阅读说明：本技术 能够用于宽大裂缝的增强型暂堵剂及其制备方法 (Enhanced temporary plugging agent capable of being used for wide and large cracks and preparation method thereof ) 是由 石磊 曾凌翔 钟兴久 于 2020-04-22 设计创作，主要内容包括：本发明提供了一种能够用于宽大裂缝的增强型暂堵剂及其制备方法,能够用于宽大裂缝的增强型暂堵剂包括暂堵剂颗粒以及包裹在暂堵剂颗粒表面的铁磁性水溶薄膜,其中,所述铁磁性水溶薄膜能够在磁力作用下被吸附,且所述铁磁性水溶薄膜能够与水反应溶解并释放被包裹的暂堵剂颗粒；所述暂堵剂颗粒能够在油气井下的高温环境下遇水可溶且可交联,从而发生胶结以封堵地层裂缝。本发明具有铁磁性水溶薄膜溶解速度快,不影响暂堵剂的胶结性能,能够对缝宽较大的天然裂缝或人造裂缝进行封堵、节约暂堵剂的用量、降低施工成本等优点。(The invention provides an enhanced temporary plugging agent capable of being used for wide cracks and a preparation method thereof, wherein the enhanced temporary plugging agent capable of being used for wide cracks comprises temporary plugging agent particles and a ferromagnetic water-soluble film coated on the surfaces of the temporary plugging agent particles, wherein the ferromagnetic water-soluble film can be adsorbed under the action of magnetic force, and can react with water to dissolve and release the coated temporary plugging agent particles; the temporary plugging agent particles can be soluble and crosslinkable in water under the high-temperature environment of an oil gas well, so that cementing can be carried out to plug formation cracks. The invention has the advantages of high dissolving speed of the ferromagnetic water-soluble film, no influence on the cementing property of the temporary plugging agent, capability of plugging natural cracks or artificial cracks with larger crack widths, saving the using amount of the temporary plugging agent, reduction of the construction cost and the like.)

1. An enhanced temporary plugging agent capable of being used for wide natural cracks or artificial cracks, which is characterized by comprising temporary plugging agent particles and a ferromagnetic water-soluble film coated on the surfaces of the temporary plugging agent particles, wherein,

the ferromagnetic water-soluble film can be adsorbed under the action of magnetic force, and the ferromagnetic water-soluble film can react with water to dissolve and release the coated temporary plugging agent particles;

the temporary plugging agent particles can be soluble and crosslinkable in water under the high-temperature environment of an oil gas well, so that cementing can be carried out to plug formation cracks.

2. An enhanced temporary plugging agent according to claim 1 wherein said ferromagnetic water soluble film is comprised directly or alloyed of a ferromagnetic first metallic element and a water reactive second metallic element.

3. An enhanced temporary plugging agent according to claim 2, wherein said first metal element is one or more of iron, cobalt and nickel and said second metal element is one or more of magnesium, aluminum and calcium.

4. An enhanced temporary plugging agent for wide natural cracks or artificial cracks according to claim 1, wherein the thickness of the ferromagnetic water-soluble film is 0.25-0.75 mm, and the particle size of the temporary plugging agent particles is 0.35-1.25 mm.

5. A preparation method of an enhanced temporary plugging agent capable of being used for wide natural fractures or artificial fractures, which is characterized by comprising the following steps:

forming temporary plugging agent particles, wherein the temporary plugging agent particles are high polymer materials which are soluble in water and can be linked under a high-temperature environment under an oil-gas well;

forming a ferromagnetic water-soluble film on the surface of the temporary plugging agent particles to obtain the enhanced temporary plugging agent, wherein the ferromagnetic water-soluble film can be adsorbed under the action of magnetic force, and can react with water to dissolve and release the wrapped temporary plugging agent particles.

6. A method for preparing an enhanced temporary plugging agent according to claim 5, wherein said ferromagnetic water soluble film is composed of a ferromagnetic first metal element and a water reactive second metal element directly or by alloying.

7. A method of making an enhanced temporary plugging agent according to claim 6 wherein said first metal element is one or more of iron, cobalt and nickel and said second metal element is one or more of magnesium, aluminum and calcium.

8. A preparation method of an enhanced temporary plugging agent according to claim 5, wherein the thickness of the ferromagnetic water-soluble film is 0.25-0.75 mm, and the particle size of the temporary plugging agent particles is 0.35-1.25 mm.

Technical Field

The invention belongs to the technical field of oil and gas exploitation, and particularly relates to an enhanced temporary plugging agent capable of being used for wide cracks and a preparation method thereof.

Background

In the process of oil and gas exploitation, the temporary plugging agent used in fracturing is mainly a water-soluble high polymer material which can be crosslinked in a high-temperature environment, and the temporary plugging agent is added into a fracturing fluid pump and sent into a stratum fracture for temporary plugging. The temporary plugging agent can generate cementation under the underground high-temperature environment, thereby plugging formation cracks and realizing temporary plugging in the cracks. After a period of time, the cementitious temporary plugging agent gradually dissolves in water to unblock the crack. The temporary plugging agent is suitable for plugging cracks with small seam widths, but when the temporary plugging agent meets natural cracks or artificial cracks with large seam widths, temporary plugging in the seams is difficult to realize through cementation of the temporary plugging agent. In addition, when temporary plugging is carried out in the crack, the specific position of the temporary plugging agent for realizing temporary plugging in the crack is not determined, so that the using amount of the temporary plugging agent is large, and the construction cost is increased.

Through modifying the temporary plugging agent particles, the temporary plugging agent particles have magnetism, and meanwhile, a magnetic field is applied to a local underground area, so that the temporary plugging agent can be gathered at a high concentration in the local area, and therefore, temporary plugging is performed on a specific area, the temporary plugging effect is improved, and the construction cost is saved.

Disclosure of Invention

The present invention aims to address at least one of the above-mentioned deficiencies of the prior art. For example, it is an object of the present invention to provide an enhanced type temporary plugging agent that can be used for wide natural fractures or artificial fractures.

In order to accomplish the above objects, an aspect of the present invention provides an enhanced type temporary plugging agent that can be used for wide natural fractures or artificial fractures. The enhanced temporary plugging agent comprises temporary plugging agent particles and a ferromagnetic water-soluble film wrapped on the surfaces of the temporary plugging agent particles, wherein the ferromagnetic water-soluble film can be adsorbed under the action of magnetic force, and can react with water to dissolve and release the wrapped temporary plugging agent particles; the temporary plugging agent particles can be soluble and crosslinkable in water under the high-temperature environment of an oil gas well, so that cementing can be carried out to plug formation cracks.

In one exemplary embodiment of an aspect of the present invention, the ferromagnetic water-soluble film may be composed directly or alloyed with a ferromagnetic first metal element and a water-reactive second metal element.

In one exemplary embodiment of an aspect of the present invention, the first metal element may be one or more of iron, cobalt, and nickel, and the second metal element may be one or more of magnesium, aluminum, and calcium.

In an exemplary embodiment of an aspect of the present invention, the ferromagnetic water-soluble film may have a thickness of 0.25 to 0.75mm, and the particle size of the particle of the temporary plugging agent may be 0.35 to 1.25 mm.

Another aspect of the present invention provides a method for preparing an enhanced temporary plugging agent that can be used for wide natural fractures or artificial fractures. The preparation method can comprise the following steps: forming temporary plugging agent particles, wherein the temporary plugging agent particles are high polymer materials which are soluble in water and can be linked under a high-temperature environment under an oil-gas well; forming a ferromagnetic water-soluble film on the surface of the temporary plugging agent particles to obtain the enhanced temporary plugging agent, wherein the ferromagnetic water-soluble film can be adsorbed under the action of magnetic force, and can react with water to dissolve and release the wrapped temporary plugging agent particles.

In an exemplary embodiment of another aspect of the present invention, the ferromagnetic water-soluble film may be composed directly or alloyed with a ferromagnetic first metal element and a water-reactive second metal element.

In one exemplary embodiment of another aspect of the present invention, the first metal element may be one or more of iron, cobalt and nickel, and the second metal element may be one or more of magnesium, aluminum and calcium.

In an exemplary embodiment of another aspect of the present invention, the ferromagnetic water-soluble film may have a thickness of 0.25 to 0.75mm, and the particle size of the particles of the temporary plugging agent may be 0.35 to 1.25 mm.

Compared with the prior art, the beneficial effects of the invention can comprise at least one of the following:

(1) according to the invention, the ferromagnetic water-soluble film is coated on the surface of the temporary plugging agent, and the magnetic field is applied to the crack entrance, so that the concentration of the temporary plugging agent at the crack entrance is improved, and the temporary plugging effect is improved;

(2) the ferromagnetic water-soluble film has high dissolving speed and cannot influence the service performance of the temporary plugging agent;

(3) the temporary plugging agent can temporarily plug cracks with large crack widths, saves the using amount of the temporary plugging agent and reduces the construction cost.

Detailed Description

Hereinafter, the enhanced temporary plugging agent for enhancing temporary plugging effect and the method for preparing the same according to the present invention will be described in detail with reference to exemplary embodiments.

An aspect of the present invention provides an enhanced temporary plugging agent that can be used for wide natural fractures or artificial fractures.

In an exemplary embodiment of the invention, the enhanced temporary plugging agent capable of being used for wide natural cracks or artificial cracks comprises temporary plugging agent particles and a ferromagnetic water-soluble film coated on the surfaces of the temporary plugging agent particles, wherein the ferromagnetic water-soluble film can be adsorbed under the action of magnetic force, and the ferromagnetic water-soluble film can react with water to dissolve and release the coated temporary plugging agent particles. The temporary plugging agent particles can be soluble and crosslinkable in water under the high-temperature environment of an oil gas well, so that cementing can be carried out to plug formation cracks. Specifically, the temporary plugging agent particles are wrapped with a ferromagnetic water-soluble film capable of reacting with water, so that the temporary plugging agent can move and gather in a specific underground area (such as a seam of a wide natural crack or an artificial crack) under the action of magnetic force, the ferromagnetic water-soluble film on the surfaces of the temporary plugging agent particles releases the temporary plugging agent particles after being dissolved, and the temporary plugging agent particles are dissolved in water and crosslinked in a high-temperature environment (such as 60-130 ℃) of a stratum so as to consolidate and plug the crack inlet, thereby realizing the temporary plugging function. Here, the particles of the temporary blocking agent may be a water-soluble crosslinkable polymer material such as benzoic acid, polypropylene, or the like.

In this embodiment, the ferromagnetic water-soluble film may be composed of a ferromagnetic first metal element and a second metal element capable of reacting with water, which are directly or alloyed. The first metal element may be one or more of iron, cobalt and nickel, and the second metal element may be one or more of magnesium, aluminum and calcium. For example, the ferromagnetic water-soluble film may comprise an iron-aluminum alloy or an iron-magnesium-aluminum alloy. Here, magnesium and aluminum in the ferromagnetic water-soluble film can chemically react with water, so that the ferromagnetic water-soluble film is rapidly dissolved, and the coated temporary plugging agent particles are released. Wherein the formula for the chemical reaction is:

2Al+6H₂0＝＝2Al(OH)₃+3H₂

Mg+2H₂O＝＝Mg(OH)₂+H₂

however, the present invention is not limited thereto, and other types of ferromagnetic water-soluble thin film materials are also possible as long as the material can adsorb under the action of magnetic force and can dissolve in water to release the coated particles of the temporary plugging agent.

In this embodiment, the ferromagnetic water-soluble film may have a thickness of 0.25 to 0.75mm, and the particle size of the temporary plugging agent particles may be 0.35 to 1.25 mm. When the thickness of the ferromagnetic water-soluble film is less than 0.25mm, the magnetic force applied to the temporary plugging agent under the action of a magnetic field is small, and the temporary plugging agent is difficult to collect or the collected concentration is not enough to plug formation cracks; when the thickness of the ferromagnetic water-soluble film is more than 0.75mm, the ferromagnetic water-soluble film reacts with water to release the temporary plugging agent particles for too long time, which is not beneficial to plugging construction. Here, the iron content of the ferromagnetic water-soluble film may be 40% to 60% by weight. When the content of iron in the ferromagnetic water-soluble film is controlled within the range, the film can be dissolved at a higher speed on the basis of having enough ferromagnetism. When the content of iron in the ferromagnetic water-soluble film is lower than 40 wt%, the ferromagnetic water-soluble film has high dissolution speed, but the ferromagnetic property is weak, so that the ferromagnetic water-soluble film is not beneficial to converging the high-concentration temporary plugging agent under the action of magnetic force; when the content of iron in the ferromagnetic water-soluble film exceeds 60 wt%, the ferromagnetic water-soluble film has strong ferromagnetic property, but the dissolving speed is slow, so that temporary plugging construction is not facilitated.

Another aspect of the present invention provides a method for preparing an enhanced temporary plugging agent that can be used for wide natural fractures or artificial fractures.

In another exemplary embodiment of the present invention, a method of preparing an enhanced temporary plugging agent that can be used for wide natural fractures or artificial fractures may include the steps of:

first, particles of the temporary plugging agent are formed. Here, the temporary plugging agent particles are a polymer material that is soluble in water and crosslinkable in a high-temperature environment in an oil-gas well. And then forming a ferromagnetic water-soluble film on the surface of the temporary plugging agent particles to obtain the enhanced temporary plugging agent. The ferromagnetic water-soluble film can be adsorbed under the action of magnetic force, and can react with water to dissolve and release the coated temporary plugging agent particles. Specifically, the temporary plugging agent for plugging is prepared into temporary plugging agent particles with a certain particle size. Then forming a ferromagnetic water-soluble film on the surface of the temporary plugging agent particles. For example, a ferromagnetic water-soluble film can be formed from the surface of the temporary plugging agent particles by electroplating. However, the present invention is not limited thereto, and other modes are also possible. The thickness of the ferromagnetic water-soluble film can be 0.25-0.75 mm, and the particle size of the temporary plugging agent particles can be 0.35-1.25 mm. When the thickness of the ferromagnetic water-soluble film is less than 0.25mm, the magnetic force applied to the temporary plugging agent under the action of a magnetic field is small, and the temporary plugging agent is difficult to collect or the collected concentration is not enough to plug formation cracks; when the thickness of the ferromagnetic water-soluble film is more than 0.75mm, the ferromagnetic water-soluble film reacts with water to release the temporary plugging agent particles for too long time, which is not beneficial to plugging construction. Here, the particles of the temporary blocking agent may be a water-soluble crosslinkable polymer material such as benzoic acid, polypropylene, or the like.

In this embodiment, the ferromagnetic water-soluble film may be composed of a ferromagnetic first metal element and a second metal element capable of reacting with water, which are directly or alloyed. The first metal element may be one or more of iron, cobalt and nickel, and the second metal element may be one or more of magnesium, aluminum and calcium. For example, the ferromagnetic water-soluble film may comprise an iron-aluminum alloy or an iron-magnesium-aluminum alloy. Here, magnesium and aluminum in the ferromagnetic water-soluble film can chemically react with water, so that the ferromagnetic water-soluble film is rapidly dissolved, and the coated temporary plugging agent particles are released. Wherein the formula for the chemical reaction is:

2Al+6H₂0＝＝2Al(OH)₃+3H₂

Mg+2H₂O＝＝Mg(OH)₂+H₂

here, the iron content of the ferromagnetic water-soluble film may be 40% to 60% by weight. When the content of iron in the ferromagnetic water-soluble film is controlled within the range, the film can be dissolved at a higher speed on the basis of having enough ferromagnetism. When the content of iron in the ferromagnetic water-soluble film is lower than 40 wt%, the ferromagnetic water-soluble film has high dissolution speed, but the ferromagnetic property is weak, so that the ferromagnetic water-soluble film is not beneficial to converging the high-concentration temporary plugging agent under the action of magnetic force; when the content of iron in the ferromagnetic water-soluble film exceeds 60 wt%, the ferromagnetic water-soluble film has strong ferromagnetic property, but the dissolving speed is slow, so that temporary plugging construction is not facilitated. However, the present invention is not limited thereto, and other types of ferromagnetic water-soluble thin film materials are also possible as long as the material can adsorb under the action of magnetic force and can dissolve in water to release the coated particles of the temporary plugging agent.

Another aspect of the present invention also provides a method of using the enhanced temporary plugging agent that can be used for wide natural or artificial fractures.

In still another exemplary embodiment of the invention, the method for using the enhanced temporary plugging agent capable of being used for wide natural cracks or artificial cracks aims at natural cracks or artificial cracks with the crack width of 1-5 mm, the enhanced temporary plugging agent in the above one exemplary embodiment is added into fracturing fluid according to the mass-to-volume ratio of 2-5: 100 and the unit of kg/L, and then the fracturing fluid is pumped into a stratum through a perforation hole or a sleeve sliding sleeve injection hole with a magnetic adsorption function for temporary plugging, wherein the pumping capacity of the fracturing fluid can be 0.4-1 m³Specifically, when temporary plugging is carried out, 2-5 kg of enhanced temporary plugging agent is added into 100L fracturing fluid, the temporary plugging agent enters underground along with the fracturing fluid and enters a stratum crack through a perforation hole or a sleeve sliding sleeve injection hole with a magnetic adsorption function, and the temporary plugging agent acts as a magnetic field of the perforation hole or the injection holeThe temporary plugging agent is collected at the crack entrance by the lower end, when the ferromagnetic water-soluble film wrapping the temporary plugging agent is dissolved, the particles of the temporary plugging agent are released and are cemented in the high-temperature environment of the underground stratum, so that the crack entrance is plugged, and the temporary plugging is realized. Here, the discharge amount of the fracturing fluid is controlled to be 0.4 to 1m³And/min, which is to ensure that the ferromagnetic water-soluble film coated on the surface of the temporary plugging agent particles is dissolved and the temporary plugging agent particles are fully cemented for sufficient time. When the pumping and discharging amount of the fracturing fluid is controlled in the range, temporary plugging construction can be well carried out. When the pumping capacity of the fracturing fluid is less than 0.4m³In the time of/min, the temporary plugging agent can sink under the action of the self weight, and the temporary plugging agent cannot be reliably brought to a specified position depending on the discharge capacity; when the pumping discharge amount of the fracturing fluid is higher than 1m³At the time of/min, the impact force of the discharge capacity on the temporary plugging agent per se is larger than the magnetic force applied to the temporary plugging agent per se, and the temporary plugging agent cannot be effectively gathered near the seam.

In summary, the beneficial effects of the invention include at least one of the following:

(1) according to the invention, the ferromagnetic water-soluble film is coated on the surface of the temporary plugging agent particles, and a magnetic field is applied at the crack entrance, so that the concentration of the temporary plugging agent at the crack entrance is improved, and the temporary plugging effect is improved;

(2) the ferromagnetic water-soluble film has high dissolving speed and cannot influence the service performance of the temporary plugging agent;

(3) the temporary plugging agent is easy to prepare and can be produced in large scale underground;

(4) the enhanced temporary plugging agent can temporarily plug natural cracks or artificial cracks with large crack widths by matching with a perforation hole with a magnetic adsorption function or a sleeve sliding sleeve injection hole, saves the using amount of the temporary plugging agent and reduces the construction cost.

While the present invention has been described above in connection with exemplary embodiments, it will be apparent to those of ordinary skill in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.