阅读说明：本技术 钻井液用固壁剂及其制备方法和应用 (Wall-fixing agent for drilling fluid and preparation method and application thereof ) 是由 冯海平 赵玉浩 赵俊岭 郭中文 余进 于德成 卓绿燕 杜庆福 赵诚 于 2020-07-15 设计创作，主要内容包括：本发明提出钻井液用固壁剂及其制备方法和应用,属于钻井液技术领域。该钻井液用固壁剂,由包括如下重量份数原料制备而得：丙烯酰胺10～25份,粘合剂10～25份,二甲基二烯丙基氯化铵10～25份,丙烯酸1～5份,2-丙烯酰胺-2-甲基丙磺酸1～5份,链转移剂1～5份,引发剂2～5份,氢氧化钠5～12份,蒸馏水80～100份。本发明提出的固壁剂,通过增强岩石颗粒间的内聚力、粘附力来提高井壁岩石强度,从而提高钻井液的防塌性能。尤其页岩在水化膨胀时的水化力等可被“仿生壳”的内聚力削弱或完全抵消,提高井壁稳定性,使得该固壁剂在水环境中具有较好的粘附性能。(The invention provides a wall-fixing agent for drilling fluid and a preparation method and application thereof, belonging to the technical field of drilling fluid. The wall-fixing agent for the drilling fluid is prepared from the following raw materials in parts by weight: 10-25 parts of acrylamide, 10-25 parts of an adhesive, 10-25 parts of dimethyldiallylammonium chloride, 1-5 parts of acrylic acid, 1-5 parts of 2-acrylamide-2-methylpropanesulfonic acid, 1-5 parts of a chain transfer agent, 2-5 parts of an initiator, 5-12 parts of sodium hydroxide and 80-100 parts of distilled water. The wall consolidating agent provided by the invention improves the rock strength of a well wall by enhancing the cohesive force and the adhesive force among rock particles, thereby improving the anti-collapse performance of the drilling fluid. Particularly, the hydration force of the shale during hydration expansion and the like can be weakened or completely offset by the cohesive force of the bionic shell, so that the stability of the well wall is improved, and the wall solidifying agent has better adhesion performance in a water environment.)

1. The wall fixing agent for the drilling fluid is characterized by being prepared from the following raw materials in parts by weight:

10-25 parts of acrylamide, 10-25 parts of an adhesive, 10-25 parts of dimethyldiallylammonium chloride, 1-5 parts of acrylic acid, 1-5 parts of 2-acrylamide-2-methylpropanesulfonic acid, 1-5 parts of a chain transfer agent, 2-5 parts of an initiator, 5-12 parts of sodium hydroxide and 80-100 parts of distilled water.

2. The wall-fixing agent according to claim 1,

the adhesive comprises at least one of vinyl alcohol, vinyl ester, polyvinyl alcohol, vinyl acetate and diethyl acetate.

3. The wall-fixing agent according to claim 1 or 2,

the binder is a mixture of vinyl acetate and polyvinyl alcohol.

4. The wall-fixing agent according to claim 1,

the chain transfer agent is formate.

5. The wall-fixing agent according to claim 1,

the initiator comprises at least one of ammonium persulfate, sodium bisulfite and azobisisobutyronitrile.

6. The method for preparing the wall-fixing agent according to any one of claims 1 to 5, characterized by comprising the steps of:

(1) mixing acrylamide, dimethyl diallyl ammonium chloride and part of distilled water, heating to 65-70 ℃, adding an adhesive and part of an initiator, and reacting at a constant temperature of 65-70 ℃ to obtain a product I;

(2) mixing a chain transfer agent, sodium hydroxide and the rest of distilled water, adding 2-acrylamide-2-methylpropanesulfonic acid, stirring, adding acrylic acid, adjusting the pH value to 7-8, adding the rest of initiator, reacting at 60-65 ℃, granulating, drying and crushing to obtain a product II;

(3) and mixing the first product and the second product to obtain the wall solidifying agent.

7. The method of claim 6,

in the step (1), the addition amount of the distilled water is 1/3-2/3 of the total mass; the addition amount of the initiator is 1/3-2/3 of the total mass.

8. The method of claim 6,

in the step (1), the adhesive is added dropwise for 30-60 minutes.

9. The method of claim 6,

in the step (1), the reaction time is 3-5 hours;

in the step (2), the reaction time is 3-5 hours.

10. Use of the wall-fixing agent of any one of claims 1 to 5 in a water-based drilling fluid system.

Technical Field

The invention belongs to the technical field of drilling fluid, and particularly relates to a wall fixing agent for drilling fluid, and a preparation method and application thereof.

Background

In the process of drilling construction, due to the complex diversity of strata, the problem of borehole wall instability is always a technical problem which is addressed by domestic and foreign researchers.

At present, some researchers are dedicated to screening drilling fluid treating agents with small damage degree to effective stress of shale, and the mechanical strength of the shale of the well wall is improved to stabilize the well wall.

Some researchers are dedicated to developing wall firming agents with viscosity, and substances with viscosity are formed on the surface of rocks, so that the compressive strength of the well wall is improved, and the well wall is prevented from collapsing. For example, CN106634884B discloses a bionic wall-fixing agent for drilling fluid, which introduces bionic groups with adhesion to form a bionic shell with strong adhesiveness on the surface of shale, thereby improving the wall-fixing effect.

However, the existing wall firming agent is difficult to adsorb on the surface of rock in water environment and cannot play a role in cementing the rock.

Disclosure of Invention

The invention provides a wall-fixing agent for drilling fluid, a preparation method and application thereof, which can play a role in gluing rocks in a water environment.

The invention provides a wall-fixing agent for drilling fluid, which is prepared from the following raw materials in parts by weight:

10-25 parts of acrylamide, 10-25 parts of an adhesive, 10-25 parts of dimethyldiallylammonium chloride, 1-5 parts of acrylic acid, 1-5 parts of 2-acrylamide-2-methylpropanesulfonic acid, 1-5 parts of a chain transfer agent, 2-5 parts of an initiator, 5-12 parts of sodium hydroxide and 80-100 parts of distilled water.

Further, the adhesive comprises at least one of vinyl alcohol, vinyl ester, polyvinyl alcohol, vinyl acetate and diethyl acetate.

Further, the binder is a mixture of vinyl acetate and polyvinyl alcohol.

Further, the chain transfer agent is a formate.

Further, the initiator comprises at least one of ammonium persulfate, sodium bisulfite and azobisisobutyronitrile.

The invention also provides a preparation method of the wall-fixing agent, which comprises the following steps:

(1) mixing acrylamide, dimethyl diallyl ammonium chloride and part of distilled water, heating to 65-70 ℃, adding an adhesive and part of an initiator, and reacting at a constant temperature of 65-70 ℃ to obtain a product I;

(2) mixing a chain transfer agent, sodium hydroxide and the rest of distilled water, adding 2-acrylamide-2-methylpropanesulfonic acid, stirring, adding acrylic acid, adjusting the pH value to 7-8, adding the rest of initiator, reacting at 60-65 ℃, granulating, drying and crushing to obtain a product II;

(3) and mixing the first product and the second product to obtain the wall solidifying agent.

Further, in the step (1), the adding amount of the distilled water is 1/3-2/3 of the total mass; the addition amount of the initiator is 1/3-2/3 of the total mass.

Further, in the step (1), the adhesive is added dropwise for 30-60 minutes.

Further, in the step (1), the reaction time is 3-5 hours;

in the step (2), the reaction time is 3-5 hours.

The invention also provides the application of the wall fixing agent in a water-based drilling fluid system.

The invention has the following advantages:

the wall-fixing agent provided by the invention mainly comprises an adhesive, acrylamide, dimethyl diallyl ammonium chloride, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid and the like, wherein the adhesive directly participates in polymerization reaction of the acrylamide, the dimethyl diallyl ammonium chloride and the like, the obtained wall-fixing agent has certain adsorbability and adhesiveness, can be spontaneously adsorbed and cured on the surface of a rough rock to form a substance similar to a bionic shell, and has strong cementing capacity on the rock, so that the rock strength of a well wall is improved by enhancing the cohesion and adhesion among rock particles, the collapse resistance of drilling fluid is improved, and the problem of well wall instability is effectively solved. Particularly, the hydration force of the shale during hydration expansion and the like can be weakened or completely offset by the cohesive force of the bionic shell, so that the stability of the well wall is improved, and the wall solidifying agent has better adhesion performance in a water environment.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a diagram showing the effect of rolling clear water on rock debris recovery in test example 5 of the present invention;

FIG. 2 is a graph showing the effect of the drilling fluid rolling recovery of rock debris of the invention in test example 5 with the addition of the wall-fixing agent obtained in example 1.

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 the accompanying drawings, 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. The embodiments and features of the embodiments of the present invention may be combined with each other without conflict.

The embodiment of the invention provides a wall fixing agent for drilling fluid, which is prepared from the following raw materials in parts by weight:

10-25 parts of acrylamide, 10-25 parts of an adhesive, 10-25 parts of dimethyldiallylammonium chloride (DMDAAC), 1-5 parts of acrylic acid, 1-5 parts of 2-acrylamide-2-methylpropanesulfonic Acid (AMPS), 1-5 parts of a chain transfer agent, 2-5 parts of an initiator, 5-12 parts of sodium hydroxide and 80-100 parts of distilled water.

The wall-fixing agent provided by the embodiment of the invention mainly comprises an adhesive, acrylamide, DMDAAC, acrylic acid, AMPS and the like, wherein the adhesive directly participates in polymerization reaction of the acrylamide, DMDAAC and the like, the obtained wall-fixing agent has certain adsorbability and adhesiveness, can be spontaneously adsorbed and cured on the surface of rough rock to form a substance similar to a bionic shell, and has strong cementing capacity on the rock, so that the rock strength of a well wall is improved by enhancing the cohesion and the adhesion among rock particles, the collapse prevention performance of drilling fluid is improved, and the problem of well wall instability is effectively solved. Particularly, the hydration force of the shale during hydration expansion and the like can be weakened or completely offset by the cohesive force of the bionic shell, so that the stability of the well wall is improved, and the wall solidifying agent has better adhesion performance in a water environment.

In one embodiment of the present invention, the adhesive comprises at least one of vinyl alcohol, vinyl ester, polyvinyl alcohol, vinyl acetate, and diethyl acetate.

In a preferred embodiment of the invention, the binder is a mixture of vinyl acetate and polyvinyl alcohol. The diethyl acetate and the polyvinyl alcohol simultaneously participate in the polymerization reaction of acrylamide, DMDAAC and the like, and the obtained wall fixing agent has the best wall fixing effect. More preferably, the mass ratio of vinyl acetate to polyvinyl alcohol is 1: 1.

in one embodiment of the present invention, the chain transfer agent is a formate salt. In particular, the formate salt may be sodium formate.

In an embodiment of the present invention, the initiator includes at least one of ammonium persulfate, sodium bisulfite, and azobisisobutyronitrile. Ammonium persulfate, sodium bisulfite, azobisisobutyronitrile, and the like are added in the form of a solution.

The preparation method of the wall-fixing agent provided by the embodiment of the invention comprises the following steps:

(1) mixing acrylamide, DMDAAC and part of distilled water, heating to 65-70 ℃, adding an adhesive and part of an initiator, and reacting at constant temperature of 65-70 ℃ to obtain a product I;

(2) mixing a chain transfer agent, sodium hydroxide and the rest of distilled water, adding AMPS, stirring, adding acrylic acid, adjusting the pH value to 7-8, adding the rest of initiator, reacting at 60-65 ℃, then granulating, drying and crushing to obtain a product II;

(3) and mixing the first product and the second product to obtain the wall solidifying agent.

In one embodiment of the present invention, in the step (1), the amount of the distilled water added is 1/3-2/3 of the total mass.

In one embodiment of the present invention, in the step (1), the amount of the initiator added is 1/3-2/3 of the total mass.

In one embodiment of the invention, in the step (1), the adhesive is added dropwise for 30-60 minutes. In the embodiment of the invention, the adhesive needs to be slowly added to perform better reaction, but the dripping time is too long, so that the phenomenon that the dripping is not completed after the reaction is finished is easily caused, and the reaction is not facilitated, therefore, the optimum dripping time is 30-60 minutes.

In one embodiment of the present invention, in the step (1), the reaction time is 3 to 5 hours.

In one embodiment of the present invention, in the step (2), the reaction time is 3 to 5 hours.

In one embodiment of the present invention, in the step (2), the stirring time is 20 to 40 minutes.

The invention also provides application of the wall fixing agent in a water-based drilling fluid system. In the prior art, the wall fixing agent is easy to dissolve in water, the wall fixing agent provided by the embodiment of the invention has the adhesive participating in polymerization reaction, when the obtained wall fixing agent is used for water-based drilling fluid, the wall fixing agent can be uniformly dispersed into floccules in water, the adsorption and solidification are spontaneously carried out on the rough rock surface by utilizing the adsorbability and the adhesiveness of the water-based drilling fluid, the hydration force of shale during hydration and expansion is weakened or offset by the cohesive force generated by the wall fixing agent, and finally the wall fixing effect is realized. The wall fixing agent is used for a water-based drilling fluid system, can improve the rheological property and the filtration wall building property of the water-based drilling fluid, and particularly has good effect of improving the stability of a well wall.

The present invention will be described in detail with reference to examples.