阅读说明：本技术 一种全油基钻井液用提切剂及其制备方法 (Shear strength improving agent for full-oil-based drilling fluid and preparation method thereof ) 是由 王京光 *** 赵海锋 张雅楠 丁磊 寄晓宁 郭康 *** 赵雷 王勇强 张长庚 于 2019-09-03 设计创作，主要内容包括：本发明提供了一种全油基钻井液用提切剂及其制备方法,所述提切剂包括以下质量百分比的组分：聚合松香20％～30％；烷基胺10％～20％；乙醇胺5％～10％；白油40％～60％；脂肪醚5％～10％。本发明的提供了一种提切效果好、尤其是在全油基钻井液中仍然具有良好提切效果的油基钻井液用提切剂配方及其制备方法,该提切剂主要用于全油基钻井液,尤其是柴油、白油、气制油配制的全油基钻井液,同时适用于页岩气水平井、页岩油水平井、碳质泥岩水平井的油基钻井液施工。(The invention provides a shear strength improving agent for a full oil-based drilling fluid and a preparation method thereof, wherein the shear strength improving agent comprises the following components in percentage by mass: 20 to 30 percent of polymerized rosin; 10 to 20 percent of alkylamine; 5% -10% of ethanolamine; 40 to 60 percent of white oil; 5 to 10 percent of fatty ether. The invention provides a shear strength improving agent formula for oil-based drilling fluid and a preparation method thereof, wherein the shear strength improving agent formula has good shear strength improving effect, and particularly has good shear strength improving effect in the full-oil-based drilling fluid.)

1. The cutting agent for the full-oil-based drilling fluid is characterized by comprising the following components in percentage by mass:

20 to 30 percent of polymerized rosin;

10 to 20 percent of alkylamine;

5% -10% of ethanolamine;

40 to 60 percent of white oil;

5 to 10 percent of fatty ether.

2. The shear strength improver for the full oil-based drilling fluid according to claim 1, wherein: the polymerized rosin is the dimerization of abietic acid type resin acid, and the content of the dimer is more than 80 percent; the alkylamine is one or more of alkyl primary amines of C10-C20, and the ethanolamine is one or more of monoethanolamine, diethanolamine and triethanolamine; the fatty ether is one or more of ethylene glycol propyl ether, ethylene glycol ethyl ether, ethylene glycol butyl ether, diethylene glycol monobutyl ether and triethylene glycol butyl ether.

3. The shear strength improver for the full oil-based drilling fluid according to claim 1, wherein: the alkylamine is one or more of dodecyl primary amine, tridecyl primary amine, tetradecyl primary amine, pentadecyl primary amine, hexadecyl primary amine, heptadecyl primary amine and octadecyl primary amine.

4. The cutting agent for the full oil-based drilling fluid as claimed in claim 2, wherein the cutting agent consists of the following components in percentage by mass:

20 to 30 percent of dimerized rosin;

10-20% of primary octadecyl amine;

5 to 10 percent of triethanolamine;

40 to 60 percent of white oil;

5 to 10 percent of ethylene glycol monobutyl ether.

5. The cutting agent for the full oil-based drilling fluid as claimed in claim 4, wherein the cutting agent consists of the following components in percentage by mass:

dimerized rosin 25%;

primary octadecyl amine 15%;

5% of triethanolamine;

50% of white oil;

5% of ethylene glycol butyl ether.

6. The preparation method of the extracting and cutting agent for the full oil-based drilling fluid according to any one of claims 1 to 5, wherein the method comprises the following steps:

1) respectively weighing polymerized rosin, alkylamine, ethanolamine, white oil and fatty ether according to the proportion;

2) firstly adding a certain amount of solvent into a closed reaction kettle, and then sequentially adding polymerized rosin and alkylamine according to a certain proportion;

3) stirring at the rotating speed of 60 r/min-90 r/min, controlling the temperature of the reaction kettle at 70-90 ℃, and reacting for 2-3 h;

4) uniformly adding ethanolamine with the formula amount, raising the temperature to 100-110 ℃, stirring at the rotating speed of 100-120 r/min, and carrying out heat preservation reaction for 3-4 h;

5) distilling off the solvent;

6) and cooling to 50-70 ℃, adding the white oil and the fatty ether according to the formula ratio, and continuously stirring for 0.5-1 h to obtain the shear strength improver for the full oil-based drilling fluid.

7. The preparation method of the shear strength improving agent for the full oil-based drilling fluid, according to claim 6, is characterized in that: the solvent is toluene.

8. The preparation method of the shear strength improving agent for the full oil-based drilling fluid according to claim 7, wherein the shear strength improving agent comprises the following components in percentage by weight: the addition amount of the solvent is 2-3 times of the sum of the volumes of the primary octadecyl amine and the triethanolamine.

9. The shear strength improver for the full oil-based drilling fluid according to any one of claims 1 to 5, wherein: the shear strength improver is suitable for all-oil-based drilling fluid, including all-oil-based drilling fluid prepared from diesel oil, white oil and gas oil.

10. The shear strength improver for the full oil-based drilling fluid according to any one of claims 1 to 5, wherein: the cutting agent is suitable for oil-based drilling fluid construction of shale gas horizontal wells, shale oil horizontal wells and carbonaceous mudstone horizontal wells.

Technical Field

The invention belongs to the field of oil field drilling fluid additives, and particularly relates to a shear strength improving agent for a full oil-based drilling fluid and a preparation method thereof.

Background

Along with the large-scale development of unconventional oil and gas reservoirs marked by shale gas and shale oil at home and abroad, the oil-based drilling fluid is more and more widely applied. Compared with the traditional water-based drilling fluid, the oil-based drilling fluid is widely applied to drilling of shale gas horizontal wells due to good inhibition performance, lubricating performance and rheological performance.

The problems of low dynamic shear force and difficult control of rheological property of the oil-based drilling fluid generally exist. Rheology control of all-oil based drilling fluids is more difficult than conventional water-in-oil drilling fluids. Because the whole oil-based drilling fluid almost contains no water in the system (the oil-water ratio of the whole oil-based drilling fluid is more than 95:5), the viscosity-cutting of the new slurry is difficult to improve, and the viscosity-cutting of the old slurry in the later period is difficult to reduce.

Generally, the rheological property of the oil-based drilling fluid is regulated by adopting organic soil, so that the problems that the viscosity-cutting of new slurry is difficult to improve and the viscosity-cutting of later-stage old slurry is difficult to reduce exist, and the defects of poor viscosity-cutting effect, obvious tackifying effect, slow activation and easy high-temperature thickening failure exist. In the shale gas exploration and development process, a horizontal well mode is mostly adopted in order to obtain higher yield. The problem of sand carrying in horizontal section drilling becomes the key of safe and rapid construction, and the drilling fluid is required to have higher shearing force, particularly low-speed shearing force, to fully carry sand and clean a well hole, and to keep lower viscosity, particularly lower final shearing force, so as to prevent the pumping-on exciting pressure from being too high to hold back and leak the stratum. The problem of rheological property regulation of the full-oil-based drilling fluid is particularly obvious, and the rheological property regulation technology of the full-oil-based drilling fluid becomes a key technology for restricting safe construction of shale gas horizontal wells.

The organic soil is mainly used as a tackifying and shearing-improving agent of the oil-based drilling fluid at home, but the organic soil has limited shearing-improving performance and obvious tackifying effect. The viscosity of the prepared new slurry is low, the requirement of carrying sand underground is difficult to meet, the viscosity is greatly increased once the organic soil is excessively used, the rheological property of a system is seriously influenced, a series of problems are brought to subsequent drilling construction, the drilling fluid at the bottom of a well is thickened, and the well is difficult to pump when the well is tripped out and stopped and is tripped to the bottom of the well, so that the well leakage is induced. The excessive addition of organic soil leads to high content of low solid phase in the drilling fluid, and the increase of the mechanical drilling speed is influenced.

Foreign oil-based drilling fluid cutting-up agents were studied earlier. The foreign commonly used extracting and cutting agents include VERSAMOD, RHEFLAT, RHEMODTM, FB-MOD, etc. The main component is a polyamide with a large molecular weight. The foreign shear strength improving agent has good shear strength improving effect, has small influence on the viscosity of the oil-based drilling fluid, particularly has small influence on the rheological property of a system in the high-density oil-based drilling fluid, but has insignificant shear strength improving effect in the full-oil-based drilling fluid and is expensive. Wherein, the cutting agent VERSAMOD comes from MATERIALSAFETY DATA SHEET VERSAMOD, the cutting agent RHEFLAT comes from SAFETY DATA SHEET RHEFLAT, the cutting agent RHEODTM comes from EXP D294 Rheology Modifier for Oil Based Muds, and FB-MOD comes from MATERIAL SAFETY DATA SHEET VERSA HRP.

Therefore, according to the characteristics of the full-oil-based drilling fluid and the technical requirements of shale gas horizontal well construction on the oil-based drilling fluid, a novel oil-based drilling fluid cutting agent which has a good cutting effect (especially has a remarkable low-speed cutting force improvement), has a small influence on the viscosity of the oil-based drilling fluid and takes effect quickly is developed to solve the problems. The requirement of the oil-based drilling fluid in the exploration process of unconventional oil and gas reservoirs such as shale gas is met.

Disclosure of Invention

The invention aims to solve the problems that the existing cutting agent has poor cutting effect, obvious tackifying effect, slow activation, high-temperature excitation is needed, the dosage is difficult to accurately control, the new slurry prepared with too little dosage is easy to settle due to too low viscosity and heavy materials, and the organic soil is excited by heating after the new slurry with too much dosage is circulated at the bottom of a well, so that the drilling fluid is thickened by heating.

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

the cutting agent for the full-oil-based drilling fluid comprises the following components in percentage by mass:

20 to 30 percent of polymerized rosin;

10 to 20 percent of alkylamine;

5% -10% of ethanolamine;

40 to 60 percent of white oil;

5 to 10 percent of fatty ether.

Further, the polymerized rosin is dimer of abietic acid type resin acid, the content of dimer is more than 80%, and the dimerized rosin is preferred; the alkylamine is one or more of alkyl primary amines of C10-C20, and the ethanolamine is one or a mixture of any one of monoethanolamine, diethanolamine and triethanolamine; the fatty ether is one or more of ethylene glycol propyl ether, ethylene glycol ethyl ether, ethylene glycol butyl ether, diethylene glycol monobutyl ether and triethylene glycol butyl ether.

Further, the alkylamine is preferably one or more of primary dodecylamine, primary tridecylamine, primary tetradecylamine, primary pentadecylamine, primary hexadecylamine, primary heptadecylamine, and primary octadecylamine.

Specifically, the shear strength improving agent for the full oil-based drilling fluid comprises the following components in percentage by mass:

20 to 30 percent of dimerized rosin;

10-20% of primary octadecyl amine;

5 to 10 percent of triethanolamine;

40 to 60 percent of white oil;

5 to 10 percent of ethylene glycol monobutyl ether.

Preferably, the cutting and extracting agent for the full oil-based drilling fluid consists of the following components in percentage by mass:

dimerized rosin 25%;

primary octadecyl amine 15%;

5% of triethanolamine;

50% of white oil;

5% of ethylene glycol butyl ether.

A preparation method of a shear strength improving agent for a full oil-based drilling fluid comprises the following steps:

1) respectively weighing polymerized rosin, alkylamine, ethanolamine, white oil and fatty ether according to the proportion;

2) firstly adding a certain amount of solvent into a closed reaction kettle, and then sequentially adding polymerized rosin and alkylamine according to a certain proportion;

3) stirring at the rotating speed of 60 r/min-90 r/min, controlling the temperature of the reaction kettle at 70-90 ℃, and reacting for 2-3 h;

4) uniformly adding ethanolamine with the formula amount, raising the temperature to 100-110 ℃, stirring at the rotating speed of 100-120 r/min, and carrying out heat preservation reaction for 3-4 h;

5) distilling off the solvent;

6) and cooling to 50-70 ℃, adding the white oil and the fatty ether according to the formula ratio, and continuously stirring for 0.5-1 h to obtain the shear strength improver for the full oil-based drilling fluid.

Further, the solvent is toluene.

Preferably, the addition amount of the solvent is 2 to 3 times the volume sum of primary octadecylamine and triethanolamine.

The shear strength improver is suitable for all-oil-based drilling fluid, in particular to all-oil-based drilling fluid prepared from diesel oil, white oil and gas oil.

The cutting agent is suitable for oil-based drilling fluid construction of shale gas horizontal wells, shale oil horizontal wells and carbonaceous mudstone horizontal wells.

The invention has the following beneficial effects:

(1) shear force, especially low rate shear force, to lift whole oil based (anhydrous) drilling fluids is significant. The prepared oil-based drilling fluid has good rheological property, and is particularly suitable for the requirement of the horizontal section construction of a shale gas horizontal well on the sand carrying performance of the oil-based drilling fluid.

(2) The drilling fluid has the advantages of quick response, no need of high-temperature excitation, good cutting effect at normal temperature, and overcoming the problem that organic soil needs to be excited at high temperature.

(3) The viscosity of the oil-based drilling fluid cannot be obviously increased, the prepared oil-based drilling fluid has the characteristics of low viscosity and high shear, and the problem that the conventional shear strength increasing agent increases the shear force of the whole oil-based drilling fluid and also greatly increases the viscosity of the system, so that the whole oil-based drilling fluid is too thick is solved.

(4) Has strong adaptability to base oil and wide range. The drilling fluid is suitable for the full oil-based drilling fluid, in particular to the full oil-based drilling fluid prepared from diesel oil, white oil and gas.

(5) The oil-based drilling fluid is suitable for the construction of oil-based drilling fluids for shale gas horizontal wells, shale oil horizontal wells and carbonaceous mudstone horizontal wells.

(6) Polar groups in the cutting agent product, such as-OH, -OCO-NH-, -CONH-and the like, are interacted with other groups through electrostatic attraction and hydrogen bonds to form a network structure with large specific surface area, and long alkyl straight chains in molecules form a three-dimensional network structure through association, so that the effects of cutting and low viscosity are achieved.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to clearly understand the technical solutions of the present invention and to implement the technical solutions according to the contents of the description, the following detailed description is given with reference to the preferred embodiments of the present invention and the accompanying drawings.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below.

FIG. 1 is a dynamic shear force comparison of a shear enhancing agent and an organic soil.

FIG. 2 is a low shear rate shear force comparison of a shear enhancing agent and an organic soil.

FIG. 3 is a comparison of plastic viscosity of the shear enhancing agent and the organoclay.

FIG. 4 is a comparison of plastic viscosity of the shear enhancing agent and the organo-soil before and after hot rolling.

FIG. 5 is a dynamic shear force comparison of the shear enhancing agent and the organic soil before and after hot rolling.

FIG. 6 is a dynamic shear force comparison of shear enhancing agent and organo-soil in different base oils.

FIG. 7 is a comparison of plastic viscosity of shear strength additives and organoclays in different base oils.

FIG. 8 is a low shear rate shear force comparison of shear strength of shear enhancing agent and organo-soil in different base oils.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, 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. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The percentages in the examples are given by mass unless otherwise indicated.

First embodiment

The first embodiment of the invention relates to a cutting agent for a full-oil-based drilling fluid, which is prepared from the following raw materials in percentage by mass:

20 to 30 percent of polymerized rosin;

10 to 20 percent of alkylamine;

5% -10% of ethanolamine;

40 to 60 percent of white oil;

5 to 10 percent of fatty ether.

The embodiment also provides a preparation method of the shear strength improving agent for the full oil-based drilling fluid, which comprises the following specific preparation steps:

(1) respectively weighing polymerized rosin, alkylamine, ethanolamine, white oil and fatty ether according to the mixture ratio;

(2) adding a proper amount of toluene into a closed reaction kettle, and sequentially adding polymerized rosin and alkylamine according to a certain proportion;

(3) stirring at the rotating speed of 60 r/min-90 r/min, controlling the temperature of the reaction kettle at 70-90 ℃, and reacting for 2-3 h;

(4) ethanolamine is added uniformly and slowly, the temperature is raised to 100-110 ℃, the mixture is stirred at the rotating speed of 100-120 r/min and is kept for reaction for 3-4 h, and the heating is stopped.

(5) The solvent toluene was distilled off.

(6) Cooling to 50-70 ℃, adding white oil and fatty ether, and continuously stirring for 0.5-1 h to obtain the shear strength improver for the full oil-based drilling fluid.

The invention provides a formula of a shear strength improving agent for a full oil-based drilling fluid, which still has a good shear strength improving effect under the anhydrous condition of a full oil base, does not need high-temperature excitation, has a good shear strength improving effect at normal temperature, has small influence on the viscosity of the full oil-based drilling fluid, and meets the requirements of shale gas horizontal wells, shale oil horizontal wells, carbonaceous mudstone horizontal wells and complex wells on the construction of the full oil-based drilling fluid.

Second embodiment

In addition to the above embodiment, further, the polymerized rosin is a dimer of abietic acid-type resin acids, the product is a heterogeneous dimer, the dimer content is greater than 80%, and a dimerized rosin is preferred; the alkylamine is one or more of alkyl primary amines of C10-C20, and the ethanolamine is one or a mixture of any one of monoethanolamine, diethanolamine and triethanolamine; the fatty ether is one or more of ethylene glycol propyl ether, ethylene glycol ethyl ether, ethylene glycol butyl ether, diethylene glycol monobutyl ether and triethylene glycol butyl ether.

Specifically, the dimerized rosin is preferably dimerized rosin 95 dimerized rosin 140 dimerized rosin 145; the alkylamine is preferably one or more of primary dodecyl amine, primary tridecyl amine, primary tetradecyl amine, primary pentadecyl amine, primary hexadecyl amine, primary heptadecyl amine and primary octadecyl amine.

Third embodiment

The embodiment provides a shear strength improving agent for a full oil-based drilling fluid, which comprises the following components in percentage by mass:

20 to 30 percent of dimerized rosin;

10-20% of primary octadecyl amine;

5 to 10 percent of triethanolamine;

40 to 60 percent of white oil;

5 to 10 percent of ethylene glycol monobutyl ether.

Further, the preparation method of the shear strength improving agent for the full oil-based drilling fluid, which is protected by the embodiment, comprises the following steps:

1) respectively weighing dimerized rosin, primary octadecyl amine, triethanolamine, white oil and ethylene glycol butyl ether according to the proportion;

2) adding a proper amount of solvent into a closed reaction kettle, and sequentially adding dimerized rosin and octadecylamine-based primary amine according to a proportion;

3) stirring at the rotating speed of 60 r/min-90 r/min, controlling the temperature of the reaction kettle to be 70-90 ℃, and reacting for 2-3 h;

4) uniformly and slowly adding triethanolamine, raising the temperature to 100-110 ℃, and carrying out heat preservation reaction for 3-4 h under stirring at the rotating speed of 100-120 r/min;

5) distilling off the solvent;

6) cooling to 50-70 ℃, adding white oil and ethylene glycol monobutyl ether, and continuously stirring for 0.5h to obtain the shear strength improver for the full oil-based drilling fluid.

It is worth mentioning that the solvent is toluene, and the addition amount of toluene is 2-3 times of the sum of the volumes of the primary octadecylamine and the triethanolamine.

The toluene obtained after distillation can be refluxed into the reaction kettle to be continuously used as a solvent, so that the wastewater discharge amount can be reduced, the sewage treatment pressure can be relieved, the operation cost can be reduced, the yield of intermediates and products of each part can be obviously improved, and the greater economic benefit can be obtained. Moreover, the shear strength improving agent for the full-oil-based drilling fluid prepared by the method can obviously improve the rheological property of the newly prepared oil-based drilling fluid, and solves the problems that organic soil is used in the prior full-oil-based drilling fluid, the viscosity of the newly prepared slurry with too little addition is too low, a heavy material is easy to settle, and the organic soil is heated and excited after the newly prepared slurry with too much addition is circulated at the bottom of a well, so that the drilling fluid is heated and thickened, namely the rheological property of the newly prepared full-oil-based drilling fluid is difficult to control.

Fourth embodiment

As a preferred embodiment, the cutting-improving agent for the full oil-based drilling fluid consists of the following components in percentage by mass:

dimerized rosin 25%;

primary octadecyl amine 15%;

5% of triethanolamine;

50% of white oil;

5% of ethylene glycol butyl ether.

Further, the preparation method of the shear strength improving agent for the full oil-based drilling fluid, which is protected by the embodiment, comprises the following steps:

1) respectively weighing 25% of dimerized rosin, 15% of primary octadecyl amine, 5% of triethanolamine, 50% of white oil and 5% of butyl glycol ether by mass percentage;

2) adding a proper amount of toluene (the addition amount of the toluene is 2-3 times of the sum of the volumes of the octadecyl primary amine and the triethanolamine) into a closed reaction kettle, and then sequentially adding the dimerized rosin and the octadecyl primary amine according to the proportion;

3) stirring at the rotating speed of 60 r/min-90 r/min, controlling the temperature of the reaction kettle to be 70-90 ℃, and reacting for 2-3 h;

4) then adding triethanolamine evenly, raising the temperature to 100-110 ℃, and keeping the temperature for reaction for 3-4 h under stirring at the rotating speed of 100-120 r/min;

5) distilling out the solvent toluene;

6) cooling to 50-70 ℃, adding white oil and ethylene glycol monobutyl ether, and continuously stirring for 0.5h to obtain the shear strength improver for the full oil-based drilling fluid.

The whole oil-based drilling fluid prepared by the product has good rheological property, is easy to regulate and control, and is simpler and more convenient to operate and maintain during field application. The preparation method and the required equipment have simple conditions and are easy to implement.

Fifth embodiment

The embodiment provides a shear strength improving agent for a full oil-based drilling fluid, which comprises the following components in percentage by mass: 20% of dimerized rosin, 10% of primary octadecyl amine, 5% of triethanolamine, 60% of white oil and 5% of butyl glycol ether;

the preparation method of the shear strength improving agent for the full oil-based drilling fluid comprises the following steps:

(1) respectively weighing 20% of dimerized rosin, 10% of primary octadecyl amine, 5% of triethanolamine, 60% of white oil and 5% of butyl glycol ether according to the proportion;

(2) adding a proper amount of toluene into a closed reaction kettle, and sequentially adding dimerized rosin and octadecylamine primary amine according to a proportion;

(3) stirring at the rotating speed of 70r/min, controlling the temperature of the reaction kettle to be 90 ℃, and reacting for 2 hours;

(4) adding triethanolamine uniformly and slowly, heating to 100 deg.C, reacting for 3 hr under stirring at 100r/min, and stopping heating.

(5) The solvent toluene was distilled off.

(6) Cooling to 70 ℃, adding white oil and ethylene glycol monobutyl ether, and continuing stirring for 0.5h to obtain the shear strength improver for the full oil-based drilling fluid.

Further, the prepared shear strength improving agent for the full oil-based drilling fluid is subjected to the following performance tests:

test 1: as shown in fig. 1, fig. 2, and fig. 3, the cutting performance of the oil-based drilling fluid cutting enhancer of the present embodiment is compared with that of organic soil

The oil-based drilling fluid comprises the following formula: the base oil is 3# industrial white oil, 3.0 percent of emulsifier, 2.0 percent of calcium hydroxide, 2.0 percent of filtrate reducer, 1.0 percent of tackifier, cutting agent or organic soil, 1.0 percent of wetting agent and 40 percent of barite are calculated by weight of the base oil, and the prepared density is 1.20g/cm³After the drilling fluid is heated and rolled at 150 ℃ for 16h, the dynamic shear force, the plastic viscosity and the low-speed shear force of base slurry and test slurry (65 +/-1) DEG C are measured according to the specification in GB/T16783.2-2012.

In the formula: n-increase in dynamic shear,%;

YP₁-dynamic shear force, Pa, of the sample slurry;

YP₀the dynamic shear force of the base pulp, Pa, the base pulp is not added with the shear-extracting agent.

In the formula: LSYP-low rate shear, Pa;

φ₃-3 readings of the sample slurry;

φ₆6 readings of the sample slurry.

In the formula: r-low shear rate shear increase,%;

LSYP 1-Low shear Rate shear force, Pa, of the sample slurry;

LSYP 0-Low shear Rate shear force, Pa, of the base stock, no shear enhancing agent was added to the base stock.

From the test results, the dynamic shear force, the low-speed shear force and the plastic viscosity of the drilling fluid are increased along with the increase of the dosage of the shear-promoting agent. Compared with the full-oil-based drilling fluid prepared from organic soil, the full-oil-based drilling fluid prepared from the cutting agent has higher dynamic shear force, and particularly has higher low-speed shear force and lower plastic viscosity while having higher dynamic shear force. The whole oil-based drilling fluid using the shear strength improving agent has better rheological property.

Sixth embodiment

The embodiment provides a shear strength improving agent for a full oil-based drilling fluid, which comprises the following components in percentage by mass: 25% dimerized rosin, 15% primary octadecyl amine, 10% triethanolamine, 40% white oil, 10% butyl glycol ether;

the preparation method of the shear strength improving agent for the full oil-based drilling fluid comprises the following steps:

(1) respectively weighing 25% of dimerized rosin, 15% of primary octadecyl amine, 10% of triethanolamine, 40% of white oil and 10% of butyl glycol ether according to the proportion;

(2) adding a proper amount of toluene into a closed reaction kettle, and sequentially adding dimerized rosin and octadecylamine primary amine according to a proportion;

(3) stirring at the rotating speed of 80r/min, controlling the temperature of the reaction kettle to be 90 ℃, and reacting for 2 hours;

(4) adding triethanolamine uniformly and slowly, heating to 100 deg.C, reacting for 4 hr under stirring at 110r/min, and stopping heating.

(5) The solvent toluene was distilled off.

(6) Cooling to 70 ℃, adding white oil and ethylene glycol monobutyl ether, and continuing stirring for 0.5h to obtain the shear strength improver for the full oil-based drilling fluid. The above are all mass percentages.

The following performance tests are carried out on the extracting and cutting agent for the full oil-based drilling fluid prepared by the preparation method of the extracting and cutting agent for the oil-based drilling fluid, wherein the performance tests comprise the following steps:

and (3) testing 2: as shown in fig. 4, 5 and 6, the cut-improving performance of the oil-based drilling fluid cutting-improving agent of the embodiment and the organic soil before and after hot rolling is compared and tested

The oil-based drilling fluid comprises the following formula: the base oil is 3# industrial white oil, 3.0 percent of emulsifier, 2.0 percent of calcium hydroxide, 2.0 percent of filtrate reducer, 1.0 percent of tackifier, cutting agent or organic soil, 1.0 percent of wetting agent and 40 percent of barite are calculated by weight of the base oil, and the prepared density is 1.20g/cm³The dynamic shear force and plastic viscosity of base slurry and test slurry (65 +/-1) DEG C are measured according to the specification of GB/T16783.2-2012 before and after the drilling fluid is heated at 150 ℃ for 16 h.

From the test results, the dynamic shear force and the plastic viscosity of the full-oil-based drilling fluid prepared from the organic soil are low before hot rolling and are obviously increased after hot rolling. The problems that the new slurry prepared with too small amount of addition is easy to be settled due to too low viscosity of weighting material, and the organic soil is heated and excited after the new slurry with too large amount of addition passes through the circulation at the bottom of the well, so that the drilling fluid is heated and thickened exist in the field construction. The change of the dynamic shear force and the plastic viscosity of the cutting agent before and after the full-oil-based drilling fluid is subjected to hot rolling is small, which shows that the cutting agent can play a good cutting role without thermal excitation, and avoids the problem that the full-oil-based drilling fluid is easy to be subjected to thermal thickening.

Seventh embodiment

The embodiment provides a shear strength improving agent for a full oil-based drilling fluid, which comprises the following components in percentage by mass: 30% of dimerized rosin, 20% of primary octadecyl amine, 10% of triethanolamine, 30% of white oil and 10% of butyl glycol ether;

the preparation method of the shear strength improving agent for the full oil-based drilling fluid comprises the following steps:

(1) respectively weighing 30% of dimerized rosin, 20% of primary octadecyl amine, 10% of triethanolamine, 30% of white oil and 10% of butyl glycol ether according to the proportion;

(2) adding a proper amount of toluene into a closed reaction kettle, and sequentially adding dimerized rosin and octadecylamine primary amine according to a proportion;

(3) stirring at the rotating speed of 90r/min, controlling the temperature of the reaction kettle at 90 ℃, and reacting for 2 hours;

(4) adding triethanolamine uniformly and slowly, heating to 110 deg.C, reacting for 4 hr under stirring at 120r/min, and stopping heating.

(5) The solvent toluene was distilled off.

(6) Cooling to 70 ℃, adding white oil and ethylene glycol monobutyl ether, and continuing stirring for 0.5h to obtain the shear strength improver for the full oil-based drilling fluid. The above are all mass percentages.

The following performance tests are carried out on the extracting and cutting agent for the full oil-based drilling fluid prepared by the preparation method of the extracting and cutting agent for the oil-based drilling fluid, wherein the performance tests comprise the following steps:

and (3) testing: as shown in fig. 6, 7 and 8, the cutting performance of the oil-based drilling fluid cutting enhancer of the embodiment and the organic soil in different base oils is tested by comparing the cutting performance

The oil-based drilling fluid comprises the following formula: 3.0 percent of emulsifier, 2.0 percent of calcium hydroxide, 2.0 percent of filtrate reducer, 1.0 percent of tackifier, 2.0 percent of cutting agent or 2.0 percent of organic soil, 1.0 percent of wetting agent and 40 percent of barite based on the weight of the base oil, and the prepared density is 1.20g/cm³The dynamic shear force, the plastic viscosity and the low shear rate shear force of base slurry and test slurry (65 +/-1) DEG C are measured according to the specification of GB/T16783.2-2012 before and after the drilling fluid is heated at 150 ℃ for 16 h.

From the results, the full oil-based drilling fluid prepared by applying the shear strength improving agent disclosed by the invention has higher dynamic shear force, low shear rate shear force and lower plastic viscosity no matter the base oil in diesel oil, 3# industrial white oil and gas-made oil is adopted, namely the full oil-based drilling fluid has good rheological property. Meanwhile, the shear strength improver is suitable for oil-based drilling fluid construction of shale gas horizontal wells, shale oil horizontal wells and carbonaceous mudstone horizontal wells.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

In the case of no conflict, a person skilled in the art may combine the related technical features in the above examples according to actual situations to achieve corresponding technical effects, and details of various combining situations are not described herein.