CN106381134B

CN106381134B - Drilling fluid additive composition and its application and water-base drilling fluid and its application suitable for coal bed gas well

Info

Publication number: CN106381134B
Application number: CN201610729914.0A
Authority: CN
Inventors: 蒋官澄; 贺垠博; 刘冲; 葛庆颖; 杨丽丽; 王勇; 张永清; 王照辉; 程琳; 胡景东
Original assignee: China University of Petroleum Beijing
Current assignee: China University of Petroleum Beijing
Priority date: 2016-08-25
Filing date: 2016-08-25
Publication date: 2017-10-27
Anticipated expiration: 2036-08-25
Also published as: CN106381134A

Abstract

The present invention relates to the drilling applications of petroleum industry, in particular it relates to a kind of drilling fluid additive composition and its application and water-base drilling fluid and its application suitable for coal bed gas well.The drilling fluid additive composition contains thickening extracting and cutting agent, coating agent and fluid loss additive, wherein：The thickening extracting and cutting agent is the copolymer containing the construction unit shown in the construction unit shown in formula (1), the construction unit shown in formula (2) and formula (3)；The coating agent is combed polysaccharide compound；The fluid loss additive is nano-crystal cellulose.The composition of the present invention, by the mating reaction of above-mentioned thickening extracting and cutting agent, coating agent and fluid loss additive, can be used as additive in the salt-water drilling fluid for Solid Free so that salt-water drilling fluid acquisition rate of penetration is high, relatively low residue rate advantage.

Description

Suitable for the drilling fluid additive composition of coal bed gas well and its application and water-based drilling Liquid and its application

Technical field

The present invention relates to the drilling applications of petroleum industry, in particular it relates to which a kind of drilling fluid suitable for coal bed gas well adds Plus agent composition and its application and water-base drilling fluid and its application.

Background technology

China's coal bed gas rich reserves, but not yet realize that large-scale commercial is developed, the reason for one of them is important is Coalbed methane reservoir has high sensitivity characteristic, is easily polluted in drilling process by outside fluid, solid phase, so as to block coal-bed methane seepage Fissure channel, causes to influence coal bed gas desorption, gas output declines to a great extent.

In the case where foam drilling fluid technology and under-balanced drilling technology are not yet highly popular, coal bed gas well is bored at present Solid free brine drilling liquid technology can be used, i.e., without using bentonite, barite and remaining solid phase particles, and passes through addition Salt (such as KCl, NaCl) aggravated obtained by salt-water drilling fluid, but still untapped at present obtain can be to coal bed gas Well has the solid free brine drilling fluid compared with high-adaptability.

The content of the invention

It can preferably be applied to the drilling fluid additive group of coal bed gas well drilling well it is an object of the invention to provide a kind of Compound and its application and water-base drilling fluid and its application.

To achieve these goals, the present invention provides a kind of drilling fluid additive composition suitable for coal bed gas well, should Composition contains thickening extracting and cutting agent, coating agent and fluid loss additive, wherein：

It is described to viscosify extracting and cutting agent to contain the construction unit shown in formula (1), the construction unit shown in formula (2) and formula (3) institute The copolymer of the construction unit shown, wherein：

Wherein, R¹、R^1'、R²、R^2'、R⁵、R^5'、R⁴With each R⁷It is each independently selected from H and C1-C8 alkyl；R³、R⁶And R⁸ It is each independently selected from C0-C8 alkylidene；X is selected from-NH- or-O-；N is 1-4 integer；

The coating agent is combed polysaccharide compound, and the side chain of the combed polysaccharide compound is as shown in lower formula (I) Compound and formula (II) shown in compound provide, wherein, the sulfonate polysaccharide class compound is the starch of sulfonation, sulfonation Cellulose compound or the xanthans of sulfonation：

Wherein, L¹、L^1'、L²And L^2'It is each independently selected from H and C1-C6 alkyl；

The fluid loss additive is nano-crystal cellulose.

Present invention also offers application of the above-mentioned composition as the additive in drilling fluid.

Present invention also offers the water-base drilling fluid containing above-mentioned composition.

Present invention also offers application of the above-mentioned water-base drilling fluid in coal bed gas well drilling well.

The present invention composition, by the mating reaction of above-mentioned thickening extracting and cutting agent, coating agent and fluid loss additive, can with Additive is used as in the salt-water drilling fluid of Solid Free so that it is high (because Solid Free, machine that the salt-water drilling fluid obtains rate of penetration Tool hinders small with boring), the advantage of relatively low residue rate, the efficient drilling well of coal bed gas well can be reached and to the low of coalbed methane reservoir The purpose of injury.

Other features and advantages of the present invention will be described in detail in subsequent embodiment part.

Embodiment

The embodiment to the present invention is described in detail below.It should be appreciated that described herein specific Embodiment is merely to illustrate and explain the present invention, and is not intended to limit the invention.

The end points and any value of disclosed scope are not limited to the accurate scope or value herein, these scopes or Value should be understood to comprising the value close to these scopes or value.For number range, between the endpoint value of each scope, respectively It can be combined with each other between the endpoint value of individual scope and single point value, and individually between point value and obtain one or more New number range, these number ranges should be considered as specific open herein.

The present invention provides a kind of drilling fluid additive composition suitable for coal bed gas well, and said composition, which contains thickening and carried, cuts Agent, coating agent and fluid loss additive, wherein：

The fluid loss additive is nano-crystal cellulose.

According to the present invention, above-mentioned composition is in drilling fluid is added into, in the presence of Solid Free, you can for coal bed gas well Drilling well in, its main cause is that each composition can play good synergy in without bentonitic saltwater environment, so logical Mating reaction between each composition for the composition for crossing the present invention, can reach high power auger in the drilling well for coal bed gas well The effect of fast, low reservoir damage.It is described in order to preferably play under the mating reaction between each composition, preferable case The weight ratio for viscosifying extracting and cutting agent, coating agent and fluid loss additive is 100：5-50：100-300, preferably 100：6-30：120-200, More preferably 100：7-25：150-180.

According to the present invention, strand, and phase can be sufficiently spread out in salt solution as the copolymer of the thickening extracting and cutting agent High intensity space grid structure mutually is wound, is cut so as to even show good thickening in DWSW liquid system and carry Performance.Even at a higher temperature, the Efficient Adhesive Promotion that the copolymer is provided also can effectively lift DWSW liquid Apparent viscosity, yield value and the gel strength of system.So as to by together with other neccessary compositions of the composition of the present invention, being added into , can be under without solid-phase component, in the drilling well of coal bed gas well, reaching that rate of penetration is high, relatively low residual in salt-water drilling fluid The effect of slag rate, to realize the efficient drilling well of coal bed gas well and the Low Damage to coalbed methane reservoir.

According to the present invention, wherein, above-mentioned C1-C8 alkyl for example can be methyl, ethyl, n-propyl, isopropyl, positive fourth Base, isobutyl group, sec-butyl, the tert-butyl group, n-pentyl, isopentyl, n-hexyl, n-heptyl, n-nonyl etc..

The alkylidene that above-mentioned C0-C8 alkylidene can for example be formed by C0 alkylidene, above-mentioned C1-C8 alkyl. Wherein, C0 alkylidene, which can consider, is only connecting key or is not present, and the group at the group two ends will be joined directly together.

In order to preferably play the copolymer as the effect of extracting and cutting agent, under preferable case, the thickening is used as In the copolymer of extracting and cutting agent, R¹、R^1'、R²、R^2'、R⁵、R^5'、R⁴With each R⁷It is each independently selected from H and C1-C6 alkyl；R³、 R⁶And R⁸It is each independently selected from C0-C6 alkylidene；N is 1-3 integer.

It is highly preferred that R¹、R^1'、R²、R^2'、R⁵、R^5'And R⁴It is each independently selected from H and C1-C4 alkyl；Each R⁷Each Independently selected from C1-C6 alkyl；R³Alkylidene selected from C0-C4；R⁶And R⁸It is each independently selected from C1-C6 alkylidene.

It is further preferred that R¹、R^1'、R²、R^2'、R⁵、R^5'And R⁴Be each independently selected from H, methyl, ethyl, n-propyl, Isopropyl and normal-butyl；Each R⁷It is each independently selected from methyl, ethyl, n-propyl, isopropyl and normal-butyl；R³Selected from C0's Alkylidene ,-CH₂-、-CH₂-CH₂-、-CH₂-CH₂-CH₂-、-CH(CH₃)-CH₂-、-CH₂-CH(CH₃)-or-CH₂-(CH₂)₂- CH₂-；R⁶And R⁸It is each independently selected from-CH₂-、-CH₂-CH₂-、-CH₂-CH₂-CH₂-、-CH(CH₃)-CH₂-、-CH₂-CH (CH₃)-、-CH₂-(CH₂)₂-CH₂-、-CH₂-CH(CH₃)-CH₂-、-C(CH₃)₂-CH₂-、-CH₂-C(CH₃)₂-、-CH₂-(CH₂)₃- CH₂- and-CH₂-(CH₂)₄-CH₂-。

According to the present invention, in the copolymer as the thickening extracting and cutting agent, under preferable case, the copolymer is divided equally again Son amount is 1,000,000-6,000,000g/mol, more preferably 2,000,000-5,500,000g/mol, still more preferably For 2,500,000-5,000,000g/mol, more preferably 3,000,000-4,500,000g/mol, for example, 3,000,000- 4,000,000g/mol.When the copolymer weight average molecular weight within the above range when, particularly 3,000,000-4,500, During 000g/mol scopes, the polymer of gained can be well used as extracting and cutting agent, can keep preferable in salt-water drilling fluid Salt resistance and heat-resisting property.The molecular weight distribution index of the copolymer for example can be 1.2-4, preferably 1.5-3.

According to the present invention, in the copolymer as the thickening extracting and cutting agent, although shown in the formula (1) that the copolymer contains Construction unit, the amount of the construction unit shown in formula (2) and the construction unit shown in formula (3) can become in wider scope It is dynamic, but be in order under thickening, salt resistance and the heat-resisting property consideration of the copolymer obtained by optimization, preferable case, the knot shown in formula (1) The mol ratio of the construction unit shown in construction unit and formula (3) shown in structure unit, formula (2) is 10-40：1-10：1, more preferably For 15-30：2-5：1, it is still more preferably 18-25：3-4：1.

According to the present invention, in the copolymer as the thickening extracting and cutting agent, the copolymer is understood as a kind of line Property copolymer, can be random, block, alternate, but be generally understood as a kind of linear random copolymer. Although the copolymer, which can also include some, does not influence it as the other structures unit of extracting and cutting agent performance it should be appreciated that , for the sake of facilitating, the copolymer is as shown in the construction unit shown in formula (1), the construction unit shown in formula (2) and formula (3) Construction unit constitute, but end group is not particularly limited, but is under normal circumstances hydrogen.

According to the present invention, it can be made as the copolymer of the thickening extracting and cutting agent using the conventional method of this area, As long as can coordinate with the other compositions of the composition of the present invention, play preferably to viscosify to carry when in for salt-water drilling fluid and cut Effect, is suitable for the drilling well of coal bed gas well.Under preferable case, the preparation method of the copolymer of the thickening extracting and cutting agent is used as Including：

In aqueous solvent, in the presence of radical initiator and chain-transferring agent, by formula (1') shown compound, formula (2') (3') shown compound carries out Raolical polymerizable for shown compound and formula, wherein,

Wherein, each substituent that the monomer in the above method is related to is as described above, will not be repeated here.Formula Shown compound, formula (2') shown compound and formula (3') shown compound can also be according to described above The specific construction unit species of copolymer properly selected.

Wherein, the instantiation of formula (1') shown compound can be for example one kind in the compound shown in following formula Or it is a variety of：

In formula (1'-1)：R¹And R^1'For H (also referred to as acrylamide)；In formula (1'-2)：R¹For methyl, R^1'For H (also referred to as Methacrylamide)；In formula (1'-3)：R¹For ethyl, R^1'For H (also referred to as ethyl acrylamide)；Formula (1^'- 4) in：R¹For H, R^1'For methyl (also referred to as 2- crotonamides).

Wherein, the instantiation of formula (2') shown compound can be for example one kind in the compound shown in following formula Or it is a variety of：

In formula (2'-1)：R⁴、R²And R^2'For H, R³Alkylidene selected from C0, n=2 (also referred to as NVP)； In formula (2'-2)：R⁴、R²And R^2'For H, R³Alkylidene selected from C0, n=1；In formula (2'-3)：R⁴、R²And R^2'For H, R³Selected from C0 Alkylidene, n=3；In formula (2'-4)：R⁴、R²And R^2'For H, R³Selected from-CH₂-, n=2；In formula (2'-5)：R⁴、R²And R^2'For H, R³Selected from-CH₂-, n=1；In formula (2'-6)：R⁴、R²And R^2'For H, R³Selected from-CH₂-, n=3.

Wherein, the instantiation of formula (3') shown compound can be for example one kind in the compound shown in following formula Or it is a variety of：

In formula (3'-1)：R⁵For methyl, R^5'- O-, R are selected from for H, X⁶Selected from-CH₂-CH₂-, R⁷It is methyl, R⁸Selected from- CH₂-CH₂-CH₂- (also referred to as 3- [N, N- dimethyl-[2- (methacryloxy) ethyl] ammonium] propyl group -1- sulfonate)；

In formula (3'-2)：R⁵For methyl, R^5'- O-, R are selected from for H, X⁶Selected from-CH₂-CH₂-, R⁷It is methyl, R⁸Selected from- CH₂-CH(CH₃)-CH₂- (it is also referred to as 3- [N, N- dimethyl-[2- (methacryloxy) ethyl] ammonium] isobutyl group -1- sulfonic acid Salt)；

In formula (3'-3)：R⁵And R^5'- NH-, R are selected from for H, X⁶Selected from-CH₂-CH₂-CH₂-, R⁷It is methyl, R⁸Selected from- CH₂-CH₂-CH₂- (also referred to as [3- (methacrylamido) propyl group] dimethyl (3- sulfopropyls) ammonium hydroxide)；

In formula (3'-4)：R⁵And R^5'- NH-, R are selected from for H, X⁶Selected from-CH₂-CH₂-CH₂-, R⁷It is methyl, R⁸Selected from- CH₂-(CH₂)₂-CH₂- (also referred to as [3- (methacrylamido) propyl group] dimethyl (3- thiobutyls) ammonium hydroxide)；

In formula (3'-5)：R⁵For methyl, R^5'- O-, R are selected from for H, X⁶Selected from-CH₂-CH₂-, R⁷It is methyl, R⁸Selected from-CH (CH₃)₂-CH₂- (also referred to as 3- [N, N- dimethyl-[2- (methacryloxy) ethyl] ammonium] tert-butyl group -1- sulfonate).

According to the present invention, in the preparation method as the copolymer of the thickening extracting and cutting agent, the consumption of above-mentioned monomer can be with Selected according to the accounting and molecular weight of the construction unit of required copolymer, under preferable case, formula (1') shown chemical combination The mol ratio of thing, formula (2') shown compound and formula (3') shown compound is 10-40：1-10：1, more preferably 15- 30：2-5：1, it is still more preferably 18-25：3-4：1, for example, 20-25：3-4：1.In order to anti-suitable for the radical polymerization Under the progress answered, and the reasonably molecular weight of copolymer obtained by control, preferable case, the formula relative to 1mol is (1') shown Mole total amount of compound, formula (2') shown compound and formula (3') shown compound, the consumption of the aqueous solvent is 400-1000mL, preferably 400-600mL.Wherein, the aqueous solvent can be single water or miscible have The solute (being, for example, the one or more in sodium chloride, potassium chloride, sodium bromide, KBr etc.) of the reaction of the present invention is not influenceed The mixture of water, certainly preferably water.

According to the present invention, in the preparation method as the copolymer of the thickening extracting and cutting agent, the Raolical polymerizable Can using this area it is conventional using a variety of radical initiators triggered, it is contemplated that anti-between above-mentioned monomer Under Ying Xing, preferable case, the radical initiator be 4,4'- azos (4- cyanopentanoic acids), azo diisobutyl amidine hydrochloride, One or more in azo dicyclohexyl formonitrile HCN hydrochloride and azo diisobutyl imidazoline hydrochloride.The free radical draws The consumption of hair agent can change in relative broad range, it is preferable that formula relative to 1mol (1') shown compound, formula (2') institute Mole total amount of the compound and formula shown (3') shown compound, the consumption of the radical initiator is 0.1-0.2mmol, Preferably 0.11-0.14mmol.

According to the present invention, in the preparation method as the copolymer of the thickening extracting and cutting agent, the chain-transferring agent can be adopted The a variety of chain-transferring agents routinely used with this area, it is contemplated that the copolymer of more particularly suitable molecular weight can be obtained, it is excellent In the case of choosing, one or more of the chain-transferring agent in sodium formate, sodium acetate, ammonium hydroxide and urea, more preferably Sodium formate and/or sodium acetate.The consumption of the chain-transferring agent can change in relative broad range, it is preferable that relative to 1mol's Mole total amount of formula (1') shown compound, formula (2') shown compound and formula (3') shown compound, the chain turns The consumption for moving agent is 0.1-0.2mmol, preferably 0.13-0.15mmol.

According to the present invention, in the preparation method as the copolymer of the thickening extracting and cutting agent, under preferable case, the freedom The condition of base polymerisation includes：Temperature is 40-80 DEG C, and the time is 6-12h.It is highly preferred that the Raolical polymerizable Condition includes：Temperature is 50-70 DEG C, and the time is 7-10h.

According to the present invention, in the preparation method as the copolymer of the thickening extracting and cutting agent, in order in the system of going out Some possible metal ingredients, it is preferable that in the preparation method of above-mentioned copolymer, the Raolical polymerizable also chelating Carried out in the presence of agent.In this case, by the effect of chelating agent, just being smoothly through chelation, to suppress some possible Metal ion.The chelating agent can for example be selected from ethylenediamine tetra-acetic acid and its salt (such as sodium ethylene diamine tetracetate), the second of ammonia three One in acid and its salt (sodium ammonium triacetate), hexa metaphosphoric acid and its salt (calgon) and diethylenetriamine penta Plant or a variety of.Preferably, the formula relative to 1mol (1') shown compound, formula (2') shown compound and formula are (3') shown Compound mole total amount, the consumption of the chelating agent is 0.01-0.05mmol, more preferably 0.01-0.02mmol.

According to the present invention, in the preparation method as the copolymer of the thickening extracting and cutting agent, in order to keep initiator Deng activity, this method can also include：So that the Raolical polymerizable is carried out in an inert atmosphere, for example can be to body Nitrogen, helium, neon, argon gas etc. are passed through in system one or more and replace atmosphere therein (process can for example carry out 5- 300min, mainly deoxygenation).

According to the present invention, in the preparation method as the copolymer of the thickening extracting and cutting agent, in order to better control over The progress of above-mentioned Raolical polymerizable, it is preferable that this method includes：First by formula, (1') shown compound, formula are (2') shown Compound, (3') shown compound and aqueous solvent is mixed that (mixing condition can for example be included in 100- to formula 10-40min is mixed under 300rpm mixing speed, at 10-40 DEG C), it is re-introduced into the radical initiator, chain-transferring agent and appoints The chelating agent of choosing is mixed, and under an inert atmosphere as described in (inert atmosphere formation above described in) progress oneself By base polymerisation.

According to the present invention, in the preparation method as the copolymer of the thickening extracting and cutting agent, in order to by the copolymerization Thing is extracted in product from the reactions above, and this method can also include：By the product of the Raolical polymerizable in 70- 2-5h is dried at 100 DEG C.

According to the present invention, in the preparation method as the copolymer of the thickening extracting and cutting agent, it should be appreciated that above-mentioned side Copolymer prepared by method typically refers to the above method without the direct product of purification (or merely through the above drying Afterwards), the product of even now is probably the mixture of multiple polymers, but the present invention also includes such situation in this hair In bright scope.

According to the present invention, the combed polysaccharide compound may be considered to be connect on the main chain of sulfonate polysaccharide class compound The side chain provided on branch as the compound shown in the compound shown in formula (I) and formula (II), the side chain can be shown in formula (I) Copolymer compound chain shown in compound and formula (II) or be the equal poly chain that the compound shown in formula (I) is provided respectively With the equal poly chain with the compound shown in formula (II).The combed polysaccharide compound when for drilling fluid as coating agent, Multiple spot suction-operated by the polar group on strand to landwaste, effectively turns into big grain by the landwaste coalescence of high degree of dispersion Footpath particle is simultaneously removed during solid controlling, plays excellent encapsulation action, and above-mentioned combed polysaccharide compound can also protected Demonstrate,prove and excellent temperature resistance and anti-salt property is obtained under preferable encapsulation action.Also, surprisingly, compared to linear coating For agent polymer, combed polysaccharide compound of the invention can not only obtain higher coating performance, heat-resisting property and resist Salt performance, additionally it is possible to obtain preferably water-soluble, be so just more applicable for water-base drilling fluid.So as to pass through the group with the present invention Other neccessary compositions of compound together, are added into salt-water drilling fluid, can be under without solid-phase component, for coal bed gas well In drilling well, reach that rate of penetration is high, relatively low residue rate effect, to realize the efficient drilling well of coal bed gas well and coal bed gas is stored up The Low Damage of layer.

According to the present invention, wherein, above-mentioned C1-C6 alkyl for example can be methyl, ethyl, n-propyl, isopropyl, positive fourth Base, isobutyl group, sec-butyl, the tert-butyl group, n-pentyl, isopentyl, n-hexyl etc..

In order to preferably play the combed polysaccharide compound as the effect of coating agent, under preferable case, R¹、 R^1'、R²And R^2'It is each independently selected from H, methyl, ethyl, n-propyl, isopropyl and normal-butyl.

Wherein, the instantiation of the compound shown in formula (I) can be for example one kind in the compound shown in following formula Or it is a variety of：

In formula (I-1)：R¹And R^1'For H (also referred to as acrylamide)；In formula (I-2)：R¹For methyl, R^1'(first is also referred to as H Base acrylamide)；In formula (I-3)：R¹For ethyl, R^1'For H (also referred to as ethyl acrylamide)；In formula (I-4)：R¹For H, R^1'For Methyl (also referred to as 2- crotonamides).

Wherein, the instantiation of the compound shown in formula (II) can be for example one kind in the compound shown in following formula Or it is a variety of：

In formula (II-1)：R²And R^2'For H (also referred to as acrylic acid)；In formula (II-2)：R²For methyl, R^2'(first is also referred to as H Base acrylic acid).

According to the present invention, as in the combed polysaccharide compound of the coating agent, the sulfonate polysaccharide class compound is The xanthans of the starch of sulfonation, the cellulose compound of sulfonation or sulfonation.The polysaccharide compound of these sulfonation can be city Sell product, it would however also be possible to employ in the present invention prepared by process described below.It is considered that the polysaccharide compound of sulfonation is many Some sulfonic groups or the structure of other sulfur-containing groups are formd on saccharide compound, this is the conventional cognitive of this area, the present invention It will not be repeated here.

Wherein, the cellulose compound of the sulfonation be the carboxymethyl cellulose of sulfonation, the hydroxymethyl cellulose of sulfonation, The carboxyethyl cellulose of sulfonation, the hydroxyethyl cellulose of sulfonation, the hydroxypropyl cellulose of sulfonation or the hydroxypropyl methyl of sulfonation are fine Dimension element.

According to the present invention, although the present invention is to sulfur-containing group (such as sulfonic group, sulfuric acid on the polysaccharide compound after sulfonation Ester group, mercapto etc.) content there is no particular limitation, but be able to obtain the combed polysaccharide for being more applicable for coating agent Class compound, it is preferable that in the sulfonate polysaccharide class compound, the content of sulfur-containing group is 20-35 weight %, preferably 25- 30 weight %.

According to the present invention, as in the combed polysaccharide compound of the coating agent, the combed polysaccharide compound Molecular weight can change in relative broad range, excellent in order to obtain the combed polysaccharide compound for being more applicable for coating agent Selection of land, the weight average molecular weight of the combed polysaccharide compound is 9,000,000-15,000,000g/mol, preferably 9,500, 000-14,500,000g/mol, more preferably 10,000,000-13,500,000g/mol, it is still more preferably 12,000, 000-13,500,000g/mol。

According to the present invention, as in the combed polysaccharide compound of the coating agent, it is preferable that the combed polysaccharide In compound, the content of the construction unit provided as the compound shown in the compound shown in formula (I) and formula (II) is 80-95 weights Measure %, more preferably preferably 85-92 weight %, 88-92 weight %.When the compound and formula shown in the formula (I) of offer side chain (II) construction unit of the compound shown in and the construction unit of the sulfonate polysaccharide class compound of offer main chain meet above-mentioned weight Than under, can preferably play the synergy of each group in combed polysaccharide compound, obtain water-soluble high, thus with Excellent coating performance, heat-resisting property and anti-salt property is obtained under other neccessary compositions for the composition for closing the present invention.

According to the present invention, as in the combed polysaccharide compound of the coating agent, although compound shown in formula (I) and The mol ratio for the construction unit that compound shown in formula (II) is provided can change in relative broad range, it is preferable that formula (I) The mol ratio for the construction unit that compound shown in shown compound and formula (II) is provided is 1：0.2-1, preferably 1：0.2- 0.5, more preferably 1：0.24-0.4 (such as 1：0.25-0.33), it is still more preferably 1：0.27-0.33.When shown in formula (I) Compound and formula (II) shown in compound provide construction unit mol ratio within the range when, result in more favourable In coordinating the side chain that plays coating agent performance with main chain, as set forth above, it is possible to think that the side chain is that compound shown in formula (I) is carried The equal poly chain of the compound shown in equal poly chain and formula (II) supplied, but compound and formula (II) more preferably shown in formula (I) The copolymerization chain of shown compound formation, particularly random linear copolymerization chain.Several side chain grafts are in sulfonate polysaccharide class chemical combination On thing, comb-type structure is formed, namely form the combed polysaccharide compound of the present invention.

Although there is no particular limitation in source of the present invention to the combed polysaccharide compound as the coating agent, can with Prepared using the conventional method in this area, but be able to be easy to the acquisition of the combed polysaccharide compound, preferably In the case of, the preparation method as the combed polysaccharide compound of the coating agent includes：

(1) in aqueous solvent, polysaccharide compound and sulfonating agent is subjected to sulfonating reaction, sulfonate polysaccharide class chemical combination is obtained Thing；

(2) in aqueous solvent, in the presence of graft copolymerization catalyst, by shown in sulfonate polysaccharide class compound, formula (I) Compound shown in compound and formula (II) carries out graft copolymerization；

Wherein, the polysaccharide compound is the one or more in starch, cellulose compound and xanthans；

Wherein, shown in formula (I) compound shown in compound and formula (II) and its group is as described above, This is repeated no more.

, will be logical in step (1) in the preparation method as the combed polysaccharide compound of the coating agent according to the present invention Cross the sulfonating reaction and sulfonate polysaccharide class compound described above is provided, therefore, the polysaccharide compound can root Selected according to required sulfonate polysaccharide class compound, as one kind or many in starch, cellulose compound and xanthans Kind.

According to the present invention, in the preparation method as the combed polysaccharide compound of the coating agent, the number of the starch Average molecular weight is usually 20,000-200 ten thousand, and it can form sediment for the conventional various native starches in this area, such as potato starch, mung bean One or more in powder, starch from sweet potato, wheaten starch etc..Wherein, the optional catabolite containing it in acid of the starch, For example can be containing the one or more in dextrin, maltose and its more glucose of low molecule amount.

Wherein, the cellulose compound is carboxymethyl cellulose, hydroxymethyl cellulose, carboxyethyl cellulose, hydroxyl second One or more in base cellulose, hydroxypropyl cellulose and hydroxypropyl methyl cellulose.It should be understood that the polysaccharide Compound is usually linear macromolecular, it is believed that the polysaccharide compound after the sulfonation of following gained is also linear big point Minor structure.

According to the present invention, in the preparation method as the combed polysaccharide compound of the coating agent, the polysaccharide The molecular weight of compound can be selected according to required sulfonate polysaccharide class compound, such as be 9 in order to prepare weight average molecular weight, 000,000-15,000,000g/mol (is preferably 9,500,000-14,500,000g/mol, more preferably 10,000,000- 13,500,000g/mol, be still more preferably 12,000,000-13,500,000g/mol) combed polysaccharide compound, Preferably, the weight average molecular weight of the polysaccharide compound is 100,000-2,000,000g/mol, preferably 150,000-1, 000,000g/mol, for example, 700,000-1,000,000g/mol.

According to the present invention, in the preparation method as the combed polysaccharide compound of the coating agent, the aqueous solvent Can be single water or it is miscible have some do not influence the present invention reaction solvent (be, for example, methanol, ethanol, second One or more in glycol, propyl alcohol, isopropanol etc.) water mixture, preferably water certainly.It is applied in order to prepare The required sulfonate polysaccharide class compound of the present invention, it is preferable that in step (1), relative to the polysaccharide chemical combination of 100 parts by weight Thing, the consumption of aqueous solvent is 1000-5000 parts by weight, preferably 2000-4000 parts by weight.

According to the present invention, in the preparation method as the combed polysaccharide compound of the coating agent, to the sulfonating agent There is no particular limitation, as long as the sulfonate polysaccharide class compound of the present invention can be obtained, can be conventional using this area Various sulfonating agents, it is preferable that the sulfonating agent is that (concentration is for example for chlorosulfonic acid, sulfur trioxide, PS and the concentrated sulfuric acid For more than 90 weight %, particularly 98 weight the % concentrated sulfuric acid) in one or more.The consumption of the sulfonating agent can compared with Changed in wide scope, in order to which sulfonation of the content of sulfur-containing group for 20-35 weight % (being preferably 25-30 weight %) is made Under polysaccharide compound, preferable case, relative to the polysaccharide compound of 100 parts by weight, the consumption of the sulfonating agent is 20-40 parts by weight, preferably 25-35 parts by weight, for example, 28-30 parts by weight.

According to the present invention, in the preparation method as the combed polysaccharide compound of the coating agent, under preferable case, institute Stating the condition of sulfonating reaction includes：Temperature is 50-70 DEG C (being preferably 55-65 DEG C), and the time is 8-20h (being preferably 10-12h).

It is described in order to promote in the preparation method as the combed polysaccharide compound of the coating agent according to the present invention Dissolubility of the polysaccharide compound in aqueous solvent, above-mentioned sulfonating reaction is carried out also in the presence of cosolvent, the cosolvent For example can be the one or more in formic acid, acetic acid, ethanedioic acid and malonic acid.Wherein it is preferred to, relative to 100 parts by weight The polysaccharide compound, the consumption of the cosolvent is 8-20 parts by weight, preferably 10-15 parts by weight.

According to the present invention, in the preparation method as the combed polysaccharide compound of the coating agent, above-mentioned steps (1) can Using first the polysaccharide compound and aqueous solvent is mixed, then to introduce sulfonating agent and optional cosolvent mixed and gone forward side by side The mode of the row sulfonating reaction.

According to the present invention, in the preparation method as the combed polysaccharide compound of the coating agent, although step (1) institute The product of the sulfonating reaction obtained can be used in step (2) without any further processing, but be able to more favourable In the progress of the graft copolymerization, the step (1) also includes the product of the sulfonating reaction carrying out separation of solid and liquid (for example By the way of suction filtration) and gained solid phase is dried, so as to obtain the process of sulfonate polysaccharide class compound.

According to the present invention, in the preparation method as the combed polysaccharide compound of the coating agent, step passes through in (2) Compound shown in compound and formula (II) shown in sulfonate polysaccharide class compound, formula (I) is subjected to graft copolymerization, you can Compound in sulfonate polysaccharide class compound in grafting shown in formula (I) and the polymer side of the compound formation shown in formula (II) Chain, it is believed that self-polymerization reaction does not occur herein for sulfonate polysaccharide class compound here, is only obtained by step (1) On the basis of sulfonate polysaccharide class compound, the graft copolymerization of step (2) is passed through again using the sulfonate polysaccharide class compound as main chain The polymer lateral chain of compound formation shown in compound and formula (II) in grafting shown in formula (I).Although shown in the formula (I) Compound and formula (II) shown in the consumption of compound can be according to the side chain situation on required combed polysaccharide compound Properly selected, under preferable case, relative to the sulfonate polysaccharide class compound of 100 parts by weight, the change shown in formula (I) Total consumption of compound shown in compound and formula (II) is 500-1500 parts by weight, preferably 800-1000 parts by weight, more preferably For 850-950 parts by weight.In order to obtain the side chain that can preferably coordinate with main chain, it is preferable that the chemical combination shown in formula (I) The mol ratio of the consumption of compound shown in thing and formula (II) is 1：0.2-1, preferably 1：0.2-0.5, more preferably 1：0.24- 0.4 (such as 1：0.25-0.33), it is still more preferably 1：0.27-0.33.

According to the present invention, in the preparation method as the combed polysaccharide compound of the coating agent, containing in step (2) The progress of aqueous solvent as described above is selected, and is applied to the required combed polysaccharide compound of the present invention in order to prepare, Preferably, in step (2), relative to the sulfonate polysaccharide class compound of 100 parts by weight, the consumption of aqueous solvent is 5000- 10000 parts by weight, preferably 6000-9000 parts by weight, more preferably 6500-8000 parts by weight.

According to the present invention, in the preparation method as the combed polysaccharide compound of the coating agent, the graft copolymerization Catalyst can be using the conventional catalyst for graft copolymerization in this area, in order to which the sulfonation for being preferably applied to the present invention is more The graft copolymerization that compound shown in compound and formula (II) shown in saccharide compound, formula (I) is carried out, preferable case Under, the graft copolymerization catalyst is the one or more in high-valency metal compound and persulfate.Wherein, the high price gold Category compound for example can be compound, cobaltous compound, the compound of pentavalent vanadium, the ferric compound of quadrivalent cerium In one or more in, preferably ammonium ceric nitrate, ferric trichloride, four (4- carboxyl phenyls) Cob altporphyrins and vanadium acetylacetonate It is one or more.Preferably, the persulfate is the one or more in ammonium persulfate, sodium peroxydisulfate and potassium peroxydisulfate.Institute Stating the consumption of graft copolymerization catalyst can be adjusted according to required combed polysaccharide compound, it is preferable that relative to 100 The sulfonate polysaccharide class compound of parts by weight, the consumption of the graft copolymerization catalyst is 0.1-2 parts by weight, preferably 0.2- 1 parts by weight, more preferably 0.2-0.5 parts by weight.

According to the present invention, in the preparation method as the combed polysaccharide compound of the coating agent, under preferable case, step Suddenly in (2), the condition of the graft copolymerization includes：It (is preferably 20-35 DEG C, for example, 25-35 that temperature, which is 10-40 DEG C, DEG C), the time is 10-30h (being preferably 16-25h, for example, 20-24h).

According to the present invention, in the preparation method as the combed polysaccharide compound of the coating agent, in order to keep The activity of catalyst etc., this method can also include：, for example can be with so that the graft copolymerization is carried out in an inert atmosphere Nitrogen, helium, neon, argon gas etc. are passed through into system one or more and replace atmosphere therein (process can for example be entered Row 5-300min, mainly deoxygenation).

According to the present invention, in the preparation method as the combed polysaccharide compound of the coating agent, in order to more Fully react, step (2) can mix sulfonate polysaccharide class compound and aqueous solvent using first, then introduce formula (I) institute The compound shown in compound and formula (II) shown is mixed, and a kind of or many being passed through nitrogen, helium, neon, argon gas etc. Plant and replace after atmosphere therein, introduce the graft copolymerization catalyst and carry out the graft copolymerization.

According to the present invention, in the preparation method as the combed polysaccharide compound of the coating agent, this method can be with Including the product of the graft copolymerization is dried, so as to obtain the combed polysaccharide compound.It should be understood that It is that the combed polysaccharide compound prepared by the above method typically refers to the above method and the direct of gained is dried without purification Product, the product of even now is probably the mixture of a variety of combed polysaccharide compounds, but the present invention is also by such feelings Condition is included within the scope of the invention.

According to the present invention, in order to obtain more excellent filtrate loss controllability, the nano-crystal fiber of the fluid loss additive is used as The average grain diameter of element is preferably 100-600nm, more preferably 150-320nm.

Preferably, the nano-crystal cellulose is bar-shaped.

In the present invention, nano-crystal fiber is determined using Japanese JEOL companies model JEM-2100 transmission electron microscope (TEM) The microscopic pattern and average grain diameter of crude granule.Sample preparation methods：It is 0.1 weight % nano-crystal cellulose that concentration, which will be diluted to, Aqueous dispersions are dripped in the copper micro-grid of carbon film covering, and are dried with infrared lamp.

According to the present invention, the nano-crystal cellulose can be obtained by commercially available mode, can also pass through art technology Prepared by method known to personnel, for example, the nano-crystal cellulose is prepared by the following method：

(1) microcrystalline cellulose is mixed with acid solution；(2) mixture for obtaining step (1) is contacted with water, then The product of gained is subjected to separation of solid and liquid.

It is in step (1), microcrystalline cellulose is molten with acid in the preparation method of the nano-crystal cellulose according to the above method The purpose of liquid mixing is the noncrystalline domain for making acid solution penetrate into microcrystalline cellulose, to accelerate the hydrolysis of microcrystalline cellulose.In this hair In bright, the condition of the mixing includes：The temperature of mixing is 30-70 DEG C, preferably 35-60 DEG C；The time of mixing is 1-15h, Preferably 3-10h.The mixing preferably realizes that rotating speed can turn/min for 100-300 by homogenizer.

According to the above method, in the preparation method of the nano-crystal cellulose, in step (1), the microcrystalline cellulose and institute The weight of acid solution is stated than can be changed in wider scope, as long as microcrystalline cellulose can be hydrolyzed.Typically The weight ratio of ground, the microcrystalline cellulose and the acid solution can be 1：20-40, preferably 1：20-30.The acid solution Concentration can be 30-80 weight %, preferably 50-70 weight %.

According to the above method, in the preparation method of the nano-crystal cellulose, acid in the acid solution can for it is various often The inorganic acid or organic acid of the amorphous area that can penetrate into microcrystalline cellulose of rule.In the present invention, the inorganic acid can be normal The various inorganic acids of rule, for example, can be the one or more in hydrochloric acid, sulfuric acid, phosphoric acid and nitric acid；The organic acid can be Conventional various organic acids, such as carbon number are 1-5 unitary or binary organic carboxyl acid, are specifically as follows formic acid, acetic acid, wine One or more in stone acid and citric acid.

In the present invention, in the preparation method of the nano-crystal cellulose, the microcrystalline cellulose can pass through commercially available side Formula is obtained.In order to obtain under the nano-crystal cellulose grain with specific dimensions, preferable case, the microcrystalline cellulose crude granule it is flat Equal particle diameter is 20-80 μm, more preferably 20-50 μm.

According to the above method, in the preparation method of the nano-crystal cellulose, in step (2), the mixing that step (1) is obtained The purpose that thing is contacted with water is the hydrolysis that microcrystalline cellulose is terminated with water.Relative to the microcrystalline cellulose of 100 parts by weight Element, the consumption of water can be 2000-7500 parts by weight, preferably 4000-7500 parts by weight.

According to the above method, in the preparation method of the nano-crystal cellulose, the method for separation of solid and liquid can described in step (2) Think various conventional solid-liquid separating methods in this area, for example, can be to be separated by filtration and/or centrifuge.Preferable case Under, the separation of solid and liquid is centrifugation.In the present invention, to the condition of the centrifugation, there is no particular limitation, as long as can be with By the isolated crystal of gained suspension and liquid phase.The condition of centrifugation includes：The rotating speed of centrifugation is 3000-11000 Turn/min, preferably 6000-11000 turns/min；Centrifugation time is 5-30min, preferably 10-20min.

In the preparation method of the nano-crystal cellulose, the influence in order to avoid remaining acid to follow-up filtrate reducing effect, on The solid that the method for stating preferably includes to be centrifugally separating to obtain is washed with water until the pH value of the liquid obtained by centrifugation is 6-7, Then it is dried.The condition of the drying includes：Dry temperature is 100-110 DEG C, and the dry time is 8-12h.

According to the present invention, the compositions of additives can also containing the conventional additive for drilling fluid in this area, One or more in such as can include Waterproof lock agent, heavy weight additive, gel breaker.These other additives are being added to brill When in well liquid, it is believed that be that drilling fluid is formed in the form of the compositions of additives of the present invention, it is of course also possible to be considered this A little others additives rather than are considered as the composition of the composition of the present invention independently as the composition of drilling fluid, and this all includes Within the scope of the invention.

According to the present invention, the water-base drilling fluid contains the compositions of additives of the present invention, can obtain rate of penetration it is high, The effect of relatively low residue rate, to realize the efficient drilling well of coal bed gas well and the Low Damage to coalbed methane reservoir.Under preferable case, Relative to the water in the water-base drilling fluid of 100 parts by weight, the content of the composition is 3-10 parts by weight, preferably 4-8 Parts by weight, more preferably 5-6 parts by weight.Meeting in this case, in the water-base drilling fluid relative to 100 parts by weight Water, the content of the thickening extracting and cutting agent is preferably 1.5-5 parts by weight, preferably 2-3 parts by weight.Meeting in this case, relative Water in the water-base drilling fluid of 100 parts by weight, the content of the coating agent is preferably 0.1-0.5 parts by weight, is preferably 0.15-0.3 parts by weight.Meeting the water in this case, in the water-base drilling fluid relative to 100 parts by weight, the drop filter The content for losing agent is preferably 1-5 parts by weight, preferably 3-4 parts by weight.

According to the present invention, in addition to the compositions of additives and water of the present invention, the water-base drilling fluid can be containing this The various conventional additives used in the water-base drilling fluid in field, for example, one kind or many in Waterproof lock agent, heavy weight additive etc. Kind.Particularly, the water-base drilling fluid is salt-water drilling fluid, so that containing the salt as heavy weight additive, and do not contain other solid phases (such as bentonite, barite), is a kind of salt-water drilling fluid of Solid Free.

Wherein, the density that can adjust drilling fluid as the salt of heavy weight additive reaches required density, for example can for KCl, One or more in NaCl, KBr and NaBr etc..Preferably, relative to the water in the water-base drilling fluid of 100 parts by weight, as The content of the salt of heavy weight additive is 5-10 parts by weight.

Wherein, the Waterproof lock agent has reduction drilling fluid surface tension, prevents the effect of Water-blocking damage, for example, can be One kind in Waterproof lock agent disclosed in polyoxethylene octylphenyl phenol ether, polyoxyethylated alkyl phenol and CN102887974A etc. Or it is a variety of.Preferably, relative to the water in the water-base drilling fluid of 100 parts by weight, the content of the Waterproof lock agent is 0.1-0.5 weights Measure part.

The various materials that above-mentioned additive is can be commercially available product, can also be made according to the conventional method in this area, this In repeat no more.

According to the present invention, the salt-water drilling fluid of the water-base drilling fluid, particularly Solid Free results in higher machinery Drilling speed, relatively low residue rate, can preferably be applied to the drilling well of coal bed gas well so that the efficient drilling well of coal bed gas well and to coal The Low Damage of layer gas reservoir.

The present invention will be described in detail by way of examples below.

In following examples and comparative example, weight average molecular weight and molecular weight distributing index are using (the experiment of GPC gel chromatographies Instrument is the gel permeation chrommatograph of waters companies of the U.S., model E2695) measure.

In following preparation example, the calculation formula of the yield of nano-crystal cellulose：

In following preparation example, nano-crystal cellulose particles are determined using Japanese JEOL companies model JEM transmission electron microscope (TEM) The microscopic pattern and average grain diameter of grain.The preparation method of sample：The water for the nano-crystal cellulose that concentration is 0.1 weight % will be diluted to In the copper micro-grid that dispersant liquid drop is covered to carbon film, and dried with infrared lamp.

Fluid loss additive preparation example 1

(1) 40g microcrystalline celluloses (being purchased from Hubei Zhong Liao Chemical Co., Ltd.s, the average grain diameter of particle is 20 μm) are added Concentration for 64 weight % 700mL aqueous sulfuric acids in, and at 45 DEG C with 250 turns/min rotating speed high-speed stirred 3h；

(2) 3L deionized waters are added in the mixture obtained to step (1) to terminate the hydrolysis of microcrystalline cellulose；Will Then obtained suspension the solid obtained by centrifugation is washed with deionized for several times, directly in centrifuging 20min under 11000r/min The pH value of the clear liquid obtained to centrifugation is 7；By clean solid in drying 12h at 105 DEG C, that is, obtain 35.28g nano-crystal fiber Element, as fluid loss additive N1, yield is 88.2%.The average grain diameter of product nano-crystal cellulose is determined by transmission electron microscope (TEM) For 239nm, nano-crystal cellulose is bar-shaped.

Viscosify extracting and cutting agent preparation example 1

By acrylamide, NVP and 3- [N, the N- dimethyl-[2- (methacryloxypropyls of 1mol total amounts Base) ethyl] ammonium] (mol ratio is 25 to propyl group -1- sulfonate：4：1) it is added in 500mL water, is stirred at 150rpm, 30 DEG C Mix 30min；And 0.01mmol disodium ethylene diamine tetraacetate, 0.12mmol 4,4'- azos are added in the backward mixture The sodium acetate of (4- cyanopentanoic acids) and 0.14mmol, and nitrogen 15min is passed through with deoxygenation；Polymerisation is then carried out at 60 DEG C 8h；Polymerizate is dried into 2.5h at 90 DEG C, crushing obtains copolymer, as extracting and cutting agent A1.The Weight-average molecular of the polymer Measure as 4,000,000g/mol, molecular weight distribution index is 1.5, detected through infrared, proton nmr spectra and carbon analysis of spectrum, formula (1) construction unit (R shown in¹And R^1'For H), the construction unit (R shown in formula (2)⁴、R²And R^2'For H, R³Alkylene selected from C0 Base, n=2) and formula (3) shown in construction unit (R⁵For methyl, R^5'- O-, R are selected from for H, X⁶Selected from-CH₂-CH₂-, R⁷It is first Base, R⁸Selected from-CH₂-CH₂-CH₂-) mol ratio be 25：3.75：1.

Viscosify extracting and cutting agent preparation example 2

By the Methacrylamide of 1mol total amounts, NVP and [3- (methacrylamido) propyl group] two (mol ratio is 20 to methyl (3- sulfopropyls) ammonium hydroxide：4：1) it is added in 500mL water, is stirred at 200rpm, 30 DEG C Mix 30min；And 0.01mmol disodium ethylene diamine tetraacetate, the 0.14mmol isobutyl of azo two are added in the backward mixture The sodium formate of amidine hydrochloride and 0.15mmol, and nitrogen 20min is passed through with deoxygenation；Polymerisation 10h is then carried out at 50 DEG C； Polymerizate is dried into 3h at 80 DEG C, crushing obtains copolymer, as extracting and cutting agent A2.The weight average molecular weight of the polymer is 3, 200,000g/mol, molecular weight distribution index is 2.2, is detected through infrared, proton nmr spectra and carbon analysis of spectrum, shown in formula (1) Construction unit (R¹For methyl, R^1'For H), the construction unit (R shown in formula (2)⁴、R²And R^2'For H, R³Alkylidene selected from C0, n =2) and formula (3) shown in construction unit (R⁵And R^5'- NH-, R are selected from for H, X⁶Selected from-CH₂-CH₂-CH₂-, R⁷It is methyl, R⁸ Selected from-CH₂-CH₂-CH₂-) mol ratio be 18：3.2：1.

Viscosify extracting and cutting agent preparation example 3

By acrylamide, NVP and 3- [N, the N- dimethyl-[2- (methacryloxypropyls of 1mol total amounts Base) ethyl] ammonium] (mol ratio is 25 to propyl group -1- sulfonate：4：1) it is added in 400mL water, is stirred at 200rpm, 40 DEG C Mix 20min；And 0.02mmol disodium ethylene diamine tetraacetate, 0.12mmol 4,4'- azos are added in the backward mixture The sodium acetate of (4- cyanopentanoic acids) and 0.14mmol, and nitrogen 10min is passed through with deoxygenation；Polymerisation is then carried out at 70 DEG C 7h；Polymerizate is dried into 5h at 90 DEG C, crushing obtains copolymer, as extracting and cutting agent A3.The weight average molecular weight of the polymer For 3,000,000g/mol, molecular weight distribution index is 2.8, is detected through infrared, proton nmr spectra and carbon analysis of spectrum, formula (1) Shown construction unit (R¹And R^1'For H), the construction unit (R shown in formula (2)⁴、R²And R^2'For H, R³Alkylidene selected from C0, n =2) and formula (3) shown in construction unit (R⁵For methyl, R^5'- O-, R are selected from for H, X⁶Selected from-CH₂-CH₂-, R⁷It is methyl, R⁸ Selected from-CH₂-CH₂-CH₂-) mol ratio be 22：3.5：1.

Viscosify extracting and cutting agent preparation example 4

Method according to thickening extracting and cutting agent preparation example 1, unlike, it is used as the consumption of the water of the solvent of reaction system For 1000mL, copolymer, as extracting and cutting agent A4 are obtained so as to finally crush.The weight average molecular weight of the polymer is 2,400, 000g/mol, molecular weight distribution index is 1.7, is detected through infrared, proton nmr spectra and carbon analysis of spectrum, the knot shown in formula (1) Structure unit (R¹And R^1'For H), the construction unit (R shown in formula (2)⁴、R²And R^2'For H, R³Alkylidene selected from C0, n=2) and formula (3) construction unit (R shown in⁵For methyl, R^5'- O-, R are selected from for H, X⁶Selected from-CH₂-CH₂-, R⁷It is methyl, R⁸Selected from- CH₂-CH₂-CH₂-) mol ratio be 25：3.75：1.

Viscosify extracting and cutting agent preparation example 5

Method according to thickening extracting and cutting agent preparation example 1, unlike, the polymerisation carried out after logical nitrogen deoxygenation Temperature is 30 DEG C, and copolymer, as extracting and cutting agent A5 are obtained so as to finally crush.The weight average molecular weight of the polymer is 5,100, 000g/mol, molecular weight distribution index is 2.0, is detected through infrared, proton nmr spectra and carbon analysis of spectrum, the knot shown in formula (1) Structure unit (R¹And R^1'For H), the construction unit (R shown in formula (2)⁴、R²And R^2'For H, R³Alkylidene selected from C0, n=2) and formula (3) construction unit (R shown in⁵For methyl, R^5'- O-, R are selected from for H, X⁶Selected from-CH₂-CH₂-, R⁷It is methyl, R⁸Selected from- CH₂-CH₂-CH₂-) mol ratio be 25：3.9：1.

Viscosify extracting and cutting agent and prepare comparative example 1

Method according to thickening extracting and cutting agent preparation example 1, unlike, 3- [N, N- dimethyl-[2- (methyl is not used Acryloxy) ethyl] ammonium] propyl group -1- sulfonate, but mol ratio is used for 6：1 acrylamide and N- vinyl pyrroles Alkanone is as monomer, and total consumption of monomer is 1mol, so that copolymer, as extracting and cutting agent DA1 is made.The weight of the polymer is equal Molecular weight is 4,400,000g/mol, and molecular weight distribution index is 1.6.

Viscosify extracting and cutting agent and prepare comparative example 2

Method according to thickening extracting and cutting agent preparation example 1, unlike, NVP is not used, but Mol ratio is used for 25：1 acrylamide and 3- [N, N- dimethyl-[2- (methacryloxy) ethyl] ammonium] propyl group -1- Sulfonate is as monomer, and total consumption of monomer is 1mol, so that copolymer, as extracting and cutting agent DA2 is made.The weight of the polymer Average molecular weight is 3,200,000g/mol, and molecular weight distribution index is 2.4.

Coating agent preparation example 1

(1) 100g starch (is purchased from Sa En chemical technologies (Shanghai) Co., Ltd., molecular weight is 1,000,000g/ Mol) it is dissolved in 3000g water, and adds 12g acetic acid and 30g chlorosulfonic acid, after stirring, in reacts 12h at 60 DEG C； Products therefrom is subjected to suction filtration, and dries gained solid, so as to obtain sulfonated starch SS-1.Identified through infrared nuclear-magnetism, the sulfonation The content of sulfur-containing group is 28.5 weight % in starch；

(2) 100g sulfonated starch SS-1 is dissolved in 7000g water, and add 700g acrylamide and 200g third Olefin(e) acid, leads to nitrogen 15min after stirring, then add 0.2g ammonium ceric nitrate, and in reacting 24h at 25 DEG C, so that by institute Obtain product to be dried, crush, obtain combed polysaccharide compound, as coating agent C1.The weight of the combed polysaccharide compound Average molecular weight is 13,500,000g/mol, wherein, identified through infrared nuclear-magnetism, form the propylene of combed polysaccharide compound side chain The mol ratio for the construction unit that acid amides and acrylic acid are provided is 1：0.27, the construction unit provided by acrylamide and acrylic acid Content is 90 weight %.

Coating agent preparation example 2

(1) by 100g carboxymethyl cellulose (be purchased from Sa En chemical technologies (Shanghai) Co., Ltd., molecular weight is 700, 000g/mol) it is dissolved in 2000g water, and adds 12g acetic acid and 30g chlorosulfonic acid, after stirring, in reaction at 55 DEG C 10h；Products therefrom is subjected to suction filtration, and dries gained solid, so as to obtain sulfonation carboxymethyl cellulose SC-1.Through infrared nuclear-magnetism The content of sulfur-containing group is 29.1 weight % in identification, the sulfonation carboxymethyl cellulose；

(2) 100g sulfonation carboxymethyl cellulose SC-1 is dissolved in 8000g water, and add 710g acrylamide and 240g acrylic acid, leads to nitrogen 20min after stirring, then add 0.5g ammonium persulfate, and in reacting 22h at 25 DEG C, So as to be dried, crush by products therefrom, combed polysaccharide compound, as coating agent C2 are obtained.The combed polysaccharide The weight average molecular weight of compound is 12,500,000g/mol, wherein, identified through infrared nuclear-magnetism, form combed polysaccharide compound side The mol ratio for the construction unit that the acrylamide and acrylic acid of chain are provided is 1：0.3, the knot provided by acrylamide and acrylic acid The content of structure unit is 90.5 weight %.

Coating agent preparation example 3

(1) 100g hydroxypropyl methyl cellulose (is purchased from Sa En chemical technologies (Shanghai) Co., Ltd., molecular weight is 150,000g/mol) it is dissolved in 2000g water, and adds 15g acetic acid and 28g sulfur trioxide, after stirring, in 55 DEG C Lower reaction 10h；Products therefrom is subjected to suction filtration, and dries gained solid, so as to obtain sulfonation hydroxypropyl methyl cellulose SC-2. Identified through infrared nuclear-magnetism, the content of sulfur-containing group is 25.6 weight % in the sulfonation hydroxypropyl methyl cellulose；

(2) 100g sulfonation hydroxypropyl methyl cellulose SC-2 is dissolved in 6500g water, and adds 720g methyl-prop The methacrylic acid of acrylamide and 230g, leads to nitrogen 10min after stirring, then add 0.5g ammonium persulfate, and in 30 20h is reacted at DEG C, so that products therefrom is dried, crushed, combed polysaccharide compound, as coating agent C3 is obtained.Should The weight average molecular weight of combed polysaccharide compound is 12,000,000g/mol, wherein, identified through infrared nuclear-magnetism, form combed many The mol ratio for the construction unit that the Methacrylamide and methacrylic acid of saccharide compound side chain are provided is 1：0.31, by methyl The content for the construction unit that acrylamide and methacrylic acid are provided is 90.5 weight %.

Coating agent preparation example 4

(1) (1) prepares sulfonated starch SS-1 according to the step of embodiment 1；

(2) according to the step of embodiment 1 (2), unlike, the consumption of the acrylamide used for 620g, acrylic acid Consumption is 180g, so that combed polysaccharide compound is finally given, as coating agent C4.The weight of the combed polysaccharide compound is equal Molecular weight is 9,500,000g/mol, wherein, identified through infrared nuclear-magnetism, form the acrylamide of combed polysaccharide compound side chain The mol ratio of the construction unit provided with acrylic acid is 1：0.26, the content of the construction unit provided by acrylamide and acrylic acid For 88.9 weight %.

Coating agent preparation example 5

(2) according to the step of embodiment 1 (2), unlike, the consumption of the acrylamide used for 880g, acrylic acid Consumption is 220g, so that combed polysaccharide compound is finally given, as coating agent C5.The weight of the combed polysaccharide compound is equal Molecular weight is 14,500,000g/mol, wherein, identified through infrared nuclear-magnetism, form the acryloyl of combed polysaccharide compound side chain The mol ratio for the construction unit that amine and acrylic acid are provided is 1：0.24, the construction unit that is provided by acrylamide and acrylic acid contains Measure as 91.7 weight %.

Coating agent prepares comparative example 1

It regard the sulfonated starch SS-1 obtained by (1) the step of coating agent preparation example 1 as coating agent DC1.

Coating agent prepares comparative example 2

(1) (1) prepares sulfonated starch SS-1 according to the step of coating agent preparation example 1；

(2) according to the step of coating agent preparation example 1 (2), unlike, do not use acrylic acid, and by the use of acrylamide Amount increases to 900g, so that combed polysaccharide compound is finally given, as coating agent DC2.The combed polysaccharide compound Weight average molecular weight is 14,000,000g/mol, wherein, identified through infrared nuclear-magnetism, the side chain in the combed polysaccharide compound is only There is provided by acrylamide, and the content of the construction unit provided by acrylamide is 90 weight %.

Coating agent comparative example 3

By purchased from the polyacrylamide that the weight average molecular weight of the Tian Run chemical companies AB1000 trades mark is 10,600,000g/mol It is used as coating agent DC3.

Embodiment 1

The present embodiment is used for the composition and water-base drilling fluid for illustrating the present invention.

Water-based drilling formula of liquid：The water of 100 parts by weight, the fluid loss additive N1 of 3.5 parts by weight, the extracting and cutting agent A1 of 2 parts by weight, The coating agent C1 of 0.15 parts by weight, the Waterproof lock agent of 0.4 parts by weight (is purchased from the polyoxy second of Jinan Ying Chu Chemical Industry Science Co., Ltd Alkene octyl phenol ether), the KCl of 5 parts by weight；So as to obtain drilling fluid Y1, its density is 1.1g/cm³。

Embodiment 2

Water-based drilling formula of liquid according to embodiment 1, unlike, A1, coating agent C2 are replaced using extracting and cutting agent A2 Instead of C1, so as to obtain drilling fluid Y2, its density is 1.1g/cm³。

Embodiment 3

Water-based drilling formula of liquid according to embodiment 1, unlike, A1, coating agent C3 are replaced using extracting and cutting agent A3 Instead of C1, so as to obtain drilling fluid Y3, its density is 1.1g/cm³。

Embodiment 4

Water-based drilling formula of liquid according to embodiment 1, unlike, A1,0.2 parts by weight are replaced using extracting and cutting agent A4 Coating agent C4 replace C1, so as to obtain drilling fluid Y4, its density is 1.1g/cm³。

Embodiment 5

Water-based drilling formula of liquid according to embodiment 1, unlike, A1, coating agent C5 are replaced using extracting and cutting agent A5 Instead of C1, so as to obtain drilling fluid Y5, its density is 1.1g/cm³。

Comparative example 1

Water-based drilling formula of liquid according to embodiment 1, unlike, A1, coating agent are replaced using extracting and cutting agent DA1 DC1 replaces C1, so as to obtain drilling fluid DY1, its density is 1.1g/cm³。

Comparative example 2

Water-based drilling formula of liquid according to embodiment 1, unlike, A1, coating agent are replaced using extracting and cutting agent DA2 DC2 replaces C1, so as to obtain drilling fluid DY2, its density is 1.1g/cm³。

Comparative example 3

Water-based drilling formula of liquid according to embodiment 1, unlike, A1, coating agent are replaced using extracting and cutting agent DA2 DC3 replaces C1, so as to obtain drilling fluid DY3, its density is 1.1g/cm³。

Comparative example 4

Water-based drilling formula of liquid according to embodiment 1, unlike, Shandong get Shun Yuan (is purchased from using modified starch The LYS of Petroleum Technology Co., Ltd) fluid loss additive N1 is replaced, chemical industry (is tieed up purchased from Renqiu section using partially hydrolyzed polyacrylamide (PHPA) The A1225 of company) extracting and cutting agent A1 is replaced, coating agent is replaced using polyacrylic acid potassium (HNQ for being purchased from Hebei Yan Xing chemical companies) C1, so as to obtain drilling fluid DY4, its density is 1.1g/cm³。

Test case 1

The rheological property of above drilling fluid, filtration property and surface tension are measured, above-mentioned drilling well is specifically measured Liquid apparent viscosity (AV) before ageing, plastic viscosity (PV), yield value (YP), ratio of dynamic shear force/yield value to plastic viscosity, gel initial, 10-minute gel strength, middle press filtration Vector (API) and surface tension, the results are shown in Table shown in 1, wherein：

Apparent viscosity (AV) is using the fast viscosimeter of normal form six side according to specified in standard GB/T/T29170-2012 What method was measured, unit is mPas,

Plastic viscosity (PV) is using the fast viscosimeter of normal form six side according to specified in standard GB/T/T29170-2012 What method was measured, unit is mPas, PV=θ₆₀₀-θ₃₀₀。

Yield value (YP) is using the fast viscosimeter method according to specified in standard GB/T/T29170-2012 of normal form six Measure, YP=0.511 × (2 × φ 300- φ 600), unit is Pa.

Gel initial is calculated by the following method：10s is stirred under 600r/min speed, the maximum that φ 3 is read after 10s is stood Reading, then obtains gel initial by full-scale reading divided by 2, and unit is Pa.

10-minute gel strength is calculated by the following method：10s is stirred under 600r/min speed, stands and reads φ 3 most after 10min Big reading, then obtains 10-minute gel strength, unit is Pa by full-scale reading divided by 2.

Ratio of dynamic shear force/yield value to plastic viscosity is calculated as follows：

API refers to middle filter pressing loss, is that the method that press filtration is committed a breach of etiquette in SY/T 5621-93 standards in using is surveyed Amount, unit is mL.

Surface tension refers to drilling fluid, and it is that method in GB/T22237-2008 standards uses Contact-angle measurement Instrument, selection sessile drop method is measured.

Table 1

The drilling fluid that can be seen that the present invention by the data of table 1 has excellent rheological property, with relatively low viscosity With higher yield value, gel strength, carrying that can be good while more than 0.30 ratio of dynamic shear force/yield value to plastic viscosity can be maintained and suspension coal petrography Bits；The drilling fluid of the present invention has relatively low filter loss, can greatly reduce leakage of the Free water into coal seam in drilling fluid；This Outside, drilling fluid of the invention has low surface tension, can be effectively prevented from the generation of water lock phenomenon caused by capillary force, so that The intact of coal-bed methane seepage passage is kept, with good reservoir protection performance.

Test case 2

The residue rate of above-mentioned drilling fluid is measured, be the results are shown in Table shown in 2, detailed process includes：Take the above-mentioned brills of 300mL Well liquid, adds 0.05 weight % gel breaker potassium peroxydisulfate, is placed in after stirring evenly at 90 DEG C and stands 4h, fully breaks glue；Take certain body Product V above-mentioned drilling fluid after breaking gel is put into centrifuge, in centrifuging 30min under 10000rpm rotating speeds, is poured out and is added after supernatant Enter distilled water and centrifuge 30min under 10000rpm rotating speed again；Pour out and dried after supernatant at 90 DEG C, and determine after drying The quality m of the above-mentioned remaining residue of drilling fluid, is calculated as follows residue rate：Residue rate=m/V, unit is mg/L.

Table 2

Be can be seen that by the data of table 2 in addition to comparative example DY4, it is all test drilling fluids be respectively provided with 35mg/L with Under residue rate, illustrate that gel breaker can sufficiently act on the compositions of additives of the present invention, and can effectively make inorganic agent Failure is degraded, and level of residue is extremely low.Anti- row's operation that this performance is beneficial to after coal bed gas well finishing drilling, and low residue rate ensure that brill Well liquid inorganic agent illustrates that the drilling fluid of the present invention is very suitable for the drillng operation of coal bed gas well to the Low Damage of reservoir.

The preferred embodiment of the present invention described in detail above, still, the present invention are not limited in above-mentioned embodiment Detail, in the range of the technology design of the present invention, a variety of simple variants can be carried out to technical scheme, this A little simple variants belong to protection scope of the present invention.

It is further to note that each particular technique feature described in above-mentioned embodiment, in not lance In the case of shield, can be combined by any suitable means, in order to avoid unnecessary repetition, the present invention to it is various can The combination of energy no longer separately illustrates.

In addition, various embodiments of the present invention can be combined randomly, as long as it is without prejudice to originally The thought of invention, it should equally be considered as content disclosed in this invention.

Claims

1. a kind of drilling fluid additive composition suitable for coal bed gas well, it is characterised in that said composition, which contains thickening and carried, cuts Agent, coating agent and fluid loss additive, wherein：

The thickening extracting and cutting agent is containing shown in the construction unit shown in formula (1), the construction unit shown in formula (2) and formula (3) The copolymer of construction unit, wherein：

Wherein, R¹、R^1'、R²、R^2'、R⁵、R^5'、R⁴With each R⁷It is each independently selected from H and C1-C8 alkyl；R³、R⁶And R⁸Each Independently selected from C0-C8 alkylidene；X is selected from-NH- or-O-；N is 1-4 integer；

The coating agent is combed polysaccharide compound, and the side chain of the combed polysaccharide compound is as the change shown in lower formula (I) Compound shown in compound and formula (II) is provided, wherein, the sulfonate polysaccharide class compound is starch, the fiber of sulfonation of sulfonation Chlorins compound or the xanthans of sulfonation：

The fluid loss additive is nano-crystal cellulose.

2. composition according to claim 1, wherein, the weight ratio of the thickening extracting and cutting agent, coating agent and fluid loss additive For 100：5-50：100-300.

3. composition according to claim 2, wherein, the weight ratio of the thickening extracting and cutting agent, coating agent and fluid loss additive For 100：6-30：120-200.

4. composition according to claim 3, wherein, the weight ratio of the thickening extracting and cutting agent, coating agent and fluid loss additive For 100：7-25：150-180.

5. the composition according to any one in claim 1-4, wherein, it is used as the copolymer of the thickening extracting and cutting agent In, R¹、R^1'、R²、R^2'、R⁵、R^5'、R⁴With each R⁷It is each independently selected from H and C1-C6 alkyl；R³、R⁶And R⁸Independently of one another Alkylidene selected from C0-C6；N is 1-3 integer.

6. composition according to claim 5, wherein, in the copolymer as the thickening extracting and cutting agent, R¹、R^1'、R²、 R^2'、R⁵、R^5'And R⁴It is each independently selected from H and C1-C4 alkyl；Each R⁷It is each independently selected from C1-C6 alkyl；R³Choosing From C0-C4 alkylidene；R⁶And R⁸It is each independently selected from C1-C6 alkylidene.

7. composition according to claim 6, wherein, in the copolymer as the thickening extracting and cutting agent, R¹、R^1'、R²、 R^2'、R⁵、R^5'And R⁴It is each independently selected from H, methyl, ethyl, n-propyl, isopropyl and normal-butyl；Each R⁷Independently of one another Selected from methyl, ethyl, n-propyl, isopropyl and normal-butyl；R³Alkylidene ,-CH selected from C0₂-、-CH₂-CH₂-、-CH₂-CH₂- CH₂-、-CH(CH₃)-CH₂-、-CH₂-CH(CH₃)-or-CH₂-(CH₂)₂-CH₂-；R⁶And R⁸It is each independently selected from-CH₂-、- CH₂-CH₂-、-CH₂-CH₂-CH₂-、-CH(CH₃)-CH₂-、-CH₂-CH(CH₃)-、-CH₂-(CH₂)₂-CH₂-、-CH₂-CH(CH₃)- CH₂-、-C(CH₃)₂-CH₂-、-CH₂-C(CH₃)₂-、-CH₂-(CH₂)₃-CH₂- and-CH₂-(CH₂)₄-CH₂-。

8. the composition according to any one in claim 1-4 and 6-7, wherein, it is used as being total to for the thickening extracting and cutting agent In polymers, the mol ratio of the construction unit shown in construction unit, formula (2) shown in formula (1) and the construction unit shown in formula (3) is 10-40：1-10：1.

9. composition according to claim 8, wherein, in the copolymer as the thickening extracting and cutting agent, shown in formula (1) The mol ratio of the construction unit shown in construction unit and formula (3) shown in construction unit, formula (2) is 15-30：2-5：1.

10. composition according to claim 8, wherein, in the copolymer as the thickening extracting and cutting agent, the copolymer Weight average molecular weight be 1,000,000-6,000,000g/mol.

11. composition according to claim 10, wherein, in the copolymer as the thickening extracting and cutting agent, the copolymerization The weight average molecular weight of thing is 2,000,000-5,500,000g/mol.

12. composition according to claim 11, wherein, in the copolymer as the thickening extracting and cutting agent, the copolymerization The weight average molecular weight of thing is 2,500,000-5,000,000g/mol.

13. composition according to claim 12, wherein, in the copolymer as the thickening extracting and cutting agent, the copolymerization The weight average molecular weight of thing is 3,000,000-4,500,000g/mol.

14. the composition according to any one in claim 1-4,6-7 and 9-13, wherein, carry and cutting as the thickening The preparation method of the copolymer of agent includes：

In aqueous solvent, in the presence of radical initiator and chain-transferring agent, by formula (1') shown compound, formula (2') institute (3') shown compound carries out Raolical polymerizable to the compound and formula shown, wherein,

15. composition according to claim 14, wherein, it is used as the preparation method of the copolymer of the thickening extracting and cutting agent In, the mole dosage ratio of formula (1') shown compound, formula (2') shown compound and formula (3') shown compound is 10- 40：1-10：1.

16. composition according to claim 15, wherein, formula (1') shown compound, formula (2') shown compound Mole dosage ratio with formula (3') shown compound is 15-30：2-5：1.

17. composition according to claim 14, wherein, in the preparation method of the copolymer of the thickening extracting and cutting agent, phase For 1mol formula (1') shown compound, formula (2') shown compound and formula (3') shown compound it is mole total Amount, the consumption of the aqueous solvent is 400-1000mL.

18. composition according to claim 17, wherein, (1') shown compound, formula be (2') for formula relative to 1mol Mole total amount of shown compound and formula (3') shown compound, the consumption of the aqueous solvent is 400-600mL.

19. composition according to claim 14, wherein, it is used as the preparation method of the copolymer of the thickening extracting and cutting agent In, the radical initiator is 4,4'- azos (4- cyanopentanoic acids), azo diisobutyl amidine hydrochloride, azo diisopropyl One or more in imidazoline hydrochloride and azo diisobutyl imidazoline hydrochloride；

Formula relative to 1mol (1') shown compound, formula (2') shown compound and formula (3') shown compound is rubbed That total amount, the consumption of the radical initiator is 0.1-0.2mmol.

20. composition according to claim 19, wherein, (1') shown compound, formula be (2') for formula relative to 1mol Mole total amount of shown compound and formula (3') shown compound, the consumption of the radical initiator is 0.11- 0.14mmol。

21. composition according to claim 14, wherein, it is used as the preparation method of the copolymer of the thickening extracting and cutting agent In, one or more of the chain-transferring agent in sodium formate, sodium acetate, ammonium hydroxide and urea；

Formula relative to 1mol (1') shown compound, formula (2') shown compound and formula (3') shown compound is rubbed That total amount, the consumption of the chain-transferring agent is 0.1-0.2mmol.

22. composition according to claim 21, wherein, (1') shown compound, formula be (2') for formula relative to 1mol Mole total amount of shown compound and formula (3') shown compound, the consumption of the chain-transferring agent is 0.13-0.15mmol.

23. composition according to claim 14, wherein, it is used as the preparation method of the copolymer of the thickening extracting and cutting agent In, the condition of Raolical polymerizable includes：Temperature is 40-80 DEG C, and the time is 6-12h.

24. composition according to claim 23, wherein, it is used as the preparation method of the copolymer of the thickening extracting and cutting agent In, the condition of Raolical polymerizable includes：Temperature is 50-70 DEG C, and the time is 7-10h.

25. the composition according to claim 23 or 24, wherein, it is used as the preparation side of the copolymer of the thickening extracting and cutting agent In method, the Raolical polymerizable is carried out also in the presence of chelating agent, and the chelating agent is selected from ethylenediamine tetra-acetic acid and its salt, ammonia One or more in triacetic acid and its salt, hexa metaphosphoric acid and its salt and diethylenetriamine penta；

Formula relative to 1mol (1') shown compound, formula (2') shown compound and formula (3') shown compound is rubbed That total amount, the consumption of the chelating agent is 0.01-0.05mmol.

26. composition according to claim 25, wherein, (1') shown compound, formula be (2') for formula relative to 1mol Mole total amount of shown compound and formula (3') shown compound, the consumption of the chelating agent is 0.01-0.02mmol.

27. the composition according to claim 23 or 24, wherein, it is used as the preparation side of the copolymer of the thickening extracting and cutting agent In method, this method includes：First by formula (1') shown compound, formula (2') shown compound, formula (3') shown compound Mixed with aqueous solvent, be re-introduced into the radical initiator, chain-transferring agent and optional chelating agent, and in inert atmosphere It is lower to carry out the Raolical polymerizable.

28. the composition according to any one in claim 1-4, wherein, it is used as the combed polysaccharide of the coating agent In compound, L¹、L^1'、L²And L^2'It is each independently selected from H, methyl, ethyl, n-propyl, isopropyl and normal-butyl.

29. composition according to claim 28, wherein, the weight average molecular weight of the combed polysaccharide compound is 9, 000,000-15,000,000g/mol。

30. composition according to claim 29, wherein, the weight average molecular weight of the combed polysaccharide compound is 9, 500,000-14,500,000g/mol。

31. composition according to claim 30, wherein, the weight average molecular weight of the combed polysaccharide compound is 10, 000,000-13,500,000g/mol。

32. composition according to claim 28, wherein, as the chemical combination shown in the compound shown in formula (I) and formula (II) The content for the construction unit that thing is provided is 80-95 weight %.

33. composition according to claim 32, wherein, as the chemical combination shown in the compound shown in formula (I) and formula (II) The content for the construction unit that thing is provided is 85-92 weight %.

34. composition according to claim 28, wherein, the compound shown in compound and formula (II) shown in formula (I) The mol ratio of the construction unit of offer is 1：0.2-1.

35. composition according to claim 34, wherein, the compound shown in compound and formula (II) shown in formula (I) The mol ratio of the construction unit of offer is 1：0.2-0.5.

36. composition according to claim 35, wherein, the compound shown in compound and formula (II) shown in formula (I) The mol ratio of the construction unit of offer is 1：0.24-0.4.

37. composition according to claim 28, wherein, the cellulose compound of the sulfonation is the carboxymethyl of sulfonation Cellulose, the hydroxymethyl cellulose of sulfonation, the carboxyethyl cellulose of sulfonation, the hydroxyethyl cellulose of sulfonation, the hydroxypropyl of sulfonation Cellulose or the hydroxypropyl methyl cellulose of sulfonation.

38. the composition according to any one in claim 1-4, wherein, it is used as the combed polysaccharide of the coating agent The preparation method of compound includes：

(1) in aqueous solvent, polysaccharide compound and sulfonating agent is subjected to sulfonating reaction, sulfonate polysaccharide class compound is obtained；

(2) in aqueous solvent, in the presence of graft copolymerization catalyst, by the chemical combination shown in sulfonate polysaccharide class compound, formula (I) Compound shown in thing and formula (II) carries out graft copolymerization；

39. the composition according to claim 38, wherein, it is used as the preparation of the combed polysaccharide compound of the coating agent In method, the cellulose compound is carboxymethyl cellulose, hydroxymethyl cellulose, carboxyethyl cellulose, hydroxy ethyl fiber One or more in element, hydroxypropyl cellulose and hydroxypropyl methyl cellulose.

40. the composition according to claim 38, wherein, it is used as the preparation of the combed polysaccharide compound of the coating agent In method, the sulfonating agent is the one or more in chlorosulfonic acid, sulfur trioxide, PS and the concentrated sulfuric acid；

Relative to the polysaccharide compound of 100 parts by weight, the consumption of the sulfonating agent is 20-40 parts by weight.

41. composition according to claim 40, wherein, it is described relative to the polysaccharide compound of 100 parts by weight The consumption of sulfonating agent is 25-35 parts by weight.

42. the composition according to claim 38, wherein, it is used as the preparation of the combed polysaccharide compound of the coating agent In method, in step (1), relative to the polysaccharide compound of 100 parts by weight, the consumption of aqueous solvent is 1000-5000 Parts by weight.

43. composition according to claim 42, wherein, it is aqueous relative to the polysaccharide compound of 100 parts by weight The consumption of solvent is 2000-4000 parts by weight.

44. the composition according to claim 38, wherein, it is used as the preparation of the combed polysaccharide compound of the coating agent In method, the condition of the sulfonating reaction includes：Temperature is 50-70 DEG C；Time is 8-20h.

45. composition according to claim 44, wherein, the condition of the sulfonating reaction includes：Temperature is 55-65 DEG C； Time is 10-12h.

46. the composition according to claim 38, wherein, relative to the sulfonate polysaccharide class compound of 100 parts by weight, Total consumption of the compound shown in compound and formula (II) shown in formula (I) is 500-1500 parts by weight.

47. composition according to claim 46, wherein, relative to the sulfonate polysaccharide class compound of 100 parts by weight, Total consumption of the compound shown in compound and formula (II) shown in formula (I) is 800-1000 parts by weight.

48. composition according to claim 47, wherein, relative to the sulfonate polysaccharide class compound of 100 parts by weight, Total consumption of the compound shown in compound and formula (II) shown in formula (I) is 850-950 parts by weight.

49. composition according to claim 46, wherein, the compound shown in compound and formula (II) shown in formula (I) Consumption mol ratio be 1：0.2-1.

50. composition according to claim 49, wherein, the compound shown in compound and formula (II) shown in formula (I) Consumption mol ratio be 1：0.2-0.5.

51. composition according to claim 50, wherein, the compound shown in compound and formula (II) shown in formula (I) Consumption mol ratio be 1：0.24-0.4.

52. composition according to claim 46, wherein, the graft copolymerization catalyst is high-valency metal compound and mistake One or more in sulfate.

53. composition according to claim 52, wherein, the high-valency metal compound be ammonium ceric nitrate, ferric trichloride, One or more in four (4- carboxyl phenyls) Cob altporphyrins and vanadium acetylacetonate；The persulfate is ammonium persulfate, persulfuric acid One or more in sodium and potassium peroxydisulfate.

54. composition according to claim 52, wherein, relative to the sulfonate polysaccharide class compound of 100 parts by weight, The consumption of the graft copolymerization catalyst is 0.1-2 parts by weight.

55. composition according to claim 54, wherein, relative to the sulfonate polysaccharide class compound of 100 parts by weight, The consumption of the graft copolymerization catalyst is 0.2-1 parts by weight.

56. composition according to claim 55, wherein, relative to the sulfonate polysaccharide class compound of 100 parts by weight, The consumption of the graft copolymerization catalyst is 0.2-0.5 parts by weight.

57. composition according to claim 46, wherein, in step (2), the sulfonation relative to 100 parts by weight is more Saccharide compound, the consumption of aqueous solvent is 5000-10000 parts by weight.

58. composition according to claim 57, wherein, in step (2), the sulfonation relative to 100 parts by weight is more Saccharide compound, the consumption of aqueous solvent is 6000-9000 parts by weight.

59. composition according to claim 46, wherein, in step (2), the condition of the graft copolymerization includes： Temperature is 10-40 DEG C；Time is 10-30h.

60. composition according to claim 59, wherein, in step (2), the condition of the graft copolymerization includes： Temperature is 20-35 DEG C；Time is 16-25h.

61. the composition according to any one in claim 1-4, wherein, the average grain diameter of the nano-crystal cellulose is 100-600nm。

62. composition according to claim 61, wherein, the average grain diameter of the nano-crystal cellulose is 150-320nm.

63. composition according to claim 61, wherein, the nano-crystal cellulose is bar-shaped.

64. composition in claim 1-63 described in any one is used as the application of the additive in drilling fluid.

65. a kind of water-base drilling fluid of the composition in 1-63 containing claim described in any one.

66. water-base drilling fluid according to claim 65, wherein, relative to the water in the water-base drilling fluid of 100 parts by weight, The content of the composition is 3-10 parts by weight.

67. water-base drilling fluid according to claim 66, wherein, relative to the water in the water-base drilling fluid of 100 parts by weight, The content of the composition is 4-8 parts by weight.

68. the water-base drilling fluid according to any one in claim 65-67, wherein, the water-base drilling fluid is salt solution Drilling fluid, is 5-10 parts by weight as the content of the salt of heavy weight additive relative to the water in the water-base drilling fluid of 100 parts by weight.

69. application of the water-base drilling fluid in coal bed gas well drilling well in claim 65-68 described in any one.