CN115404053A - Organic silicon diluent for drilling fluid and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of drilling fluid, in particular to an organic silicon diluent for drilling fluid and a preparation method thereof, wherein the organic silicon diluent comprises the following components in parts by mole: 280-350 parts of condensed water, 17-22 parts of sodium hydroxide solution, 24-28 parts of 2-acrylamide-2-methylpropanesulfonic acid, hyperbranched polymer and modifier; wherein the hyperbranched polymer comprises: gamma (-2, 3-glycidoxy) propyltrimethoxysilane, phenyltrimethoxysilane, hydrochloric acid solution and dimethylchlorosilane. The drilling fluid is used for thickening the drilling fluid due to the degradation of partial components under the conditions of high temperature and high density, so that the performance of the drilling fluid is changed sharply, and the adjustment and the control are not easy.

Description

Organic silicon diluent for drilling fluid and preparation method thereof

Technical Field

The invention relates to the technical field of drilling fluid, in particular to an organic silicon diluent for drilling fluid and a preparation method thereof.

Background

In recent years, the research in the field of petroleum and natural gas in China is continuously and deeply explored and developed, drilling operation is gradually developed from shallow strata, simple strata to deep strata and complex strata, and deep wells and ultra-deep wells are the key points of future exploration and development. In the drilling exploration operation which is gradually carried out towards the deep stratum, as the reservoir is buried deeper, the stratum pressure is increased and the lithology is more complicated, the changes cause the drilling operation to be difficult to implement, the cost is high, the time is low, and accidents are more easily caused.

With the continuous deepening of the petroleum exploration and development in China, the exploration and development of deep petroleum and natural gas gradually become a main way for solving the stable yield and yield increase of the petroleum industry in China. Therefore, drilling of deep wells and ultra-deep wells is an important aspect of the petroleum industry in China.

The drilling fluid is used as the blood in the drilling industry, and the performance and the application effect of the drilling fluid directly influence the quality of drilling engineering. Drilling fluids are also beginning to face increasing complexity challenges as they are applied to today's increasingly complex production conditions. Under the conditions of medium-high temperature and high density, the drilling fluid can be thickened due to the degradation of partial components, and can also be thickened due to the increase of poor solid phase caused by the fact that finely dispersed drilling cuttings enter the drilling fluid, so that the rheological property of the drilling fluid is changed sharply, the adjustment and the control are not easy, and the drilling operation cannot be normally carried out in severe cases, so that the viscosity reduction operation of the drilling fluid by using the diluent becomes an important part in the drilling engineering.

In order to cope with complex formation conditions, the components of the corresponding drilling fluid are also complex, and the viscosity reduction is usually carried out by adopting a specific diluent according to different drilling fluid compositions and different drilling fluid thickening mechanisms. Many diluents for drilling fluids have certain limitations depending on the thickening mechanism of the drilling fluid. Therefore, the development of the drilling fluid diluent with multiple viscosity reduction effects has very important significance.

Disclosure of Invention

The invention aims to provide an organic silicon diluent for drilling fluid and a preparation method thereof, which are used for thickening the drilling fluid due to degradation of partial components, thickening the drilling fluid due to invasion of inferior solid phase and CO (carbon monoxide) under the conditions of high temperature and high density ₂ Thickening caused by pollution, so that the performance of the drilling fluid is changed sharply, and the drilling fluid is not easy to adjust and control.

The invention is realized by the following technical scheme:

an organic silicon diluent for drilling fluid comprises the following components in parts by mole:

280-350 parts of condensed water, 17-22 parts of sodium hydroxide solution, 24-28 parts of 2-acrylamide-2-methylpropanesulfonic acid, hyperbranched polymer, modifier and nano titanium oxide;

wherein the hyperbranched polymer monomer component comprises: gamma (-2, 3-glycidoxy) propyltrimethoxysilane, phenyltrimethoxysilane, hydrochloric acid solution and dimethylchlorosilane.

Furthermore, a chemical bonding mode is adopted to introduce organic silicon molecular chains into acrylate polymer molecular chains, so that organic silicon is prevented from being transferred in a small molecule mode.

Further, the modifying agent comprises a silicone fluoropolymer.

Further, the method comprises the following steps:

s1, mixing condensed water, a hyperbranched polymer and 2-acrylamide-2-methylpropanesulfonic acid to obtain a mixed solution;

s2, adding a sodium hydroxide solution into the mixed solution, and heating to obtain a heated mixed solution;

and S3, after cooling, adding the nano titanium oxide into the heated mixed liquid to obtain the diluent for the drilling fluid.

Further, the preparation method of the hyperbranched polymer comprises the following steps:

s1, adding phenyl trimethoxy silane and gamma (-2, 3-epoxypropoxy) propyl trimethoxy silane with the total amount of 0.05mol into a 100mL three-neck flask;

s2, continuously stirring at 20 ℃, and dripping a hydrochloric acid solution (with the pH value of 1-2) which accounts for 2 times of the total raw material mass;

s3, hydrolyzing for 2h, heating to 50-60 ℃, and reacting for 3h.

S4, removing unreacted raw materials and byproducts by a vacuum rotary evaporation method, and slowly increasing the vacuum degree and slowly heating in the process;

s5, finally keeping the temperature at 70 ℃ for 1h, dissolving the rotary evaporated substance into toluene, and adding 8.9g (0.05 mol) of dimethylchlorosilane into the toluene to block the silicon hydroxyl.

S6, stirring for 3 hours at 50 ℃, and removing debenzolization by rotary evaporation to obtain transparent viscous liquid;

and S7, adding an improver into the transparent viscous liquid.

Further, the preparation method of the modifying agent comprises the following steps:

mixing 14-19 parts of fluorine-based solution and 13-17 parts of methyl silicate solution, stirring at constant temperature for 40 minutes, controlling the temperature to be 60-80 ℃, and then cooling to room temperature. The mud shale drilling fluid effectively prevents the expansion of mud shale, improves the frictional resistance of mud cakes, and simultaneously reduces the interaction among the clay, so that the viscosity of the drilling fluid is reduced, and the drilling fluid has good dilution effect.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. the product of the invention has certain CO resistance ₂ The pollution is caused by the reaction of hyperbranched polysiloxane and linear polysiloxane with CO ₂ The molecular interaction and the interaction between the hyperbranched polysiloxane molecules are beneficial to CO due to a large number of cavities at the branch points of the structural defects ₂ The organic silicon molecules are diffused into the cavity structure and enter the cavity structure, so that the polymer and CO are improved ₂ The compatibility of the components;

2. the hyperbranched organic silicon polymer added with phenyl has larger volume, so that the temperature resistance of the treating agent is further improved, the high-temperature degradation of the drilling fluid treating agent is prevented to a certain extent, and the viscosity of the drilling fluid is favorably reduced;

3. the hyperbranched will be heated the point and divided into a plurality of fulcrums, also make the diluent bear the heat and increase, avoid appearing network structure, the organosilicon molecule improves the viscosity reduction effect through the structure of breaking up between polymer and the clay granule for can not only reduce apparent viscosity, also can reduce structural viscosity, simultaneously, still have certain fluid loss effect, can improve the mud cake quality, improve wall of a well stability.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a nuclear magnetic resonance hydrogen spectrum of HbSiO-Phen 63.7%;

FIG. 2 is a graph of cloud point pressure of hyperbranched silicone polymer in aqueous solution;

FIG. 3 shows infrared spectra of HbSiO-Phen77.5% (a) and HbSiO-KH (b).

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.

Example (b):

as shown in fig. 1 to fig. 3, the content of each component of the present invention is as follows in terms of mole fraction:

280-350 parts of condensed water, 17-22 parts of sodium hydroxide solution, 24-28 parts of 2-acrylamide-2-methylpropanesulfonic acid, a hyperbranched polymer, a modifier and nano titanium oxide; wherein the hyperbranched polymer comprises: gamma (-2, 3-glycidoxy) propyltrimethoxysilane, phenyltrimethoxysilane, hydrochloric acid solution and dimethylchlorosilane.

It should be noted that, a chemical bonding method is adopted to introduce the organic silicon molecular chain into the acrylate polymer molecular chain, so as to prevent the organic silicon from transferring in the form of small molecules.

The modifying agent includes a silicone fluoropolymer.

It should be noted that the method comprises the following steps:

s1, mixing condensed water, a hyperbranched polymer and 2-acrylamide-2-methylpropanesulfonic acid to obtain a mixed solution;

s2, adding a sodium hydroxide solution into the mixed solution, and heating to obtain a heated mixed solution;

and S3, after cooling, adding the nano titanium oxide into the heated mixed liquid to obtain the diluent for the drilling fluid.

The preparation method of the hyperbranched polymer comprises the following steps:

s1, adding phenyl trimethoxy silane and gamma (-2, 3-epoxypropoxy) propyl trimethoxy silane with the total amount of 0.05mol into a 100mL three-neck flask;

s2, continuously stirring at 20 ℃, and dripping hydrochloric acid solution (pH is 1-2) which accounts for 2 times of the total raw material mass;

s3, hydrolyzing for 2 hours, heating to 50-60 ℃, and reacting for 3 hours;

s4, removing unreacted raw materials and byproducts by a vacuum rotary evaporation method, and slowly increasing the vacuum degree and slowly heating in the process;

s5, finally keeping the temperature at 70 ℃ for 1h, dissolving the rotary evaporated substance into toluene, adding 8.9g (0.05 mol) of dimethylchlorosilane into the toluene, and blocking the silicon hydroxyl;

s6, stirring for 3 hours at 50 ℃, and removing debenzolization by rotary evaporation to obtain transparent viscous liquid;

and S7, adding an improver into the transparent viscous liquid.

Namely HbSiO-KH, hbSiO-Phen63.7% and HbSiOPhen77.5% (the percentage is the phenyl mole fraction), the charging amount of the corresponding phenyltrimethoxysilane in the raw material is 0, 0.032 and 0.039mol respectively. The synthetic route is shown below.

Wherein: r does not contain phenyl, and the product is marked as HbSiO-KH; r contains phenyl and epoxy at the same time, and the product is marked as: hbSiO-Phen.

The introduction of phenyl groups into the polymer is effective in increasing the stiffness of the treating agent and further increasing the temperature resistance of the treating agent, but also results in a decrease in the solubility of the polymer in the drilling fluid, typically as indicated by an increase in cloud point pressure. In order to avoid adding cosolvent in the using process, the polymer needs to have thickening property and maintain CO ₂ Solubility, while conventional polymer structures such as linear and branched cannot meet the above requirements. The hyperbranched structure polymer has less intermolecular chain entanglement, and the hyperbranched polymerThe cavity structure between molecular chains can effectively prevent the migration of the silicon-containing polymer with small molecular weight, and a large number of cavities exist at the branch points of the structural defects, thereby being beneficial to CO ₂ Can diffuse into the cavity structure to promote diffusion and dissolution, so that CO can be diffused into the cavity structure ₂ Further dissolution was carried out.

CO ₂ The viscosity reduction efficiency is reduced when the modified silicon-containing hyperbranched polymer enters a diluent, silicon-containing functional groups are dispersed on hyperbranched carbon chains through the added hyperbranched polymer, certain stability is achieved through the added phenyl, and when CO is dissolved in water ₂ The interaction force between the molecules of the hyperbranched polymer is smaller than that of the linear polymer, and a proper amount of phenyl is introduced, so that the intermolecular interaction can be reduced, and CO is favorably diffused into the cavity structure ₂ Compatible with hyperbranched structures, hyperbranched polymers having attractive CO ₂ The effect of (2) is to supply sufficient CO ₂ Is sucked into the hyperbranched cavity structures, and each cavity structure contains a proper amount of CO ₂ Hyperbranched structures and CO ₂ Dissolving, separating the silicon-containing functional group from the hyperbranched carbon chain to disperse the organic silicon molecules, wherein part of CO is dissolved by the hyperbranched carbon chain ₂ Thus small amount of remaining CO ₂ Most organic silicon molecules can not be damaged in a large amount when entering the reaction kettle, so that the organic silicon molecules still can play a viscosity reduction effect by breaking the structure between polymer macromolecules and clay particles, and the phenomenon that a large amount of CO is generated in the early stage is avoided ₂ The viscosity reduction efficiency of the diluent is reduced due to the influence on organic silicon molecules.

The preparation method of the modifying agent comprises the following steps:

mixing 14-19 parts of fluorine-based solution and 13-17 parts of methyl silicate solution, stirring at constant temperature for 40 minutes, controlling the temperature to be 60-80 ℃, and then cooling to room temperature.

The chemical structure of the silicon-fluorine polymer (SF) applied to the drilling fluid is as follows:

in the formula: r _f 、R _f ' - - - - -is a fluorine-containing group such as CH ₃ 、C ₂ H ₄ CF ₃ And C ₂ H ₄ C ₈ F ₁₇ Etc.; r1 and R2: is a saturated alkyl group; m _e : is methyl CH ₃ (ii) a X, Y: are terminal groups of the polymer chain. May be an inert group. It may also be a reactive group. The SF polymer is a linear molecule and is a basic bond type of SF chemistry, an SF main chain is formed by silica, fluorine-containing groups and other organic groups are macromolecular side groups, and Si-O bond energy is high, so that the SF has good thermal stability.

The 3d empty orbital on Si forms a covalent bond with a non-covalent electron pair of an oxygen atom, resulting in Si-O with partial double bond character. The Si-O bond angle is large, so that the Si-O bond is easy to rotate and is very soft. Because mutual compensation is carried out between covalent bonds and Si-O dipoles, the side group with the chain structure of spiral Si-O as the fluorocarbon group of the main chain is surrounded on the periphery of the main chain, thus forming protection to the main chain, having multilayer resisting effect on the influence of external environment and medium, improving the stability of the polymer, and reducing the sensitivity to salt towards the high-stability structure part of the fluorocarbon bond of the fluorocarbon group outside the interface. Due to the spiral structure, nonpolar methyl on the side chain is arranged outwards in a directional mode to play a role in shielding and preventing water molecules from entering, a hydrophobic effect is achieved, the overall surface activity of the drilling fluid system is improved, meanwhile, the isolation performance, the lubricating performance and the defoaming capacity of the drilling fluid system are improved, and fluorine-containing hydrocarbon groups on SF are hydrophobic and oleophobic. Due to the hydrophobicity, the silicon-fluorine drilling fluid has good hydrophobicity and good oil repellency, and can be not easily attached to other substances, so that the surface activity of the silicon-fluorine drilling fluid system is improved, and the surface tension is well reduced.

The ≡ Si-OH in SF molecules and the ≡ Si-O-bond on the surface of the clay particles form the ≡ Si-O-Si ≡ bond, so that a layer of-CH-O-Si ≡ bond is adsorbed on the surface of the clay particles ₃ Hydrophobic group-CH ₃ The hydrophilic surface is inverted outwards to generate hydrophobic capillary action, so that the expansion of the shale is effectively prevented, the frictional resistance of mud cakes is improved, and meanwhile, the interaction among the clay is reduced, so that the viscosity of the drilling fluid is reduced, and the drilling fluid is well diluted. nonpolar-CH on a side chain ₃ Watch with outward low orientationThe surface tension is active in the drilling fluid system to effectively prevent and destroy the sol-gel in the drilling fluid so as to keep the stable viscosity of the system.

FIG. 1 shows an example of HbSiO-Phen63.7%, and the NMR spectrum of the product after end capping with dimethylchlorosilane is shown in FIG. 3. The percentage of phenyl groups in the product based on the total mass of epoxide groups and phenyl groups can be calculated by the integral of the peak marked "e" in FIG. 1 and the integral of all peaks corresponding to the hydrogen on the phenyl groups, i.e., the phenyl mole fraction = (Ag + h + h '+ i + i'/5)/(Ag + h + h '+ i + i'/5 +Ae/2). According to the nuclear magnetic hydrogen spectrum peak area, 63.7% of phenyl in HbSiO-Phen63.7% accounts for total substances of epoxy groups and phenyl.

FIG. 2 shows that the introduction of phenyl groups into the hyperbranched polysiloxane did not bring about a significant increase in the cloud point pressure, which was reduced below 4.5%. The polymer cloud point pressure curves are very close when the molar fractions of the phenyl groups are 63.7% and 77.5%, respectively, and the cloud point pressure does not exceed 20MPa when the addition amount is 5%. The amount of PPG-2000 added to CO2 was 1.5% of the cloud point pressure, i.e., more than 25MPa. It can be seen that hyperbranched polysiloxanes have a far better solubility in carbon dioxide than linear PPG. Hyperbranched polysiloxanes in CO ₂ When the additive amount is 1-3%, the cloud point pressure is not obviously increased, and the molecular molar mass of the PDMS is 1530g/mol, and the PDMS is terminated by naphthyl of an aromatic group in CO ₂ The addition amount is 4%, and the corresponding cloud point pressure exceeds 50MPa.

FIG. 3 shows the IR spectra of the products HbSiO-Phen77.5% and HbSiO-KH for a and b, respectively. 2 curves are 1000-1200 cm ^-1 All have broad peaks, which indicates the formation of Si-O-Si bonds. In FIG. 3, 1429cm ^-1 Vibration absorption peak at 1591cm of aromatic ring ^-1 Is an extension vibration absorption peak in an aromatic ring; 902cm apart from the phenyl absorption peak ^-1 An epoxy characteristic absorption peak appears. FIG. 3 shows the IR spectrum of a hyperbranched polysiloxane HbSiO-KH without phenyl groups and containing only epoxy groups, which was endcapped with dimethylchlorosilane, 2132cm ^-1 The position is a Si-H stretching vibration absorption peak on the end group.

Experimental data:

preparing base slurry: 20.0g of bentonite and 1.4g of sodium carbonate are added into 400mL of distilled water, and the mixture is stirred at a high speed for 30min. And standing and hydrating at room temperature for 24 hours to obtain the base slurry.

0.2% (mass/volume ratio, the same applies hereinafter) of 0.8g of a sample and 2.0g of a 0.5% sample were added to the base slurry, and after stirring at a high speed for 10 minutes, the viscosities and shear forces of the base slurry and the sample slurry were measured with a six-speed rotational viscometer at room temperature. As shown in the following table:

TABLE 1 viscosity reduction Effect of different amounts of diluents in Bentonite-based slurries

Item	AV/mPa.s	PV/mPa.s	YP/Pa	G10s/Pa	G10min/Pa
						5% bentonite-based slurry	13	8	5	3	3
5% Bentonite-based slurry +0.2% sample	7	5.5	1.5	0.5	1
						5% Bentonite-based slurry +0.5% sample	6	5	1	0	0.5

Getting the on-site CO ₂ Contaminated well slurries were tested for viscosity at room temperature using a six-speed rotary viscometer and for viscosity of well slurries with 0.5% and 1.0% samples added, respectively, and HTHP fluid loss at 150 ℃ was measured using an HTHP fluid loss apparatus, as shown in the following table.

TABLE 2 Effect of different amounts of diluent on viscosity reduction in contaminated well slurries

It can be seen from tables 1 and 2 above that the example diluent samples are effective in reducing the viscosity of the base slurry. Meanwhile, in the polluted site drilling fluid well slurry, the obvious viscosity reduction and dilution effect can be achieved, and meanwhile the drilling fluid also has a certain auxiliary fluid loss reduction effect.

The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only examples of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (6)

1. The organic silicon diluent for the drilling fluid is characterized by comprising the following components in parts by mole:

280-350 parts of condensed water, 17-22 parts of sodium hydroxide solution, 24-28 parts of 2-acrylamide-2-methylpropanesulfonic acid, hyperbranched polymer, modifier and nano titanium oxide;

wherein the hyperbranched polymer comprises: gamma (-2, 3-glycidoxy) propyltrimethoxysilane, phenyltrimethoxysilane, hydrochloric acid solution and dimethylchlorosilane.

2. The organic silicon diluent for the drilling fluid as claimed in claim 1, characterized in that a chemical bonding manner is adopted to introduce organic silicon molecular chains into acrylate polymer molecular chains.

3. The silicone diluent for drilling fluids of claim 1 wherein the modifier comprises a silicone fluoropolymer.

4. The preparation method of the organic silicon diluent for the drilling fluid as claimed in any one of claims 1 to 3, characterized by comprising the following steps:

s1, mixing condensed water, a hyperbranched polymer and 2-acrylamide-2-methylpropanesulfonic acid to obtain a mixed solution;

s2, adding a sodium hydroxide solution into the mixed solution, and heating to obtain a heated mixed solution;

and S3, after cooling, adding nano titanium oxide into the heated mixed liquid to obtain the diluent for the drilling fluid.

5. The preparation method of the organic silicon diluent for the drilling fluid, according to claim 4, is characterized in that the preparation method of the hyperbranched polymer comprises the following steps:

s11, adding phenyl trimethoxy silane and gamma (-2, 3-epoxypropoxy) propyl trimethoxy silane with the total amount of 0.05mol into a 100mL three-neck flask;

s12, continuously stirring at 20 ℃, and dripping hydrochloric acid solution (pH is 1-2) which accounts for 2 times of the total raw material mass;

s13, hydrolyzing for 2 hours, heating to 50-60 ℃, and reacting for 3 hours;

s14, removing unreacted raw materials and byproducts by a vacuum rotary evaporation method, and slowly increasing the vacuum degree and slowly heating in the process;

s15, finally keeping the temperature at 70 ℃ for 1h, dissolving the rotary evaporated substance into toluene, adding 8.9g (0.05 mol) of dimethylchlorosilane into the toluene, and blocking the silicon hydroxyl;

s16, stirring for 3 hours at 50 ℃, and removing debenzolization by rotary evaporation to obtain transparent viscous liquid;

s17, adding the modifying agent into the transparent viscous liquid.

6. The preparation method of the organic silicon diluent for the drilling fluid according to claim 5, wherein the preparation method of the modifier comprises the following steps:

mixing 14-19 parts of fluorine-based solution and 13-17 parts of methyl silicate solution, stirring at constant temperature for 40 minutes, controlling the temperature to be 60-80 ℃, and then cooling to room temperature.

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