1. An environment-friendly multifunctional microemulsion viscosity reducer comprises the following components in percentage by mass: 15-25% of white oil, 15-20% of an improver, 5-10% of a dispersant, 6-20% of a mutual solvent and the balance of water.

2. The environment-friendly multifunctional microemulsion viscosity reducer as claimed in claim 1, which is characterized in that: the improver is binuclear copolymerized crosslinked polyether.

3. The environment-friendly multifunctional microemulsion viscosity reducer as claimed in claim 1, which is characterized in that: the white oil is any one of 5#, 8#, 10#, 15# or 20# white oil; the dispersant is isomeric dodecyl alcohol polyoxyethylene ether.

4. The environment-friendly multifunctional microemulsion viscosity reducer as claimed in claim 1, which is characterized in that: the mutual solvent is two compounds of diethylene glycol dibutyl ether and diethylene glycol monobutyl ether.

5. The environment-friendly multifunctional microemulsion viscosity reducer as claimed in claim 4, wherein: the compound ratio of the diethylene glycol dibutyl ether to the diethylene glycol monobutyl ether is 1: 1-5.

6. The preparation method of the environment-friendly multifunctional microemulsion viscosity reducer as claimed in claim 1, comprising the following steps:

firstly, adding white oil, improver binuclear copolymerized cross-linked polyether and dispersant isomeric dodecyl polyoxyethylene ether into a reaction kettle according to a certain proportion, and stirring to form an oil phase;

secondly, adding the mutual solvent diethylene glycol dibutyl ether, diethylene glycol monobutyl ether and water into a reaction kettle according to a proportion, and stirring to form a water phase;

and step three, completely adding the solution prepared in the step 1 into the solution prepared in the step 2, homogenizing and stirring, and changing the solution from turbid to clear to obtain the environment-friendly multifunctional microemulsion viscosity reducer.

7. The preparation method of the environment-friendly multifunctional microemulsion viscosity reducer as claimed in claim 6, wherein the preparation method comprises the following steps: the stirring time is 15-30 minutes.

8. The environment-friendly multifunctional microemulsion viscosity reducer as claimed in claim 1 is used for paraffin removal and viscosity reduction of high water-containing oil wells.

9. Use according to claim 8, characterized in that: the addition amount of the environment-friendly multifunctional micro-emulsion viscosity reducer is 5 ppm.

10. Use according to claim 8, characterized in that: the environment-friendly multifunctional microemulsion viscosity reducer is used for paraffin removal and viscosity reduction of a high-water-content oil well, and only needs to increase the dosage and change the dosage from 'wax prevention' to 'wax removal' without stopping the well, and then reduces the dosage and change the dosage from 'wax removal' to 'wax prevention' after a load current returns to normal.

Background art:

wax precipitation and pump blockage often occur in the oil extraction process, and the wax precipitation is caused by film adsorption and liquid drop adsorption. In order to block the adsorption process of asphalt, colloid and paraffin, the traditional viscosity reducer excessively emphasizes the emulsification effect, so that adverse effects are generated on the subsequent treatment of crude oil. Meanwhile, the conventional viscosity reducer is set at 40 ℃, and wax is crystallized if the temperature is too low, so that the viscosity reducer is not effective. Obviously, in cold northern areas, especially in wellhead locations, this condition is difficult to guarantee. In order to solve the problem, the paraffin removal viscosity reducer is frequently used, and the most commonly used oil-based paraffin removal viscosity reducer at present has quick response, good effect but is not suitable for high-water-content oil wells, and is low in specific gravity, inflammable, large in smell, high in aromatic hydrocarbon-containing toxicity and easy to cause cancer.

The invention content is as follows:

the invention aims to solve the problems that the existing oil-based paraffin removal viscosity reducer used in the prior art is not suitable for a high-water-content oil well and has high cost and potential safety hazard, and provides the environment-friendly multifunctional microemulsion viscosity reducer. The invention also provides a preparation method and application of the environment-friendly multifunctional microemulsion viscosity reducer.

The invention can solve the problems by the following technical scheme: an environment-friendly multifunctional microemulsion viscosity reducer comprises the following components in percentage by mass: 15-25% of white oil, 15-20% of an improver, 5-10% of a dispersant, 6-20% of a mutual solvent and the balance of water.

Preferably, the improver is binuclear copolymerized crosslinked polyether.

Preferably, the white oil is any one of 5#, 8#, 10#, 15# or 20# white oil; the dispersant is isomeric dodecyl alcohol polyoxyethylene ether.

Preferably, the mutual solvent is a compound of diethylene glycol dibutyl ether and diethylene glycol monobutyl ether.

Preferably, the compound ratio of the diethylene glycol dibutyl ether to the diethylene glycol monobutyl ether is 1: 1-5.

The invention also provides a preparation method of the environment-friendly multifunctional microemulsion viscosity reducer, which comprises the following steps:

firstly, adding white oil, improver binuclear copolymerized cross-linked polyether and dispersant isomeric dodecyl polyoxyethylene ether into a reaction kettle according to a certain proportion, and stirring to form an oil phase;

secondly, adding the mutual solvent diethylene glycol dibutyl ether, diethylene glycol monobutyl ether and water into a reaction kettle according to a proportion, and stirring to form a water phase;

and step three, completely adding the solution prepared in the step 1 into the solution prepared in the step 2, homogenizing and stirring, and changing the solution from turbid to clear to obtain the environment-friendly multifunctional microemulsion viscosity reducer.

Preferably, the stirring time is 15 to 30 minutes.

The invention also provides an environment-friendly multifunctional microemulsion viscosity reducer for paraffin removal and viscosity reduction of a high-water-content oil well; the addition amount of the environment-friendly multifunctional micro-emulsion viscosity reducer only needs to be 5 ppm; the environment-friendly multifunctional microemulsion viscosity reducer is used for paraffin removal and viscosity reduction of a high-water-content oil well, and only needs to increase the dosage and change the dosage from 'wax prevention' to 'wax removal' without stopping the well, and then reduces the dosage and change the dosage from 'wax removal' to 'wax prevention' after a load current returns to normal.

The microemulsion has ultralow interfacial tension, so that the microemulsion balls can achieve isotropy, are not bonded or agglomerated, have thermodynamic stability, and cannot be layered or demulsified after being placed for a long time. The particle size of the microemulsion globule is less than 10-50 nm, so the microemulsion is transparent or semitransparent; the particle size of the emulsion globule is 100-500 nm, so the system is turbid. Regarding the formation of microemulsion, the model of "instantaneous negative interfacial tension" is typical at present, and the theory is that the addition of mutual solvent can rapidly reduce the oil/water interfacial tension, even generate instantaneous negative interfacial tension, the instantaneously generated negative interfacial tension enables the system to form microemulsion, and the surfactant and mutual solvent are adsorbed on the oil/water interface to form an interface protection film, so that the stability of the system is enhanced.

The environment-friendly multifunctional microemulsion viscosity reducer has the effects that the white oil has the functions of penetration, dispersion and removal; diethylene glycol dibutyl ether and diethylene glycol monobutyl ether are used as mutual solvents, so that oil and water can be mutually dissolved, the stability of a system is enhanced, and the adsorption value of a surfactant can be reduced to the minimum by using the mutual solvents in the viscosity reduction process of an oil well; the binuclear copolymerized crosslinked polyether is an improver, can be adsorbed on the metal surface to form a polar surface so as to prevent the adsorption and deposition of non-polar wax crystals on the metal surface, and can also be adsorbed on the wax crystal surface to change the lattice characteristics, so that the effects of wax prevention and viscosity reduction are achieved; the isomeric dodecyl alcohol polyoxyethylene ether is a dispersant, and can reasonably configure the HLB value and the micelle concentration, thereby realizing the stability of the product. In the preparation process of the product, a phase inversion emulsification method is adopted, namely, oil-soluble white oil and a surfactant are mixed to form water-in-oil, then the water-in-oil is added into a water phase containing a mutual solvent to form oil-in-water, and uniform, stable and transparent microemulsion is finally formed through reverse emulsification and multiple emulsification.

The environment-friendly multifunctional microemulsion viscosity reducer is a water-soluble cleaning and preventing integrated agent, has a high flash point (>95 ℃), is non-toxic, tasteless, safe and environment-friendly, reduces the current of an oil well motor after field application, and has a good viscosity reduction effect. The agent contains wax crystal modifier and dispersant, the modifier is adsorbed on the metal surface to form polar surface and to prevent the adsorption and deposition of non-polar wax crystal on the metal surface, so as to prevent wax and reduce viscosity. When the wax block is added into an oil well, the wax block can be dispersed, so that crystal grains are thinned and are not easy to combine with each other to flow out of the oil well along with the oil well, or the wax block deposited on the well wall permeates into the oil well through gaps on the wax block, so that the adhesion force of the wax block and the well wall is weakened, the wax block on the well wall falls off, and the fallen wax block is continuously dispersed into small wax blocks or smaller wax crystals and is suspended in the liquid flow of the oil well to flow out of the oil well along with the liquid flow to play a role in removing wax and reducing viscosity.

Compared with the background technology, the invention has the following beneficial effects:

1. safety and environmental protection: the environment-friendly multifunctional microemulsion viscosity reducer has the advantages of high flash point (>95 ℃), no toxicity, no smell, absolute safety, environmental protection, high viscosity reduction rate and good use effect. The viscosity reducing effect of the thickened oil is remarkable, the viscosity reduction rate can reach more than 90 percent at most, and is more than two times of the viscosity reduction effect of the existing oil production viscosity reducer.

2. The use is simple and convenient: in the past, the well needs to be stopped when the phenomenon of wax deposition and pump blockage occurs, the paraffin removal viscosity reducer is added after hot washing, the labor and time are wasted, the yield is also influenced, the well does not need to be stopped when the environment-friendly multifunctional microemulsion viscosity reducer is used, the dosage is only required to be increased to change wax prevention into wax removal, and the dosage is reduced to change wax prevention from wax removal after the load current returns to normal. Taking the experimental well XFU 7-3-propyl 619 as an example, the average liquid production amount per day is 10m³5kg of the medicine is added every day, the load current is controlled to be below 50 (the current is controlled to be 30-50 generally, the medicine adding amount is controlled to be 3-5 kg/day, and the medicine is diluted by water and then injected into a shaft). When the load current is more than 55, the dosage is increased, 100-200 kg of the drug is injected at one time, and the wax is changed from 'preventing' wax to 'clear' wax. The agent is added from the oil sleeve into the air, so that the normal production and other operations of the oil well are not influenced. The microemulsion preparation not only has the effects of removing and preventing wax, but also has the effects of reducing coagulation, reducing viscosity and removing blockage. When the current is reduced to about 30, the normal dosage is restored to 5 kg/day, and the wax is changed from clear wax to anti-wax.

3. The cost is reduced: the dosage of the traditional like product is 10ppm (calculated according to the liquid production amount of the oil well), the viscosity reduction effect can be achieved by only adding 5ppm (calculated according to the liquid production amount of the oil well) into the environment-friendly multifunctional micro-emulsion viscosity reducer, the cost is obviously reduced, and if the traditional well stopping and operation cost during wax deposition and pump clamping is added, the comprehensive cost can be doubled.

Drawings

FIG. 1 is a process flow diagram of the present invention.

The specific implementation mode is as follows:

the invention is further illustrated by the following examples:

the environment-friendly multifunctional microemulsion viscosity reducer comprises the following components in percentage by mass: 15-25% of white oil, 15-20% of binuclear copolymerized crosslinked polyether, 5-10% of isomeric dodecyl alcohol polyoxyethylene ether, 1-10% of diethylene glycol dibutyl ether, 5-10% of diethylene glycol monobutyl ether and the balance of water.

The preparation process of the environment-friendly multifunctional micro-emulsion viscosity reducer product adopts a phase inversion emulsification method, namely, oil-soluble white oil and a surfactant are mixed to form water-in-oil, then the water-in-oil is added into a water phase containing a mutual solvent to form oil-in-water, and uniform, stable and transparent micro-emulsion is finally formed through reversed phase emulsification and multiple emulsification.

As shown in figure 1, the preparation method of the environment-friendly multifunctional microemulsion viscosity reducer comprises the following steps:

firstly, adding white oil, binuclear copolymerized cross-linked polyether and isomeric dodecyl polyoxyethylene ether into a reaction kettle according to a certain proportion, and stirring for 15-30 minutes; the step is to fully fuse oil and an emulsifier to form water-in-oil;

secondly, adding diethylene glycol dibutyl ether, diethylene glycol monobutyl ether and water into the reaction kettle according to the proportion, and stirring for 15-30 minutes; fully fusing a mutual solvent and water to form a water phase;

and step three, completely adding the solution prepared in the step 1 into the solution prepared in the step 2, homogenizing and stirring for 15-30 minutes until the solution is clear from turbid, thus obtaining the environment-friendly multifunctional microemulsion viscosity reducer. The oil phase is added into the water phase to form oil-in-water, the turbidity phenomenon occurs due to the larger particle size of the emulsion at the initial stage, the oil-water interfacial tension is rapidly reduced along with the full fusion of the oil phase and the water phase to generate the instantaneous negative interfacial tension, and a uniform, stable and transparent microemulsion system is finally formed through reverse emulsification and multiple emulsification. If coalescence of the microemulsion droplets occurs, the total interfacial area will be reduced, which in turn creates a transient interfacial tension, thereby counteracting coalescence of the microemulsion droplets. The mutual solvent in the water phase has strong solubilization, when strong interaction exists between the surfactant molecules, insoluble liquid crystal can be formed, and the mutual solvent can effectively prevent the formation of hard liquid crystal.

The invention also provides an environment-friendly multifunctional microemulsion viscosity reducer for paraffin removal and viscosity reduction of a high-water-content oil well. The addition amount of the environment-friendly multifunctional microemulsion viscosity reducer is 5ppm (calculated according to the liquid production amount of an oil well), the environment-friendly multifunctional microemulsion viscosity reducer is used for paraffin removal and viscosity reduction of a high-water-content oil well, the oil well does not need to be stopped, only the dosage needs to be increased, the dosage is changed from 'wax prevention' to 'clear wax', and the dosage is reduced after the load current returns to normal. Example 1:

according to the formula: 25% of No. 5 white oil, 20% of binuclear copolymerized crosslinked polyether, 10% of isomeric dodecyl alcohol polyoxyethylene ether, 10% of diethylene glycol dibutyl ether, 10% of diethylene glycol monobutyl ether and 25% of water, and weighing the components for later use;

a. adding 50ml of white oil into a 250ml three-neck flask, simultaneously adding 40ml of binuclear copolymerized cross-linked polyether and 20ml of isomeric dodecyl polyoxyethylene ether, and stirring for 15 minutes to prepare homogeneous liquid;

b. respectively adding 20ml of diethylene glycol dibutyl ether, 20ml of diethylene glycol monobutyl ether and 50ml of water into a 500ml homogenizing kettle, and stirring for 15 minutes to obtain transparent liquid;

c. and (c) adding the product obtained in the step (a) into the step (b), and homogenizing and stirring for 15 minutes to obtain the transparent and uniform micro-emulsion viscosity reducer.

Example 2:

according to the formula: 15% of No. 5 white oil, 15% of binuclear copolymerized crosslinked polyether, 5% of isomeric dodecyl alcohol polyoxyethylene ether, 5% of diethylene glycol dibutyl ether, 10% of diethylene glycol monobutyl ether and 50% of water, and weighing the components for later use;

a. adding 30ml of white oil into a 250ml three-neck flask, simultaneously adding 30ml of binuclear copolymerized cross-linked polyether and 10ml of isomeric dodecyl polyoxyethylene ether, and stirring for 15 minutes to prepare homogeneous liquid;

b. respectively adding 10ml of diethylene glycol dibutyl ether, 20ml of diethylene glycol monobutyl ether and 100ml of water into a 500ml homogenizing kettle, and stirring for 15 minutes to obtain transparent liquid;

c. and (c) adding the product obtained in the step (a) into the step (b), and homogenizing and stirring for 15 minutes to obtain the transparent and uniform micro-emulsion viscosity reducer.

Example 3

According to the formula: 20% of No. 5 white oil, 18% of binuclear copolymerized crosslinked polyether, 8% of isomeric dodecyl alcohol polyoxyethylene ether, 3% of diethylene glycol dibutyl ether, 9% of diethylene glycol monobutyl ether and 42% of water, and weighing the components for later use;

a. adding 40ml of white oil into a 250ml three-neck flask, simultaneously adding 36ml of binuclear copolymerized cross-linked polyether and 16ml of isomeric dodecyl polyoxyethylene ether, and stirring for 15 minutes to prepare homogeneous liquid;

b. respectively adding 6ml of diethylene glycol dibutyl ether, 18ml of diethylene glycol monobutyl ether and 84ml of water into a 500ml homogenizing kettle, and stirring for 15 minutes to obtain transparent liquid;

c. and (c) adding the product obtained in the step (a) into the step (b), and homogenizing and stirring for 15 minutes to obtain the transparent and uniform micro-emulsion viscosity reducer.

Example 4

According to the formula: 20% of No. 5 white oil, 18% of binuclear copolymerized crosslinked polyether, 8% of isomeric dodecyl alcohol polyoxyethylene ether, 2% of diethylene glycol dibutyl ether, 8% of diethylene glycol monobutyl ether and 44% of water, and weighing the components for later use;

a. adding 40ml of white oil into a 250ml three-neck flask, simultaneously adding 36ml of binuclear copolymerized cross-linked polyether and 16ml of isomeric dodecyl polyoxyethylene ether, and stirring for 15 minutes to prepare homogeneous liquid;

b. respectively adding 4ml of diethylene glycol dibutyl ether, 16ml of diethylene glycol monobutyl ether and 88ml of water into a 500ml homogenizing kettle, and stirring for 15 minutes to obtain transparent liquid;

c. and (c) adding the product obtained in the step (a) into the step (b), and homogenizing and stirring for 15 minutes to obtain the transparent and uniform micro-emulsion viscosity reducer.

Example 5

According to the formula: 18% of No. 5 white oil, 18% of binuclear copolymerized crosslinked polyether, 8% of isomeric dodecyl alcohol polyoxyethylene ether, 2% of diethylene glycol dibutyl ether, 10% of diethylene glycol monobutyl ether and 45% of water, and weighing the components for later use;

a. adding 36ml of white oil into a 250ml three-neck flask, simultaneously adding 36ml of binuclear copolymerized cross-linked polyether and 16ml of isomeric dodecyl polyoxyethylene ether, and stirring for 15 minutes to prepare homogeneous liquid;

b. respectively adding 4ml of diethylene glycol dibutyl ether, 20ml of diethylene glycol monobutyl ether and 90ml of water into a 500ml homogenizing kettle, and stirring for 15 minutes to obtain transparent liquid;

c. and (c) adding the product obtained in the step (a) into the step (b), and homogenizing and stirring for 15 minutes to obtain the transparent and uniform micro-emulsion viscosity reducer.

Example 6

According to the formula: 18% of No. 5 white oil, 18% of binuclear copolymerized crosslinked polyether, 7% of isomeric dodecyl alcohol polyoxyethylene ether, 5% of diethylene glycol dibutyl ether, 10% of diethylene glycol monobutyl ether and 42% of water, and weighing the components for later use;

a. adding 36ml of white oil into a 250ml three-neck flask, simultaneously adding 36ml of binuclear copolymerized cross-linked polyether and 14ml of isomeric dodecyl polyoxyethylene ether, and stirring for 15 minutes to prepare homogeneous liquid;

b. respectively adding 10ml of diethylene glycol dibutyl ether, 20ml of diethylene glycol monobutyl ether and 84ml of water into a 500ml homogenizing kettle, and stirring for 15 minutes to obtain transparent liquid;

c. and (c) adding the product obtained in the step (a) into the step (b), and homogenizing and stirring for 15 minutes to obtain the transparent and uniform micro-emulsion viscosity reducer.

The modifier binuclear copolymerized crosslinked polyether is produced by Daqing oil field development chemical company Limited.

The microemulsion viscosity reducer prepared in the embodiment 1-6 is used for viscosity reduction experiments of the four mine remaining oil layer numbers XFU-3-propyl 619 and XFU-7-3-SB624 in the four oil extraction plants of the Daqing oilfield, the load current is reduced to 26 from the original 51, and the effect is very obvious.

In the case of crude oil in which a certain amount of paraffin is dissolved, a so-called waxing phenomenon occurs as the temperature and pressure are lowered and gas is precipitated during the production. The wax deposition can block an oil production layer, reduce the yield of an oil well, and increase the load of the oil well at the same time, thereby causing production accidents. The medicament is added into a shaft, and is dissolved and mixed in shaft fluid, and then enters an oil pipe through a suction inlet to play a role of wax prevention.

Taking the experimental well XFU 7-3-propyl 619 as an example, the average liquid production amount per day is 10m³5kg of the medicine is added every day, the load current is controlled to be below 50 (the current is controlled to be 30-50 generally, the medicine adding amount is controlled to be 3-5 kg/day, and the medicine is diluted by water and then injected into a shaft). When the load current is more than 55, the dosage is increased, 100-200 kg of the drug is injected at one time, and the wax is changed from 'preventing' wax to 'clear' wax. The agent is added from the oil sleeve into the air, so that the normal production and other operations of the oil well are not influenced. The microemulsion preparation not only has the effects of removing and preventing wax, but also has the effects of reducing coagulation, reducing viscosity and removing blockage. When the current is reduced to about 30, the normal dosage is restored to 5 kg/day, and the wax is changed from clear wax to anti-wax.

The performance evaluation experiment of the environment-friendly multifunctional microemulsion viscosity reducer comprises the following steps:

the performance of the microemulsion viscosity reducer prepared in the embodiments 1-6 is evaluated by adopting the industrial standard ' technical conditions for cleaning and wax prevention for oil recovery ' SYT 6300-2009 ', and the evaluation result is compared with other 2 oil recovery viscosity reducers applied on site, and is listed in Table 1. In the past, when old viscosity reducers such as HY01 and 0KP-023 are used, the paraffin removal procedure is very complicated, and the cost is more than 20 ten thousand. The method comprises the steps of firstly judging the approximate position of wax deposition according to experience, wherein the most serious wax deposition is hard at a position 100-300 m away from a wellhead, a soft wax area is arranged at a 300-400 m well section, and a valve cover and an inlet are also the places which are most easy to wax deposition. And secondly, judging the specific position and form according to the indicator diagram. And thirdly, stopping the well, wherein the production is influenced when the well stopping procedure is complex each time, so that the paraffin is usually removed when the paraffin precipitation is serious, and mechanical paraffin removal, thermal paraffin removal and chemical paraffin removal are required all together. And fourthly, starting the well, and starting the well in time after the wax precipitation well is cleaned, wherein the wax precipitation is most easily caused in the well stopping stage.

TABLE 1

Wherein HY010 and KP-023 are respectively oil extraction viscosity reducers produced by Daqing Huaying chemical industry Co., Ltd.

The results show that the microemulsion viscosity reducer provided by the invention has good capacity of reducing the viscosity of the thick oil, has a remarkable effect of reducing the viscosity of the thick oil, has the viscosity reduction rate up to more than 90%, and is more than twice of the viscosity reduction effect of the conventional oil recovery viscosity reducers HY010 and KP-023.