CN111334261B - Preparation method of high-temperature-resistant binary copolymerization low-molecular-weight polyamine inhibitor for water-based drilling fluid - Google Patents

Abstract

The invention relates to a preparation method of a high-temperature-resistant binary copolymerization low-molecular-weight polyamine inhibitor for water-based drilling fluid. Mainly solves the problems of poor temperature resistance and poor stability of the existing inhibitor. The preparation method of the inhibitor is characterized in that a monomer A and a monomer N-vinyl pyrrolidone are subjected to multi-step reaction by a catalytic hydrogenation method under the action of metal catalysts such as sodium borohydride and Raney nickel according to a molar ratio of 1: 2-1: 10, and the low molecular weight polymer inhibitor is synthesized by an aqueous solution polymerization mode. The high-temperature-resistant binary copolymer low-molecular-weight polyamine inhibitor for the water-based drilling fluid has stronger temperature resistance and stability, can improve the inhibiting effect of the water-based drilling fluid on a shale stratum, improve the stability of a well wall, reduce underground complexity, and promote the progress of the water-based drilling fluid technology and the smooth oil-gas exploration.

Description

A kind of preparation method of high temperature resistant binary copolymer low molecular weight polyamine inhibitor for water-based drilling fluid

Technical field:

The invention relates to the technical field of synthesis and preparation of water-soluble organic polymers for oil drilling, in particular to a preparation method of a high temperature resistant binary copolymer low molecular weight polyamine inhibitor for water-based drilling fluids.

Background technique:

Instability of wellbore in shale formation is a technical problem often encountered in drilling engineering, causing at least about 600 million US dollars in losses to the world oil industry every year, and the time consumed accounts for about 5% to 6% of the total drilling time. According to statistics, mud shale formations account for 70% of the total drilled formations, and more than 90% of the wellbore instability problems occur in mud shale formations. Water-sensitive activated mudstone and soft mudstone are easily hydrated and swelled, leading to downhole complexities such as diameter shrinkage, collapse, bit mud bag and sticking. At the same time, the hydration and dispersion of activated mud shale will also cause the clay content in the drilling fluid to increase. The increase of micron and sub-micron solid phase particles leads to increased viscosity and performance of drilling fluids, and virtual mud cakes appear on the well wall. Hard and brittle mud shale will form relatively obvious bedding during the deposition process. The content of illite and illite mixed layers is high and the micro-fractures are very developed. After contacting with the drilling fluid, the filtrate will preferentially drain from the capillary and positive pressure difference. Micro-fractures with better permeability enter the formation, illite is prone to surface hydration, and the illite-Monomixed layer occurs interlayer spallation, resulting in an increase in formation pore pressure, and formation of micro-fractures to extend, expand and connect with each other, and eventually destroy the formation. The pressure balance leads to spalling, block drop and even well collapse.

Oil-based drilling fluids have unparalleled advantages over water-based drilling fluids in inhibiting the hydration and dispersion of shale, but oil-based drilling fluids have problems such as high cost and environmental hazards. In order to meet the requirements of environmental protection and reduce the cost of drilling fluids, a water-based drilling fluid system with oil-based drilling fluid performance has been developed at home and abroad, focusing on improving the anti-slump performance of water-based drilling fluids.

In recent years, some researchers at home and abroad have successively developed a series of high-performance water-based drilling fluid systems with performance equivalent to oil-based drilling fluids. One of the main ingredients of such drilling fluid systems is a new type of low molecular weight polymer inhibitor Agent - Amine compound inhibitor. Although this inhibitor has outstanding performance in inhibiting shale hydration, it is mostly formed by the polymerization of polyetheramines and alkylene oxides under the action of catalysts. It is easy to break, so its temperature resistance is generally low, mostly less than 150 ℃. Therefore, it is necessary to redesign the molecular structure of polyamine, improve its temperature resistance and stability, develop a high-efficiency shale inhibitor with stronger temperature resistance and stability, and promote the further development of water-based drilling fluid technology. Meet the exploration and development needs of deep and ultra-deep wells.

Invention content:

The present invention is to overcome the problems of poor temperature resistance and stability of existing inhibitors in the background technology, and provide a preparation method of a high temperature resistant binary copolymer low molecular weight polyamine inhibitor for water-based drilling fluids. High temperature resistant binary copolymer low molecular weight polyamine inhibitor for fluid, with stronger temperature resistance and stability, can improve the inhibitory effect of water-based drilling fluid on shale formations, improve wellbore stability, reduce downhole complexity, and promote water The advancement of drilling fluid technology and the smooth progress of oil and gas exploration.

The present invention solves its problem and can be achieved through the following technical solutions: the preparation method of the high temperature resistant binary copolymer low molecular weight polyamine inhibitor for the water-based drilling fluid comprises the following steps:

(1) Add monomer A, N-vinyl pyrrolidone monomer and initiator respectively in a molar ratio of 1:2-1:10 in a high-temperature and high-pressure reaction kettle, and stir and reflux at a temperature of 180-200 °C After 2 to 3 hours of reaction, the polymer intermediate M containing carbonyl groups on the main chain can be obtained;

(2) after cleaning and purifying the polymer intermediate M generated by the first step reaction, add it into a high-temperature and high-pressure reaction kettle, prepare an aqueous solution with a mass concentration of 2% to 5%, and use a sodium borohydride catalyst at 200 to 5%. Under the temperature condition of 220°C, high-purity hydrogen is introduced to stabilize the pressure between 1.8 and 2.2Mpa, and the intermediate N is generated by the method of catalytic hydrogenation;

(3) in the high temperature and high pressure reactor equipped with intermediate N, add a metal catalyst, and add a calculated amount of ethylenediamine, feed high-purity hydrogen to stabilize the pressure between 2.6～3.2Mpa, and heat up to 220～ 240 ℃ and keep it stable. After 4-5 hours of high temperature reaction under stirring, add molecular weight regulator. After cooling, after cooling, extraction and purification steps, a low molecular weight polyamine containing multiple primary amine groups can be finally obtained. Agent JY-2.

Described step (1) monomer A is a kind of in divinylbenzene, styrene, divinylethylene glycol, allyl alcohol; Step (1) initiator is potassium persulfate, sodium persulfate, ammonium persulfate one of the.

The metal catalyst in the step (3) is palladium or platinum catalyst; the molecular weight regulator in the step (3) is dodecyl mercaptan, diisopropyl xanthate disulfide, p-tert-butylbenzoic acid a kind of.

Compared with the above-mentioned background technology, the present invention can have the following beneficial effects:

(1) High temperature resistant binary copolymer low molecular weight polyamine inhibitor has good compatibility with water-based drilling fluid;

(2) The high temperature resistant binary copolymerization low molecular weight polyamine inhibitor has a very strong shale inhibitory ability, and the mudstone with a recovery rate of 6.8% clear water is calculated in terms of mass volume ratio. The hourly recovery rate is greater than 70%;

(3) The high-performance water-based drilling fluid constructed with high temperature resistant binary copolymer low molecular weight polyamine inhibitor as the main agent can resist temperature up to 200℃, has good inhibitory performance, and can effectively improve the wellbore stability of shale formations and the protective effect of reservoirs with higher shale content.

Description of drawings:

Accompanying drawing 1 is the infrared spectrogram of synthetic product amine inhibitor JY-2 in Example 1 of the present invention;

Accompanying drawing 2 TG thermal analysis curve of synthetic product amine inhibitor JY-2 of embodiment 1 of the present invention;

Accompanying drawing 3 embodiment of the present invention 1 synthetic product amine inhibitor JY-2 inhibits clay pulping experiment curve diagram;

Accompanying drawing 4 is a three-time rolling recovery experiment diagram of the synthetic product amine inhibitor JY-2 in Example 1 of the present invention.

Detailed ways:

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

Example 1:

Divinyl ethylene glycol, NVP monomer and potassium persulfate (0.02% of the total amount of monomers) were added to the high temperature and high pressure reactor at a molar ratio of 1:2, and the reaction was stirred and refluxed at a temperature of 180 to 200 °C. After 2 to 3 hours; use sodium borohydride as a catalyst, and under certain temperature and pressure conditions, adopt the method of catalytic hydrogenation to reduce all the carbonyl groups on divinyl glycol into hydroxyl groups; use palladium as a catalyst, add and calculate A good amount of ethylenediamine is introduced into high-purity hydrogen to stabilize the pressure between 2.6 and 3.2 Mpa, and the temperature is raised to 220 to 240 ° C and kept stable. Then, the amine-based inhibitor JY-2 containing multiple primary amine (-NH ₂ ) groups can be finally obtained. The preparation reaction is as follows:

1. The characterization analysis of the inhibitor JY-2 prepared in Example 1 is as follows:

1. Infrared spectroscopy (FT-IR) test

Using Nicolet-Nexus670 Fourier transform infrared spectrometer (scanning range of 400-4000cm ^-1 ), the synthesized product was tested by FT-IR by KBr tablet method, and the infrared spectrum was shown in Figure 1, as shown in Figure 1 , ^3371.94cm -1 is the non-associative NH contraction vibration absorption peak; 2989.56cm ^-1 is the stretching vibration absorption peak of CH ₂ group; 600-750cm ^-1 is the out-of-plane rocking vibration absorption band of -NH ₂ , 1270cm ^{- 1} is CN bond stretching vibration; 1690cm ^-1 is -CN- strong absorption peak; 900cm ^-1 , 1400cm ^-1 and 710cm ^-1 are the bending vibration absorption peaks of methyl/methylene. It can be seen that the molecular chain of the copolymer has the originally designed molecular groups, and does not contain easily broken ether-oxygen bonds, so the structure of the target product is consistent with the design.

2. Thermogravimetric (TG) test results

The thermal stability of JY-2 was determined by thermogravimetric synchronous analyzer. The experimental conditions for this analysis are as follows: under the protection of argon, the temperature range of thermal analysis is set to 30-600 °C, and the heating rate is 10 °C/min, and the TG thermal analysis curve is obtained in Figure 2. As shown in Figure 2, the product did not degrade significantly before the temperature reached 299.5 °C, indicating that the functional group of the product did not fail due to thermal degradation, and the product had good temperature resistance.

2. Inhibitory evaluation of the inhibitor JY-2 prepared in Example 1:

Microscopic analysis (X-ray diffraction analysis method) and macroscopic analysis (inhibition of clay pulping method, rolling recovery experiment) were used to evaluate the inhibition of JY-2, and the inhibition was compared with three similar products at home and abroad.

1. X-ray diffraction microscopic analysis method

Inhibitors were added to 3% sodium bentonite suspension respectively, stirred at high speed for 30 minutes and sealed for 24 hours. After high-speed centrifugation, the sediment at the bottom of the centrifuge tube was collected for wet X-ray diffraction analysis (XRD) to evaluate the concentration of inhibitors at different mass concentrations. The effect of the following on the clay interlayer spacing (d001). As shown in Table 1 below, when the amount of JY-2 is 0.5%, the interlayer spacing of sodium bentonite is reduced from 1.932nm (the interlayer spacing of sodium bentonite in clear water) to 1.418nm, and the reduced interlayer distance is related to the molecular diameter of JY-2. (0.502nm), and with the increase of the amount of JY-2, the interlayer spacing almost no longer changes, indicating that the adsorption capacity of JY-2 molecules is stronger than that of water molecules, and can be embedded in the sodium bentonite layer and adsorbed in the clay lattice. At the level, a "station" effect is formed to prevent water molecules from entering the interlayer, so as to achieve a good inhibitory effect. At the same time, JY-2 can inhibit the hydration of clay to the greatest extent when the dosage is very small, and the inhibition effect on the interlayer spacing of sodium bentonite is much better than that of PF-HCS and UHIB.

Table 1

2. Inhibition of clay pulping

In 400 mL of inhibitor solution with a mass concentration of 1%, add 5% soil powder, measure the rheology after aging at 150 °C for 16 hours, then add 5% soil powder and continue aging until the viscosity cannot be measured. As shown in Figure 3, take the apparent viscosity AV as the ordinate and the number of times of adding soil powder as the abscissa. From Fig. 3, it can be seen that the number of times of adding soil powder to the JY-2 solution is the most, and the growth trend of the apparent viscosity is the slowest, indicating that the synthesized JY-2 can effectively inhibit the hydration and dispersion of clay, and the anti-clay pollution ability is slightly higher than that of Ultrahib. During the process, it can effectively prevent the shale formation from shrinking in diameter and other complications.

3. Rolling recycling experiment

The mud shale cuttings (6-10 mesh) in a certain layer of Daqing Oilfield were selected, and three rolling recovery experiments (220 °C) were carried out with 1% mass concentration of polyamine and water respectively. The experimental results are shown in Figure 4. It can be seen from Figure 4 that the primary recovery rate of JY-2 is similar to Ultrahib, and much higher than the other two polyamine samples, indicating that JY-2 has the strongest inhibition; It is close to that of Ultrahib and other samples, indicating that JY-2 has firm adsorption on the surface of cuttings and has a long acting time, that is, JY-2 has strong long-term inhibition and can maintain long-term stability of the wellbore during drilling.

After the above microscopic and macroscopic analysis, it is known that the synthesized high temperature anti-high temperature binary copolymer low molecular weight polyamine inhibitor JY-2, its inhibitory property is similar to that of the foreign similar product Ultrahib, stronger than other polyamine products, and has a very strong inhibitory property. The ability to inhibit the hydration and dispersion of mud shale and the good ability to resist clay pollution, the long-term inhibition is outstanding.

3. Evaluation of drilling fluid compatibility with inhibitor JY-2 prepared in Example 1

JY-2 was used to replace the inhibitor in freshwater drilling fluid and KCl brine drilling fluid, and added to the system according to different dosages to measure drilling fluid rheology, filtration loss and rolling recovery rate. It can be seen from Table 2 below that after adding JY-2 to the fresh water system and the salt water system, it has no effect on the rheological properties of the drilling fluid, the filtration volume still has a downward trend, and the system inhibition is greatly improved, and when the addition amount is 1.5% , the system has the best inhibition, and increasing the dosage will only increase the cost of drilling fluid. Therefore, JY-2 has good compatibility with fresh water system and KCl brine system, and the recommended dosage in drilling fluid is 1.5%.

Table 2

Claims (2)

1. a preparation method of high temperature resistant binary copolymer low molecular weight polyamine inhibitor for water-based drilling fluid, is characterized in that: comprise the following steps: (1) Add monomer A, N-vinylpyrrolidone monomer and initiator accounting for 0.02% of the total amount of monomers in the high temperature and high pressure reaction kettle at a molar ratio of 1:2—1:10. At 180 After stirring and refluxing for 2 to 3 hours at a temperature of ~200°C, a polymer intermediate M containing carbonyl groups is obtained; the monomer A is a mixture of divinylbenzene, styrene, divinylethylene glycol, and acryl alcohol. a kind of; (2) After cleaning and purifying the polymer intermediate M generated by the first step reaction, add it into a high temperature and high pressure reaction kettle, and prepare an aqueous solution with a mass concentration of 2% to 5%. Under the temperature condition of 220°C, high-purity hydrogen is introduced to stabilize the pressure between 1.8~2.2Mpa, and the intermediate N is generated by the method of catalytic hydrogenation; (3) In the high-temperature and high-pressure reaction kettle equipped with intermediate N, add a metal catalyst, and add a calculated amount of ethylenediamine, feed high-purity hydrogen to stabilize the pressure between 2.6~3.2Mpa, and heat up to 220~ 240 ℃ and keep it stable. After 4~5 hours of high temperature reaction under stirring, molecular weight regulator is added. After cooling, extraction and purification steps, the low molecular weight polyamine inhibitor JY-2 containing multiple primary amine groups is finally obtained. The metal catalyst is a palladium or platinum catalyst; the molecular weight regulator is one of dodecyl mercaptan, diisopropyl xanthate disulfide and p-tert-butyl benzoic acid. 2. The preparation method of a high temperature resistant binary copolymerization low molecular weight polyamine inhibitor for water-based drilling fluid according to claim 1, characterized in that: the initiator in step (1) is potassium persulfate, sodium persulfate, One of the ammonium persulfate.

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