阅读说明：本技术 一种高强度纳米封堵剂 (High-strength nano plugging agent ) 是由 牛文智 于 2020-05-21 设计创作，主要内容包括：本发明公开一种高强度纳米封堵剂,包括以下重量份数配比的原料：无机纳米粒子10-55份,复合改性剂2-8份,有机纳米粒子5-20份、阻燃剂12-30份、去离子水30-50份,其中无机纳米粒子采用10-30nm和100-200nm两种粒径范围,不同粒径的无机纳米粒子混合后作为原料增强了封堵剂的强度,而复合改性剂的加入,能够使制备过程中纳米颗粒不易团聚,无机纳米粒子和有机纳米粒子高度聚合,进一步增强了制备得到的纳米封堵剂的强度,获得更好的封堵效果。(The invention discloses a high-strength nano plugging agent which comprises the following raw materials in parts by weight: 10-55 parts of inorganic nanoparticles, 2-8 parts of composite modifier, 5-20 parts of organic nanoparticles, 12-30 parts of flame retardant and 30-50 parts of deionized water, wherein the inorganic nanoparticles adopt two particle size ranges of 10-30nm and 100-200nm, the inorganic nanoparticles with different particle sizes are mixed and used as a raw material to enhance the strength of the plugging agent, and the addition of the composite modifier can ensure that the nanoparticles are not easy to agglomerate in the preparation process, the inorganic nanoparticles and the organic nanoparticles are highly polymerized, so that the strength of the prepared nano plugging agent is further enhanced, and a better plugging effect is obtained.)

1. The high-strength nano plugging agent is characterized by comprising the following raw materials in parts by weight: 10-55 parts of inorganic nanoparticles, 2-8 parts of composite modifier, 5-20 parts of organic nanoparticles, 12-30 parts of flame retardant, 30-50 parts of deionized water, 10-30 parts of isopropanol, 5-8 parts of sodium bisulfite and ammonium persulfate, wherein two inorganic nanoparticles with different particle size ranges of 10-30nm and 100-200nm are adopted, and the weight ratio of the two inorganic nanoparticles with different particle size ranges is 1: 1.

2. The high-strength nano plugging agent according to claim 1, wherein the inorganic nanoparticles are one or more of nano silica particles, nano ferroferric oxide particles, nano calcium carbonate particles, nano alumina particles and nano cement particles.

3. The high-strength nano plugging agent according to claim 1, wherein the organic nanoparticles are one or more nanoparticles selected from acrylamide, methyl methacrylate, styrene, acrylic acid, sodium p-styrenesulfonate, 2-acrylamido-2-methylpropanesulfonic acid and the like.

4. The high-strength nano plugging agent according to claim 1, wherein the composite modifier consists of a modifier A and a modifier B, and the mass ratio of the modifier A to the modifier B in the composite modifier is 1: 2;

the structural formula of the modifier A is as follows:

the structural formula of the modifier B is as follows:

5. the high-strength nano plugging agent according to claim 4, wherein the flame retardant is one or two of tributyl phosphate, tricresyl phosphate, triphenyl phosphate, chlordane anhydride, tellurium compounds, aluminum hydroxide, magnesium hydroxide and borate.

6. The high-strength nano plugging agent as claimed in claim 1, wherein the inorganic nanoparticles are preferably a mixture of nano silica particles, nano ferroferric oxide particles and nano calcium carbonate particles, and the particle size of the inorganic nanoparticle mixture comprises two different particle size ranges of 10-30nm and 100-200 nm.

7. The high strength nano blocking agent according to claim 1, wherein the organic nanoparticles are preferably a mixture of acrylamide and methyl methacrylate particles.

8. The high strength nano blocking agent according to claim 1, wherein the flame retardant is preferably tributyl phosphate.

9. The high-strength nano blocking agent according to any one of claims 1 to 8, wherein the preparation process of the high-strength nano blocking agent comprises the following steps:

(1) placing inorganic nanoparticles with particle sizes of 10-30nm and 100-200nm into a dryer, drying to remove water, and standing in a room for 2 h;

(2) putting the dried mixture of the two inorganic nano particles with different particle sizes into a grinding machine for grinding, wherein the mass ratio of the two inorganic nano particles with different particle sizes is 1:1, putting the ground inorganic nano particle mixed powder into a stirring box, adding isopropanol, and stirring for 30-45 min;

(3) grinding the organic nano particles in a grinding machine to form powder with the size similar to that of the inorganic nano particle powder; putting the ground organic nano particle powder into a stirrer, then putting deionized water into the stirrer, and stirring the mixture at the stirring speed of 45 revolutions per minute;

(4) mixing the composite modifier, the inorganic nanoparticle mixed solution and the organic nanoparticle mixed solution, and reacting for 30min under stirring at 60 ℃ in a reaction environment consisting of a sodium bisulfite and ammonium persulfate mixed solution to perform a polymerization reaction for 4 h;

(5) mixing the product of the polymerization reaction with a flame retardant, and continuously heating and stirring for 1h at the temperature of 60 ℃;

(6) and (3) drying the mixture solution obtained in the step (5) at 70 ℃ for 24h, and crushing after drying to obtain the high-strength nano plugging agent.

10. The method for preparing the high-strength nano plugging agent according to claim 9, wherein the inorganic nanoparticles are preferably a mixture of nano silica particles, nano ferroferric oxide particles and nano calcium carbonate particles, the organic nanoparticles are preferably a mixture of acrylamide and methyl methacrylate particles, and the flame retardant is preferably tributyl phosphate.

Technical Field

The invention belongs to the field of functional nano materials for oil and gas drilling, and particularly relates to a high-strength nano plugging agent.

Background

In the process of oil field development, due to reservoir fracture development or production fracturing, most oil reservoir reservoirs have fractures, the fractures provide good seepage channels for crude oil exploitation, and meanwhile, excessive formation water flows into a production well, so that the problems of high water content of produced liquid, low utilization rate of injected water and the like occur, and further the oil field recovery rate is low. To improve the above problems, plugging agents are widely used in reservoirs. Meanwhile, for the drilling fluid with strong inhibition capacity, the hydraulic pressure is transmitted through the microcracks to be one of the main reasons for causing borehole wall instability, and the plugging property of the drilling fluid to the microcracks must be enhanced.

At present, the commonly used plugging material has large particles and can effectively plug the stratum with larger pores, but can effectively plug the stratum with tiny pores and microcracks, but is difficult to realize effective plugging for the stratum with tiny pores and microcracks, especially the shale stratum. The size of the microcracks is generally between nanometer and micrometer, and the conventional plugging agent has too large size and cannot achieve good plugging effect, so that the plugging agent with nanometer size must be added into the drilling fluid, and the compatibility of the plugging agent and the formation pore size is improved, so that effective plugging can be realized.

In the continuous research of drilling fluid, the nano plugging agent also makes some breakthrough, for example, inorganic nano particles are taken as main materials, CN102329600A discloses an oil well nano particle plugging agent, which is prepared by using calcium oxide, silicon oxide, aluminum oxide, iron oxide, triethanolamine, bentonite, a condensation polymer of acetone and formaldehyde, and iron chromium lignosulfonate; if organic nanoparticles are taken as the main material, CN104762071A discloses a preparation method of a water-based shale micro-nano particle plugging agent, which comprises adding an initiator into an aqueous medium containing an acrylate or methacrylate monomer and a vinyl monomer in the presence of a cosolvent to initiate a polymerization reaction to form the micro-nano particle plugging agent; if inorganic nanoparticles and organic nanoparticles are mainly mixed, CN103602323A discloses a nano plugging agent and a preparation method thereof, and the nano plugging agent is prepared by utilizing a composite system of inorganic nanoparticles and organic nanoparticles.

However, the nano plugging agent still has a plurality of problems: the particle size of the nano water shutoff agent is fixed and single, the gap diameter of the microcracks is in a certain micro-nano range, the plugging effect of the nano water shutoff agent with the single particle size on the microcracks is not ideal, and the strength of the nano water shutoff agent is not ideal; in addition, the nano plugging agent is easy to agglomerate, the particle size after agglomeration is obviously increased, agglomerated particles are difficult to redisperse to a nano scale only by stirring, and the agglomeration of the nano particles not only influences the plugging effect of the plugging agent, but also influences the compression and bending strength of the plugging agent, so that the plugging agent is weak in scour resistance and stability, and is not beneficial to plugging of oil reservoirs at high temperature and high pressure.

Disclosure of Invention

In order to solve the technical problem that the compression resistance and the folding resistance of the nano plugging agent in the prior art are further improved, the invention provides the high-strength nano plugging agent which can keep a better plugging effect.

A high-strength nano plugging agent comprises the following raw materials in parts by weight: 10-55 parts of inorganic nanoparticles, 2-8 parts of composite modifier, 5-20 parts of organic nanoparticles, 12-30 parts of flame retardant, 30-50 parts of deionized water, 10-30 parts of isopropanol, 5-8 parts of sodium bisulfite and ammonium persulfate, and is characterized in that two inorganic nanoparticles with different particle size ranges of 10-30nm and 100-200nm are adopted, and the weight ratio of the two inorganic nanoparticles with different particle size ranges is 1: 1.

Further, the inorganic nano particles are one or more of nano silicon oxide particles, nano ferroferric oxide particles, nano calcium carbonate particles, nano aluminum oxide particles and nano cement particles.

Further, the organic nanoparticles are one or more nanoparticles of monomers such as acrylamide, methyl methacrylate, styrene, acrylic acid, sodium p-styrene sulfonate, 2-acrylamido-2-methylpropanesulfonic acid and the like.

Further, the composite modifier consists of a modifier A and a modifier B, wherein the mass ratio of the modifier A to the modifier B in the composite modifier is 1: 2;

the structural formula of the modifier A is as follows:

the structural formula of the modifier B is as follows:

further, the flame retardant is one or two of tributyl phosphate, tricresyl phosphate, triphenyl phosphate, chlordane anhydride, a tellurium compound, aluminum hydroxide, magnesium hydroxide and borate.

Furthermore, the inorganic nanoparticles are preferably a mixture of nano silicon oxide particles, nano ferroferric oxide particles and nano calcium carbonate particles, and the particle size of the inorganic nanoparticle mixture comprises two different particle size ranges of 10-30nm and 100-200 nm.

Further, the organic nanoparticles are preferably a mixture of acrylamide and methyl methacrylate particles.

Further, the flame retardant is preferably tributyl phosphate.

Further, the preparation process of the high-strength nano plugging agent comprises the following steps:

(1) placing inorganic nanoparticles with particle sizes of 10-30nm and 100-200nm into a dryer, drying to remove water, and standing in a room for 2 h;

(2) putting the dried mixture of the two inorganic nano particles with different particle sizes into a grinding machine for grinding, wherein the mass ratio of the two inorganic nano particles with different particle sizes is 1:1, putting the ground inorganic nano particle mixed powder into a stirring box, adding isopropanol, and stirring for 30-45 min;

(3) grinding the organic nano particles in a grinding machine to form powder with the size similar to that of the inorganic nano particle powder; putting the ground organic nano particle powder into a stirrer, then putting deionized water into the stirrer, and stirring the mixture at the stirring speed of 45 revolutions per minute;

(4) mixing the composite modifier, the inorganic nanoparticle mixed solution and the organic nanoparticle mixed solution, and reacting for 30min under stirring at 60 ℃ in a reaction environment consisting of a sodium bisulfite and ammonium persulfate mixed solution to perform a polymerization reaction for 4 h;

(5) mixing the product of the polymerization reaction with a flame retardant, and continuously heating and stirring for 1h at the temperature of 60 ℃;

(6) and (3) drying the mixture solution obtained in the step (5) at 70 ℃ for 24h, and crushing after drying to obtain the high-strength nano plugging agent.

In the preparation process, the inorganic nanoparticles are preferably a mixture of nano silicon oxide particles, nano ferroferric oxide particles and nano calcium carbonate particles, the organic nanoparticles are preferably a mixture of acrylamide and methyl methacrylate particles, and the flame retardant is preferably tributyl phosphate.

The invention has the beneficial effects that:

1. the nano blocking agent is formed by mixing inorganic nanoparticles and organic nanoparticles, and a composite modifier of the modifiers with a specific proportion and a specific type is used to modify a single nanoparticle, so that the agglomeration of the inorganic nanoparticle mixture can be effectively avoided, the polymerization reaction of the inorganic nanoparticles and the organic nanoparticles is realized, the prepared nano blocking agent is well dispersed in the drilling fluid, the agglomeration is not easy to occur, and the nano blocking agent has better compressive strength, flexural strength and blocking effect.

2. Compared with the method that the inorganic nanoparticle mixture with a single particle size is used as a raw material, the method disclosed by the invention has the advantages that the two inorganic nanoparticle mixtures with specific particle size ranges are mixed, the reasonable distribution of the particle sizes in the prepared nano plugging agent is realized, and the compressive strength and the flexural strength of the prepared nano plugging agent are further improved.

3. According to the invention, the flame retardant is added to enable the water shutoff agent to achieve the fireproof effect, so that the safety of the water shutoff agent is improved.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.