1. A self-adaptive temporary plugging ball is characterized in that: comprises 60-95% of high polymer material, 10-36% of inorganic material and 4-10% of processing aid, wherein the high polymer material is a water-soluble high polymer material or a mixture of a plurality of high polymer materials which can be melt and processed,

the inorganic material may be in powder form and may be water soluble or insoluble,

the processing aid is a plasticizer which can be a water-soluble oligomer or a water-soluble organic compound.

2. The adaptive temporary plugging ball according to claim 1, wherein: the water-soluble high polymer material can be processed by hot melting, and can be selected from the following materials: one or more of polyethylene glycol, ethylene/vinyl alcohol copolymer, vinyl alcohol/vinyl acetate copolymer and polyhydroxyacetate alcohol and other water-soluble polymers.

3. The adaptive temporary plugging ball according to claim 1, wherein: the inorganic material can be dissolved or dispersed in the solution after the high molecular material is dissolved in water or other downhole media, does not agglomerate, can flow out along with liquid, does not remain in the stratum, does not influence the permeability of the stratum,

the inorganic material can be water-soluble inorganic salt or insoluble inorganic salt powder, and the particle size of the insoluble inorganic salt powder is less than or equal to 30 mu m.

4. The adaptive temporary plugging ball according to claim 3, wherein: the inorganic material can be selected from: one or more of sodium chloride, calcium carbonate, calcium chloride, magnesium hydroxide, aluminum oxide, talcum powder and the like.

5. The adaptive temporary plugging ball according to claim 1, wherein: the plasticizer is a water-soluble solid plasticizer or a liquid plasticizer, and the plasticizer can be selected from the following materials: one or more of monohydroxymethyl urea, bis-hydroxymethyl urea, hydroxyethyl formamide, sorbitol and xylitol, glycerol, ethylene glycol, etc.

6. A method of manufacturing a self-adaptive ball, comprising the steps of:

selecting a proper water-soluble polymer according to the underground use temperature, selecting a proper inorganic material according to the requirement of plugging time, selecting a proper plasticizer according to the type of the material,

step two, weighing the following components in percentage by mass: 60-95% of high polymer material, 10-36% of inorganic material, 4-10% of processing aid,

step three, stirring and mixing the materials in the step two to obtain a uniform mixture,

step four, putting the mixture obtained in the step three into a screw extruder, heating the mixture into viscous-state plastic through the hot melting action of screw extrusion, injecting the plastic into a spherical or hemispherical mold,

and step five, further shaping the spherical or hemispherical plugging material obtained in the step four to obtain the water-soluble temporary plugging ball with accurate size.

7. The manufacturing method of the adaptive ball according to claim 6, characterized in that: the processing temperature of the mixture in the screw extruder is 140-180 ℃, and whether granulation is carried out before injection molding or compression molding can be determined according to the extrusion molding quality.

8. The manufacturing method of the adaptive ball according to claim 6, characterized in that: the temporary plugging ball is further processed by coating a layer of water-soluble high polymer material which is sensitive to the dissolving temperature on the outer layer of the preliminarily molded plugging ball by a solution method.

9. The method for manufacturing an adaptive ball according to claim 8, wherein: the water-soluble polymer material can be selected from methylcellulose, chitosan and polyvinyl alcohol.

Background

Along with the wide application of the steering fracturing technology, the temporary plugging agent playing an important role in the technology is also greatly developed, the water-soluble temporary plugging agent also becomes the main development, so that the current near-wellbore area self-adaptive guiding staged fracturing technology is adopted in a low-permeability compact reservoir horizontal well, the technology is widely applied to the multi-stage staged fracturing technology of the clustered perforation, and in the fracturing well section of the clustered perforation, the special self-adaptive guiding agents with different particle size combinations are utilized to effectively bridge and plug perforation holes, perforation ducts and near-wellbore fracturing cracks of the fractured well section, so that the subsequent fracturing can extend the fracturing cracks again in the non-fractured clustered perforation well section, and the aim of dynamic multi-stage staged fracturing is achieved.

The composite particle size self-adaptive guiding material has stable property and good matching with fracturing fluid, when fracturing construction is finished, the guiding agent can be automatically degraded, a temporarily blocked well section is released to form a channel for oil gas to enter a well, the degraded self-adaptive guiding agent material returns to the ground along with the fracturing fluid, no damage and pollution are caused to a reservoir, the self-adaptive guiding fracturing technology utilizes the self-adaptive guiding materials with different particles to quickly block bridges formed at perforation holes, perforation holes and near-well cracks, leakage is reduced, the self-adaptive guiding effect is achieved, the net pressure at the bottom of the well is quickly increased, new cracks are pressed, the guiding new cracks of the fracturing fluid are further expanded and prolonged, the dissolving capacity of the self-adaptive guiding material is not influenced by the formation pressure and the construction pressure, and the reservoir is free of pollution after self-degradation.

The water-soluble temporary plugging agent has various types, such as particles, threads, rubber plugs and mixtures thereof in use forms, and various synthetic or natural high-molecular polymers with crosslinking or non-crosslinking in chemical compositions, the main degradation materials in the market are basically polylactic acid (PLA), polybutylene terephthalate succinate (PBAT) and other materials which can meet the requirements on mechanical properties, and the materials are prepared into products with various shapes, are used for fibrous objects, fracturing plugging balls, even soluble bridge plugs and the like, and have certain market scale. However, studies have shown that the temporary plugging agent after temporary plugging is difficult to completely remove from the formation, and the resulting residue may permanently reduce the formation permeability, wherein these common degradable materials, which are not water soluble, cannot meet the requirement of dissolution within a certain period of time (72 hours).

At present, the degradation process of the degradable high polymer materials which are industrially produced needs a longer time period and cannot meet the implementation requirements of the petroleum fracturing exploitation technology, some researchers try to prepare dissolving balls by water-soluble high polymer materials, but researches find that many polymer resins slowly dissolved in water are difficult to mold into balls. Other polymer resins are either too hard or too soft and have insufficient compressive strength. Still other polymer resins swell upon contact with moisture, which can cause storage stability problems prior to use as well as operational problems such as clogging of the ball syringe and reduced sealing efficiency during use. Still other polymer resins require acid treatment to remove them. Which is a major technical disadvantage of the conventional art.

Disclosure of Invention

The technical scheme adopted by the invention is as follows: a self-adaptive temporary plugging ball comprises 60-95% of a high polymer material, 10-36% of an inorganic material and 4-10% of a processing aid, wherein the high polymer material is a water-soluble high polymer material capable of being processed in a melting mode or a mixture of a plurality of high polymer materials, and the inorganic material is in a powder shape and can be water-soluble or insoluble.

The processing aid is a plasticizer which can be a water-soluble oligomer or a water-soluble organic compound, the water-soluble high polymer material can be processed by hot melting, the hydrolysis rate of the water-soluble high polymer material is more than or equal to 98%, and the water-soluble high polymer material can be selected from the following components: one or more of polyethylene glycol, ethylene/vinyl alcohol copolymer, vinyl alcohol/vinyl acetate copolymer and polyhydroxyacetate alcohol and other water-soluble polymers.

After the high molecular material is dissolved in water or other downhole media, the inorganic material can be dissolved or dispersed in the solution, does not agglomerate, can flow out along with liquid, cannot remain in the stratum, and cannot influence the permeability of the stratum.

The inorganic material can be water-soluble inorganic salt or insoluble inorganic salt powder, and the particle size of the insoluble inorganic salt powder is less than or equal to 30 mu m.

The inorganic material has a reinforcing effect on the temporary plugging ball.

The inorganic material can be selected from: one or more of sodium chloride, calcium carbonate, calcium chloride, magnesium hydroxide, aluminum oxide, talcum powder and the like.

The plasticizer is a water-soluble solid plasticizer or a liquid plasticizer, and the plasticizer can be selected from the following materials: one or more of monohydroxymethyl urea, bis-hydroxymethyl urea, hydroxyethyl formamide, sorbitol and xylitol, glycerol, ethylene glycol, etc.

A method of manufacturing a self-adaptive ball, comprising the steps of:

selecting a proper water-soluble polymer according to the underground use temperature, selecting a proper inorganic material according to the requirement of plugging time, and selecting a proper plasticizer according to the type of the material.

Step two, weighing the following components in percentage by mass: 60-95% of high polymer material, 10-36% of inorganic material and 4-10% of processing aid.

And step three, stirring and mixing the materials in the step two to obtain a uniform mixture.

And step four, putting the mixture obtained in the step three into a screw extruder, heating the mixture into viscous-state plastic through the hot melting effect of screw extrusion, and injecting the plastic into a spherical or hemispherical mold.

And step five, further shaping the spherical or hemispherical plugging material obtained in the step four to obtain the water-soluble temporary plugging ball with accurate size.

In specific embodiments, the mixing of the polymer material, the inorganic material, and the processing aid is performed at room temperature.

In specific implementation, the processing temperature of the mixture in the screw extruder is 140-180 ℃, and whether the mixture is pelletized before injection molding or compression molding can be determined according to the extrusion molding quality.

In the specific implementation, the further treatment of the temporary plugging ball is to coat a layer of water-soluble high polymer material which is sensitive to the dissolving temperature on the outer layer of the preliminarily molded plugging ball by a solution method,

the water-soluble polymer material can be selected from methyl cellulose, chitosan, polyvinyl alcohol with controllable polymerization degree and the like.

The invention has the following effective effects: the composite particle size self-adaptive guiding material has stable property and is well matched with fracturing fluid, after fracturing construction is finished, the temporary plugging material can be automatically degraded to release a temporarily plugged well section to form a channel for oil gas to enter a well, the degraded self-adaptive guiding agent material is returned to the ground along with the fracturing fluid, and no damage or pollution is caused to a reservoir stratum.

The self-adaptive guide fracturing technology utilizes self-adaptive guide materials with different particles, quickly blocks the bridge formed at the positions of perforation holes, perforation ducts and near-well cracks, reduces leakage loss, plays a role of self-adaptive guide, quickly raises the net pressure at the bottom of a well, presses new cracks open, and enables the guide new cracks of fracturing fluid to extend and extend from one part of the guide new cracks.

The water-soluble polymer material is adopted as a matrix, the melt processing performance of the water-soluble polymer material is adjusted through formula modification, the technical problem of molding and forming of the water-soluble polymer material is solved, and the compressive strength of the dissolving ball is improved through adding the inorganic material.

Drawings

FIG. 1 is a schematic diagram of the spherical and semispherical structures of the temporary plugging ball of the present invention.

Detailed Description

As shown in figure 1, the self-adaptive temporary plugging ball comprises 60-95% of a high polymer material, 10-36% of an inorganic material and 4-10% of a processing aid, wherein the high polymer material is a melt-processable water-soluble high polymer material or a mixture of a plurality of high polymer materials.

The inorganic material may be in the form of a powder, which may be water-soluble or insoluble.

The processing aid is a plasticizer which can be a water-soluble oligomer or a water-soluble organic compound.

The water-soluble polymer material can be processed by hot melting, and the hydrolysis rate of the water-soluble polymer material is more than or equal to 98 percent.

The water-soluble polymer material can be selected from: one or more of polyethylene glycol, ethylene/vinyl alcohol copolymer, vinyl alcohol/vinyl acetate copolymer and polyhydroxyacetate alcohol and other water-soluble polymers.

After the high molecular material is dissolved in water or other downhole media, the inorganic material can be dissolved or dispersed in the solution, does not agglomerate, can flow out along with liquid, cannot remain in the stratum, and cannot influence the permeability of the stratum.

The inorganic material can be water-soluble inorganic salt or insoluble inorganic salt powder, and the particle size of the insoluble inorganic salt powder is less than or equal to 30 mu m.

The inorganic material has a reinforcing effect on the temporary plugging ball.

The inorganic material can be selected from: one or more of sodium chloride, calcium carbonate, calcium chloride, magnesium hydroxide, aluminum oxide, talcum powder and the like.

The plasticizer is a water-soluble solid plasticizer or a liquid plasticizer, and the plasticizer can be selected from the following materials: one or more of monohydroxymethyl urea, bis-hydroxymethyl urea, hydroxyethyl formamide, sorbitol and xylitol, glycerol, ethylene glycol, etc.

A method of manufacturing a self-adaptive ball, comprising the steps of:

selecting a proper water-soluble polymer according to the underground use temperature, selecting a proper inorganic material according to the requirement of plugging time, and selecting a proper plasticizer according to the type of the material.

Step two, weighing the following components in percentage by mass: 60-95% of high polymer material, 10-36% of inorganic material and 4-10% of processing aid.

And step three, stirring and mixing the materials in the step two to obtain a uniform mixture.

And step four, putting the mixture obtained in the step three into a screw extruder, heating the mixture into viscous-state plastic through the hot melting effect of screw extrusion, and injecting the plastic into a spherical or hemispherical mold.

And step five, further shaping the spherical or hemispherical plugging material obtained in the step four to obtain the water-soluble temporary plugging ball with accurate size.

In specific embodiments, the mixing of the polymer material, the inorganic material, and the processing aid is performed at room temperature.

In specific implementation, the processing temperature of the mixture in the screw extruder is 140-180 ℃, and whether the mixture is pelletized before injection molding or compression molding can be determined according to the extrusion molding quality.

In the specific implementation, the further treatment of the temporary plugging ball is to coat a layer of water-soluble high polymer material which is sensitive to the dissolving temperature on the outer layer of the preliminarily molded plugging ball by a solution method,

the water-soluble polymer material can be selected from methyl cellulose, chitosan, polyvinyl alcohol with controllable polymerization degree and the like.

In use, the first embodiment uses the following steps,

selecting a proper water-soluble polymer according to the underground use temperature, selecting a proper inorganic material according to the requirement of plugging time, and selecting a proper plasticizer according to the type of the material.

Weighing the following components in percentage by mass:

weighing the following raw materials:

179970 percent of polyvinyl alcohol

23 percent of calcium carbonate powder

Sorbitol 4%

3 percent of glycerol

And (III) stirring and mixing the materials in the step (II) by using a high-speed mixer to obtain a uniform mixture.

And (IV) putting the material obtained in the step (III) into the screw extruder, heating the mixture into viscous-state plastic through the hot melting action of screw extrusion, and injecting the plastic into a spherical or hemispherical mold, wherein the temperature of the screw extruder is controlled to be 150-180 ℃.

And (V) further shaping the spherical or hemispherical plugging material obtained in the step (IV) to obtain the water-soluble temporary plugging ball with accurate size.

The temporary plugging ball can be completely dissolved within 72 hours at a certain temperature of 100 ℃, the dissolution rate is 100%, and the temporary plugging ball can bear 40MPFK pressure and can play an obvious temporary plugging effect.

The second embodiment differs from the first embodiment in that different compositions are selected for different downhole temperature requirements, the second embodiment uses the following steps,

selecting a proper water-soluble polymer according to the underground use temperature, selecting a proper inorganic material according to the requirement of plugging time, and selecting a proper plasticizer according to the type of the material.

Weighing the following components in percentage by mass:

weighing the following raw materials:

vinyl alcohol/vinyl acetate copolymer 76%

20 percent of calcium carbonate powder

4 percent of plasticizer

And (III) stirring and mixing the materials in the step (II) by using a high-speed mixer to obtain a uniform mixture.

And (IV) putting the mixture obtained in the step (III) into a screw extruder, heating the mixture into viscous-state plastic through the hot melting action of screw extrusion, and injecting the plastic into a spherical or hemispherical mold, wherein the temperature of the screw extruder is controlled to be 150-180 ℃.

And (V) further shaping the spherical or hemispherical plugging material obtained in the step (IV) to obtain the water-soluble temporary plugging ball with accurate size.

The temporary plugging agent can be completely dissolved within 72 hours at a certain temperature of 80 ℃, and the dissolution rate is 98%. The blocking ball can bear 40MPFK pressure, and can play a role in obviously temporarily blocking.