CN104927832A - Self-diverting acid for acidifying modification of heterogeneous reservoir - Google Patents

Abstract

The invention provides a self-steering acid used for acidizing transformation of heterogeneous reservoirs. The composition of the self-steering acid is: 6-8% of the acidifying steering agent octadecyl butyl dihydroxyethyl ammonium bromide, 0.3%-0.5% of the steering synergist hydroxypropyl guar gum, and a cross-linking agent organic boron LGD (BOH) ₆ 0.2%-0.4%, anti-swelling and sand-inhibiting agent polyepichlorohydrin-dimethylamine 2%-4%, drainage aid triple quaternary ammonium salt surfactant 0.5%-1.5%, wetting inversion Alcohol ether 8%-12%, hydrochloric acid 6%-10%, and the rest of water. The temperature range of the self-diverting acid of the present invention is 40-60°C. During the acidizing process, it can automatically divert, penetrate deeply, and acidify the formation uniformly and efficiently. After encountering hydrocarbons, it will automatically break the gel, easy to flow back, no residue, no secondary damage, and low toxicity.

Description

A self-steering acid for acidizing transformation of heterogeneous reservoirs

This application is a divisional application of an invention patent application with application number 201410604181.9 and titled "An acidifying diverting agent octadecylbutyl dihydroxyethyl ammonium bromide and its preparation method and application".

technical field

The invention relates to an acidification diverting agent octadecyl butyl dihydroxyethyl ammonium bromide and a preparation method and application thereof, belonging to the technical field of petrochemical industry.

Background technique

Acidizing can effectively remove the pollution and clogging of oil layers near the wellbore, improve the connectivity between the wellbore and the reservoir near the wellbore, and increase the productivity of the oil well. The flow of acid liquid follows the principle of least resistance, and acid liquid preferentially enters the reservoir with better permeability during the acidizing process. In reservoirs with strong heterogeneity, most of the acid liquid enters the medium and high permeability layers, and only a small amount of acid liquid or even no acid liquid enters the low permeability layer, which not only makes it difficult to achieve uniform acidification of the reservoir and increase oil well productivity On the contrary, it will further enhance the heterogeneity of the reservoir and increase the difficulty of mining. Therefore, the use of acid fluid diversion technology to achieve uniform acidification of reservoirs and improve the acidification profile is of great significance for oil and gas well stimulation.

According to the steering mechanism, the acid steering technology is generally divided into mechanical steering and chemical steering. Mechanical diversion mainly includes packer diversion and particle diversion. Mechanical diversion technology is relatively mature, but the operation is complicated and expensive. When diverting and acidizing reservoirs containing many small thin layers and fractures, the diversion effect of acid fluid is poor; Compared with the mechanical steering technology, the chemical steering technology has the characteristics of convenient construction and low risk. The chemical steering technology mainly includes particle steering, foam steering, polymer steering and surfactant steering. The particle steering technology is likely to cause secondary damage to the reservoir. Foam diversion technology has limited diversion ability, which is easy to cause fluid loss in high-permeability reservoirs. Polymer diversion technology still has a large amount of polymer remaining in the reservoir after flowback, causing serious secondary damage to the reservoir.

The viscoelastic surfactant diverting technology has the characteristics of simple process, good diverting effect, slow speed and reduced fluid loss. The self-diverting acid with viscoelastic surfactant as the main agent has been widely used in the acidification of heterogeneous reservoirs. For example, patent CN103086909A provides a self-steering agent for heterogeneous carbonatite hydrochlorination system, which is erucamide propyl betaine, and the acid liquid system prepared with it can automatically become viscous as the acid-rock reaction proceeds , produce higher flow resistance, realize the effective distribution of the acid liquid in the reservoir, reduce the fluid loss of the acid liquid, increase the penetration distance of the acid liquid, and ensure the effective self-steering of the acid liquid system; patent CN102559168A invention An acid-sensitive viscous mixed surfactant is developed. The surfactant described in the invention is prepared by mixing a sulfonate gemini surfactant and an alkyl glycoside nonionic surfactant at a mass ratio of 1:4 to 4:1. The viscosity of the mixed system is high, but after adding acid to the system, the viscosity drops rapidly. The acid-containing acid-sensitive mixed surfactant system causes the viscosity of the solution to increase through the consumption of acid. It has the characteristics of automatically finding low-permeability intervals during oil reservoir acidification, and has the function of self-steering, which can realize uniform acidification and obtain Good acidifying effect. Acid-containing acid-sensitive mixed surfactants have high viscosity after acidification, but when they contact with crude oil or hydrocarbons, they will automatically reduce their viscosity, and their viscosity is close to that of water, which is easy to flow back.

Contents of the invention

Based on the deficiencies of the prior art, the invention provides an acidifying diverting agent octadecylbutyl dihydroxyethyl ammonium bromide and a preparation method thereof.

The present invention also provides the application of octadecyl butyl dihydroxyethyl ammonium bromide as an acidification diverting agent.

The invention also provides an oil and gas field acidification method.

The invention also provides a self-steering acid composition prepared by using octadecyl butyl dihydroxyethyl ammonium bromide as an acidification diverting agent (main agent). The self-steering acid prepared with octadecylbutyldihydroxyethylammonium bromide as the acidizing diverting agent (main agent) can effectively uniformly acidify heterogeneous reservoirs.

Technical scheme of the present invention is as follows:

An acidification diverting agent is characterized in that it is octadecyl butyl dihydroxyethyl ammonium bromide. Molecular formula: C ₂₆ H ₅₆ O ₂ BrN. Structural formula is shown in following formula I:

A preparation method of acidifying diverting agent octadecyl butyl dihydroxyethyl ammonium bromide, comprising two-step reaction, the steps are as follows:

(1) Condensation reaction

Diethanolamine and n-bromobutane are mixed in a molar ratio of 1:1, sodium bicarbonate is added as an auxiliary agent, stirred and refluxed for 3-5 hours under the condition of a constant temperature oil bath at 90-110°C, and the generated water is distilled off under reduced pressure to obtain N-Butyldiethanolamine.

In this step (1), the condensation reaction temperature is preferably 100°C; the reflux reaction time is preferably 4h;

(2) Quaternization reaction

N-butyldiethanolamine prepared in step (1) is mixed with bromooctadecane in a molar ratio of 1:1, sodium bicarbonate is added as an auxiliary agent, and stirred and refluxed for 9-11 hours under the condition of a constant temperature oil bath at 130-150°C, The generated water was distilled off under reduced pressure to obtain octadecyl butyl dihydroxyethyl ammonium bromide.

In this step (2), the quaternization reaction temperature is preferably 140° C.; the reaction time is preferably 10 h.

According to the present invention, the reaction formula of two-step reaction is as follows:

Step (1) reaction formula is as follows:

Step (2) reaction formula is as follows:

Preferably according to the present invention, adding sodium bicarbonate auxiliary agent in step (1), (2) helps to remove the hydrogen bromide that reaction generates. Sodium bicarbonate in step (1):diethanolamine=1～1.5:1 molar ratio, sodium bicarbonate in step (2):bromooctadecane=1～1.2:1 molar ratio.

The octadecyl butyl dihydroxyethyl ammonium bromide of the invention is used as an acidification diverting agent to uniformly acidify heterogeneous reservoirs.

According to the present invention, the application of octadecyl butyl dihydroxyethyl ammonium bromide as an acidifying diverting agent is the self-steering acid prepared with octadecyl butyl dihydroxyethyl ammonium bromide as the main agent, wherein ten The dosage concentration of octaalkylbutyldihydroxyethylammonium bromide in the self-steering acid is 6-8% by mass ratio, and the optimum dosage is 6% by mass ratio.

The use temperature range of self-steering acid prepared from octadecyl butyl dihydroxyethyl ammonium bromide is 40-60°C.

Self-steering acid formulated with octadecylbutyldihydroxyethylammonium bromide is effective for uniform acidification of heterogeneous reservoirs.

An oil-gas field acidizing method is characterized in that the octadecylbutyl dihydroxyethyl ammonium bromide described in the present invention is used as an acidizing diverting agent to acidify oil-gas wells in an oil-gas field.

A self-steering acid used for acidizing transformation of heterogeneous reservoirs, consisting of the following components in mass percentage:

Acidifying diverting agent octadecyl butyl dihydroxyethyl ammonium bromide: 6-8%;

Steering synergist hydroxypropyl guar gum: 0.3%-0.5%,

Organic boron crosslinking agent LGD(BOH) ₆ : 0.2%-0.4%,

Anti-swelling and sand-inhibiting agent polyepichlorohydrin-dimethylamine: 2%-4%,

Drainage aid Triple quaternary ammonium salt surfactant: 0.5%-1.5%,

Wetting reversal agent alcohol ether: 8%-12%, alcohol ether is composed of ethylene glycol and propylene glycol, the mass ratio is 0.75-1:1;

Hydrochloric acid: 6%-10% (calculated as HCl);

The rest is water.

Preferably according to the present invention, the mass ratio of the self-steering acid is: the concentration of the acidifying steering agent octadecylbutyl dihydroxyethyl ammonium bromide in the self-steering acid is 6-8%, and the concentration of the steering synergist The dosage concentration of hydroxypropyl guar gum is 0.4%, the dosage concentration of crosslinking agent organic boron LGD (BOH) ₆ is 0.3%, and the dosage concentration of polyepichlorohydrin-dimethylamine anti-swelling agent is 3%. The dosage concentration of surfactant triple quaternary ammonium salt is 1%, and the dosage concentration of wetting reversal agent alcohol ether is 10%. The alcohol ether is composed of ethylene glycol and propylene glycol 0.85:1, hydrochloric acid is 8%, and the rest is water.

The above-mentioned raw materials are all known materials and can be purchased through the market.

The inventor found that octadecyl butyl dihydroxyethyl ammonium bromide has a wide temperature range, and when the lowest temperature reaches 40°C, it exhibits significant viscoelasticity; Intertwined and entangled into a three-dimensional network structure, and the structure has a strong sense of hierarchy, as shown in Figure 1. Octadecylbutyldihydroxyethylammonium bromide product has good viscosity in the residual acid system, which can make the acid liquid have the ability to divert in the formation.

The self-steering acid prepared with octadecylbutyldihydroxyethylammonium bromide as the acidizing diverting agent can automatically divert, penetrate deeply, and acidify the formation uniformly and efficiently during the acidizing process. The acidizing diverting agent has good adsorption and can Effectively reduce acid fluid loss, automatically break gel when encountering hydrocarbons after acidification, easy to flow back, no residue, no secondary damage, low toxicity.

Description of drawings

Fig. 1 is the octadecyl butyl dihydroxyethyl ammonium bromide product SEM observation gel structure chart prepared in embodiment 1.

Fig. 2 is the octadecyl butyl dihydroxyethyl ammonium bromide product that embodiment 1 makes, white viscous colloid.

Fig. 3 is the relation curve of residual acid system viscosity and octadecyl butyl dihydroxyethyl ammonium bromide concentration.

Fig. 4 is the relationship curve between the viscosity of the residual acid system and the pH value of the residual acid system.

Fig. 5 is the relationship curve between the viscosity and temperature of the residual acid system.

Figure 6 shows the state of the residual acid solution under the conditions of 6 wt% octadecylbutyldihydroxyethyl ammonium bromide, 22 wt% CaCl ₂ , pH=5.4, and a temperature of 21°C.

Figure 7 is the acidification construction curve.

Detailed ways

The main reagents used in the examples are diethanolamine (CP), n-butane bromide (CP) and octadecane bromide (CP), all of which were purchased from Sinopharm Chemical Reagent Co., Ltd. Polyepichlorohydrin-dimethylamine was purchased from Zibo Sanfu Chemical Development Co., Ltd. Hydroxypropyl guar gum and organic boron LGD(BOH) ₆ as a crosslinking agent were produced and sold by Dongying Xinde Chemical Co., Ltd., and triple quaternary ammonium salt surfactant was purchased from Ningbo Dongfang Yongning Chemical Technology Co., Ltd.

The concentrations in the examples are all mass percent concentrations, unless otherwise specified.

Embodiment 1: the preparation of octadecyl butyl dihydroxyethyl ammonium bromide

(1) Condensation reaction

Take 0.05mol diethanolamine and 0.05mol n-bromobutane and mix them into a 500mL three-necked flask with a condensing reflux device, then add 0.05mol sodium bicarbonate (for removing the hydrogen bromide generated by the reaction), and place at a constant temperature In an oil bath, stir and reflux at 100°C for 4 hours, and distill off the generated water under reduced pressure to obtain the slightly viscous, dark yellow liquid N-butyldiethanolamine solution of the intermediate product.

(2) Quaternization reaction

Take the tertiary amine obtained in the previous step reaction and put it into a 500mL three-necked flask, add 0.05mol bromooctadecane and 0.05mol sodium bicarbonate, put it in a constant temperature oil bath, stir and reflux at 140°C for 10h, and distill under reduced pressure. Go out the water of generation, finally obtain white pasty liquid, be octadecyl butyl dihydroxyethyl ammonium bromide (see Figure 2).

Embodiment 2, with the octadecyl butyl dihydroxyethyl ammonium bromide prepared in embodiment 1, the concentration of preparing 5 groups of octadecyl butyl dihydroxyethyl ammonium bromide is respectively 4%, 5%, 6%, 7%, 8% residual acid solution, the method is as follows:

(1) Take 5 clean beakers (200mL in size), and add 74g, 73g, 72g, 71g, 70g of distilled water into the 5 beakers in turn;

(2) Weigh 5 groups of CaCl ₂ solids at room temperature, 22g in each group, add them to 5 beakers filled with distilled water, and stir until uniform; add octadecylbutyldihydroxyethylammonium bromide at room temperature , 4g, 5g, 6g, 7g, 8g for each group, stir until uniform;

(3) Add hydrochloric acid respectively in above-mentioned 5 groups of solutions, the pH value of 5 groups of solutions is adjusted to 5.4, the concentration that makes octadecyl butyl dihydroxyethyl ammonium bromide is 4%, 5%, 6%. , 7%, 8% residual acid solution;

_The CaCl concentrations of the above five groups of residual acid solutions were all 22%, the pH value was 5.4, and the concentrations of octadecylbutyldihydroxyethylammonium bromide were 4%, 5%, 6%, 7%, and 8%, respectively. The viscosity was measured at 60°C, and the results are shown in Table 1 and Figure 3.

Table 1 The data table of the viscosity of the residual acid solution at 60°C as a function of the concentration of octadecylbutyldihydroxyethylammonium bromide

concentration/% 4 5 6 7 8 Viscosity/mPa·s 54.3 62.0 523.1 704.5 796.7

It can be seen from Table 1 and Figure 3 that with the increase in the concentration of octadecylbutyldihydroxyethylammonium bromide, the viscosity of the residual acid system also increases significantly. When the concentration is small, the viscosity of the residual acid system is less than 100mPa s, this is because the concentration of octadecylbutyldihydroxyethylammonium bromide is near the critical micelle concentration, and spherical micelles are mainly formed in the system, and the viscosity Low; when the concentration of octadecylbutyldihydroxyethylammonium bromide reaches 6%, the viscosity of the system increases rapidly, reaching 523.1mPa s, and then as the concentration continues to increase, the viscosity of the residual acid system also continues At this time, the acidified diverting agent molecules in the system form columnar micelles, resulting in a significant increase in viscosity. From the experimental data and analysis, it can be determined that the concentration of octadecylbutyldihydroxyethylammonium bromide should be greater than 6%. Considering the cost factor, the concentration is determined to be 6-8%, and the optimum dosage is 6%.

Embodiment 3, with the octadecyl butyl dihydroxyethyl ammonium bromide prepared in embodiment 1, the preparation of 4 groups of pH values is respectively 4, 5, 6, and 7 residual acid solutions, and the method is as follows:

(1) Take 4 clean beakers (200mL in size), and add 72g of distilled water to each beaker;

(2) Take by weighing 4 groups of _CaCl2 solids at room temperature, each group of 22g, add respectively in 4 beakers filled with distilled water, stir until uniform; add octadecylbutyldihydroxyethylammonium bromide, each Mix 6g, stir until uniform;

(3) Add hydrochloric acid to the above four groups of solutions respectively, and adjust the pH values of the solutions to 4, 5, 6 and 7 respectively.

The concentration of _CaCl2 in the above four groups of residual acid solutions is 22%, the concentration of octadecylbutyldihydroxyethylammonium bromide is 6%, and the pH values are 4, 5, 6, 7 respectively. The viscosity was measured respectively, and the measurement results are shown in Table 2 and Figure 4.

Table 2 The data table of the change of viscosity of residual acid solution with pH value at 60°C

pH 4 5 6 7 Viscosity/mPa·s 376.2 520.0 525.7 560.5

It can be seen from Table 2 and Figure 4 that as the pH value of the system increases, the viscosity of the residual acid system also increases. When the pH of the residual acid system is >5, the viscosity of the residual acid system can reach more than 500mPa·s. The instrument used to measure the viscosity of the residual acid system is a Brookfield viscometer. Because its rotor is easily corroded by acid liquid, the experiment did not measure the pH< The viscosity of the residual acid system at 4 o'clock can be seen from the trend of the curve in Figure 4. For the fresh acid solution, that is, the pH value is in the range of 1 to 2, the viscosity is lower than 100mPa·s. It can be determined from the experimental data and analysis that the octadecane The self-steering acid prepared by using butyl dihydroxyethyl ammonium bromide as a steering agent has good steering performance.

Embodiment 4, prepare 6 groups of residual acid solutions with the octadecyl butyl dihydroxyethyl ammonium bromide prepared in embodiment 1:

(1) Take 6 clean beakers (200mL in size), and add 72g of distilled water to each beaker;

(2) Weigh 6 groups of CaCl ₂ solids at room temperature, 22g in each group, add them to 6 beakers filled with distilled water, stir until uniform; add octadecylbutyldihydroxyethylammonium bromide at room temperature , 6g per group, stir until uniform;

(3) Hydrochloric acid was added to the above six groups of solutions at room temperature to adjust the pH value of the six groups of solutions to 5.4.

The above 6 groups of residual acid solution _CaCl2 concentration is 22%, pH=5.4, octadecyl butyl dihydroxyethyl ammonium bromide concentration is 6%, the viscosity of the residual acid system at different temperatures respectively, the experimental results are shown in Table 3, Figure 5.

Table 3 Data table of residual acid solution viscosity changing with temperature

temperature/℃ 47.1 49.6 54.4 59.6 64.2 79.5 Viscosity/mPa·s 1003.0 879.2 589.5 538.3 64.0 79.2

It can be seen from Table 3 and Figure 5 that the viscosity of the residual acid solution gradually decreases as the temperature increases. The instrument used to measure viscosity is the Brookfield viscometer. The maximum viscosity it can measure is 8000mPa·s. When the temperature is lower than 47.1°C, the viscosity of the residual acid system has exceeded the maximum measurement range of the viscometer. At this time, the solution viscosity Very tall and mushy (see Figure 6). When the temperature is higher than 60°C, the viscosity of the residual acid system decreases rapidly, between 60 and 80mPa·s. From the experimental data and analysis, it can be determined that the operating temperature range of octadecylbutyldihydroxyethylammonium bromide is 40-60°C.

Embodiment 5: Self-steering acid composition and application

(1) adopt the octadecyl butyl dihydroxyethyl ammonium bromide prepared by embodiment 1 to prepare self-steering acid as an acidifying diverting agent, and the mass percentage is composed as follows:

Acidification diverting agent octadecyl butyl dihydroxyethyl ammonium bromide 6%;

Steering synergist hydroxypropyl guar gum 0.4%;

Crosslinking agent organic boron LGD (BOH) ₆ 0.3%;

Anti-swelling sand inhibitor polyepichlorohydrin - dimethylamine 3%;

Drainage aid triple quaternary ammonium salt surfactant 1%;

The alcohol ether concentration of the wetting reversal agent is 10%; the alcohol ether is composed of ethylene glycol and propylene glycol 0.85:1 hydrochloric acid 8% (calculated as HCl);

The rest is water.

When preparing the self-steering acid liquid, industrial hydrochloric acid with a mass concentration of 30%-38% is used, and the mass concentration of HCl in the prepared self-steering acid is 8%.

(2) Application of self-steering acid:

The self-steering acid prepared according to the formula in (1) was field tested in well X of fault block Chen 3 in the Chenbao structure of Gaoyou sag, Jiangsu. The test well adopts the self-steering acidizing process, the designed acid volume is 38m ³ , the construction span is 5m (2150.6-2155.6m), the displacement is 0.28-0.35m ³ /min, and the construction pressure is 17-20MPa. The acidification construction curve is shown in Figure 7. When the acid liquid enters the formation, the discharge rate does not change much at the initial stage, but the pressure increases significantly, indicating that the viscosity of the self-diverting acid entering the high-permeability zone increases rapidly, forcing the follow-up fresh acid to divert into the low-permeability zone, and the diversion acidification effect is obvious. After the construction, the liquid production rate of the oil well increased from 3t/d before the measures to 21t/d after the measures, and the effect of removing plugging and increasing liquid was remarkable.

Claims (3)

1., for a self-diverting acid for heterogeneous reservoir acidifying transformation, be made up of following mass percent component:

Acidified diverting agent octadecyl butyl dihydroxy ethyl brometo de amonio: 6-8%;

Turn to synergistic agent hydroxypropylguar gum: 0.3%-0.5%,

Linking agent organic boron LGD (BOH) ₆: 0.2%-0.4%,

Anti-swollenly press down sand agent Hydrin-dimethylamine: 2%-4%,

Cleanup additive three quaternary surfactant: 0.5%-1.5%,

Reverse wetting agent alcohol ether: 8%-12%, alcohol ether is made up of ethylene glycol and propylene glycol, mass ratio 0.75-1:1;

Hydrochloric acid, in HCl: 6%-10%,

All the other are water.

2. as claimed in claim 1 for the self-diverting acid of heterogeneous reservoir acidifying transformation, it is characterized in that, the quality proportioning of described self-diverting acid is: acidified diverting agent octadecyl butyl dihydroxy ethyl brometo de amonio consumption concentration in self-diverting acid is 6-8%, synergistic agent hydroxypropylguar gum consumption concentration is turned to be 0.4%, linking agent organic boron LGD (BOH) ₆consumption concentration is 0.3%, prevent that but swollen sand agent Hydrin-dimethylamine consumption concentration is 3%, cleanup additive three quaternary surfactant consumption concentration is 1%, reverse wetting agent alcohol ether consumption concentration is 10%, wherein alcohol ether is made up of ethylene glycol and propylene glycol 0.85:1, hydrochloric acid is 8%, and all the other are water.

3., as claimed in claim 1 for the self-diverting acid of heterogeneous reservoir acidifying transformation, it is characterized in that, described acidified diverting agent octadecyl butyl dihydroxy ethyl brometo de amonio is prepared by the following method:

Diethanolamine and bromination of n-butane press 1:1 mixed in molar ratio, add sodium bicarbonate and make auxiliary agent, stirring and refluxing reaction 3-5h under 90-110 DEG C of constant temperature oil bath condition, and underpressure distillation steams the water of generation, obtains N butyl diethanol amine; N butyl diethanol amine and bromo-octadecane press 1:1 mixed in molar ratio, add sodium bicarbonate and make auxiliary agent, and stirring and refluxing reaction 9-11h under 130-150 DEG C of constant temperature oil bath condition, underpressure distillation steams the water of generation, obtains octadecyl butyl dihydroxy ethyl brometo de amonio.