阅读说明：本技术 一种硝酸钾钻井液及其制备方法 (potassium nitrate drilling fluid and preparation method thereof ) 是由 马文英 钟灵 刘晓燕 王善举 史沛谦 殷子横 于 2018-07-18 设计创作，主要内容包括：本发明提供了一种硝酸钾钻井液,由包括以下组分的原料制备而成：水100重量份；钠基膨润土2重量份～4重量份；碳酸钠0.1重量份～0.2重量份；羧甲基纤维素钠盐0.5重量份～0.7重量份；降滤失剂0.3重量份～0.5重量份；稳定剂5重量份～9重量份；硝酸钾5重量份～10重量份；所述稳定剂由磺化酚醛树脂、磺化褐煤和磺化沥青组成。与现有技术相比,本发明提供的硝酸钾钻井液采用特定含量组分,各组分之间具有较好的相互作用,使产品同时具有良好的流变性和抑制性,并且该钻井液不使用氯化钾,消除了氯离子对地表水和土壤的污染以及对植物生长的不利影响,提高了环保性。(The invention provides potassium nitrate drilling fluid which is prepared from the following raw materials, by weight, 100 parts of water, 2-4 parts of sodium bentonite, 0.1-0.2 part of sodium carbonate, 0.5-0.7 part of sodium carboxymethyl cellulose, 0.3-0.5 part of fluid loss additive, 5-9 parts of stabilizer and 5-10 parts of potassium nitrate.)

1, potassium nitrate drilling fluid, which is prepared from the following raw materials:

100 parts by weight of water;

2-4 parts of sodium bentonite;

0.1 to 0.2 weight portions of sodium carbonate;

0.5 to 0.7 weight portion of sodium carboxymethyl cellulose;

0.3 to 0.5 weight portion of filtrate reducer;

5-9 parts of a stabilizer;

5 to 10 parts by weight of potassium nitrate;

the stabilizer consists of sulfonated phenolic resin, sulfonated lignite and sulfonated asphalt.

2. The potassium nitrate drilling fluid according to claim 1, wherein the fluid loss additive has a structure represented by formula (I):

in the formula (I), x is 14-22, y is 2-12, z is 4-10, and r is 0.42.

3. The potassium nitrate drilling fluid according to claim 1, wherein the mass ratio of the sulfonated phenolic resin, the sulfonated lignite and the sulfonated asphalt in the stabilizer is (2-3): (2-3): (1-3).

4. The potassium nitrate drilling fluid of any of claims 1-3, further comprising:

0.1 to 140 parts by weight of barite.

5, method for preparing potassium nitrate drilling fluid as claimed in any of claims 1-3, comprising the following steps:

a) mixing water, sodium bentonite and sodium carbonate, and curing to obtain base slurry;

b) mixing the base slurry obtained in the step a) with sodium carboxymethyl cellulose, a filtrate reducer, a stabilizer and potassium nitrate, and aging to obtain the potassium nitrate drilling fluid.

6. The method according to claim 5, wherein the mixing in step a) is performed at 10000-12000 r/min for 10-30 min.

7. The method according to claim 5, wherein the curing in step a) is greenhouse closing curing; the curing time is 20-30 h.

8. The preparation method according to claim 5, wherein the mixing in step b) is specifically performed by:

sequentially adding sodium carboxymethyl cellulose, a fluid loss additive and a stabilizer into the base slurry obtained in the step a) to carry out times of stirring, and then adding potassium nitrate to carry out a second stirring to obtain a mixture.

9. The preparation method according to claim 5, wherein the aging in step b) is carried out at a pH of 9-10, a temperature of 120-150 ℃ and a time of 14-18 h.

10. The method of any one of claims 5 to 9 and , wherein the step b) further comprises, before aging:

barite was added to the mixture.

Technical Field

The invention relates to the technical field of drilling fluids, in particular to potassium nitrate drilling fluids and a preparation method thereof.

Background

Along with the deep exploration and development, the drilling develops towards a deep well and an ultra-deep well, the stratum encountered by drilling is more and more complex, for the water-sensitive shale and the hard and brittle shale stratum, underground complex conditions such as stratum slurrying, well wall block falling and collapse and the like frequently occur in the drilling process, about 75 percent of well wall instability occurs in the stratum, the well wall instability problem is a technical problem frequently encountered in oil and gas drilling engineering and is a permanent problem accompanied with the drilling engineering, and according to statistics, the cost for processing the well wall stability problem in the world petroleum industry every year is up to 7 dollars billion, so that the effective solution of the well wall instability problem in the drilling process is which is an important task of petroleum workers.

The well wall instability problem in the well drilling process is related to geology, well drilling engineering, drilling fluid and the like, and the aim of good control can be achieved by adjusting well drilling engineering parameters and the performance of the drilling fluid, in the aspect of the drilling fluid, the oil-based drilling fluid has strong well wall stability, but has the defects of strong temperature sensitivity, poor environmental friendliness and the like, so that the use of the oil-based drilling fluid is limited, the water-based drilling fluid is a drilling fluid system which is most researched and applied in , the most commonly used shale inhibitor is potassium chloride, in the early 20 th century 70 s, the potassium chloride polymer drilling fluid is applied in cycles, the inhibition capability of the drilling fluid is improved, and the requirement of well wall stability can be basically met.

However, the use of potassium chloride imparts a high chloride content to the drilling fluid, causing pollution to the surrounding surface water and soil quality, while inhibiting plant growth, and if the drilling fluid is pulled away from the well site for centralized disposal, the post-treatment costs of the drilling fluid increase, thereby increasing drilling costs. With the stricter and stricter requirements of various countries on environmental protection, from the viewpoint of environmental protection, research on the use of new inhibitive drilling fluid becomes inevitable, and environmental and benefit are important to be considered. Therefore, the existing drilling fluid using potassium chloride as an inhibitor cannot well meet the requirement of environmental protection, and the drilling fluid has the problem that the inhibition needs to be improved while good rheological property is maintained.

Disclosure of Invention

In view of the above, the invention aims to provide types of potassium nitrate drilling fluid and a preparation method thereof, and the potassium nitrate drilling fluid provided by the invention has good rheological property and inhibition property, eliminates pollution of chlorine ions to surface water and soil and adverse effects on plant growth, and improves environmental protection property.

The invention provides potassium nitrate drilling fluid which is prepared from the following raw materials:

100 parts by weight of water;

2-4 parts of sodium bentonite;

0.1 to 0.2 weight portions of sodium carbonate;

0.5 to 0.7 weight portion of sodium carboxymethyl cellulose;

0.3 to 0.5 weight portion of filtrate reducer;

5-9 parts of a stabilizer;

5 to 10 parts by weight of potassium nitrate;

the stabilizer consists of sulfonated phenolic resin, sulfonated lignite and sulfonated asphalt.

Preferably, the fluid loss additive has a structure represented by formula (I):

in the formula (I), x is 14-22, y is 2-12, z is 4-10, and r is 0.42.

Preferably, the mass ratio of the sulfonated phenolic resin to the sulfonated lignite to the sulfonated asphalt in the stabilizer is (2-3): (2-3): (1-3).

Preferably, the method further comprises the following steps:

0.1 to 140 parts by weight of barite.

The invention also provides preparation methods of the potassium nitrate drilling fluid, which comprises the following steps:

a) mixing water, sodium bentonite and sodium carbonate, and curing to obtain base slurry;

b) mixing the base slurry obtained in the step a) with sodium carboxymethyl cellulose, a filtrate reducer, a stabilizer and potassium nitrate, and aging to obtain the potassium nitrate drilling fluid.

Preferably, the rotation speed of the mixing in the step a) is 10000r/min to 12000r/min, and the time is 10min to 30 min.

Preferably, the curing in the step a) is greenhouse closed curing; the curing time is 20-30 h.

Preferably, the mixing process in step b) is specifically:

sequentially adding sodium carboxymethyl cellulose, a fluid loss additive and a stabilizer into the base slurry obtained in the step a) to carry out times of stirring, and then adding potassium nitrate to carry out a second stirring to obtain a mixture.

Preferably, the aging in the step b) has a pH value of 9-10, a temperature of 120-150 ℃ and a time of 14-18 h.

Preferably, before the aging in step b), the method further comprises:

barite was added to the mixture.

The invention provides potassium nitrate drilling fluid which is prepared from the following raw materials, by weight, 100 parts of water, 2-4 parts of sodium bentonite, 0.1-0.2 part of sodium carbonate, 0.5-0.7 part of sodium carboxymethyl cellulose, 0.3-0.5 part of fluid loss additive, 5-9 parts of stabilizer and 5-10 parts of potassium nitrate.

In addition, the preparation method provided by the invention is simple, mild in condition and suitable for large-scale industrial production.

Drawings

Figure 1 is a photograph of a recovered rock debris of a potassium nitrate drilling fluid provided in example 1 of the present invention.

Detailed Description

The technical solution of the present invention will be described clearly and completely with reference to the embodiments of the present invention, and it should be understood that the described embodiments are only a partial embodiment , rather than a complete embodiment.

The invention provides potassium nitrate drilling fluid which is prepared from the following raw materials:

100 parts by weight of water;

2-4 parts of sodium bentonite;

0.1 to 0.2 weight portions of sodium carbonate;

0.5 to 0.7 weight portion of sodium carboxymethyl cellulose;

0.3 to 0.5 weight portion of filtrate reducer;

5-9 parts of a stabilizer;

5 to 10 parts by weight of potassium nitrate;

the stabilizer consists of sulfonated phenolic resin, sulfonated lignite and sulfonated asphalt.

In the invention, the sodium bentonite is a slurry preparation material, and the sodium bentonite increases viscosity and shearing force after hydration, improves the purification capacity of a well hole and is beneficial to forming mud cakes. The source of the sodium bentonite in the present invention is not particularly limited, and commercially available products known to those skilled in the art may be used. In the invention, the potassium nitrate drilling fluid comprises 2-4 parts by weight of sodium bentonite.

In the present invention, the sodium carbonate is used to activate sodium bentonite. The source of the sodium carbonate in the present invention is not particularly limited, and commercially available products known to those skilled in the art may be used. In the invention, the potassium nitrate drilling fluid comprises 0.1-0.2 parts by weight of sodium carbonate.

In the invention, the sodium carboxymethyl cellulose mainly has the function of forming a low-permeability, flexible, thin and compact mud cake on the well wall and reducing the medium-pressure filtration loss of the drilling fluid. The source of the carboxymethyl cellulose sodium salt in the present invention is not particularly limited, and commercially available products known to those skilled in the art may be used. In the invention, the potassium nitrate drilling fluid comprises 0.5-0.7 parts by weight of sodium carboxymethyl cellulose.

In the present invention, the fluid loss additive preferably has a structure represented by formula (I):

in formula (I), x is 14 to 22, y is 2 to 12, z is 4 to 10, and r is 0.42. in a preferred embodiment of the present invention, x is 21.1, y is 10.6, z is 4.8, and r is 0.42. in another preferred embodiments of the present invention, x is 14, y is 4.9, z is 9.6, and r is 0.42.

In the invention, the preparation method of the fluid loss additive is preferably as follows:

the mass ratio is (10-20): (10-15): (2-8): mixing 1 of 2-methyl-2-acryloyloxypropylsulfonic acid, acrylamide, acrylic acid and 2-hydroxy-3-methacryloyloxypropyltrimethylammonium chloride to prepare an aqueous solution, adjusting the pH value of the aqueous solution to 9-11, adding a polymerization reaction initiator to perform polymerization reaction, wherein the initial temperature of the polymerization reaction is 20-50 ℃, the polymerization time is 5-30 min, and granulating, drying and crushing a polymerization product to obtain the filtrate reducer.

In a preferred embodiment of the present invention, the preparation method of the fluid loss additive comprises:

preparing 26g of 2-methyl-2-acryloyloxypropylsulfonic acid, 39g of acrylamide, 20g of acrylic acid and 2.6g of 2-hydroxy-3-methacryloyloxypropyltrimethylammonium chloride into an aqueous solution at room temperature, adjusting the pH value of the aqueous solution to 9 by using sodium hydroxide, adding 0.05g of ammonium persulfate and 0.05g of sodium bisulfite to initiate polymerization, wherein the initial temperature of the polymerization reaction is 20 ℃, the polymerization time is 5min, and granulating, drying and crushing the product to obtain the filtrate reducer with the structure shown in the formula (I-1);

in another preferred embodiments of the present invention, the fluid loss additive is prepared by the following steps:

preparing 56g of 2-methyl-2-acryloyloxypropylsulfonic acid, 28g of acrylamide, 10g of acrylic acid and 2.8g of 2-hydroxy-3-methacryloyloxypropyltrimethylammonium chloride into an aqueous solution at room temperature, adjusting the pH value of the aqueous solution to 11 by using sodium hydroxide, adding 0.2g of potassium persulfate and 0.2g of sodium thiosulfate to initiate polymerization, wherein the initial temperature of the polymerization reaction is 50 ℃, the polymerization time is 20min, and granulating, drying and crushing the product to obtain the filtrate reducer with the structure shown in the formula (I-2);

by adopting the filtrate reducer, the liquid phase viscosity of the drilling fluid can be improved under the high-salt and high-temperature environment, and the filtrate loss of the drilling fluid is further reduced by .

In the invention, the stabilizer is composed of sulfonated phenolic resin, sulfonated lignite and sulfonated asphalt, the mass ratio of the sulfonated phenolic resin to the sulfonated lignite to the sulfonated asphalt in the stabilizer is preferably (2-3) to (1-3), in the invention, the potassium nitrate drilling fluid comprises 5-9 parts by weight of the stabilizer, in a preferred embodiment of the invention, the potassium nitrate drilling fluid comprises 6 parts by weight of the stabilizer, wherein the mass ratio of the sulfonated phenolic resin to the sulfonated lignite to the sulfonated asphalt is 2: 2: 2, namely the potassium nitrate drilling fluid comprises 2 parts by weight of the sulfonated phenolic resin, 2 parts by weight of the sulfonated lignite and 2 parts by weight of the sulfonated asphalt, in another preferred embodiments of the invention, the potassium nitrate drilling fluid comprises 5 parts by weight of the stabilizer, wherein the mass ratio of the sulfonated phenolic resin to the sulfonated lignite to the sulfonated asphalt is 2: 2: 1, namely the potassium nitrate drilling fluid comprises 2 parts by weight of the sulfonated phenolic resin, 2 parts by weight of the sulfonated lignite and 1 part by weight of the sulfonated asphalt, in another preferred embodiments of the potassium nitrate drilling fluid comprises 3 parts by weight of the sulfonated phenolic resin and 3 parts by weight of the sulfonated asphalt.

In the invention, the main functions of the sulfonated phenolic resin and the sulfonated lignite are to improve the temperature resistance of the drilling fluid and reduce the high-temperature and high-pressure filtration loss of the drilling fluid; the sulfonated asphalt is mainly used for plugging micro-pores and micro-cracks of the stratum and preventing drilling fluid from entering the stratum; more importantly, the sulfonated phenolic resin, the sulfonated lignite and the sulfonated asphalt can realize better interaction with other components in a drilling fluid system taking potassium nitrate as an inhibitor, the well wall stabilizing effect is good, and the product has good rheological property and inhibition property at the same time.

In the invention, the potassium nitrate is an inhibitor, and the main function of the potassium nitrate is to improve the inhibition capability of the drilling fluid; in addition, potassium ions and nitrate ions in the potassium nitrate can be quickly absorbed by crops, and cannot adversely affect surface water and soil. The source of potassium nitrate in the present invention is not particularly limited, and commercially available products known to those skilled in the art may be used. In the invention, the potassium nitrate drilling fluid comprises 5-10 parts by weight of potassium nitrate.

In the present invention, the potassium nitrate drilling fluid preferably further comprises:

0.1 to 140 parts by weight of barite. In the invention, the barite has the main function of adjusting the density of the drilling fluid to achieve near-balanced drilling and ensure the safety of drilling construction; can be optionally added. The source of the barite is not particularly limited in the present invention, and commercially available products well known to those skilled in the art may be used.

The potassium nitrate drilling fluid provided by the invention adopts specific content components, the components have better interaction, so that the product has good rheological property and inhibition property, and potassium chloride is not used in the drilling fluid, so that the pollution of chloride ions to surface water and soil and the adverse effect on plant growth are eliminated, and the environmental protection property is improved.

The invention also provides preparation methods of the potassium nitrate drilling fluid, which comprises the following steps:

a) mixing water, sodium bentonite and sodium carbonate, and curing to obtain base slurry;

b) mixing the base slurry obtained in the step a) with sodium carboxymethyl cellulose, a filtrate reducer, a stabilizer and potassium nitrate, and aging to obtain the potassium nitrate drilling fluid.

The invention firstly mixes water, sodium bentonite and sodium carbonate, and carries out maintenance to obtain base slurry. In the present invention, the sodium bentonite and the sodium carbonate are the same as those described in the above technical scheme, and are not described herein again.

In the invention, the rotation speed of the mixing is preferably 10000 r/min-12000 r/min, more preferably 11000 r/min-12000 r/min; the mixing time is preferably 10 to 30min, more preferably 20 min.

In the present invention, the curing method is preferably greenhouse-closed curing. In the present invention, the curing time is preferably 20 to 30 hours, and more preferably 24 hours.

After the base slurry is obtained, the obtained base slurry is mixed with sodium carboxymethyl cellulose, a filtrate reducer, a stabilizer and potassium nitrate, and the mixture is aged to obtain the potassium nitrate drilling fluid. In the present invention, the carboxymethyl cellulose sodium salt, the fluid loss additive, the stabilizer and the potassium nitrate are the same as those described in the above technical solution, and are not described herein again.

In the present invention, the mixing process preferably includes:

sequentially adding sodium carboxymethyl cellulose, a fluid loss additive and a stabilizer into the base slurry obtained in the step a) to carry out times of stirring, and then adding potassium nitrate to carry out a second stirring to obtain a mixture.

In the invention, the rotating speed of the th stirring is preferably 6000 r/min-12000 r/min, more preferably 8000 r/min-10000 r/min, and the time of the th stirring is preferably 10 min-30 min, more preferably 20 min.

In the invention, the rotation speed of the second stirring is preferably 6000 r/min-12000 r/min, and more preferably 8000 r/min-10000 r/min. The time for the second stirring is not particularly limited, and the potassium nitrate can be fully dissolved.

After the mixture is obtained, the obtained mixture is aged to obtain the potassium nitrate drilling fluid. In the present invention, before the aging, it is preferable to further include:

barite was added to the mixture. In the present invention, the barite is the same as that described in the above technical solution, and is not described herein again.

The equipment for the aging process is not particularly limited in the present invention, and an aging tank well known to those skilled in the art is used. In the invention, the pH value of the aging is preferably 9-10; the method of adjusting the pH value is not particularly limited in the present invention, and the pH value can be adjusted by using sodium hydroxide which is well known to those skilled in the art. In the present invention, the temperature of the aging is preferably 120 to 150 ℃; the aging time is preferably 14 to 18 hours, and more preferably 16 hours.

The invention provides potassium nitrate drilling fluid which is prepared from the following raw materials, by weight, 100 parts of water, 2-4 parts of sodium bentonite, 0.1-0.2 part of sodium carbonate, 0.5-0.7 part of sodium carboxymethyl cellulose, 0.3-0.5 part of fluid loss additive, 5-9 parts of stabilizer and 5-10 parts of potassium nitrate.

To further illustrate the present invention, the following examples are given in detail, wherein the carboxymethyl cellulose sodium salt used in the following examples is carboxymethyl cellulose LV-CMC supplied by Puyang central China industry Co., Ltd, the sulfonated phenolic resin used in the following examples is sulfonated phenolic resin SMP supplied by Puyang China chemical industry Co., Ltd, the sulfonated lignite used in the following examples is sulfonated lignite SMC supplied by Puyang China chemical industry Co., Ltd, and the sulfonated asphalt used in the following examples is sulfonated asphalt FT-1 supplied by seventh chemical industry Co., Ltd, furthermore, the fluid loss additive used in the following examples of the present invention is prepared by the preparation method of the above technical scheme, wherein the fluid loss additive with the structure represented by formula (I-1) has the structural formula:

the structural formula of the fluid loss additive with the structure shown in the formula (I-2) is as follows: