CN101735787A - Nano material-based water-based oil field injection agent and preparation method thereof - Google Patents

Abstract

The invention relates to a nanomaterial-based water-based oilfield injection booster and a preparation method thereof. The injection booster is composed of four components: 20-60wt% diesel oil, 30-70wt% surfactant, 1-10wt% nanomaterial and 1-20wt% additive, and the nanomaterial is surface-modified nano-silica , nano-titanium oxide, nano-magnesium oxide, nano-alumina or one or more of them. The preparation method is as follows: firstly weigh diesel oil according to the proportion, then add nano materials, emulsify and disperse in an emulsifier, then add surfactants and additives, mechanically stir and disperse at room temperature or in a water bath to obtain nano water-based injection booster stock solution. The injection booster can be mixed with water in any proportion to obtain a homogeneous emulsified dispersion. After the emulsified dispersion liquid is injected into the oil field by a specific process, the water injection pressure can be significantly reduced, the water injection volume can be increased, the oil production efficiency can be improved, and the purpose of energy saving and injection increase can be achieved.

Description

A water-based oilfield injection booster based on nanomaterials and its preparation method

technical field

The invention relates to the technical field of oilfield exploitation, in particular to a nanomaterial-based water-based oilfield booster injection agent suitable for secondary and tertiary oil recovery in low-permeability oilfields and a preparation method thereof.

Background technique

Using nanotechnology to improve the resistance characteristics of formation pores can achieve the purpose of reducing water injection pressure and increasing water injection volume. This is a new technology that is still in the stage of mechanism exploration, and is mainly suitable for low-permeability oilfields. Secondary and tertiary mining. In 2000, Sinopec introduced nano-silica enhanced injection technology from Russia, conducted field tests and applications in 12 wells in Shengli Oilfield and Zhongyuan Oilfield, and achieved success. According to statistics of the test results, the maximum drop in pressure reaches 9MPa, and the daily water injection volume increases up to 100m ³ . Some "old and difficult" wells with poor effect of conventional measures such as acidification have achieved a significant effect of reducing pressure and increasing injection through nano-drag reduction and increasing injection measures, and the validity period has been extended from less than 1 month to more than 6 months.

The nano decompression and enhanced injection technology is to uniformly disperse the hydrophobic nano powder in a specific dispersion medium, inject it into the target layer, shut down the well for 24 hours, and start the well for water injection. Hydrophobic nanoparticles are surface-modified nano-oxide materials with extremely strong hydrophobicity, and the general size is 10-100nm. So far, the mechanism of nano-oxide depressurization and increased injection technology has not been clearly understood, and has caused controversy within a certain range. Oil-soluble solvents such as diesel oil are often used as the dispersion medium of nanomaterial carriers, and the effect of reducing pressure and increasing injection is recognized, but the cost is high. The present invention proposes a nanometer water-based oilfield booster injection agent with low price, stable performance and remarkable booster injection effect and a preparation method thereof, which will definitely promote the further research and development of the nanoscale depressurization booster injection technology.

At present, some low-permeability reservoirs are facing serious problems of under-injection under high pressure. According to incomplete statistics, the two major domestic oil companies, PetroChina and Sinopec, currently have more than 45,000 water injection wells, with an annual under-injection volume of more than 17.5 million cubic meters. The invention aims to use the special properties of nanometer materials to physically modify the liquid flow channels of low-permeability oil reservoirs to form slip channels with special nanometer characteristics, so as to effectively reduce the liquid flow resistance and achieve the purpose of reducing pressure and increasing injection. The research of this technology will be very significant in terms of economic and social benefits, and it is also a successful combination of nanotechnology and petroleum engineering technology, which is of great significance.

Contents of the invention

The object of the present invention is to provide a water-based oilfield injection booster based on nanomaterials and a preparation method thereof. The injection booster can be dispersed in water to form a homogeneous emulsified dispersion. After the emulsified dispersion liquid is injected into the oil field by a specific process, the water injection pressure can be significantly reduced, the water injection volume can be increased, the oil production efficiency can be improved, and the purpose of saving energy and increasing oil can be achieved.

The technical solution adopted in the present invention is: the nanometer water-based injection booster for oil recovery in low-permeability oilfields, characterized in that the booster includes four components: diesel oil, surfactants, nanometer materials and additives.

The content of each component is as follows by weight percentage: diesel oil accounts for 20wt% to 60wt% of the total amount, surfactant accounts for 30wt% to 70wt% of the total amount, nanomaterials account for 1wt% to 10wt% of the total amount, and additives account for the total amount 1wt%～20wt% of the four components, the sum of the four components is 100wt%.

The nanometer material used in the injection agent is one or several kinds of surface-modified nano silicon dioxide, titanium oxide, magnesium oxide and aluminum oxide, with an average particle diameter of ≤100nm and an activation degree of more than 95%. The nanomaterial surface modifier is one of fatty acid, fatty acid sodium salt, silane coupling agent and methyl silicone oil.

The surfactant used in the injection agent is one or more of anionic surfactants, cationic surfactants, and nonionic surfactants. Anionic surfactants refer to alkylsulfonate anionic surfactants; cationic surfactants are one of tertiary amine salts and quaternary ammonium salt cationic surfactants; nonionic surfactants are Span, Tween, One or more of OP and NP nonionic surfactants.

The additive used in the injection booster is one of ethanol, ethylene glycol, glycerol, toluene and butyl ether.

A preparation method for a water-based oilfield injection enhancer based on nanomaterials, characterized in that the method has the following process: according to the above-mentioned ratio of nanomaterial-based water-based oilfield injection increasers, first weigh the diesel oil, and then Add nano-materials, emulsify machine speed 3000-8000rpm, emulsify and disperse for 2-5 minutes, then add surfactants and additives according to the ratio, and mechanically stir and disperse for 10-30 minutes at room temperature or in a water bath at 40-80°C to obtain nano-water-based additives. Injection stock solution.

The beneficial effects of the present invention are: the present invention relates to a nanometer water-based injection booster suitable for oil recovery in low-permeability oilfields and its preparation method. The booster has a strong emulsifying ability and can be mixed with water in any proportion , forming a homogeneous emulsified dispersion that can exist stably for a long time at room temperature. The nano water-based dispersion has a certain acid and alkali resistance, and its stability time and demulsification time can be controlled by adjusting the formula, so as to achieve the best use effect in accordance with different rock formation states. The invention utilizes the special properties of nanometer materials to physically modify the liquid flow channels in low-permeability oilfields to form slip channels with special nanometer characteristics, so that the liquid flow resistance can be effectively reduced, and the purpose of reducing pressure and increasing injection can be realized. The nano water-based injection booster has been evaluated by laboratory tests and field tests, and can effectively reduce water injection pressure, increase water injection volume, and achieve the purpose of reducing pressure, increasing injection, and increasing production capacity. The research of this technology will be very significant in terms of economic and social benefits, and it is also a successful combination of nanotechnology and petroleum engineering technology, which is of great significance.

Description of drawings

Fig. 1 is the TEM photomicrograph of the modified nano silicon dioxide described in Example 1.

Fig. 2 is the TEM photomicrograph of the modified nano silicon dioxide described in Example 2.

Fig. 3 is the TEM photomicrograph of the modified nano titanium oxide described in embodiment 4

FIG. 4 is a photo of the contact angle of the core piece 4 adsorbed by nanomaterials.

Figure 5 is the SEM photographs of the core slices without and after nanomaterial adsorption treatment.

Detailed ways

The present invention will be further described below through examples, but the protection scope of the present invention is not limited to these examples.

Example 1

Preparation of nanometer water-based injection booster stock solution: Weigh 40wt% of the total amount of diesel oil, add 2wt% of γ-(methacryloyloxy)propyl trimethoxysilane modified nano-silica, the average particle size About 20nm, activation degree ≥ 99%, emulsification machine 7000rpm emulsification dispersion 2min, then add other surfactants and additives, OP-10 accounted for 15wt%, Span80 accounted for 25wt%, sodium dodecylsulfonate accounted for 10wt%, Ethanol accounted for 8wt%, water bath at 40°C, and mechanically stirred for 10 minutes to obtain the original solution of nanometer water-based injection enhancer.

Preparation of nanometer water-based dispersion: measure 1L of tap water, add 10wt%, 15wt%, 20wt% of the above-mentioned injection booster stock solution, stir and mix evenly, and obtain nanometer water-based dispersion.

The TEM photomicrograph of nano-silica modified by γ-(methacryloyloxy)propyltrimethoxysilane is shown in Fig. 1 .

Example 2

Preparation of nano-water-based injection booster stock solution: Weigh 40wt% of the total amount of diesel oil, add 2wt% oleic acid-modified nano-silica, the average particle size is about 30nm, the activation degree is ≥99.5%, and the emulsifier is 7000rpm Emulsify and disperse for 2 minutes, then add other surfactants and additives, sodium petroleum sulfonate accounted for 15wt%, oleic acid accounted for 20wt%, cetyltrimethylammonium chloride accounted for 10wt%, ethanol accounted for 13wt%, water bath 60 ℃ , and mechanically stirred for 10 minutes to obtain the original solution of nanometer water-based injection enhancer.

The preparation of the nano water-based dispersion is the same as in Example 1.

The TEM photomicrograph of oleic acid-modified nano-silica is shown in Figure 2.

Example 3

Preparation of nano-water-based injection booster stock solution: Weigh 35wt% of the total diesel oil, add 2wt% simethicone modified nano-silica, the average particle size is about 50nm, the activation degree is ≥ 98%, emulsified Machine 4000rpm emulsification dispersion 5min, then add other surfactants and additives, sodium dodecylbenzenesulfonate accounted for 15wt%, oleic acid accounted for 15wt%, NP-10 accounted for 13wt%, ethylene glycol accounted for 20wt%, at room temperature Stir mechanically for 20 minutes to obtain the original solution of nanometer water-based injection enhancer.

The preparation of the nano water-based dispersion is the same as in Example 1.

Example 4

Preparation of nanometer water-based injection booster stock solution: Weigh 35wt% diesel oil, add 5wt% γ-(methacryloyloxy)propyltrimethoxysilane modified nano-titanium oxide, the average particle size is about 30nm, activation degree ≥ 99.5%, emulsification and dispersion at 4000rpm for 5min, then add other surfactants and additives, sodium petroleum sulfonate accounted for 15wt%, oleic acid accounted for 20wt%, triethanolamine accounted for 10wt%, ethylene glycol accounted for 15wt%, water bath at 60°C, and mechanically stirred for 20 minutes to obtain the original solution of nanometer water-based injection enhancer.

The preparation of the nano water-based dispersion is the same as in Example 1.

The TEM photomicrograph of nano-titanium oxide modified by γ-(methacryloyloxy)propyltrimethoxysilane is shown in FIG. 3 .

Example 5

Preparation of nano water-based injection booster stock solution: Weigh 40wt% of the total amount of diesel oil, add 5wt% oleic acid-modified nano-magnesium oxide, the average particle size is about 80nm, the activation degree is ≥ 98%, and the emulsifier is emulsified at 6000rpm Disperse for 3 minutes, then add other surfactants and additives, sodium dodecylbenzenesulfonate accounted for 15wt%, OP-10 accounted for 15wt%, Span85 accounted for 10wt%, butyl ether accounted for 15wt%, mechanically stirred at room temperature for 30min, that is Obtain the original solution of nanometer water-based injection enhancer.

The preparation of the nano water-based dispersion is the same as in Example 1.

Example 6

Preparation of nanometer water-based injection booster stock solution: Weigh 35wt% diesel oil, add 2.5wt% simethicone modified nano silicon dioxide and 2.5wt% gamma-(methacryloxy) Propyltrimethoxysilane-modified nano-titanium oxide, the average particle size is about 40nm, the degree of activation is ≥98%, the emulsifier is 6000rpm to emulsify and disperse for 5min, and then add other surfactants and additives, sodium petroleum sulfonate accounts for 10wt% , OP-10 accounted for 15wt%, Tween60 accounted for 15wt%, butyl ether accounted for 20wt%, water bath 40 ℃, mechanical stirring for 30min, that is to obtain the original solution of nano water-based injection enhancer.

The preparation of the nano water-based dispersion is the same as in Example 1.

Example 7

Preparation of nanometer water-based injection booster stock solution: Weigh 40wt% diesel oil, add 1wt% γ-(methacryloyloxy)propyltrimethoxysilane modified nano silicon dioxide and 1wt% Oleic acid modified nano-magnesium oxide, the average particle size is about 60nm, the activation degree is ≥98%, the emulsifier is 7000rpm to emulsify and disperse for 2min, and then add other surfactants and additives, OP-10 accounts for 15wt%, Span80 accounts for 25wt% 10wt% of sodium dodecylsulfonate, 8wt% of ethanol, in a water bath at 40°C, and mechanically stirred for 10min to obtain the stock solution of nanometer water-based injection enhancer.

The preparation of the nano water-based dispersion is the same as in Example 1.

Example 8

Preparation of nanometer water-based injection booster stock solution: Weigh 40wt% diesel oil, add 3wt% γ-(methacryloyloxy) propyl trimethoxysilane modified nano-titanium oxide and 2wt% di Nano-alumina modified by methyl silicone oil, the average particle size is about 70nm, the activation degree is ≥98%, the emulsifier is emulsified and dispersed at 6000rpm for 3min, and then other surfactants and additives are added, sodium dodecylbenzenesulfonate accounts for 15wt%, OP-10 15wt%, Span85 10wt%, butyl ether 15wt%, and mechanically stirred at room temperature for 30 minutes to obtain the nano water-based injection enhancer stock solution.

The preparation of the nano water-based dispersion is the same as in Example 1.

Injection effect laboratory evaluation:

Adsorption test of nanometer water-based injection agent on oil field core: prepare 2g/L nanometer water-based dispersion, cut thin slices from natural cores in different regions, immerse in water-based dispersion, 60°C, 48h. The water drop adsorption method was used to test the contact angle of nanomaterials adsorbed core pieces, and the results are shown in Table 1. The water droplet contact angles of the core slices treated with nano-water-based dispersions are all greater than 90°, and the maximum contact angle can reach more than 140°. Figure 4 is a schematic diagram of the contact angle of the core slice 4, showing strong hydrophobicity.

Table 1 Comparison of contact angles of core slices

serial number Core 1 Core 2 Core 3 Core 4 Core 5 Core 6 Contact angle/° 126.1 90.5 111.8 141.3 104.5 134.3

Laboratory flow test of nano water-based injection agent: first prepare 2g/L nano water-based dispersion liquid, under the set temperature and pressure, measure the water content of the core before and after the treatment of nano water-based dispersion liquid on the core flow tester. phase permeability. From the data in Table 2, it can be seen that the ratio of water phase permeability ( _after K/ _before K) of the core before and after treatment with nano-water-based dispersion is greater than 1, indicating that the water-phase permeability has been improved to varying degrees after treatment with nano-water-based dispersion. , the processing effect is obvious. Figure 5 is the SEM photographs of the core slices without and after nanomaterial adsorption treatment.

Table 2 Comparison of core permeability before and after nano water-based dispersion treatment

Claims (5)

1. A water-based oilfield booster injection based on nanomaterials, characterized in that the booster comprises diesel oil, surfactants, nanomaterials and additives, wherein diesel oil accounts for 20wt% to 60wt of the total amount %, surfactants account for 30wt% to 70wt% of the total, nanomaterials account for 1wt% to 10wt% of the total, additives account for 1wt% to 20wt% of the total, and the sum of the four components is 100wt%. 2. The water-based oilfield injection booster based on nanomaterials according to claim 1, characterized in that said nanomaterials are surface-modified nano-silicon dioxide, nano-titanium oxide, nano-magnesia, nano-alumina One or more of them, the average particle size is less than or equal to 100nm, and the degree of activation is more than or equal to 95%. The nanomaterial surface modifier is one of fatty acid, fatty acid sodium salt, silane coupling agent, and methyl silicone oil. 3. The water-based oilfield injection booster based on nanomaterials according to claim 1, characterized in that said surfactant is one of anionic surfactant, cationic surfactant, nonionic surfactant or Several kinds; The anionic surfactant is an alkylsulfonate anionic surfactant, the cationic surfactant is a kind of tertiary amine salt, quaternary ammonium salt cationic surfactant, and the nonionic surfactant is Span One or more of class, Tween class, OP class, NP class nonionic surfactants. 4. The water-based oilfield injection booster based on nanomaterials according to claim 1, characterized in that said auxiliary agent is one of ethanol, ethylene glycol, glycerol, toluene, and butyl ether. 5. A preparation method for the water-based oilfield injection booster based on nanomaterials as claimed in claim 1, characterized in that the method has the following process: by the nanomaterial-based water-based oilfield injection enhancement of claim 1 The ratio of the agent, first weigh the diesel oil, then add the nanomaterials, the emulsifier speed is 3000-8000rpm, emulsify and disperse for 2-5min, then add the surfactant and additives according to the ratio, at room temperature or in a water bath at 40-80°C, mechanically stir After dispersing for 10 to 30 minutes, the original solution of nanometer water-based injection enhancer is obtained.

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