阅读说明：本技术 用于酸压的吸附缓释酸体系及其制备方法 (Adsorption slow-release acid system for acid fracturing and preparation method thereof ) 是由 唐汝众 段秀全 程鹏 周德川 于 2019-10-16 设计创作，主要内容包括：本发明属于油田增产领域,具体地,涉及一种用于酸压的吸附缓释酸体系。用于酸压的吸附缓释酸体系,原料质量百分比组成如下：缓释酸稠化剂0.3％-1.0％,吸附剂5.0％-60.0％,增效剂0.5％-1.5％,缓蚀剂1.0％-5.0％,铁离子稳定剂0.5％-1.0％,余量为质量分数15-28％的盐酸。采用多元共聚的聚合物作为缓释酸的稠化剂,该稠化剂与增效剂能够产生粘弹作用,使得缓释酸在高温下具有较好的流变性能,根据储层地质特征和施工排量等调节吸附剂的加砂比,在有效防止砂堵的同时,也实现缓释酸总量的调节,该体系不仅仅充分利用了已有酸液体系的性能优势,独创的利用固体吸附剂来向酸压裂缝前缘输送高浓度酸液,同时吸附剂还可以起到暂堵、转向等多重作用。(The invention belongs to the field of oil field production increase, and particularly relates to an adsorption slow-release acid system for acid fracturing. The adsorption slow-release acid system for acid fracturing comprises the following raw materials in percentage by mass: 0.3-1.0% of slow-release acid thickening agent, 5.0-60.0% of adsorbent, 0.5-1.5% of synergist, 1.0-5.0% of corrosion inhibitor, 0.5-1.0% of iron ion stabilizer and the balance of hydrochloric acid with the mass fraction of 15-28%. The polymer of multicomponent copolymerization is used as the thickening agent of the slow-release acid, the thickening agent and the synergist can generate viscoelastic action, so that the slow-release acid has better rheological property at high temperature, the sand adding ratio of the adsorbent is adjusted according to reservoir geological characteristics, construction discharge capacity and the like, sand blockage is effectively prevented, the total amount of the slow-release acid is adjusted, the system not only fully utilizes the performance advantages of the existing acid liquid system, the solid adsorbent is originally utilized to convey high-concentration acid liquid to the front edge of the acid fracturing fracture, and meanwhile, the adsorbent can play multiple roles of temporary blockage, steering and the like.)

1. An adsorption slow-release acid system for acid fracturing is characterized by comprising the following raw materials in percentage by mass:

the balance is 15-28% of hydrochloric acid by mass.

2. An adsorptive slow release acid system for acid fracturing according to claim 1, wherein: the slow-release acid thickening agent is AM-AMPS copolymer with the molecular weight of 600-1500 ten thousand.

3. An adsorptive slow release acid system for use in acid fracturing according to claims 1-2, wherein: the adsorbent is ceramic porous particles, silicate artificial porous particles or natural rock porous particles.

4. An adsorptive slow release acid system for use in acid fracturing according to claims 1 to 3, wherein: the synergist is alkylphenol polyoxyethylene.

5. An adsorptive slow release acid system for use in acid fracturing according to claims 1 to 4, wherein: the corrosion inhibitor is a mixture of Mannich base and methanol, wherein the mass ratio of the Mannich base to the methanol mixture is 45: 55.

6. an adsorptive slow release acid system for use in acid fracturing according to claims 1 to 5, wherein: the iron ion stabilizer is sodium citrate.

7. The process for preparing an adsorptive slow-release acid system for use in acid fracturing according to claims 1 to 6, comprising the steps of:

preparing hydrochloric acid with the mass fraction of 15-28%;

② adding 0.3-1.0 percent of slow-release acid thickening agent under the stirring condition, and continuously stirring for 20 min;

thirdly, adding 1.0 to 5.0 percent of corrosion inhibitor under the stirring condition;

adding 0.5-1.0% of iron ion stabilizer under stirring;

5.0-60.0 percent of adsorbent and 0.5-1.5 percent of synergist are added simultaneously under the acid fracturing construction condition.

8. The method for preparing the adsorption slow-release acid system for the acid fracturing as claimed in claim 7, wherein the method for preparing the adsorption slow-release acid thickener for the acid fracturing comprises the following steps:

the preparation method comprises the following steps of: adding 2-acrylamide-2-methylpropanesulfonic Acid (AMPS) into a modulation reaction kettle according to the mass ratio of 5: 1-2, mixing, and adjusting the pH value to 11-12 by using NaOH;

pumping the mixed reactant in the preparation reaction kettle into a polymerization reaction kettle, adding azodiisobutyronitrile serving as a catalyst, and keeping the temperature between 0 and 5 ℃ by adopting nitrogen;

slowly adding dimethyl diallyl ammonium chloride under the stirring condition, observing the temperature change, controlling the reaction temperature within 10 ℃, and continuously reacting for 4 hours to obtain the slow-release acid thickening agent which is an AM-AMPS copolymer with the molecular weight of 800-1200 ten thousand;

pressurizing with nitrogen, extruding the reaction product, and primarily crushing by a crusher to obtain particles with the size of about 5-10 mm; and then drying by adopting fluidized drying equipment, and then granulating in a granulator.

Technical Field

The invention belongs to the field of oil field production increase, and particularly relates to an adsorption slow-release acid system for acid fracturing and a preparation method thereof.

Background

The storage space of the carbonate reservoir is a hole seam, but due to the low matrix permeability of the reservoir, the acid fracturing is a key technology for improving the productivity of the reservoir under the condition that the natural yield of the carbonate reservoir cannot realize industrial and economic exploitation. The general acid system achieves the technical purpose by reducing the reaction speed of acid and rock, mainly improves the viscosity and the temperature resistance of the acid system, and improves the utilization rate of the acid by reducing the filtration loss of the acid and reducing the reaction speed of the acid and the rock, so that the length of the acid corrosion crack is improved, and the flow conductivity of the acid corrosion crack is further improved.

The invention patent with publication number CN103525393A discloses an instant acid thickener, which comprises the following raw materials in parts by weight: 45-65 parts of organic alcohol, 25-45 parts of polymer and 1-10 parts of dispersant; the instant acid thickener prepared by the invention has good acid resistance and temperature resistance, the viscosity of thickening acid prepared by the instant acid thickener and hydrochloric acid can be ensured to be more than 50mPa.s, and the viscosity loss rate is less than 10% at 90 ℃.

The invention patent with the publication number of CN101857663A discloses a polymer for acid fracturing temperature control viscosity change and a preparation method of a polymer cross-linked body. The polymer cross-linked body prepared by the method can only be used for stratum acid fracturing within 120 ℃, the viscosity is only about 20mPa.s at 25 ℃, and the viscosity can only be kept at 10-20mPa "S at 120 ℃.

The invention discloses a ground cross-linking acid liquid and a preparation method thereof, wherein the ground cross-linking acid liquid comprises the following components in percentage by mass: 15-25% of hydrochloric acid (calculated by pure hydrogen chloride), 0.6-1.2% of EVA-180 thickening agent, 1-5% of organic metal cross-linking agent zirconium acetylacetonate and the balance of water. At normal temperature, adding a certain amount of thickening agent into hydrochloric acid solution, rapidly stirring until the thickening agent is completely dissolved, then standing for 2-4h to obtain uniform viscous liquid, finally adding organic metal cross-linking agent, and uniformly stirring.

The acid liquor systems such as the thickening acid and the cross-linking acid related to the patent carry out a large amount of improvement work in the aspects of temperature resistance, shearing resistance, acid rock reaction speed reduction and the like, so that the maximum capability of the temperature resistance and shearing resistance of the acid liquor system is improved, but the deep carbonate rock reservoir is high in stratum temperature, the viscosity of the acid liquor system is lower at high temperature, the acid liquor filtration is large, the acid rock reaction speed is high, the acid liquor can hardly enter the deep part of the reservoir, and the acid fracturing effect is seriously influenced.

Disclosure of Invention

Aiming at the defects of the prior acid liquor system technology, the invention provides an adsorption slow-release acid system for acid fracturing, which adopts a solid adsorbent for adsorbing high-concentration acid liquor, can reduce filtration loss and have temporary plugging and steering effects along with the fact that the acid liquor enters the deep part of the front edge of an acid-etched crack, and can also be combined with other acid fracturing section plugs, and the adsorbent slowly releases the high-concentration acid liquor at the fixed point in the crack under the action of the crack closing pressure after the acid fracturing is finished, so that the wall surface of the crack further reacts, the crack has higher flow conductivity, and the acid fracturing effect is further improved.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the adsorption slow-release acid system for acid fracturing comprises the following raw materials in percentage by mass:

the balance is 15-28% of hydrochloric acid by mass.

Preferably, the slow-release acid thickening agent is an AM-AMPS copolymer with the molecular weight of 600-1500 ten thousand.

Preferably, the adsorbent is ceramic porous particles, silicate artificial porous particles or natural rock porous particles.

Preferably, the synergist is alkylphenol ethoxylates.

Preferably, the corrosion inhibitor is a mixture of mannich base and methanol, and the mass ratio of the mannich base to the methanol mixture is 45: 55.

preferably, the iron ion stabilizer is sodium citrate.

The preparation method of the adsorption slow-release acid system for acid fracturing comprises the following steps:

preparing hydrochloric acid with the mass fraction of 15-28%.

② adding 0.3-1.0 percent of slow-release acid thickening agent under the condition of stirring, and continuously stirring for 20 min.

③ adding 1.0 to 5.0 percent of corrosion inhibitor under the stirring condition.

And fourthly, adding 0.5 to 1.0 percent of iron ion stabilizer under the stirring condition.

5.0-60.0 percent of adsorbent and 0.5-1.5 percent of synergist are added simultaneously under the acid fracturing construction condition.

The preparation method of the adsorption slow-release acid thickening agent for acid fracturing comprises the following steps:

first, an Acrylamide Monomer (AM): adding 2-acrylamide-2-methylpropanesulfonic Acid (AMPS) into a modulation reaction kettle according to the mass ratio of 5: 1-2, mixing, and adjusting the pH value to 11-12 by using NaOH;

pumping the mixed reactant in the preparation reaction kettle into a polymerization reaction kettle, adding azodiisobutyronitrile serving as a catalyst, and keeping the temperature between 0 and 5 ℃ by adopting nitrogen;

slowly adding dimethyl diallyl ammonium chloride under the stirring condition, observing the temperature change, controlling the reaction temperature within 10 ℃, and continuously reacting for 4 hours to obtain the slow-release acid thickening agent which is an AM-AMPS copolymer with the molecular weight of 800-1200 ten thousand;

pressurizing with nitrogen, extruding the reaction product, and primarily crushing by a crusher to obtain particles with the size of about 5-10 mm; and then drying by adopting fluidized drying equipment, and then granulating in a granulator.

The invention adopts the multipolymer as the thickening agent of the slow-release acid, the thickening agent and the synergist can generate viscoelastic action, so that the slow-release acid has better rheological property at high temperature, the sand adding ratio of the adsorbent is adjusted according to reservoir geological characteristics, construction discharge capacity and the like, the total amount of the slow-release acid is adjusted while sand blocking is effectively prevented, the system not only fully utilizes the performance advantages of the existing acid liquid system, but also originally utilizes the solid adsorbent to convey high-concentration acid liquid to the front edge of the acid fracturing fracture, and meanwhile, the adsorbent can play multiple roles of temporary blocking, steering and the like.

Compared with the prior art, the invention has the following beneficial effects:

1. the adopted slow-release acid thickener has high dissolution speed, is completely dissolved in hydrochloric acid with the mass fraction of 15-28% for 30min, and has stable performance in acid liquor.

2. The adsorbent and the synergist can be used for adjusting the concentration of the adsorbent in the acid liquor and the high-temperature rheological property of the acid liquor base liquid according to the requirements of site construction, particularly sand carrying, so that the fixed-point quantitative acidizing treatment on the acid fracturing fracture is realized.

3. The adopted synergist is alkylphenol ethoxylates which can form a viscoelastic acid liquid system with the slow-release acid thickener, and has good temperature resistance and shear resistance under the conditions of high temperature of 120 ℃ and 140 ℃.

4. The corrosion inhibitor is a mannich base: methanol in a mass ratio of 45: 55, the system has the advantage that the corrosion inhibition requirement of the construction pipe column can be met at the high temperature of 120-160 ℃.

5. The iron ion stabilizer is sodium citrate, has good iron ion stability, and has good compatibility with other additives of the slow-release acid system.

6. The adsorption slow-release acid system realizes the adjustment of the total amount of the high-concentration acid liquor at the far end of the crack by adjusting the addition concentration of the adsorbent, thereby realizing the improvement of the flow conductivity of the deep part of the acid fracturing crack.

Drawings

FIG. 1 is a schematic diagram of 120 ℃ rheological curve of adsorption sustained-release acid.

Detailed Description

The present invention is described in detail below by way of specific embodiments. The invention is further illustrated, but is not to be construed as being limited, by the following examples. All percentages in the examples are by mass, unless otherwise specified, and all raw materials used are commercially available materials.

The adsorption slow-release acid system for acid fracturing comprises the following raw materials in percentage by mass:

the balance is 15-28% of hydrochloric acid by mass.

The slow-release acid thickening agent is an AM-AMPS copolymer with the molecular weight of 600-1500 ten thousand.

The adsorbent is ceramic porous particles, silicate artificial porous particles and natural rock porous particles.

The synergist is alkylphenol polyoxyethylene.

The corrosion inhibitor is a mixture of Mannich base and methanol, wherein the mass ratio of the Mannich base to the methanol mixture is 45: 55.

the iron ion stabilizer is sodium citrate.

The preparation method of the adsorption slow-release acid thickening agent for acid fracturing comprises the following steps:

the preparation method comprises the following steps of: adding 2-acrylamide-2-methylpropanesulfonic Acid (AMPS) into a modulation reaction kettle according to the mass ratio of 5: 1-2, mixing, and adjusting the pH value to 11-12 by using NaOH;

pumping the mixed reactant in the preparation reaction kettle into a polymerization reaction kettle, adding azodiisobutyronitrile serving as a catalyst, and keeping the temperature between 0 and 5 ℃ by adopting nitrogen;

slowly adding dimethyl diallyl ammonium chloride under the stirring condition, observing the temperature change, controlling the reaction temperature within 10 ℃, and continuously reacting for 4 hours to obtain the slow-release acid thickening agent which is an AM-AMPS copolymer with the molecular weight of 800-1200 ten thousand;

pressurizing with nitrogen, extruding the reaction product, and primarily crushing by a crusher to obtain particles with the size of about 5-10 mm; and then drying by adopting fluidized drying equipment, and then granulating in a granulator.

The preparation method of the adsorption slow-release acid system for acid fracturing comprises the following steps:

preparing hydrochloric acid with the mass fraction of 15-28%.

② adding 0.3-1.0 percent of slow-release acid thickening agent under the condition of stirring, and continuously stirring for 20 min.

③ adding 1.0 to 5.0 percent of corrosion inhibitor under the stirring condition.

And fourthly, adding 0.5 to 1.0 percent of iron ion stabilizer under the stirring condition.

5.0-60.0 percent of adsorbent and 0.5-1.5 percent of synergist are added simultaneously under the acid fracturing construction condition.