A drilling fluid inhibitor composition, method of making and use

Abstract

This invention provides a drilling fluid inhibitor composition, its preparation method, and its application. The drilling fluid inhibitor composition, by mass fraction, comprises: 20-50% small molecule organic amine, 10-20% organosilicon cationic copolymer, 20-40% aminosilane, and the remainder being water. The organosilicon cationic copolymer is obtained by copolymerization of acrylamide, cationic monomer, and vinyl silane agent, with a viscosity-average molecular weight of 5000-100000 and a cationic content of 10-40% (wt). This drilling fluid inhibitor composition utilizes a combination of large and small molecules to achieve intercalation and encapsulation of clay and rock cuttings, effectively inhibiting the hydration and dispersion of clay and rock cuttings. A 0.4% addition achieves an inhibition rate ≥93%, and a 1% addition achieves a rock cuttings rolling recovery rate ≥90%. The molecular structure does not contain ether or ester bonds, exhibiting high temperature resistance up to 240℃. It binds to clay and rock cuttings through both physical and chemical adsorption, overcoming the disadvantage of high-temperature desorption, with an adsorption retention rate ≥96% at 240℃.

Description

Technical Field

[0001] This invention belongs to the field of drilling engineering technology. Specifically, this invention relates to a drilling fluid inhibitor composition, its preparation method, and its application. Background Technology

[0002] Wellbore instability has always been a technical challenge in drilling projects involving high shale content and water-sensitive formations, severely impacting geological data acquisition, drilling speed, quality, and cost. A key factor contributing to wellbore instability is shale hydration, which essentially involves the hydration of clay minerals within the shale. Clay hydration increases clay volume, hindering the transport of cuttings from the wellbore to the surface, increasing friction between the drill string and the wellbore, and inhibiting the formation of the thin mud cake used to seal formation water, thus causing wellbore instability.

[0003] To address the aforementioned shale hydration problem, inhibitors are typically added to the drilling fluid during on-site construction to suppress clay hydration. Currently, commonly used drilling fluid inhibitors mainly include inorganic salt inhibitors, bituminous inhibitors, silicate inhibitors, polymeric alcohol inhibitors, and polyamine inhibitors. However, these shale inhibitors all have some drawbacks. Large doses of inorganic salt inhibitors can lead to the deposition of environmental pollutants on the soil surface in the drilling area, severely negatively impacting the rheology and wall-building properties of the drilling fluid, making the transformation and maintenance of the drilling fluid system more complex and difficult. Bituminous drilling fluids have weak inhibitory capabilities when using shale inhibitors and are prone to environmental pollution. Silicate drilling fluids using shale inhibitors make it difficult to control the rheology of the drilling fluid. Polymer alcohol inhibitors are ineffective against highly water-sensitive shale and lack temperature resistance. Polymers, due to their large molecular size, cannot penetrate the clay layers and only adsorb onto the clay surface, failing to fully exert their inhibitory function. Furthermore, they exhibit a cloud point effect and have stringent temperature requirements for application. Polyamine inhibitors, low-molecular-weight polymer amine inhibitors, while performing well in inhibiting shale hydration, are mostly polymerized from polyether amines and epoxy alkanes under catalysis. The ether oxygen bonds in their molecular structure are easily broken at high temperatures, resulting in generally low temperature resistance, mostly below 150℃. Additionally, due to the surfactant properties of polyethers, they are prone to foaming during use.

[0004] CN105086955B discloses a method for synthesizing polyamine inhibitors using polyamine-based organic compounds (such as ethylenediamine, diethylenetriamine, and polyethylenepolyamine) and epichlorohydrin as raw materials. The molecule contains primary amines, tertiary amines, and hydroxyl groups, meaning the molecular chain has numerous adsorption sites, allowing the molecular chain to adsorb onto clay, binding the clay's layered structure and hindering hydration and swelling. The adsorption between this polyamine inhibitor and clay is physical adsorption; however, it is prone to desorption and inactivation under high temperatures.

[0005] CN111117580B discloses a strong adsorption amine inhibitor for drilling fluid and its preparation method. The method involves reacting polyetheramine or polyethyleneamine with an isocyanate silane coupling agent to obtain a strong adsorption amine inhibitor. This inhibitor can effectively increase the adsorption amount of the inhibitor on the clay surface and enhance the inhibitory properties of the drilling fluid under high temperature conditions. However, the large molecular weight of this inhibitor prevents it from penetrating into the interlayer of clay, resulting in poor performance in inhibiting the dispersion of clay moisture.

[0006] CN111763504A discloses an environmentally friendly, temperature-resistant ether amine shale inhibitor and a water-based drilling fluid made from it. This environmentally friendly, temperature-resistant ether amine shale inhibitor is prepared by reacting halogenated alkanes with ether amine compounds. The water-based drilling fluid prepared with this as the main agent is suitable for the hydration and swelling of highly water-sensitive mudstone and shale formations, significantly reducing the shale swelling rate, preventing wellbore collapse and diameter reduction, stabilizing the wellbore, and reducing the occurrence of complex downhole conditions. However, the main structure of this inhibitor is still polyether amine, so its temperature resistance is still difficult to exceed 150℃. Furthermore, the adsorption between this polyamine inhibitor and clay is physical adsorption, which is prone to desorption and failure under high temperatures.

[0007] CN111676003A discloses an environmentally friendly low molecular weight branched polyetheramine as a shale intercalation inhibitor. This low molecular weight polyetheramine is synthesized from ester compounds containing amino and ether bonds and ether compounds containing olefin bonds using a one-pot synthesis or stepwise synthesis method. The shale intercalation inhibitor made from the low molecular weight branched polyetheramine is prepared by mixing the low molecular weight branched polyetheramine with water, wherein the mass ratio of the low molecular weight branched polyetheramine in the shale intercalation inhibitor is 0.5%-3%. This inhibitor contains ether bonds, which are prone to chain breakage under high temperature conditions, and its temperature resistance needs to be improved.

[0008] Currently, most shale inhibitors on the market cannot simultaneously meet the performance requirements of inhibition, temperature resistance, and other aspects. This has limited the promotion of water-based drilling fluids to some extent. Therefore, it is necessary to develop an inhibitor with stronger temperature resistance and stability to promote the further development of water-based drilling fluid technology and meet the exploration and development needs of deep and ultra-deep wells. Summary of the Invention

[0009] This invention aims to overcome the problems of existing inhibitors in the prior art, such as weak temperature resistance, desorption under high temperature conditions, and inability to simultaneously inhibit the hydration, dispersion, and swelling of clay (rock cuttings). It provides a drilling fluid inhibitor composition, its preparation method, and its application to solve the problems of high-temperature desorption, high-temperature chain breakage, and the inability to simultaneously inhibit the hydration, dispersion, and swelling of clay (rock cuttings). The drilling fluid inhibitor composition provided by this invention contains small-molecule organic amines. These small-molecule organic amine molecules do not contain ether bonds, but only CC and CN bonds. They exhibit high temperature resistance and have a small molecular weight, allowing them to insert into clay layers, thereby preventing the entry of water molecules and effectively preventing the hydration of clay layers. The organosilicon cationic copolymer in the inhibitor composition does not contain ester groups in its polymer molecular structure, making it less prone to hydrolysis and chain scission. It exhibits excellent temperature resistance. The cationic groups in the molecular structure can reduce the electronegativity of the clay particle surface, compressing and diffusing the electric double layer, effectively inhibiting clay hydration. Furthermore, the introduction of siloxanes into the molecular chain allows for the condensation reaction between hydrolyzed Si-OH and Si-OH on the clay surface, achieving chemical adsorption of the organosilicon cationic copolymer on the clay surface. This effectively increases the adsorption capacity of the organosilicon cationic copolymer on the clay surface, further enhancing temperature resistance. The long molecular chains can coat the clay and drill cuttings surfaces, effectively blocking contact between the clay and drill cuttings surfaces and water in the drilling fluid, improving inhibition. The aminosiloxane in the inhibitor composition, on the one hand, utilizes the inhibitory effect of the amino groups to achieve the inhibitory function; on the other hand, through the condensation reaction between hydrolyzed Si-OH and Si-OH on the clay surface, the aminosilane molecules achieve chemical adsorption on the clay surface, effectively increasing the adsorption capacity and reducing desorption under high-temperature conditions. The silica sol in the inhibitor composition can, on the one hand, seal microfractures in the formation, and on the other hand, react with organosilicon cationic copolymers and aminosilanes in the formation via Si-OH, further reducing the desorption properties of the inhibitor composition under high-temperature conditions. Therefore, the drilling fluid inhibitor composition provided by this invention has excellent temperature resistance and inhibitory properties, which can meet the requirements of deep and ultra-deep wells for drilling fluid inhibitors, and has good application prospects. Moreover, the preparation method of this drilling fluid inhibitor composition is simple and easy to industrialize and promote its application.

[0010] The present invention achieves the above objectives through the following technical solutions.

[0011] The drilling fluid inhibitor composition of the present invention is characterized in that, by mass fraction, the composition comprises: 20-50% small molecule organic amine, 10-20% organosilicon cationic copolymer, 20-40% aminosilane, and the remainder is water. The organosilicon cationic copolymer is obtained by copolymerization of acrylamide, cationic monomer and vinyl silane agent, with a viscosity-average molecular weight of 5000-100000 and a cationic content of 10-40% (wt).

[0012] The drilling fluid inhibitor composition of the present invention is characterized in that the small molecule organic amine includes one or more of the following: 1,2-propanediamine, 1,3-propanediamine, isopropanolamine, N-ethylethylenediamine, N-diethylethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0013] The drilling fluid inhibitor composition of the present invention is characterized in that the cationic monomer comprises one or more of methyl-dihydroxyethylallyl ammonium chloride, methyl-dihydroxymethylallyl ammonium chloride, dimethyl diallyl ammonium chloride, and allyltrimethyl ammonium chloride; and the vinyl silane agent is one or more of vinyltrimethoxysilane and vinyltriethoxysilane.

[0014] The drilling fluid inhibitor composition of the present invention is characterized in that the aminosilane comprises one or more of the following: aminopropyltriethoxysilane, aminopropyltrimethoxysilane, aminoethyltriethoxysilane, aminoethyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2-aminoethylamino)propyltriethoxysilane, N-aminoethyl-3-aminopropylmethyldimethoxysilane, N-aminoethyl-3-aminopropylmethyldiethoxysilane, diethylenetriaminopropyltrimethoxysilane, triethylenetetraaminopropyltrimethoxysilane, diethylenetriaminopropyltriethoxysilane, and triethylenetetraaminopropyltriethoxysilane.

[0015] The method for preparing an inhibitor composition for drilling fluid according to the present invention is characterized by comprising the following steps:

[0016] A1: Add the weighed deionized water, emulsifier, sodium bicarbonate, and acrylamide to a reactor equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and vent pipe. Stir to emulsify, purge with nitrogen for protection, and raise the temperature to the required temperature. Add the cationic monomer and 66-90% (wt) of initiator dropwise to the reactor through a constant pressure dropping funnel, and maintain the temperature for a period of time.

[0017] A2: Continue to slowly drip vinylsiloxane and 10-34% (wt) of initiator into the reactor through a constant pressure dripping funnel. After the dripping is completed, continue to react at the reaction temperature for a period of time to obtain an organosilicon cationic copolymer.

[0018] A3: Add small molecule organic amine, aminosilane, water and the organosilicon cationic copolymer obtained in step A2 into the reactor in proportion, and stir for a certain time at the reaction temperature to obtain the drilling fluid inhibitor composition.

[0019] The method for preparing a drilling fluid inhibitor composition according to the present invention is characterized in that the emulsifier is a composite emulsifier composed of dodecylbenzenesulfonic acid and alkylphenol polyoxyethylene ether (OP-10), the mass ratio of dodecylbenzenesulfonic acid to alkylphenol polyoxyethylene ether (OP-10) is 1:1, and the amount of composite emulsifier added is 3-8% (wt); the initiator is either ammonium persulfate or potassium persulfate, and the amount of initiator added is 0.3-1% (wt).

[0020] The method for preparing a drilling fluid inhibitor composition according to the present invention is characterized in that the mass ratio of acrylamide, cationic monomer and vinylsiloxane is (50-70):(10-40):(10-20).

[0021] The method for preparing a drilling fluid inhibitor composition according to the present invention is characterized in that the reaction conditions in step A1 include: a reaction temperature of 70-90℃ and a reaction time of 0.5-2h; and / or the reaction conditions in step A2 include: a reaction temperature of 70-90℃ and a reaction time of 1-3h; and / or the reaction conditions in step A3 include: a reaction temperature of 40-60℃, a stirring speed of 100-300r / min, and a reaction time of 1-2h.

[0022] The application of the drilling fluid inhibitor composition described in this invention in drilling engineering.

[0023] All of the above-mentioned raw materials used in this invention can be prepared in-house or purchased commercially; this invention does not impose any particular limitations on them.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] (1) The drilling fluid inhibitor composition adopts a combination of large and small molecules to achieve intercalation and encapsulation of clay and rock cuttings, effectively inhibiting the hydration and dispersion of clay and rock cuttings. The inhibition rate of 0.4% is ≥93%, and the rock cuttings rolling recovery rate of 1% is ≥90%.

[0026] (2) The molecular structure does not contain ether bonds and ester bonds, and has high temperature resistance, with a temperature resistance of 240℃;

[0027] (3) It combines with clay and rock fragments through the dual action of physical adsorption and chemical adsorption, overcoming the disadvantage of high-temperature desorption, and the adsorption retention rate at 240℃ is ≥96%;

[0028] (4) The preparation method of this drilling fluid inhibitor composition is simple and easy to industrialize. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0030] Example 1

[0031] In a reactor equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and vent pipe, 60g of acrylamide, 120g of deionized water, 0.6g of sodium bicarbonate, and 3g of composite emulsifier were added. Emulsification was carried out under nitrogen protection. The temperature was then raised to 70℃, and 30g of methyl-dihydroxyethylallyl ammonium chloride and 0.2g of potassium persulfate were added dropwise to the reactor through a constant-pressure dropping funnel. The reaction was carried out at 75℃ for 0.5h. Subsequently, 10g of vinyltrimethoxysilane and 0.1g of potassium persulfate were added to the reactor through the constant-pressure dropping funnel, and the reaction was carried out at 70℃ for 1h, yielding organosilicon cationic polymer 1. # It has a cationic content of 30% (wt) and a viscosity-average molecular weight of 100,000.

[0032] In a reactor equipped with a stirrer and a thermometer, add 50g of 1,2-propanediamine and 10g of organosilicon cationic polymer 1. # 30g of aminopropyltriethoxysilane and 10g of deionized water were reacted at 100r / min and 40℃ for 1h to obtain a drilling fluid inhibitor composition, denoted as S1.

[0033] Example 2

[0034] In a reactor equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and vent pipe, 50g of acrylamide, 120g of deionized water, 0.6g of sodium bicarbonate, and 4g of composite emulsifier were added. Emulsification was carried out under nitrogen protection. The temperature was then raised to 80℃, and 40g of dimethyl diallyl ammonium chloride and 0.3g of ammonium persulfate were added dropwise to the reactor through a constant-pressure dropping funnel. The reaction was carried out at 80℃ for 1.5h. Subsequently, 10g of vinyltrimethoxysilane and 0.1g of ammonium persulfate were added to the reactor through the constant-pressure dropping funnel, and the reaction was carried out at 80℃ for 1.5h, yielding organosilicon cationic polymer 2. # It has a cationic content of 40% (wt) and a viscosity-average molecular weight of 80,000.

[0035] In a reactor equipped with a stirrer and a thermometer, add 40g of 1,3-propanediamine and 20g of organosilicon cationic polymer 2. #30g of aminoethyltriethoxysilane and 10g of deionized water were reacted at 150r / min and 50℃ for 1.5h to obtain a drilling fluid inhibitor composition, denoted as S2.

[0036] Example 3

[0037] In a reactor equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and vent pipe, 55g of acrylamide, 120g of deionized water, 0.6g of sodium bicarbonate, and 5g of composite emulsifier were added. Emulsification was carried out under nitrogen protection. The temperature was then raised to 85℃, and 35g of methyl-dihydroxymethylallyl ammonium chloride and 0.3g of potassium persulfate were added dropwise to the reactor through a constant-pressure dropping funnel. The reaction was carried out at 85℃ for 2 hours. Subsequently, 10g of vinyltrimethoxysilane and 0.1g of potassium persulfate were added to the reactor through the constant-pressure dropping funnel, and the reaction was carried out at 75℃ for 2.5 hours, yielding organosilicon cationic polymer 3. # It has a cationic content of 35% (wt) and a viscosity-average molecular weight of 70,000.

[0038] In a reactor equipped with a stirrer and a thermometer, add 20g of isopropanolamine and 20g of organosilicon cationic polymer 3. # 40g of 3-(2-aminoethylamino)propyltrimethoxysilane and 20g of deionized water were reacted at 200r / min and 60℃ for 2h to obtain a drilling fluid inhibitor composition, denoted as S3.

[0039] Example 4

[0040] In a reactor equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and vent pipe, 65g of acrylamide, 120g of deionized water, 0.6g of sodium bicarbonate, and 6g of composite emulsifier were added. Emulsification was carried out under nitrogen protection. The temperature was then raised to 90℃, and 25g of allyltrimethylammonium chloride and 0.4g of ammonium persulfate were added dropwise to the reactor through a constant-pressure dropping funnel. The reaction was carried out at 90℃ for 0.5h. Subsequently, 10g of vinyltrimethoxysilane and 0.1g of ammonium persulfate were added to the reactor through the constant-pressure dropping funnel, and the reaction was carried out at 70℃ for 3h, yielding organosilicon cationic polymer 4. # It has a cationic content of 25% (wt) and a viscosity-average molecular weight of 60,000.

[0041] In a reactor equipped with a stirrer and a thermometer, add 30g of N-ethylethylenediamine and 20g of organosilicon cationic polymer 4. # 30g of 3-(2-aminoethylamino)propyltriethoxysilane and 20g of deionized water were reacted at 300r / min and 55℃ for 1h to obtain a drilling fluid inhibitor composition, denoted as S4.

[0042] Example 5

[0043] In a reactor equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and vent pipe, 65g of acrylamide, 120g of deionized water, 0.6g of sodium bicarbonate, and 7g of composite emulsifier were added. Emulsification was carried out under nitrogen protection. The temperature was then raised to 85℃, and 20g of methyl-dihydroxymethylallyl ammonium chloride and 0.6g of potassium persulfate were added dropwise to the reactor through a constant-pressure dropping funnel. The reaction was carried out at 85℃ for 1.5h. Subsequently, 15g of vinyltriethoxysilane and 0.1g of potassium persulfate were added to the reactor through the constant-pressure dropping funnel, and the reaction was carried out at 75℃ for 2.5h, yielding organosilicon cationic polymer 5. # The cationic content is 20% (wt), and the viscosity-average molecular weight is 50,000.

[0044] In a reactor equipped with a stirrer and a thermometer, add 45g of N-diethylethylenediamine and 15g of organosilicon cationic polymer 5. # 30g of N-aminoethyl-3-aminopropylmethyldimethoxysilane and 10g of deionized water were reacted at 250r / min and 45℃ for 2h to obtain a drilling fluid inhibitor composition, denoted as S5.

[0045] Example 6

[0046] In a reactor equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and vent pipe, 60g of acrylamide, 120g of deionized water, 0.6g of sodium bicarbonate, and 8g of composite emulsifier were added. Emulsification was carried out under nitrogen protection. The temperature was then raised to 80℃, and 25g of methyl-dihydroxyethylallyl ammonium chloride and 0.7g of potassium persulfate were added dropwise to the reactor through a constant-pressure dropping funnel. The reaction was carried out at 80℃ for 1 hour. Subsequently, 15g of vinyltrimethoxysilane and 0.1g of potassium persulfate were added to the reactor through the constant-pressure dropping funnel, and the reaction was carried out at 90℃ for 2 hours, yielding organosilicon cationic polymer 6. # It has a cationic content of 25% (wt) and a viscosity-average molecular weight of 40,000.

[0047] In a reactor equipped with a stirrer and a thermometer, add 45g of diethylenetriamine and 20g of organosilicon cationic polymer 6. # 30g of diethylenetriaminopropyltrimethoxysilane and 5g of deionized water were reacted at 100r / min and 50℃ for 1.5h to obtain a drilling fluid inhibitor composition, denoted as S6.

[0048] Example 7

[0049] In a reactor equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and vent pipe, 50g of acrylamide, 120g of deionized water, 0.6g of sodium bicarbonate, and 3.5g of composite emulsifier were added. Emulsification was carried out under nitrogen protection. The temperature was then raised to 75℃, and 35g of dimethyl diallyl ammonium chloride and 0.2g of potassium persulfate were added dropwise to the reactor through a constant-pressure dropping funnel. The reaction was carried out at 75℃ for 1.5h. Subsequently, 15g of vinyltrimethoxysilane and 0.1g of potassium persulfate were added to the reactor through the constant-pressure dropping funnel, and the reaction was carried out at 85℃ for 3h, yielding organosilicon cationic polymer 7. # It has a cationic content of 35% (wt) and a viscosity-average molecular weight of 20,000.

[0050] In a reactor equipped with a stirrer and a thermometer, add 35g of triethylenetetramine and 15g of organosilicon cationic polymer 7. # 35g of triethylenetetraminepropyltrimethoxysilane and 15g of deionized water were reacted at 300r / min and 55℃ for 2h to obtain a drilling fluid inhibitor composition, denoted as S7.

[0051] Example 8

[0052] In a reactor equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and vent pipe, 60g of acrylamide, 120g of deionized water, 0.6g of sodium bicarbonate, and 4.5g of composite emulsifier were added. Emulsification was carried out under nitrogen protection. The temperature was then raised to 85℃, and 20g of methyl-dihydroxymethylallyl ammonium chloride and 0.9g of potassium persulfate were added dropwise to the reactor through a constant-pressure dropping funnel. The reaction was carried out at 85℃ for 1 hour. Subsequently, 20g of vinyltriethoxysilane and 0.1g of potassium persulfate were added to the reactor through the constant-pressure dropping funnel, and the reaction was carried out at 85℃ for 1 hour, yielding organosilicon cationic polymer 8. # The cationic content is 20% (wt), and the viscosity-average molecular weight is 5000.

[0053] In a reactor equipped with a stirrer and a thermometer, add 50g of tetraethylenepentamine and 15g of organosilicon cationic polymer 8. # 25g of triethylenetetraminepropyltriethoxysilane and 10g of deionized water were reacted at 250r / min and 60℃ for 1h to obtain a drilling fluid inhibitor composition, denoted as S8.

[0054] Example 9

[0055] In a reactor equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and vent pipe, 55g of acrylamide, 120g of deionized water, 0.6g of sodium bicarbonate, and 5.5g of composite emulsifier were added. Emulsification was carried out under nitrogen protection. The temperature was then raised to 90℃, and 35g of methyl-dihydroxyethylallyl ammonium chloride and 0.2g of potassium persulfate were added dropwise to the reactor through a constant-pressure dropping funnel. The reaction was carried out at 90℃ for 1.5h. Subsequently, 15g of vinyltrimethoxysilane and 0.1g of potassium persulfate were added to the reactor through the constant-pressure dropping funnel, and the reaction was carried out at 85℃ for 2.5h, yielding organosilicon cationic polymer 9. # It has a cationic content of 35% (wt) and a viscosity-average molecular weight of 90,000.

[0056] In a reactor equipped with a stirrer and a thermometer, add 40g of pentaethylenehexamine and 20g of organosilicon cationic polymer 9. # 35g of triethylenetetraminepropyltriethoxysilane and 5g of deionized water were reacted at 200r / min and 45℃ for 1.5h to obtain a drilling fluid inhibitor composition, denoted as S9.

[0057] Example 10

[0058] In a reactor equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and vent pipe, 70g of acrylamide, 120g of deionized water, 0.6g of sodium bicarbonate, and 6.5g of composite emulsifier were added. Emulsification was carried out under nitrogen protection. The temperature was then raised to 90℃, and 20g of methyl-dihydroxyethylallyl ammonium chloride and 0.8g of potassium persulfate were added dropwise to the reactor through a constant-pressure dropping funnel. The reaction was carried out at 90℃ for 2 hours. Subsequently, 10g of vinyltrimethoxysilane and 0.1g of potassium persulfate were added to the reactor through the constant-pressure dropping funnel, and the reaction was carried out at 85℃ for 1 hour, yielding organosilicon cationic polymer 10. # It has a cationic content of 20% (wt) and a viscosity-average molecular weight of 10,000.

[0059] In a reactor equipped with a stirrer and a thermometer, add 25g of 1,2-propanediamine and 20g of organosilicon cationic polymer 10g. # 35g of aminopropyltrimethoxysilane and 20g of deionized water were reacted at 150r / min and 40℃ for 2h to obtain a drilling fluid inhibitor composition, denoted as S10.

[0060] Example 11

[0061] In a reactor equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and vent pipe, 70g of acrylamide, 120g of deionized water, 0.6g of sodium bicarbonate, and 7.5g of composite emulsifier were added. Emulsification was carried out under nitrogen protection. The temperature was then raised to 70℃, and 10g of methyl-dihydroxyethylallyl ammonium chloride and 0.4g of ammonium persulfate were added dropwise to the reactor through a constant-pressure dropping funnel. The reaction was carried out at 70℃ for 0.5h. 20g of vinyltrimethoxysilane and 0.1g of ammonium persulfate were then added to the reactor through the constant-pressure dropping funnel, and the reaction was carried out at 90℃ for 1h, yielding organosilicon cationic polymer 1. # It has a cationic content of 10% (wt) and a viscosity-average molecular weight of 60,000.

[0062] In a reactor equipped with a stirrer and a thermometer, add 40g of N-ethylethylenediamine and 15g of organosilicon cationic polymer 11. # 25g of 3-(2-aminoethylamino)propyltrimethoxysilane and 20g of deionized water were reacted at 100r / min and 55℃ for 1h to obtain a drilling fluid inhibitor composition, denoted as S11.

[0063] Example 12

[0064] In a reactor equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and vent pipe, 65g of acrylamide, 120g of deionized water, 0.6g of sodium bicarbonate, and 3g of composite emulsifier were added. Emulsification was carried out under nitrogen protection. The temperature was then raised to 70℃, and 15g of dimethyl diallyl ammonium chloride and 0.4g of ammonium persulfate were added dropwise to the reactor through a constant-pressure dropping funnel. The reaction was carried out at 70℃ for 0.5h. 20g of vinyltrimethoxysilane and 0.1g of ammonium persulfate were then added to the reactor through the constant-pressure dropping funnel, and the reaction was carried out at 90℃ for 1h, yielding organosilicon cationic polymer 12. # The cationic content is 30% (wt), and the viscosity-average molecular weight is 40,000.

[0065] In a reactor equipped with a stirrer and a thermometer, add 35g of 1,3-propanediamine and 10g of organosilicon cationic polymer 12. # 35g of N-aminoethyl-3-aminopropylmethyldimethoxysilane and 10g of deionized water were reacted at 300r / min and 60℃ for 1.5h to obtain a drilling fluid inhibitor composition, denoted as S12.

[0066] Example 13

[0067] In a reactor equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and vent pipe, 45g of acrylamide, 120g of deionized water, 0.6g of sodium bicarbonate, and 4g of composite emulsifier were added. Emulsification was carried out under nitrogen protection. The temperature was then raised to 80℃, and 40g of allyltrimethylammonium chloride and 0.5g of potassium persulfate were added dropwise to the reactor through a constant-pressure dropping funnel. The reaction was carried out at 80℃ for 1.5h. Subsequently, 15g of vinyltrimethoxysilane and 0.1g of potassium persulfate were added to the reactor through the constant-pressure dropping funnel, and the reaction was carried out at 80℃ for 2h, yielding organosilicon cationic polymer 13. # It has a cationic content of 40% (wt) and a viscosity-average molecular weight of 30,000.

[0068] In a reactor equipped with a stirrer and a thermometer, add 50g of diethylenetriamine and 20g of organosilicon cationic polymer 13. # 25g of diethylenetriaminopropyltriethoxysilane and 5g of deionized water were reacted at 250r / min and 40℃ for 1h to obtain a drilling fluid inhibitor composition, denoted as S13.

[0069] Comparative Example 1

[0070] Following the method of Example 1, except that 1,3-propanediamine was replaced with polyetheramine, and all other conditions were the same as in Example 1, drilling fluid inhibitor composition D1 was prepared.

[0071] Comparative Example 2

[0072] The method is the same as in Example 1, except that the organosilicon cationic polymer 1 is used. # The drilling fluid inhibitor composition D2 was prepared by replacing the cationic polyacrylamide with the same conditions as in Example 1.

[0073] Comparative Example 3

[0074] Following the method of Example 1, except that aminosilane was replaced with epoxysilane, and all other conditions were the same as in Example 1, drilling fluid inhibitor composition D3 was prepared.

[0075] Test Example 1

[0076] The ability of the drilling fluid inhibitor composition to inhibit the hydration and dispersion of drilling cuttings and the temperature resistance of the drilling fluid inhibitor composition were evaluated by the cuttings rolling recovery rate test. The specific test steps are as follows, and the results are shown in Table 1.

[0077] Weigh 50.00 g (accurate to 0.01 g) of 4-8 mesh rock cuttings and place them in an aging vessel containing 350 mL of 1% (wt) inhibitor solution. Seal the vessel tightly. Place the aging vessel in a 120℃ roller furnace for 16 hours. Remove the vessel and allow it to cool to room temperature. Pour the liquid and rock sample from the vessel onto a 40-mesh sieve and wet-wash for 1 minute. Place the remaining rock sample in a 105±3℃ forced-air constant-temperature drying oven for 4 hours. After cooling, weigh the sample (accurate to 0.01 g) and calculate the rolling recovery rate using Equation 1.

[0078] (Equation 1)

[0079] In the formula:

[0080] R: 16h core rolling recovery rate, %

[0081] m: Mass of rock sample remaining after sieving through a 40-mesh sieve, in g.

[0082] Table 1. Cuttings rolling recovery rate at different temperatures

[0083]

[0084] Note: Sample addition was 1%.

[0085] Test Example 2

[0086] The ability of the drilling fluid inhibitor composition to inhibit clay hydration and dispersion and the temperature resistance of the drilling fluid inhibitor composition were evaluated by the relative inhibition rate experiment. The specific test steps are as follows, and the results are shown in Table 2.

[0087] Preparation of base slurry: Take 350 mL of distilled water, add 0.84 g of sodium carbonate and 21.00 g of sodium bentonite for drilling fluid testing to each portion, and stir on a high-speed mixer for 20 min, interrupting at least twice during the process to scrape off the material adhering to the cup wall.

[0088] Sample preparation: Take 350 mL of distilled water, add 1.40 g of sample to each sample, and stir to dissolve completely. Then add 0.84 g of sodium carbonate and 21.00 g of sodium bentonite for drilling fluid testing to each sample, and stir on a high-speed mixer for 20 minutes, interrupting at least twice to scrape off the material adhering to the cup wall.

[0089] Relative inhibition rate test: The above slurry was hot rolled at a certain temperature for 16 hours. After cooling, the sample was taken and stirred for 5 minutes. The φ100 value was determined at room temperature according to GB / T16783.1. The calculation formula is shown in Equation 2.

[0090] (Equation 2)

[0091] In the formula:

[0092] X — Relative inhibition rate, %;

[0093] Φ 100 —Stable reading of the base slurry at 100 r / min using a direct-reading rotational viscometer;

[0094] φ' 100 —Stable reading of the slurry sample at 100 r / min using a direct-reading rotational viscometer.

[0095] Table 2. Relative inhibition rate at different temperatures

[0096]

[0097] Note that the sample volume should be increased by 0.4%.

[0098] Test Example 3

[0099] The adsorption performance of the drilling fluid inhibitor composition on the clay surface was evaluated by testing the drying loss at different temperatures. The specific operating steps are as follows, and the results are shown in Table 3:

[0100] (1) Preparation of room temperature modified bentonite: The bentonite used for drilling fluid test was soaked in inhibitor solution, filtered and the filter cake was collected and dried. Then the filter cake was crushed and soaked in water, filtered and washed with water 5 times. Finally, the filter cake was dried and crushed to prepare room temperature modified bentonite.

[0101] (2) Preparation of high temperature modified bentonite: The bentonite used for drilling fluid test was soaked in an inhibitor solution, and then the filter cake was collected by high temperature and high pressure filtration using a high temperature and high pressure filtration instrument. The inhibitor solution containing bentonite was treated at high temperature for 8 hours in the high temperature and high pressure filtration instrument and then dried. The filter cake was then crushed and soaked in water, filtered and washed with water 5 times. Finally, the filter cake was dried and crushed to obtain high temperature modified bentonite.

[0102] (3) Room temperature adsorption capacity: Weigh a certain mass of room temperature modified bentonite, place it in a muffle furnace, ashed at 800℃ to completely decompose the inhibitor, weigh the mass after ashing, and use bentonite as a blank test.

[0103] (4) High temperature adsorption capacity: Weigh the same mass of high temperature modified bentonite as in step (3), place it in a muffle furnace, ashing at 800℃ to completely decompose the inhibitor, weigh the mass after ashing, and use bentonite as a blank test.

[0104] (5) Adsorption retention rate: The adsorption retention rate is calculated using Equation 3.

[0105] (Equation 3)

[0106] m: Mass of high-temperature modified bentonite (bentonite mass); g

[0107] m1: Mass of room temperature modified bentonite after ashing; g

[0108] m2: Mass of bentonite after ashing; g

[0109] m3: Mass of high-temperature modified bentonite after ashing; g.

[0110] Table 3 Adsorption Retention Rate at Different Temperatures

[0111]

[0112] In summary, the drilling fluid inhibitor composition of the present invention utilizes a combination of large and small molecules to achieve intercalation and encapsulation of clay and rock cuttings, effectively inhibiting the hydration and dispersion of clay and rock cuttings. A 0.4% addition results in an inhibition rate ≥93%, and a 1% addition results in a rock cuttings rolling recovery rate ≥90%. The molecular structure contains no ether or ester bonds, exhibiting high temperature resistance up to 240℃. Through a dual action of physical and chemical adsorption, it binds to clay and rock cuttings, overcoming the drawbacks of high-temperature desorption, with an adsorption retention rate ≥96% at 240℃.

[0113] Any numerical value mentioned in this invention, if there is only a two-unit interval between any minimum and any maximum value, includes all values ​​that increase by one unit each time from the minimum to the maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, or time, is stated as 50-90, in this specification it means specifically listing values ​​such as 51-89, 52-88, ..., 69-71, and 70-71. For non-integer values, it may be appropriately considered that a unit is 0.1, 0.01, 0.001, or 0.0001. These are merely some specifically specified examples. In this application, in a similar manner, all possible combinations of numerical values ​​between the listed minimum and maximum values ​​are considered to have been disclosed.

[0114] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A drilling fluid inhibitor composition, characterized in that, The composition comprises, by mass fraction: 20-50% small molecule organic amine, 10-20% organosilicon cationic copolymer, 20-40% aminosilane, and the remainder is water. The organosilicon cationic copolymer is obtained by copolymerization of acrylamide, cationic monomer and vinyl silane agent, with a viscosity-average molecular weight of 5000-100000 and a cationic content of 10-40% (wt). The small molecule organic amines include one or more of the following: 1,2-propanediamine, 1,3-propanediamine, isopropanolamine, N-ethylethylenediamine, N-diethylethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine; The cationic monomer includes one or more of methyl-dihydroxyethylallyl ammonium chloride, methyl-dihydroxymethylallyl ammonium chloride, dimethyldiallyl ammonium chloride, and allyltrimethylammonium chloride; the vinyl silane agent is one or more of vinyltrimethoxysilane and vinyltriethoxysilane. The aminosilanes include one or more of the following: aminopropyltriethoxysilane, aminopropyltrimethoxysilane, aminoethyltriethoxysilane, aminoethyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2-aminoethylamino)propyltriethoxysilane, N-aminoethyl-3-aminopropylmethyldimethoxysilane, N-aminoethyl-3-aminopropylmethyldiethoxysilane, diethylenetriaminopropyltrimethoxysilane, triethylenetetraaminopropyltrimethoxysilane, diethylenetriaminopropyltriethoxysilane, and triethylenetetraaminopropyltriethoxysilane.

2. A method for preparing the drilling fluid inhibitor composition of claim 1, characterized in that, Includes the following steps: A1: Add the weighed deionized water, emulsifier, sodium bicarbonate, and acrylamide to a reactor equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and vent pipe. Stir to emulsify, purge with nitrogen for protection, and raise the temperature to the required temperature. Add the cationic monomer and 66-90% (wt) of initiator dropwise to the reactor through a constant pressure dropping funnel, and maintain the temperature for a period of time. A2: Continue to slowly drip vinylsiloxane and 10-34% (wt) of initiator into the reactor through a constant pressure dripping funnel. After the dripping is completed, continue to react at the reaction temperature for a period of time to obtain an organosilicon cationic copolymer. A3: Add small molecule organic amine, aminosilane, water and the organosilicon cationic copolymer obtained in step A2 into the reactor in proportion, and stir for a certain time at the reaction temperature to obtain the drilling fluid inhibitor composition.

3. The preparation method according to claim 2, characterized in that, The emulsifier is a composite emulsifier composed of dodecylbenzenesulfonic acid and alkylphenol polyoxyethylene ether OP-10, with a mass ratio of dodecylbenzenesulfonic acid to alkylphenol polyoxyethylene ether OP-10 of 1:1, and the amount of composite emulsifier added is 3-8% (wt); the initiator is either ammonium persulfate or potassium persulfate, and the amount of initiator added is 0.3-1% (wt).

4. The preparation method according to claim 2, characterized in that, The mass ratio of acrylamide, cationic monomer and vinylsiloxane is (50-70):(10-40):(10-20).

5. The preparation method according to claim 2, characterized in that, The reaction conditions in step A1 include: a reaction temperature of 70-90℃ and a reaction time of 0.5-2h; and / or the reaction conditions in step A2 include: a reaction temperature of 70-90℃ and a reaction time of 1-3h; and / or the reaction conditions in step A3 include: a reaction temperature of 40-60℃, a stirring speed of 100-300r / min, and a reaction time of 1-2h.

6. The application of the drilling fluid inhibitor composition as described in claim 1, characterized in that: Used in drilling projects.

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