glycolic acid polymer subjected to the end capping treatment is significantly lower than that of a product (e.g., product 3) comprising the degradable elastic temporary plugging particles made of the glycolic acid polymer not subjected to the end capping treatment, as a result, it can be seen that the thermal degradation of the glycolic acid polymer during the subsequent processing can be effectively inhibited by the end capping treatment of the glycolic acid polymer, and the heat resistance of the final product can be suitably improved (i.e., the degradation rate is reduced at the same temperature over the same time); on the other hand, the functionalized graphene modified glycolic acid polymer is introduced into the matrix material of the degradable elastic temporary plugging granule on the basis of the end capping treatment, so that the degradation rate of the obtained product (for example, product 11) is only about 8.9% in 12 hours, thereby demonstrating that the introduction of the functionalized graphene modified glycolic acid polymer can generate a synergistic effect with the end capping treated glycolic acid polymer, and the heat resistance of the final product can be further improved.

It can be known from the comparison of the degradation test results of the comparative products 1 and 2 that the existence of the flexible bag can delay the degradation speed of the product to a certain extent, which may be because the flexible bag itself plays a role similar to a protective barrier for the temporary plugging agent particles contained therein in the initial stage, and slows down the degradation stimulation of the external water body to the temporary plugging agent particles. For the reasons stated above, comparative product 2 generally has a lower degradation rate than comparative product 1 under the same conditions.

Comparing the degradation test results of comparative products 1 with 3 and 4, it can be seen that under the same conditions (e.g., at 110 ℃), the degradation rate of the degradable elastic temporary plugging particles of the present invention is significantly lower than that of the temporary plugging agent particles made of only glycolic acid homopolymer, e.g., after 12 hours at 110 ℃, the degradation rate of comparative product 4 is only about 15.7%, while the degradation rate of comparative product 3 is about 34.5%, both of which are significantly lower than that of comparative product 1 (i.e., about 56.4%). It can be seen that the heat resistance of the degradable elastic temporary plugging particles of the present invention is effectively improved compared to temporary plugging agent particles made of only glycolic acid homopolymer.

Temporary plugging performance test

The products 1-14 and the comparative products 1-4 are tested for temporary plugging performance, wedge-shaped crack steel rocks (the crack width is 1-3mm) are adopted, and the specific test method is as follows:

A) directly mixing the temporary plugging agent to be tested with a proper amount of clear water, and stirring for 30 minutes at 1000 revolutions per minute by using a stirrer to prepare temporary plugging slurry (the mass concentration of the temporary plugging agent is 10 g/L);

B) putting the wedge-shaped crack steel rock into a holder, applying a confining pressure of 30MPa to the wide surface of the steel rock crack which is the inlet end of the temporary plugging agent, and closing an outlet valve;

C) introducing the temporary plugging slurry into a clamp holder kettle body, ensuring that the filling thickness of the temporary plugging agent in the wedge-shaped crack is about 10mm, and connecting an inlet pipeline and a pressure sensor;

D) opening pressure monitoring software, starting the displacement pump in a constant flow mode, and opening an outlet valve;

E) starting a displacement pump to gradually increase the pumping pressure from 0MPa to 1.0-2.0MPa each time, and stabilizing the pressure of each pressure point for 5-10 minutes;

F) and when the inlet pressure cannot be stabilized to a certain pressure point, taking the pressure stabilizing point closest to the pressure point as the pressure bearing capacity of the temporary plugging agent.

The results of the plugging performance (experimental temperature 100 ℃) measured by the above method are shown in Table 5 below.

Table 5 plugging test results

Item	Plugging pressure (/ MPa)
		Product 1	About 19.8
Product 2	About 15.9
		Product 3	About 21.3
Product 4	About 14.7
		Product 5	About 19.2
Product 6	About 22.5
		Product 7	About 18.1
Product 8	About 27.2
		Product 9	About 23.3
Product 10	About 28.3
		Product 11	About 43.6
Product 12	About 31.8
		Product 13	About 37.5
Product 14	About 39.1
		Comparative product 1	About 8.7
Comparative product 2	About 11.3
		Comparative product 3	About 16.6
Comparative product 4	About 34.2

Note: in table 5, the particles of the temporary blocking agent in comparative products 1 and 2 were made of only glycolic acid homopolymer (molecular weight about 21.9 ten thousand) and were free of other auxiliaries and components.

As can be seen from the results of the blocking test in table 5, the blocking pressure of the product (e.g., product 8) containing the degradable elastic temporary blocking particles made of the glycolic acid polymer subjected to the end-capping treatment is significantly higher than that of the product (e.g., product 3) containing the degradable elastic temporary blocking particles made of the glycolic acid polymer not subjected to the end-capping treatment, which is probably because the thermal degradation of the glycolic acid homopolymer during the subsequent processing can be effectively inhibited after the end-capping treatment, which is beneficial for maintaining the molecular weight of the glycolic acid homopolymer, and is further beneficial for improving the strength of the final product, and can suitably increase the blocking pressure; and on the basis of end capping treatment, functionalized graphene modified glycolic acid polymer is introduced into the matrix material of the degradable elastic temporary plugging granule, so that the plugging pressure of the obtained product (for example, the product 11) can be up to about 43.6Mpa, which is probably due to the introduction of the functionalized graphene modified glycolic acid polymer, and the functionalized graphene modified glycolic acid polymer and the end capping treated glycolic acid polymer can generate synergistic effect, so that the strength of the final product can be improved, and the heat resistance of the final product can also be improved, and the final product can still maintain the strength of the final product for a longer time at higher temperature (for example, 100 ℃) so as to obtain higher plugging pressure.

Based on table 5, will compare product 1 and 2, it can effectively improve shutoff pressure to find to fill the shutoff crack with temporary plugging agent granule in flexible bag, this probably is because flexible bag self has certain deformability, it can produce certain self-adaptation deformation owing to receiving the extrusion in the crack, be favorable to forming comparatively compact shutoff layer, and the existence of flexible bag is favorable to weakening the degradation stimulation of the temporary plugging agent granule that the water held in to flexible bag, can effectively delay the degradation degree of temporary plugging agent granule, be favorable to maintaining the self intensity of temporary plugging agent granule, and then can obtain higher shutoff pressure relatively. Similarly, the products 1 to 14 of the invention fill the degradable elastic temporary plugging particles into the flexible bag, the degradable elastic temporary plugging particles have better strength and toughness, the degradable elastic temporary plugging particles and the flexible bag can generate certain self-adaptive deformation under the action of crack pressure, the degradable elastic temporary plugging particles and the flexible bag have synergistic effect, and a plurality of composite temporary plugging agents (including the flexible bag and the degradable elastic temporary plugging particles filled in the flexible bag) which generate self-adaptive deformation can realize quick and effective accumulation and bridging to form the plugging band with stable pressure-bearing effect.

Comparing the plugging pressures of comparative products 1 with 3 and 4, it can be seen that the degradable elastic temporary plugging particles of the present invention can achieve higher plugging pressures for plugging fractures than temporary plugging agent particles made of glycolic acid homopolymer alone, probably because: compared with the temporary plugging agent particles only made of ethanol homopolymer with higher rigidity, the degradable elastic temporary plugging material particles have better toughness, can generate certain self-adaptive deformation due to extrusion in cracks, are favorable for forming a compact plugging layer and are favorable for improving plugging pressure; further, the matrix material of the degradable elastic temporary plugging material particles of comparative product 4 adopts the glycolic acid polymer subjected to end capping treatment and introduces the functionalized graphene modified glycolic acid polymer, so that the two have synergistic effects, the strength of the final product can be improved, the heat resistance of the final product can be improved, and the strength of the final product can be maintained for a longer time at a higher temperature (for example, 100 ℃) so as to obtain a higher plugging pressure.

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims

1. The self-adaptive deformation composite temporary plugging agent is characterized by comprising a flexible container and the temporary plugging agent filled in the flexible container.

2. An adaptively deformable composite temporary plugging agent according to claim 1, wherein said flexible container is made of a material comprising a water-soluble resin or/and a degradable resin.

3. The adaptive deformation composite temporary plugging agent according to claim 1, wherein said temporary plugging agent is prepared from a material comprising a degradable resin or/and a water-soluble resin.

4. An adaptively deformable composite temporary plugging agent according to claim 3, wherein said temporary plugging agent comprises degradable elastic temporary plugging granules.

5. The adaptive deformation composite temporary plugging agent according to claim 4, wherein the degradable elastic temporary plugging granules are mainly prepared by taking polymers containing glycolic acid repeating units and thermoplastic elastomers as matrix materials and adding processing aids.

6. The adaptive deformation composite temporary plugging agent according to claim 5, wherein the mass ratio of the polymer containing glycolic acid repeating units to the thermoplastic elastomer is 1-100: 10.

7. The adaptive deformation composite temporary plugging agent according to claim 5, wherein the matrix material further comprises functionalized graphene modified polymer containing glycolic acid repeating units.

8. The self-adaptive deformation composite temporary plugging agent according to claim 7, wherein the mass ratio of the polymer containing glycolic acid repeating units to the functionalized graphene modified polymer containing glycolic acid repeating units in the matrix material is 5-10: 1;

in the functionalized graphene modified polymer containing glycolic acid repeating units, the amount of the functionalized graphene is 0.1-5 wt% of the theoretical mass of the glycolic acid polymer obtained by calculating the mass of the glycolic acid monomer.

9. The adaptive deformation composite temporary plugging agent according to claim 1, wherein the temporary plugging agent is formed by mixing temporary plugging granules with different particle size distributions.

10. The method for preparing an adaptive deformation composite temporary plugging agent according to any one of claims 1 to 9, comprising the steps of: