CN106432632A - Amido polymer filtrate loss reducer for water-based drilling fluid resistant to high temperature, salt and calcium and preparation method and application thereof - Google Patents

Abstract

The present invention proposes an amine-based polymer fluid loss reducer for high-temperature and salt-resistant calcium water-based drilling fluids and its preparation method and application. It is prepared from sulfonic acid, allyl polyethylene glycol, and trihydroxyethylallyl ammonium bromide, and the molar ratio of the four monomers is 8.1-20.2:9-15.2:2.1-4.3:8-10. The fluid loss control agent can be effectively adsorbed on the clay particles. At the same time, the hydration group sulfonic acid group and hydroxyl group can bring an adsorbed hydration layer to the clay particles, which enhances the dimensional stability of the dispersion system and effectively inhibits the fine particles. Coalesce to form a dense mud cake, so as to achieve the effect of filtration loss reduction. There are van der Waals force and electrostatic attraction between cationic quaternary ammonium groups and negatively charged clay particles on the surface, which can be firmly adsorbed on the surface of clay particles. The steric hindrance generated by the long side chains of polyoxyethylene groups can enhance the rigidity of the main chain, thereby improving Thermal properties of polymers.

Description

An amine-based polymer fluid loss reducer for high temperature and salt-resistant calcium water-based drilling fluid and its preparation preparation methods and applications

technical field

The invention relates to the technical field of drilling fluids, in particular to an amine-based polymer fluid loss reducer for high-temperature and salt-resistant calcium water-based drilling fluids and its preparation method and application. The amine-based polymer fluid loss reducer is suitable for petroleum Oil and gas drilling process encounters drilling fluid in deep high-temperature and high-pressure formations.

Background technique

Due to the rapid increase in demand for oil and natural gas resources in my country and the depletion of oil and gas energy in shallow formations, the development of oil and gas energy in deep formations is the main way out for the future development of my country's petroleum industry, and deep well and ultra-deep well drilling technology is indispensable. High-temperature resistant water-based drilling fluid technology is a key technology for drilling high-temperature deep wells, and has always been a difficult problem in the world.

During deep well drilling, due to the geothermal gradient, the deeper the vertical depth, the higher the temperature in the lower wellbore. In addition, the time for the drilling fluid to stay and circulate downhole is also extended. Therefore, drilling fluid treatment is required to maintain good performance at high temperatures. In addition, deep wells and ultra-deep wells often encounter complex formations, such as salt layers, salt-gypsum layers or high-pressure brine layers. Salt and calcium intrusion can affect drilling fluid performance. The effects of salt-calcium intrusion are exacerbated at high temperatures. Therefore, it is required that the fluid loss reducer for drilling fluid can resist high temperature and salt and calcium pollution.

The molecular weight of polymer fluid loss reducer is often high, and its use in low-density drilling fluid has little effect on the rheology of drilling fluid. However, when used in high-density drilling fluids, due to the high solid content of the drilling fluid and the muddy shale formation, it is difficult to add the amine-based polymer fluid loss reducer to the drilling fluid, even if a small amount of fluid loss reducer is added. Fluid loss additives will also lead to a sharp increase in the viscosity and shear force of the drilling fluid, and large fluctuations in the rheological properties of the drilling fluid. Finally, such fluid loss additives cannot be used. Therefore, it is of urgent practical significance to study the amine-based fluid loss reducer used in drilling fluids resistant to high temperature and salt and calcium.

Contents of the invention

The object of the present invention is to provide a kind of high temperature and salt-calcium resistant amine-based polymer fluid loss reducer for drilling fluid. Strong, low viscosity effect on drilling fluid.

Another object of the present invention is to provide a preparation method of the amine-based polymer fluid loss control agent, which has simple operation, mild conditions and high yield.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions to achieve:

An amine-based polymer fluid loss reducer for high-temperature and anti-salt-calcium water-based drilling fluids. The general structural formula of the amine-based polymer fluid loss reducer is as follows:

Wherein, m=40%～45%, n=40%～45%, p=1-m-n-q, q=8%～10%, K is 9～20, m, n, p, q represent mole percentage .

Preferably, the amine-based polymer fluid loss control agent is mainly composed of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, allyl polyethylene glycol, trihydroxyethylallyl bromide Ammonium is prepared as a raw material, and the molar ratio of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, allyl polyethylene glycol, and trihydroxyethylallyl ammonium bromide is 8.1 to 20.2: 9-15.2: 2.1-4.3: 8-10, and the molecular weight of allyl polyethylene glycol is between 400-1000.

The preparation method of the above-mentioned amine-based polymer fluid loss reducer for high-temperature and anti-salt-calcium water-based drilling fluid comprises the following steps:

(1) The molar ratio of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, allyl polyethylene glycol, and trihydroxyethylallyl ammonium bromide is 8.1~20.2:9~15.2 : 2.1 ~ 4.3: 8 ~ 10 Weigh monomer raw materials;

(2) Dissolve 2-acrylamide-2-methylpropanesulfonic acid in deionized water, adjust the pH value of the solution to 7-8, and then add acrylamide, allyl polyethylene glycol, trihydroxyethyl Add allyl ammonium bromide into the solution, stir to dissolve evenly, and add molecular weight regulator, pass nitrogen to exhaust oxygen;

(3) After passing nitrogen for 30 minutes, heat up to 40°C-60°C, add an initiator until the total monomer concentration is 12.5%-25%, and react for 4-6 hours to obtain a gel solution;

(4) The gel solution is dissolved in an organic solvent to extract, purified, sheared, granulated, dried and crushed to obtain a quaternary copolymerization product.

As preferably, in the step (2), adjusting the pH value is realized by adding potassium hydroxide solution.

Preferably, in the step (2), the molecular weight regulator is at least one of C ₃ -C ₁₂ mercaptan compounds or isopropanol, and its added amount is 0.1 wt% - 1.0% of the total amount of polymerized monomers. wt%.

As preferably, in the step (3), the initiator is a redox initiation system, and the oxidizing agent in the initiator is selected from at least one of potassium persulfate, ammonium persulfate, and hydrogen peroxide; the reducing agent in the initiator is selected from At least one of sodium bisulfite, sodium thiosulfate, and tetramethylethylenediamine, the amount of initiator added is acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, allyl poly 0.2 wt% to 0.6 wt% of the total mass of ethylene glycol and trihydroxyethyl allyl ammonium bromide.

As preferably, the organic solvent in the step (4) is absolute ethanol.

The present invention also proposes the application of the above-mentioned amine-based polymer fluid loss reducer in drilling fluid.

The molecular structure of the fluid loss control agent prepared by the present invention has adsorption groups such as amide groups, ether bonds, hydroxyl groups, and quaternary ammonium groups, which can effectively adsorb on clay particles. At the same time, the hydration group sulfonic acid groups and hydroxyl groups can give clay particles Brings an adsorption hydration layer, enhances the dimensional stability of the dispersion system, effectively inhibits the coalescence of fine particles, and forms a dense mud cake, thereby achieving the effect of reducing fluid loss.

There is not only van der Waals force but also stronger electrostatic attraction between cationic quaternary ammonium groups and negatively charged clay particles on the surface, so it can be firmly adsorbed on the surface of clay particles, and it is not easy to desorb even at high temperatures. In addition, the quaternary ammonium ion group can be completely ionized in water, which can increase the stretching degree of the polymer molecular chain in aqueous solution. The steric hindrance produced by the long side chain of polyoxyethylene group can enhance the rigidity of the main chain, making it difficult to curl up and entangle, and also reduce the hydrolysis rate of the amide group, thereby improving the temperature resistance of the polymer. The sulfonic acid group has good stability and is not sensitive to high temperature and external cation attack, which is beneficial to enhance the high temperature resistance and salt calcium resistance of the copolymer. The amine-based polymer fluid loss control agent is based on the carbon-carbon main chain as the skeleton, and the macromolecular side chain as the branch chain, which slows down the degradation of the fluid loss control agent at high temperature, and is conducive to exerting its role in fluid loss control at high temperature.

The molecular weight of the amine-based polymer fluid loss reducer is moderate, and the viscosity of the drilling fluid will not be greatly affected after being added. Immediately adding barite and other weighting agents to increase the density of the drilling fluid, the viscosity of the drilling fluid does not increase much.

Description of drawings

Fig. 1 is an infrared spectrum analysis chart of the fluid loss control agent of the present invention.

detailed description

In order to allow those skilled in the art to understand the present invention more clearly and intuitively, the present invention will be further described below in conjunction with the accompanying drawings.

Example 1

An amine-based polymer fluid loss reducer for high-temperature and anti-salt-calcium water-based drilling fluids, composed of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, allyl polyethylene glycol, triethylene glycol The mole of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, allyl polyethylene glycol, trihydroxyethyl allyl ammonium bromide The ratio is 8.1～20.2:9～15.2:2.1～4.3:8～10, and the reaction formula is:

Wherein, m=40%～45%, n=40%～45%, p=1-m-n-q, q=8%～10%, and the molecular weight of allyl polyethylene glycol is between 400～1000, K 9 to 20, m, n, p, q represent mole percentage.

The preparation method of the amine-based polymer fluid loss reducer comprises the following steps: press acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, allyl polyethylene glycol, trihydroxyethylallyl bromide The molar ratio of ammonium chloride is 8.1~20.2:9~15.2:2.1~4.3:8~10 Weigh the monomer raw material; dissolve 2-acrylamido-2-methylpropanesulfonic acid in deionized water and oxidize it with hydrogen When the pH value of the potassium solution reaches 7-8, pour it into the reaction vessel and put in acrylamide, allyl polyethylene glycol, trihydroxyethyl allyl ammonium bromide in turn, stir and dissolve evenly; add C ₃ ～C ₁₂ sulfur Molecular weight modifier of alcohol compound or isopropanol, its addition amount is 0.1wt% ~ 1.0wt% of the total amount of polymerized monomers, then blow nitrogen to exhaust oxygen; after blowing nitrogen for 30 minutes, heat up to 40°C ~ 60°C, add The initiator of the redox initiation system is added in an amount of 0.2wt% to 0.6wt% of the total mass of raw materials, so that the total monomer concentration is 12.5% to 25%, and the reaction is 4 to 6 hours to obtain a gel solution; the gel solution Wash and purify with absolute ethanol, shear granulate, dry and pulverize to obtain the quaternary copolymerization product.

Structural characterization of the amino polymer fluid loss control agent obtained in Example 2

It can be seen from Figure 1 that 1044.28cm ^-1 is the characteristic absorption peak of -SO ³ - , indicating that the molecular structure of the polymer product contains sulfonic acid groups; 2920.67cm ^-1 is the bending vibration absorption peak of CH ₂ groups; 1660.47cm ^{- 1} is the C=O stretching vibration absorption peak of amide group; 1544.04cm ^-1 is the NH bond bending vibration and CN bond stretching vibration absorption peak in the secondary amide -CONH- group; 1397.41cm ^-1 is the _-CH3 Characteristic absorption peak; 1277.38cm ^-1 is CN stretching vibration absorption peak; 982.24cm ^-1 is bending vibration peak of =CH in RCH=CH ₂ ; 3400.21cm ^-1 is non-associated NH contraction vibration absorption peak; 1174.31cm There is a characteristic absorption peak at ^-1 , indicating that the product molecule contains etheroxy groups. 3262.82cm ^-1 is the stretching vibration peak of hydroxyl, and 954.26cm ^-1 is the absorption peak of quaternary ammonium salt ion N ⁺ stretching vibration. 1444.04cm ^-1 is the stretching vibration peak of -CH ₂ . It shows that the product molecule contains TAAC. In addition, there is no characteristic absorption peak of carbon-carbon double bond at 1680～1620cm ^-1 , indicating that the polymerization reaction is complete. Analyzing the infrared spectrum of the polymer, the polymer molecular chain contains the designed functional group. According to this, the structure of the target product is consistent with the molecular structure design.

Aqueous solution performance research of the amino polymer fluid loss reducer obtained in embodiment 3

Table 1: Rheology of Amine-Based Polymer Fluid Loss Control Agents

Addition amount of fluid loss control agent (wt%) 0.5 1.0 1.5 2 Apparent viscosity (mPa·s) 2.5 4.5 7.0 8.5 Plastic viscosity (mPa·s) 2.0 4.0 6.5 8.5

It can be seen from Table 1 that the viscosity of the polymer solution gradually increases with the increase in the amount of fluid loss control agent added. When the solution concentration is 2%, its apparent viscosity and plastic viscosity are only 8.5mPa·s, which shows that the viscosity enhancing effect of fluid loss control agent is limited.

Implementation Case 4 Research on Drilling Fluid Performance of Amino-Based Polymer Fluid Loss Control Agent

Base slurry: Add 4% calcium bentonite (conforming to the oil and gas industry standard SY/T 5060-93) into 1000ml warm water, add 2.4g of soda ash after stirring, stir at high speed for 2 hours, and maintain at room temperature for 24 hours to obtain the base slurry .

Weigh different amounts of fluid loss additives successively, dissolve them in 400ml of fresh water bentonite slurry, stir at high speed for 20 minutes, seal and maintain for 24 hours, take them out after hot rolling at 180°C for 16 hours, and test their rheological properties after cooling to room temperature. API fluid loss and high temperature and high pressure (HTHP) fluid loss. The results are shown in Table 2.

Table 2: Influence of the dosage of amino polymer fluid loss reducer on the rheology and fluid loss performance of drilling fluid

It can be seen from the experimental data that the addition of amine-based polymer fluid loss reducer can effectively reduce the water loss of freshwater base pulp. As the temperature increases, the API fluid loss and high temperature and high pressure (HTHP) fluid loss gradually decrease.

By comparing the apparent viscosity and plastic viscosity, it can be seen that with the increase of the copolymer concentration, the apparent viscosity and plastic viscosity of the drilling fluid increase gradually, but the increase range is not large, indicating that the copolymer has little influence on the viscosity of the drilling fluid system.

Implementation Case 5 Research on Drilling Fluid Performance of Amino-based Polymer Fluid Loss Control Agent

Add 1.5wt% fluid loss control agent to the base slurry, stir well, add a certain mass of barite weighting agent, use a density meter to measure its density, and measure various performance parameters of the weighted drilling fluid. The results are shown in Table 3.

Table 3: Rheology and fluid loss performance of drilling fluid with fluid loss reducer concentration of 1.5wt%

It can be seen from Table 3 that the addition of fluid loss control agent did not significantly increase the apparent viscosity and plastic viscosity of the drilling fluid. Even in heavy drilling fluids, the addition of fluid loss control agents did not cause a sharp increase in drilling fluid viscosity.

Implementation Case 6 Study on Salt Resistance Performance of Amino-Based Polymer Fluid Loss Control Agent

Add 1.5wt% fluid loss control agent to the base slurry, stir well, then add different concentrations of NaCl to study the salt resistance performance of the amine-based polymer fluid loss control agent. The results are shown in Table 4.

Table 4: Salt Resistance Performance of Amino Polymer Fluid Loss Control Agents

It can be seen from the table that the viscosity of the drilling fluid before and after aging decreases with the increase of NaCl. The addition of electrolyte compresses the electric double layer, the clay particles are prone to coalescence, and the dispersion of the drilling fluid is reduced, so the macroscopic performance is that the viscosity of the drilling fluid is reduced. The API fluid loss of the drilling fluid increased with the increase of NaCl, but no malignant fluid loss occurred, so it can be explained that the amine-based polymer fluid loss control agent has a strong salt resistance ability. Because the anion of the sulfonic acid group is very stable, it is less affected by external metal ions, so it has strong salt resistance. At the same time, the sulfonic acid group and the polyoxyethylene side chain have strong hydrophilicity and can still bring sufficient hydration film to the clay even in the electrolyte environment, ensuring that the drilling fluid system has good salt resistance.

Implementation Case 7 Study on Anti-calcium Performance of Amino-based Polymer Fluid Loss Control Agent

Add 1.5wt% fluid loss control agent to the base slurry, stir well, and then add different concentrations of CaCl ₂ to study the anti-calcium performance of the amine-based polymer fluid loss control agent. The results are shown in Table 5.

Table 5: Anti-calcium properties of amine-based polymer fluid loss control agents

It can be seen from the table that the viscosity of the drilling fluid decreases with the increase of the CaCl ₂ concentration, and the API fluid loss increases. It shows that the addition of CaCl ₂ intensifies the coalescence of clay particles and reduces the dispersion of drilling fluid. However, no malignant fluid loss occurred, indicating that the polymer drilling fluid has good anti-calcium performance.

Although the present invention has been described in detail with general descriptions and specific embodiments above, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, the modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the protection scope of the present invention.

Claims (8)

1. a kind of high-temperature resisting and salt-resisting calcium water-base drilling fluid with amine based polymer fluid loss additive it is characterised in that this amine based polymer The general structure of fluid loss additive is as follows：

Wherein, m=40%～45%, n=40%～45%, p=1-m-n-q, q=8%～10%, K is 9～20.

2. amine based polymer fluid loss additive according to claim 1 is it is characterised in that described amine based polymer fluid loss additive Mainly by acrylamide, 2- acrylamide-2-methylpro panesulfonic acid, allyl polyglycol, trihydroxyethyl allylic bromination ammonium It is prepared from for raw material, acrylamide, 2- acrylamide-2-methylpro panesulfonic acid, allyl polyglycol, trihydroxyethyl allyl The mol ratio of base ammonium bromide is 8.1～20.2：9～15.2：2.1～4.3：8～10, and the molecular weight of allyl polyglycol is Between 400～1000.

3. the preparation method of amine based polymer fluid loss additive according to claim 1 and 2 is it is characterised in that include as follows Step：

(1) acrylamide, 2- acrylamide-2-methylpro panesulfonic acid, allyl polyglycol, trihydroxyethyl allylic bromination are pressed The mol ratio of ammonium is 8.1～20.2：9～15.2：2.1～4.3：8～10 weigh raw material monomer；

(2) 2- acrylamide-2-methylpro panesulfonic acid is dissolved in deionized water, regulation solution ph to 7～8, then successively Acrylamide, allyl polyglycol, trihydroxyethyl allylic bromination ammonium are added in solution, stirring and dissolving uniformly, and adds Molecular weight regulator, logical nitrogen deoxygenation；

(3) lead to nitrogen and after 30 minutes, be warming up to 40 DEG C～60 DEG C, add initiator, be 12.5%～25% to total monomer concentration, Reaction obtains gel solution in 4～6 hours；

(4) will extract in gel solution organic solvent, shear granulation dries pulverizing after purification, obtain final product quarternary copolymerized product.

4. the preparation method of amine based polymer fluid loss additive according to claim 3 is it is characterised in that described step (2) In, adjust pH value and pass through to add potassium hydroxide solution to realize.

5. the preparation method of amine based polymer fluid loss additive according to claim 3 is it is characterised in that described step (2) In, molecular weight regulator is C₃～C₁₂At least one in sulfur alcohol compound or isopropanol, its addition is that polymerized monomer is total 0.1wt%～the 1.0wt% of amount.

6. the preparation method of amine based polymer fluid loss additive according to claim 3 is it is characterised in that described step (3) In, initiator is for the oxidant in redox initiation system, and initiator in potassium peroxydisulfate, ammonium persulfate, hydrogen peroxide At least one；Reducing agent in initiator be selected from sodium hydrogensulfite, sodium thiosulfate, in tetramethylethylenediamine at least one Kind, the addition of initiator is acrylamide, 2- acrylamide-2-methylpro panesulfonic acid, allyl polyglycol, trihydroxyethyl 0.2wt%～the 0.6wt% of allylic bromination ammonium gross mass.

7. the preparation method of amine based polymer fluid loss additive according to claim 3 is it is characterised in that described step (4) In organic solvent be absolute ethyl alcohol.

8. application in drilling fluid for the amine based polymer fluid loss additive according to claim 1 and 2.