CN106520085B - A kind of dendritic polyether shale inhibitor and preparation method and application - Google Patents

Abstract

The invention discloses a dendritic polyether shale inhibitor, a preparation method and application thereof. The inhibitor is a dendritic polyether mud shale inhibitor obtained by reacting an amino-terminated dendritic polymer with an alkylene oxide. The dendritic polyether mud shale inhibitor prepared by the present invention has excellent shale inhibition performance, can significantly inhibit the hydration expansion and dispersion of mud shale, and has a good synergistic inhibition effect with potassium salt, and has outstanding performance and environmental protection Good acceptability, long acting time and other advantages.

Description

A kind of dendritic polyether shale inhibitor and its preparation method and application

technical field

The invention relates to a mud shale inhibitor for drilling fluid, in particular to a dendritic polyether mud shale inhibitor, a preparation method and application thereof, and belongs to the field of petroleum engineering.

Background technique

Wellbore stability has always been a worldwide technical problem in oil and gas drilling engineering. According to statistics, about 75% of the drilled formations are mud shale formations, and 90% of wellbore instability problems occur in mud shale formations. Shale hydration is one of the main causes of wellbore instability. For a long time, people have carried out a lot of research on the hydration mechanism of shale, and put forward corresponding technical countermeasures, and successively developed various types of shale inhibitors, such as inorganic salts, cationic polymers, modified asphalt, amphoteric Ionic polymers, methyl glucosides, silicates, positive gels, polymeric alcohols, organic salts, organic amines, etc. Different anti-slump water-based drilling fluid systems have been constructed with the above-mentioned inhibitors as the main treatment agents, and the field application has achieved some success, but there are still various limitations. For example, although potassium chloride has excellent inhibitory properties, its use concentration is too high, which easily interferes with mud logging and has an impact on the environment; asphalt products have environmental problems; silicate has excellent plugging inhibition performance, but its rheology is easy Affected by pH; the amount of glucoside treatment agent is large. Therefore, it is still necessary to develop new and efficient shale inhibitors.

Dendritic polymers appeared in the mid-1980s. They are a new class of three-dimensional, highly ordered polymers that can control and design molecular size, shape, structure and functional groups at the molecular level. Dendritic polymers mainly have the following structural characteristics: (1) precise molecular structure, (2) high geometric symmetry, (3) a large number of functional groups, (4) cavity in the molecule, (5) relative molecular mass has Controllability, (6) The molecules themselves are nanometer-sized. The above-mentioned structural characteristics of dendrimers have some special properties and functions, thus showing potential application value in different fields, and have attracted the attention of many researchers. In the field of drilling fluids, people have also begun to try to use dendritic polymers to inhibit shale hydration expansion and dispersion.

Chinese patent document CN 103917623 A discloses the use of a hyperbranched polylysine in the development, exploitation and completion of underground mineral oil and natural gas deposits and in deep wells, especially in water-based drilling magma, completion fluid or stimulation Use as a shale inhibitor in liquid. The inhibitor has excellent performance, is non-toxic, biodegradable, and does not accumulate in organisms.

Chinese patent document CN 104130758 A discloses a dendritic polyamine-based polymer drilling fluid for mud rock drilling. It is composed of dendritic polyamine-based polymer, drilling fluid bentonite, soda ash, polymer coating agent, potassium polyacrylate, hydrolyzed polyacrylonitrile ammonium salt, anti-mud bag lubricant and water. The use of polyamine-based dendritic polymers can improve the inhibition of drilling fluids, and can also greatly improve the inhibition of drilling fluids on clay and cuttings, reduce the plasticity of clay rocks, avoid water absorption and dispersion of clay rocks, reduce friction, and prevent The mud bag of the drill bit is beneficial to improve the ROP and ensure the safety of the downhole.

Chinese patent document CN 104250380 A discloses a dendritic polymer and a dendritic polymer monomer as well as a preparation method and application thereof. The dendritic polymer monomer can be used as a comonomer to prepare hyperbranched polymers for oilfields, and the obtained hyperbranched polymers can be used as drilling fluid inhibitory fluid loss reducers, flocculants, coating agents, and temperature-resistant and salt-resistant polymers Oil displacement agent, fracturing fluid thickener, etc. This monomer can also be used to prepare branched water-soluble polymer quaternary emulsion polymerization internal surfactant for other purposes.

Chinese patent document CN 104250358 A discloses a hyperbranched copolymer and its preparation method and application. The apparent viscosity of the 1 mass % aqueous solution of the hyperbranched copolymer is 20-60mPa.s, and it has good filter reduction under high temperature (180°C) high salt (saturated brine) and high calcium (10% calcium chloride) conditions Loss characteristics, while ensuring good suppression ability of drilling fluid, it has no adverse effect on the filtration loss of drilling fluid.

Chinese patent document CN 104449596 A discloses a polyether polyol shale inhibitor and its preparation and application. Using polyol as the starting agent, using KOH as the catalyst, adding polyethylene oxide (EO) and propylene oxide (PO), after the reaction, it is neutralized with acid, adsorbed by adsorbent, and filtered with a filter to make drilling fluid Shale inhibitor polyether polyol is used; the polyether polyol shale inhibitor has various functions such as inhibiting clay hydration expansion, stabilizing the well wall, improving the lubrication performance of drilling fluid, and preventing drill bits from bagging, etc., and is low-toxic, easy to Biodegradable, in line with environmental protection technical requirements.

According to the characteristics of dendritic polymers, Amanullah (SPE164162, 2013) analyzed that: the three-dimensional nano-spherical structure of dendritic polymers provides the basis for effectively plugging micro-nano pores and cracks in shale; there are a large number of functional groups on the surface of dendritic polymers, For example, modifying cationic groups can form multi-point strong adsorption on the surface of mud shale, which can effectively inhibit the hydration and dispersion of mud shale. In addition, by encapsulating special small molecular compounds in the inner cavity of dendrimers, or modifying the functional groups on the outer surface to endow dendrimers with special functions such as self-assembly behavior and environmental responsiveness, it will provide diversified ways to stabilize the well wall. From this, Amanullah predicted that dendritic polymers have great application potential in inhibiting the hydration of the inner and outer surfaces of shale, improving the efficiency of shale membranes, retarding or even eliminating pore pressure transmission, prolonging the inhibition timeliness, and strengthening the wellbore while drilling. , and provides the possibility for the future development of "smart" drilling fluid.

Although a lot of research has been carried out on polyether polyols as shale inhibitors for drilling fluids, linear polyethers are generally used, and the dosage is often large, and the inhibitory performance is still not ideal. In addition, because it is easy to cause drilling fluid foaming and viscosity increase, it will have an adverse effect on drilling fluid rheology and fluid loss. Therefore, aiming at the shortage of current polyether shale inhibitors, we developed an environment-friendly dendritic polyether shale inhibitor to solve the problem of strong activity Wellbore stability in shale formations.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a dendritic polyether shale inhibitor and its preparation method and application. The dendritic polyether shale inhibitor has the advantages of less dosage, excellent inhibitory performance, environmental acceptability and the like.

Technical scheme of the present invention is as follows:

The invention relates to a dendritic polyether mud shale inhibitor, which is a modified product obtained by reacting an amino-terminated dendritic polymer with an alkylene oxide.

Preferably according to the present invention, the amine-terminated dendrimers are polypropyleneimine dendrimers (PPI) or polyamidoamine dendrimers (PAMAM).

Preferably, the generation number of the polypropyleneimine dendritic polymer is from generation 0 (G0) to generation 5 (G5); the generation number of the polyamide-amine dendritic polymer is generation 0 (G0) to generation 5 (G5) .

Further preferably, the generation number of the polypropyleneimine dendritic polymer is from generation 0 (G0) to generation 3 (G3); the generation number of the polyamide-amine dendritic polymer is generation 0 (G0) to generation 3 (G3 ).

Preferably according to the present invention, the central initiator core of the amine-terminated dendritic polymer is ethylenediamine, propylenediamine, butylenediamine, pentamethylenediamine, hexamethylenediamine or ammonia.

Preferably according to the present invention, the alkylene oxide is one or a combination of ethylene oxide or propylene oxide.

Preferably according to the present invention, the dendritic polyether shale inhibitor is light yellow viscous liquid or light yellow solid.

A preparation method of dendritic polyether mud shale inhibitor, comprising steps as follows:

Under vacuum conditions, the amino-terminated dendritic polymer and the alkylene oxide react under the action of the catalyst, and the reaction is stopped after the pressure in the reactor drops to a constant value; after aging, cooling, discharging, acid neutralization, and desalination, the Dendritic polyether mud shale inhibitor was obtained.

Preferably according to the present invention, the catalyst is one or a combination of two or more of sodium hydroxide, potassium hydroxide or sodium ethoxide.

Preferably according to the present invention, the mass ratio of the amine-terminated dendritic polymer to the catalyst is: 100:0.1 to 100:1; preferably, the mass ratio of the amine-terminated dendritic polymer to the catalyst is: 100:0.1 ～100:0.5; the molar concentration ratio of described amine-terminated dendrimer and alkylene oxide is: 1:(the number of terminal amine groups of 4×amine-terminated dendrimer)～1:(20×terminal amine number of terminal amine groups of the base dendrimers).

Preferably, according to the present invention, the reaction temperature is 90-150°C; preferably, the reaction temperature is 110-130°C.

Preferably according to the present invention, the acid neutralization is neutralization with glacial acetic acid or phosphoric acid.

Preferably according to the present invention, the aging time is 1 h.

Preferably according to the present invention, the preparation method of described dendritic polyether mud shale inhibitor comprises steps as follows:

Add the amine-terminated dendritic polymer and the catalyst into the reactor, purge with nitrogen, and evacuate; heat up to 60-80°C, add alkylene oxide, react at 90-150°C, and wait until the pressure in the reactor drops When the temperature is constant, the reaction is stopped; after aging, cooling, discharging, acid neutralization, and desalination, the dendritic polyether shale inhibitor is obtained.

Preferably, the adding rate of the alkylene oxide is 1-10 g/min.

Preferably according to the present invention, the preparation method of described dendritic polyether mud shale inhibitor comprises steps as follows:

Add the amine-terminated dendritic polymer and the catalyst into the reactor, purge with nitrogen, and evacuate; heat up to 60-80°C, add propylene oxide, and react at a temperature of 90-150°C; wait until the pressure in the reactor drops To a constant temperature, lower the temperature to 60-80°C, add ethylene oxide, react at a temperature of 90-130°C, stop the reaction after the pressure in the reactor drops to a constant level; after aging, cooling, discharging, acid neutralization, and desalination The dendritic polyether mud shale inhibitor is obtained.

Preferably, the molar concentration ratio of propylene oxide to ethylene oxide is 1:1˜1:10.

Preferably, the adding rate of the propylene oxide is 1-8 g/min, and the adding rate of the ethylene oxide is 1-10 g/min.

An application of a dendritic polyether mud shale inhibitor, wherein the dendritic polyether mud shale inhibitor is applied in drilling fluid in conjunction with potassium salt.

Preferably according to the present invention, the potassium salt is one or a combination of two or more of potassium chloride, potassium bromide, potassium iodide, potassium sulfate, potassium carbonate, potassium nitrate, potassium formate, potassium acetate or potassium citrate.

Preferably according to the present invention, the mass concentration of the dendritic polyether shale inhibitor in the drilling fluid is 0.1-5wt%, and the mass concentration of the potassium salt is 0.5-15wt%; preferably, the dendritic polyether shale inhibitor in the drilling fluid The mass concentration of the polyether shale inhibitor is 0.5-3 wt%, and the mass concentration of the potassium salt is 3-10 wt%.

According to the present invention, the amine-terminated dendrimers can be purchased from the market, or can be prepared according to the prior art, for reference: Chinese patent documents 201110073112.6, 201010586069.9 and 201210290336.7.

The main mechanism of action of dendritic polyether shale inhibitor of the present invention to inhibit hydration expansion and dispersion of shale is as follows:

(1) The amine-terminated dendritic polymer introduces a large amount of hydroxyl groups by reacting with alkylene oxides, and the large amount of hydroxyl groups contained on the surface can be adsorbed on the clay surface, displacing the water molecules adsorbed on the clay surface; (2) when potassium ions exist Potassium ions compress the clay to diffuse the electric double layer, reduce the hydration repulsion of clay particles, and facilitate the formation of a stable single-layer adsorption of dendritic polyether shale inhibitors on the clay surface, weakening the hydration of clay particles; (3) Significantly different from linear polymers, a large number of functional groups on the surface of dendritic polyether make it more strongly interact with the clay surface; (4) Similar to polyalcohols, dendritic polyether mud shale inhibitors also interact with potassium ions There is a synergistic inhibitory effect between them. Accordingly, the dendrimers according to the invention have outstanding inhibitory properties.

Compared with the prior art, the present invention has the following advantages:

(1) The dendritic polyether mud shale inhibitor prepared by the present invention can effectively inhibit the hydration expansion and dispersion of mud shale (especially active mud shale);

(2) dendritic polyether mud shale inhibitor prepared by the present invention has a low use concentration;

(3) Due to the presence of a large number of hydroxyl groups on the outer surface of the dendritic polyether mud shale inhibitor prepared by the present invention, it can be adsorbed on the mud shale surface through multiple points, which can effectively inhibit the hydration and dispersion of mud shale, and is not easy to desorb , so it can play a long-term effect.

(4) The dendritic polyether mud shale inhibitor prepared by the present invention can act synergistically with potassium ions, showing outstanding inhibitory performance.

Description of drawings

Fig. 1 is the infrared spectrogram of the dendritic polyether shale inhibitor prepared in Example 1.

Fig. 2 is the infrared spectrogram of the dendritic polyether shale inhibitor prepared in Example 2.

Detailed ways

The present invention will be further described below in conjunction with specific examples, but not limited thereto.

At the same time, the experimental methods described in the following examples, unless otherwise specified, are conventional methods; the reagents and materials, unless otherwise specified, can be obtained from commercial sources.

With ethylenediamine as the initiator nucleus, methyl acrylate and ethylenediamine as the reaction raw materials, Michael addition reaction and amidation reaction are alternately carried out to obtain polyamide-amine dendrimers of different generations (PAMAM-Gn, n is Algebra), the specific synthesis steps refer to Chinese patent document CN201110073112.6.

With ethylenediamine as the initiator nucleus and acrylonitrile as the repeating unit, the N-alkylation reaction and the reduction reaction of polynitriles are alternately repeated to obtain polypropyleneimine dendrimers of different generations (PPI-Gn, n is the generation number ), its synthesis method refers to Chinese patent documents CN201010586069.9 and 201210290336.7.

Example 1

Add 0.1mol (51.6g) initiator GOPAMAM (ethylenediamine as the core) polyamide-amine dendritic polymer and 0.2g potassium hydroxide in a 250mL high-temperature and high-pressure reactor, and purge the pipeline with nitrogen gas after sealing and react kettle 3 times, and then vacuumize the inside of the reactor. Heat the reaction kettle, and when the temperature rises to 80°C, slowly add 1.2mol (52.8g) of ethylene oxide through the metering tank, and add all the ethylene oxide in 10 minutes. After all the ethylene oxide was added, the temperature was raised to 110°C and the temperature was kept stable. When the pressure in the kettle dropped to a constant value, it indicated that the reaction was over. Pass circulating water to cool to room temperature, release the pressure and discharge the material, neutralize the reaction product with acetic acid, desalt by suction filtration, dendritic polyether mud shale inhibitor.

The synthetic route is as follows:

The infrared spectrum of the dendritic polyether shale inhibitor prepared in this example is shown in Figure 1. It can be seen from Figure 1 that 3380cm ^-1 is the OH stretching vibration absorption peak, 2920cm ^-1 is the CH stretching vibration absorption peak, 1650cm ^-1 is the C=O stretching vibration absorption peak (amide I peak), and 1560cm ^-1 is the CNH bending Vibration absorption peak (amide II peak), 1100cm ^-1 is the CO stretching vibration absorption peak, indicating that GOPAMAM reacted with ethylene oxide to obtain the target product.

The same method can be used to prepare polyamide-amine modified dendritic polyether shale inhibitors of different generations, which are respectively marked as PAMAM-G0-E, PAMAM-G1-E and PAMAM-G2-E.

Example 2

Add 0.1mol (28.8g) starter GOPPI (ethylenediamine as the core) polypropyleneimine dendritic polymer and 0.1g potassium hydroxide in a 250mL high-temperature and high-pressure reactor, and purge the pipeline and reaction with nitrogen gas after sealing. kettle 3 times, and then vacuumize the inside of the reactor. Heat the reaction kettle, and when the temperature rises to 70°C, slowly add 0.8mol (46.4g) of propylene oxide through the metering tank. After all the addition is completed within 10 minutes, the temperature is raised to 130°C and the temperature is kept stable. When the pressure in the reactor does not change any more, cool down to about 60°C with circulating water, then add 0.8mol (35.2g) of ethylene oxide through the metering tank, and after adding all of it within 10 minutes, raise the temperature to 110°C and keep the temperature stable . As the reaction proceeds, the pressure in the reactor drops, and when the pressure drops to a constant value, it indicates that the reaction is over. Pass circulating water to cool to room temperature, release the pressure and discharge the material, neutralize the reaction product with acetic acid, filter and desalt with suction to obtain dendritic polyether shale inhibitor.

The synthetic route is as follows:

The infrared spectrum of the dendritic polyether shale inhibitor prepared in this example is shown in Figure 2. It can be seen from Figure 2 that 3360cm ^-1 is the absorption peak _of OH stretching vibration, 2970cm ^-1 is the absorption peak of _-CH stretching vibration, 2930cm ^-1 is the absorption peak of -CH stretching vibration, and 1570cm ^-1 is the absorption peak of CNH bending vibration (Amide II peak), 1470cm ^-1 and 1380cm ^-1 are C-CH asymmetric and symmetric bending vibration absorption peaks respectively, _and 1100cm ^-1 is CO stretching vibration absorption peak, indicating that GOPPI is compatible with propylene oxide and ethylene oxide A reaction took place and the target product was obtained.

Polypropyleneimine-modified dendritic polyethers of different generations can be prepared by the same method, which are respectively marked as PPI-G0-PE, PPI-G1-PE and PPI-G2-PE.

Test example 1

inhibitory evaluation

The dendritic polyether mud shale inhibitors prepared in Examples 1 and 2 were evaluated experimentally by using bentonite slurry-making experiments and shale rolling dispersion experiments.

1. Inhibition of bentonite slurry experiment

The step of inhibiting bentonite slurrying experiment is: add 4g dendritic polyether mud shale inhibitor prepared by the present invention in 400mL tap water, add 10g sodium-based bentonite (Shandong Huawei Bentonite Co., Ltd.) for drilling fluid after stirring and dissolving. After stirring at 10000rpm for 20min, the slurry was transferred into an aging tank, heated at 70°C for 16h, then taken out of the aging tank, and cooled to room temperature. After stirring at 10000rpm for 10min, the rheology of the slurry was tested with a ZNN-D6 six-speed rotational viscometer. Then add 10g of sodium bentonite for drilling fluid, heat roll at 70°C for 16h, take out the aging tank, cool to room temperature, stir at 10000rpm for 10min, and test the rheology of the slurry. Repeat the above experimental steps until the viscosity of the slurry exceeds the measuring range of the instrument.

In order to investigate the synergistic effect of dendritic polyether shale inhibitor and potassium salt, the performance of dendritic polyether shale inhibitor and KCl in inhibiting bentonite slurry was tested, and the amount of KCl added was 12g.

Table 1 is the change of the readings of different systems with the addition of bentonite

Table 2 is the change of the readings of different systems with the addition of bentonite

Table 3 is the change of the readings of different systems with the addition of bentonite

Table 4 is the change of the readings of different systems with the addition of bentonite

From table 1 and table 3 test results, after adding the dendritic polyether mud shale inhibitor prepared by the present invention, compared with blank sample, along with the increase of bentonite addition, 600 turn readings, 300 turn readings and 3 The relatively slow increase in the number of rotations indicates that the prepared dendritic polyether can relatively effectively inhibit the hydration swelling and dispersion of clay. From the test results of Table 2 and Table 4, it can be seen that after the dendritic polyether prepared by the present invention is compounded with KCl, as the amount of bentonite increases, the 600-turn reading, 300-turn reading and 3-turn reading increase very slowly, and obviously It is better than the system with KCl added alone. It shows that the prepared dendritic polyether can effectively play a synergistic effect after compounding with KCl, and effectively inhibit the hydration expansion and dispersion of shale.

2. Shale rolling dispersion experiment

The steps of the shale rolling dispersion experiment are as follows: add a certain amount of dendritic polyether mud shale inhibitor prepared by the present invention in 350mL tap water, transfer the solution to the aging tank after stirring and dissolving, and simultaneously add 50g of 5mm cuttings (taken from the third member of the Shahejie Formation in Shengli Oilfield). After hot rolling at 77°C for 16 hours, the cuttings were washed with standard brine and passed through a 40-mesh standard sieve, and the residue was dried at 105°C for 4 hours and then weighed. The ratio of the dried cuttings mass to the initial mass was the cuttings recovery rate, Expressed as a percentage.

In order to investigate the synergistic effect of dendritic polyether and potassium salt, the recovery rate of cuttings when dendritic polyether is used in conjunction with KCl is tested, and the amount of KCl added is 10.5g

Table 5 Cuttings recovery rate of different shale inhibitors

testing sample Cuttings recovery rate (%) testing sample Cuttings recovery rate (%) blank sample 20.6 3% KCl 43.4 1% PAMAM-G0-E 41.6 1%PAMAM-G0-E+3%KCl 56.0 1%PAMAM-G1-E 43.0 1%PAMAM-G1-E+3%KCl 58.2 1%PAMAM-G2-E 46.4 1%PAMAM-G2-E+3%KCl 65.3

Note: The cuttings used are 3170m cuttings from a well in Tahe Oilfield.

Table 6. Cuttings recovery rate of different shale inhibitors

Note: The cuttings used are 2900m cuttings from a well in Tahe Oilfield.

As can be seen from Tables 5 and 6, the dendritic polyether mud shale inhibitor of the present invention can effectively inhibit the hydration expansion and dispersion of mud shale, and compared with clear water, the cuttings recovery rate is significantly improved; when combined with KCl After use, the recovery rate of cuttings is further improved, indicating that the two have a significant synergistic effect.

Claims (12)

1. a dendritic polyether mud shale inhibitor, is characterized in that, this inhibitor is the modified product that obtains by the reaction of amine-terminated dendrimers and alkylene oxide; The molar concentration ratio of the amino-terminated dendrimers and alkylene oxides is 1:12 or 1:16; The amine-terminated dendrimers are polypropyleneimine dendrimers (PPI) or polyamide-amine dendrimers (PAMAM). 2. dendritic polyether shale inhibitor according to claim 1, is characterized in that, the generation number of described polypropylene imine dendrimers is 0 generation (G0) to 5 generation (G5); Polyamide - The generation numbers of the amine dendrimers are from generation 0 (G0) to generation 5 (G5). 3. The dendritic polyether shale inhibitor according to claim 1, characterized in that, the alkylene oxide is one or a combination of ethylene oxide or propylene oxide. 4. The dendritic polyether shale inhibitor according to claim 1, characterized in that, the dendritic polyether shale inhibitor is light yellow viscous liquid or light yellow solid. 5. the preparation method of dendritic polyether shale inhibitor as described in any one of claim 1-4, comprises steps as follows: Under vacuum conditions, the amino-terminated dendritic polymer and the alkylene oxide react under the action of the catalyst, and the reaction is stopped after the pressure in the reactor drops to a constant value; after aging, cooling, discharging, acid neutralization, and desalination, the Obtain dendritic polyether mud shale inhibitor; The molar concentration ratio of the amino-terminated dendrimers and alkylene oxides is 1:12 or 1:16; The amine-terminated dendrimers are polypropyleneimine dendrimers (PPI) or polyamide-amine dendrimers (PAMAM). 6. the preparation method of dendritic polyether shale inhibitor according to claim 5, is characterized in that, described catalyzer is the combination of one or more in sodium hydroxide, potassium hydroxide or sodium ethylate . 7. The preparation method of dendritic polyether shale inhibitor according to claim 5, characterized in that, the mass ratio of the amine-terminated dendritic polymer to the catalyst is: 100:0.1˜100:1. 8 . The preparation method of dendritic polyether shale inhibitor according to claim 5 , characterized in that, the reaction temperature is 90-150° C.; the aging time is 1 h. 9. the preparation method of dendritic polyether mud shale inhibitor according to claim 5, is characterized in that, the preparation method of described dendritic polyether mud shale inhibitor comprises steps as follows: Add the amine-terminated dendritic polymer and the catalyst into the reactor, purge with nitrogen, and evacuate; heat up to 60-80°C, add alkylene oxide, react at 90-150°C, and wait until the pressure in the reactor drops To constant, stop the reaction; after aging, cooling, discharging, acid neutralization and desalination, the dendritic polyether shale inhibitor is obtained; The adding rate of the alkylene oxide is 1-10 g/min. 10. the preparation method of dendritic polyether mud shale inhibitor according to claim 5, is characterized in that, the preparation method of described dendritic polyether mud shale inhibitor, comprises steps as follows: Add the amine-terminated dendritic polymer and the catalyst into the reactor, purge with nitrogen, and evacuate; heat up to 60-80°C, add propylene oxide, and react at a temperature of 90-150°C; wait until the pressure in the reactor drops To a constant temperature, lower the temperature to 60-80°C, add ethylene oxide, react at a temperature of 90-130°C, stop the reaction after the pressure in the reactor drops to a constant level; after aging, cooling, discharging, acid neutralization, and desalination The obtained dendritic polyether shale inhibitor; The molar concentration ratio of the propylene oxide and ethylene oxide is 1:1～1:10; The adding rate of the propylene oxide is 1-8 g/min, and the adding rate of the ethylene oxide is 1-10 g/min. 11. the application of dendritic polyether mud shale inhibitor as described in any one of claim 1-4, described dendritic polyether mud shale inhibitor cooperates and is applied in drilling fluid with potassium salt; The mass concentration of the dendritic polyether shale inhibitor in the liquid is 0.1-5wt%, and the mass concentration of the potassium salt is 0.5-15wt%. 12. the application of dendritic polyether shale inhibitor according to claim 11, is characterized in that, in the described drilling fluid, dendritic polyether shale inhibitor mass concentration is 0.5～3wt%, and the potassium salt The mass concentration is 3-10wt%.