CN111604002A - A dispersant for shale gas oil-based drilling cuttings degreasing - Google Patents

Abstract

This invention relates to a dispersant for oil removal from shale gas and oil-based drill cuttings. The dispersant raw materials, by mass, consist of 10-40 parts inorganic alkali, 0.01-2 parts organic alkali, 0.01-2 parts surfactant, 0.01-0.5 parts defoamer, and 5-30 parts sodium hexametaphosphate. After mixing the oil-based drill cuttings with the dispersant of this invention at room temperature, the oil and rock cuttings solid phases are well separated. Following further separation, the oil and water phases are recovered separately. The oil and water phases are further homogenized with acid and emulsified, and finally, the oil phase can be recovered through oil-water separation. This dispersant is readily available, non-toxic, and can be industrially applied to the treatment of the oil phase in shale gas and oil-based drill cuttings, turning waste into a valuable resource.

Description

A dispersant for shale gas oil-based drilling cuttings degreasing

technical field

The invention belongs to the technical field of oil-based drilling cuttings processing in shale gas drilling, relates to the technical field of environmental protection, and particularly relates to a dispersant for oil-removing oil-based drilling cuttings in shale gas, and its specific application.

Background technique

Oil-based drilling cuttings are oil-based drilling fluids used in the drilling process of oil and gas fields. During the drilling process, the drilling cuttings are taken out of the oil well with the drilling fluid, and are evenly mixed with the oil-based drilling fluid. Environmentally hazardous black viscous oil-based cuttings formed. It is a complex multiphase system containing mineral oil, alkanes and their derivatives and various heavy metals. If they are stacked for a long time, with the infiltration of rainfall or snowfall, the harmful substances in the oil-based drilling cuttings will gradually be brought into the soil or penetrated. Into the groundwater, it will pollute the surrounding soil and water resources, inhibit the growth and survival of animals and plants, and even threaten human health and the environment that can survive. With the increasing development of unconventional energy sources for shale gas around the world, the amount ^of drill cuttings produced by drilling is increasing day by day. Beginning in the 1980s, the global awareness of environmental protection continued to increase, and the oil and gas industry and its regulators began to understand and pay attention to the potential impact of drilling cuttings on the ecological environment and human health. Oil-based drilling cuttings have been included in the National Hazardous Waste (National Hazardous Waste List, HW08) because they contain pollutants such as petroleum hydrocarbons, heavy metals and organics. The method of detoxification has become the research purpose of various professionals.

At present, the main methods of treating oil-based drill cuttings include: extraction, incineration, landfill, pyrolysis, solidification, reinjection, biological treatment, etc.

The extraction method uses the different solubility of petroleum substances in different solvents to transfer the petroleum substances from the surface of the drill cuttings to the organic solvent, and according to the different boiling points of petroleum hydrocarbons and organic solvents, the separation of petroleum hydrocarbons and solvents is achieved by means of distillation. The purpose is that the separated petroleum hydrocarbons can be reused to reconfigure oil-based mud, and the extractant can also be used for secondary extraction; however, the extractant is expensive, there is a certain loss in the treatment process, the cost is high, and there are potential safety hazards and Secondary pollution problem.

Incineration method is to dispose of oil-based drilling cuttings by using the characteristics of high organic content and certain calorific value of oil-based drilling cuttings, which is a direct and simple solid waste treatment method; To do dehydration pretreatment to make it meet the combustion requirements, the investment and operating costs of incineration equipment are high, complex toxic gases will be generated during the incineration process, and the generated fly ash, slag and flue gas will be difficult to meet the standard treatment.

The landfill method is a method of selecting a suitable natural site or a suitable site for artificial transformation on land, and covering the oil-based drilling cuttings with soil layers; however, the site construction and drilling cuttings transportation costs are high, the area is large, and the drilling cuttings The petroleum hydrocarbons and chemical agents in it cannot be decomposed in a short time, causing pollution to groundwater.

The pyrolysis method is to heat oil-based drilling cuttings to a certain temperature under anaerobic conditions to desorb hydrocarbons and organic matter, separate them from the drilling cuttings, and realize the recycling of hydrocarbon components. The hydrocarbons obtained by pyrolysis can be condensed into recovered oil. The non-condensable gas can be used as fuel gas; but the process is generally carried out at high temperature, the energy consumption and reaction conditions are relatively high, and the operation is relatively complicated.

The curing method is a harmless treatment process in which the oil-based drilling cuttings are cured or contained in an inert curing substrate by physical and chemical methods; however, this method has higher requirements on the oil content and salt content of the oil-based drilling cuttings. , too high oil content and salt content will greatly reduce the curing strength.

Reinjection is the process of processing oil-based drill cuttings through shearing, crushing and sorting, and reinjecting the remainder into the formation. However, this method is greatly affected by pipelines and equipment. The injection pipelines are subjected to high pressure and corrosion for a long time, and are easily damaged. Once the injection pipelines are damaged, pollution will be caused; in addition, the processing speed of this method is limited.

Biological treatment uses microorganisms to degrade petroleum hydrocarbons and organic matter in oil-based drilling cuttings, convert them into harmless CO ₂ and H ₂ O, and increase soil humus content at the same time. However, this method takes a long time, requires strict control of pH, humidity, temperature and other conditions during processing, and also has high technical requirements for operators.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present invention is to provide a dispersant for oil-removing oil-based drilling cuttings in shale gas with high-efficiency oil-water phase separation and its application.

To achieve the above object, the present invention provides the following technical solutions:

1. A dispersant for shale gas oil-based drilling cuttings degreasing, the dispersant raw material is composed of the following components in parts by mass: 10-40 parts of inorganic bases, 0.01-2 parts of organic bases, surface 0.01-2 parts of active agent, 0.01-0.5 part of defoamer, and 5-30 parts of sodium hexametaphosphate.

Further, the raw material of the dispersant is composed of the following components in parts by mass: 15-35 parts of inorganic base, 0.05-2 parts of organic base, 0.5-2 parts of surfactant, 0.1-0.5 part of defoamer, six parts 10 to 25 parts of sodium metaphosphate.

Further, the dispersant raw material is composed of the following components in parts by mass: 30 parts of inorganic base, 2 parts of organic base, 2 parts of surfactant, 0.4 part of defoamer, and 25 parts of sodium hexametaphosphate.

Further, the inorganic base is any one of sodium carbonate and sodium hydroxide; the organic base is any one of triethylamine, triethylenediamine, tetramethylethylenediamine; the surfactant is a cation A mixture of surfactant and nonionic surfactant; the defoamer is tributyl phosphate.

Further, the mass ratio of the cationic surfactant and the nonionic surfactant in the surfactant is 1:1-3.

Further, the mass ratio of the cationic surfactant and the nonionic surfactant in the surfactant is 1:1.

2. The application of any one of the above dispersants in the degreasing of oil-based drill cuttings.

Further, the applied method is to add oil-based drill cuttings to the dispersant, stir at room temperature, and stand for stratification.

Further, the stirring speed is 150rpm to 450rpm, and the stirring time is 40-90min.

Further, it is characterized in that the volume ratio of the oil-based drill cuttings and the dispersant is 1:1-3, and the mass fraction of the dispersant is 5-35%.

Further, it is characterized in that the volume ratio of the oil-based drill cuttings and the dispersant is 1:2, and the mass fraction of the dispersant is 10-20%.

The beneficial effects of the present invention are as follows: a dispersant for effective oil-water separation is provided, which can be used for the separation of oil content and solid phase of cuttings in oil-based drilling cuttings, and has universality and is not affected by the composition and properties of oil-based drilling cuttings After the oil-based drilling cuttings and the dispersant of the present invention are mixed and processed at room temperature, the oil content and the solid phase of the cuttings are well separated, and then separated into layers and recovered respectively, and the oil-water phase is further homogenized by adding acid, Emulsification treatment, and finally the oil-water separation can recover the oil phase. The components of the dispersant are easy to obtain, non-toxic, and can be industrially applied to the oil phase treatment of shale gas oil-based drilling cuttings, turning waste into treasure. Using the dispersant of the present invention to treat oil-based drilling cuttings has the advantages of simple treatment method, simple equipment, mild treatment conditions, less dosage of chemicals, low energy consumption, low cost, and no potential safety hazard; The oil rate is less than 0.5%, which meets the national standard. It can be used to prepare non-burning bricks, sintered bricks, road materials, etc. to reduce land occupation; the oil component recovery rate is high, and it can be returned to oil-based drilling fluid to realize resource recycling and reduce environmental protection. Pollution.

Description of drawings

In order to make the purpose, technical solutions and beneficial effects of the present invention clearer, the present invention provides the following drawings for description:

Fig. 1 is the flow chart of the oil removal method of shale gas oil-based drill cuttings of the present invention;

Figure 2 shows the effect of the final oil-water phase obtained by three different treatment methods in the comparative example and the embodiment.

Detailed ways

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The experimental methods for which specific conditions are not indicated in the examples are usually in accordance with conventional conditions or in accordance with the conditions suggested by the manufacturer.

A dispersant for shale gas oil-based drill cuttings

The raw materials are: 10-40 parts of inorganic base, 0.01-2 parts of organic base, 0.01-2 parts of surfactant, 0.01-0.5 part of defoamer, and 5-30 parts of sodium hexametaphosphate.

The preferred raw materials are: 15-35 parts of inorganic base, 0.05-2 parts of organic base, 0.5-2 parts of surfactant, 0.1-0.5 part of defoamer, and 10-25 parts of sodium hexametaphosphate.

Wherein, the inorganic base is any one of sodium carbonate and sodium hydroxide; the organic base is any one of triethylamine, triethylenediamine, tetramethylethylenediamine; the surfactant is a cationic (octadecane) Alkyl trimethyl ammonium chloride, cetyl trimethyl ammonium bromide) and non-ionic (Tween, Span, monolauryl phosphate) are mixed, the mass ratio of the two is 1:1-3, 1:1 is preferred; the defoamer is tributyl phosphate. When used, it is formulated into a mass fraction of 1% to 35%, preferably 10 to 20%.

The dispersant of the invention is added with inorganic base and surfactant to synergistically reduce the interfacial tension of oil and water and enhance the degreasing effect; the synergistic effect of the cationic and nonionic surfactants enhances the demulsification function and the solubilization effect; the organic base acts as a It is not easy to emulsify it again. The function of sodium hexametaphosphate is to disperse and wet; a large amount of foam will appear during the dispersion process, which affects the dispersion effect. The function of tributyl phosphate is to reduce the surface tension and make the foam burst.

A method for removing oil from shale gas oil-based drill cuttings, Fig. 1 is a flow chart of the method for removing oil from shale gas oil-based drill cuttings according to the present invention, and the specific steps are:

1) in container 1, add oil-based drill cuttings by volume ratio of 1:1～3, add above-mentioned dispersant, stir at room temperature, stirring speed is 150rpm～450rpm, stirring time is 40-90min, stand for stratification; Pour out the oil-water phase and place it in the container 2. The remaining solid phase is placed in 50-90 ℃ hot water, and the volume ratio of the amount of hot water to the solid phase is 1.5-3.0: 1. Continue stirring for 40-90 minutes, and the oil-water phase is again heated. Poured into container 2, the remaining solid phase was filtered and dried.

The volume ratio of oil-based drill cuttings and dispersant is preferably 1:2, and the mass fraction of dispersant is 10-20%.

2) Add a sulfuric acid solution with a mass fraction of 0.1% to 10% in container 2, adjust the pH to 3-4, and stir for 5 to 30 minutes; after the stirring is completed, perform centrifugal separation, and the centrifugal speed is 5000 to 12000 rpm and the time is 8 to 20 minutes. , the upper oil phase was recovered.

The oil-removing method for oil-based cuttings of the present invention 1. has universality and is not affected by the composition and properties of oil-based cuttings, such as two typical oil-based cuttings: horizontal well (drilling fluid matrix is white oil) And vertical wells (drilling fluid matrix is diesel) can be used.

2. The process and equipment are simple, the treatment conditions are mild, the dosage of chemicals is small, the energy consumption is low, the cost is low, and there is no potential safety hazard.

3. The oil removal is thorough, and the residual oil rate of the deoiled residue is less than 0.5%, which meets the national standard. It can be used to prepare non-burning bricks, sintered bricks, road materials, etc., and reduce land occupation.

4. The recovery rate of oil components is high, and the oil-based drilling fluid is returned to realize resource recycling and reduce environmental pollution.

Example 1

A dispersant for oil removal from shale gas oil-based drilling cuttings and a method for removing oil, specifically:

a. Degreasing and dispersing agent for shale gas oil-based drilling cuttings: 20 parts of inorganic alkali sodium hydroxide, 1 part of organic alkali triethylenediamine, 2 parts of surfactant, 0.3 part of defoamer tributyl phosphate, hexametaphosphoric acid 10 parts of sodium; the surfactant is a mixture of cationic surfactant and non-ionic surfactant, 1 part of octadecyltrimethylammonium chloride and 1 part of Tween; add water to prepare the dispersant to a mass fraction of 10% solvent;

b. Weigh 400g of oil-based drill cuttings in beaker 1, then add 600g of degreasing dispersant, and stir at room temperature. The stirring speed is 150rpm to 450rpm, and the stirring time is 50min. Let stand for stratification; pour out the oil-water phase In beaker 2, the remaining solid phase is placed in 50-90 ℃ hot water, and the volume ratio of the amount of hot water to the solid phase is 1.5:1. Continue stirring for 40-90 min, and pour the oil-water phase into beaker 2 again. Phase filtration, drying, detection;

c. Add sulfuric acid solution with a mass fraction of 5% in beaker 2, adjust the pH to 3-4, and stir for 5-30 minutes; after the stirring is completed, perform centrifugal separation, the centrifugal speed is 5000-12000rpm, and the time is 8-20min, and the upper layer is recovered oil phase.

Example 2

A dispersant for oil removal from shale gas oil-based drilling cuttings and a method for removing oil, specifically:

a. Degreasing and dispersing agent for shale gas oil-based drilling cuttings: 40 parts of inorganic alkali sodium carbonate, 0.5 parts of organic alkali triethylamine, 2 parts of surfactant, 0.5 part of defoamer tributyl phosphate, 20 parts of sodium hexametaphosphate The surfactant is a mixture of cationic surfactant and non-ionic surfactant, 1 part of octadecyltrimethyl ammonium chloride and 1 part of Span; add water to prepare the dispersant into a solvent with a mass fraction of 5%;

b. Weigh 500g of oil-based drill cuttings in beaker 1, then add 1000g of degreasing dispersant, and stir at room temperature. The stirring speed is 150rpm to 450rpm, and the stirring time is 50min. Let stand for stratification; In beaker 2, the remaining solid phase is placed in 50-90 ℃ hot water, and the volume ratio of the amount of hot water to the solid phase is 2:1, continue stirring for 40-90 min, and pour the oil-water phase into beaker 2 again, and the remaining solid Phase filtration, drying, and detection.

c. Add a sulfuric acid solution with a mass fraction of 10% in beaker 2, adjust the pH to 3-4, and stir for 5-30 minutes; after the stirring is completed, perform centrifugal separation, the centrifugal speed is 5000-12000rpm, and the time is 8-20min, and the upper layer is recovered oil phase.

Example 3

A dispersant for oil removal from shale gas oil-based drilling cuttings and a method for removing oil, specifically:

a. Degreasing and dispersing agent for shale gas oil-based drilling cuttings: 30 parts of inorganic alkali sodium hydroxide, 1.5 parts of organic alkali triethylenediamine, 1.5 parts of surfactant, 0.3 part of defoamer tributyl phosphate, hexametaphosphoric acid 20 parts of sodium; the surfactant is a mixture of cationic surfactant and non-ionic surfactant, 0.75 part of cetyl trimethyl ammonium bromide and 0.75 part of Span; add water to prepare the dispersant to a mass fraction of 15% solvent;

b. Weigh 400g of oil-based drill cuttings in beaker 1, then add 600g of degreasing dispersant, and stir at a temperature of 50°C. The stirring speed is 150rpm-450rpm, and the stirring time is 50min. Pour it out and place it in beaker 2. The remaining solid phase is placed in 50-90 ℃ hot water. The volume ratio of hot water and solid phase is 2:1. Continue stirring for 40-90 minutes. Pour the oil-water phase into beaker 2 again. , and the remaining solid phase is filtered, dried and detected.

c. Add a sulfuric acid solution with a mass fraction of 5% in the beaker 2, adjust the pH to 3-4, and stir for 5-30 minutes; after the stirring is completed, perform centrifugation. Mutually.

Example 4

A dispersant for oil removal from shale gas oil-based drilling cuttings and a method for removing oil, specifically:

a. Degreasing and dispersing agent for shale gas oil-based drilling cuttings: 25 parts of inorganic alkali sodium hydroxide, 1.5 parts of organic alkali tetramethylethylenediamine, 1 part of surfactant, 0.3 part of defoamer tributyl phosphate, six parts 25 parts of sodium metaphosphate; the surfactant is a mixture of cationic surfactant and non-ionic surfactant, 0.4 part of octadecyl trimethyl ammonium chloride and 0.6 part of Tween; add water to prepare the dispersant to the mass fraction 10% solvent;

b. Weigh 500g of oil-based drill cuttings in beaker 1, then add 1000g of degreasing dispersant, and stir at a temperature of 50°C. The stirring speed is 150rpm to 450rpm, and the stirring time is 50min. Pour it out and place it in beaker 2. The remaining solid phase is placed in 50-90 ℃ hot water, and the volume ratio of the amount of hot water to the solid phase is 3:1. Continue stirring for 40-90 minutes, and pour the oil-water phase into beaker 2 again. , and the remaining solid phase is filtered, dried and detected.

c. Add sulfuric acid solution with a mass fraction of 3% in the beaker 2, adjust the pH to 3-4, and stir for 5-30 minutes; after the stirring is completed, perform centrifugation. Mutually.

Example 5

A dispersant for oil removal from shale gas oil-based drilling cuttings and a method for removing oil, specifically:

a. Degreasing and dispersing agent for shale gas oil-based drilling cuttings: 30 parts of inorganic alkali sodium hydroxide, 2 parts of organic alkali triethylenediamine, 0.5 part of surfactant, 0.5 part of defoamer tributyl phosphate, hexametaphosphoric acid 15 parts of sodium; the surfactant is a mixture of cationic surfactant and non-ionic surfactant, 0.2 part of cetyl trimethyl ammonium bromide and 0.3 part of monolauryl phosphate; add water to prepare the dispersant to a mass Fraction 5% solvent;

b. Weigh 500g of oil-based drill cuttings in beaker 1, then add 1000g of degreasing dispersant, and stir at a temperature of 50°C. The stirring speed is 150rpm to 450rpm, and the stirring time is 50min. Pour it out and place it in beaker 2. The remaining solid phase is placed in 50-90 ℃ hot water, and the volume ratio of the amount of hot water to the solid phase is 3:1. Continue stirring for 40-90 minutes, and pour the oil-water phase into beaker 2 again. , and the remaining solid phase is filtered, dried and measured.

c. Add a sulfuric acid solution with a mass fraction of 10% in the beaker 2, adjust the pH to 3-4, and stir for 5-30 minutes; after the stirring is completed, perform centrifugation. Mutually.

Example 6

A dispersant for oil removal from shale gas oil-based drilling cuttings and a method for removing oil, specifically:

a. Degreasing and dispersing agent for shale gas oil-based drilling cuttings: 30 parts of inorganic alkali sodium carbonate, 2 parts of organic alkali triethylamine, 2 parts of surfactant, 0.4 part of defoamer tributyl phosphate, 25 parts of sodium hexametaphosphate The surfactant is a mixture of cationic surfactant and non-ionic surfactant, 1 part of octadecyltrimethyl ammonium chloride and 1 part of Span; add water to prepare the dispersant into a solvent with a mass fraction of 10%;

b. Weigh 500g of oil-based drill cuttings in beaker 1, then add 1000g of degreasing dispersant, and stir at a temperature of 50°C. The stirring speed is 150rpm to 450rpm, and the stirring time is 50min. Pour it out and put it in beaker 2. The remaining solid phase is placed in 50-90 ℃ hot water. The volume ratio of the amount of hot water to the oil-based drill cuttings is 2.5:1. Continue stirring for 40-90 minutes, and pour the oil-water phase into the beaker again. In 2, the remaining solid phase was filtered, dried and measured.

c. Add a sulfuric acid solution with a mass fraction of 10% in the beaker 2, adjust the pH to 3-4, and stir for 5-30 minutes; after the stirring is completed, perform centrifugation. Mutually.

Comparative Example 1

Dispersant: 40 parts of sodium carbonate and 2 parts of spanner were formulated into a 10% aqueous solution.

The rest of the treatment methods are the same as in Example 6.

Comparative Example 2

Dispersant: 40 parts of sodium carbonate are formulated into a 10% aqueous solution.

The rest of the treatment methods are the same as in Example 6.

Comparative Example 3

Dispersant: 2 parts of the spanner were formulated into a 10% aqueous solution.

The rest of the treatment methods are the same as in Example 6.

Determination of oil content: use OIL460 infrared spectroscopic oil meter to determine the oil content of oil-based drilling cuttings, carbon tetrachloride as extraction agent:

1. Weigh a certain mass (m) of oil-based drill cuttings (dry basis), (accurate to 0.0001g);

2. Measure 25mL of carbon tetrachloride and oil-based drill cuttings, mix and stir for 30min, and let stand for 20min;

3. Take 5mL of the extract after standing in the previous step, add it to a 25mL colorimetric tube, dilute it to the mark with carbon tetrachloride, shake and mix evenly, and measure the oil content (C, unit: mg/L);

4. Convert the measured data into the oil content in oil-based drill cuttings (dry basis) according to the dilution ratio. The formula for calculating the residual oil rate is:

Determination of loss on ignition:

1. Dry and pulverize the solid phase obtained by dispersing, weigh 1g (M) of solid powder and spread it evenly in the ash dish (accurate to 0.0001g);

2. Put the ash dish into the muffle furnace whose temperature does not exceed 100℃, close the furnace door and leave a gap of about 15mm in the furnace door.

3. Slowly raise the furnace temperature to 500°C within a period of not less than 30min, and keep it at this temperature for 30min. Continue to rise to 815-10 ° C, and burn at this temperature for 1 h.

4. Take out the ash dish from the furnace, put it on a heat-resistant plate or asbestos plate, cool it in the air for about 5 minutes, move it into a desiccator, cool it to room temperature (about 20 minutes), and weigh it (m).

5. Carry out inspection burning for 20 min each time until the mass of the coal sample dried twice in succession does not exceed 0.001g, and use the mass of the last burning as the basis for calculation. An inspection burn is not required when the ash content is less than 15%.

Calculation formula of loss on ignition: (M-m)/M.

Each processing data in the oil-based drill cuttings processing methods of Examples 1 to 6 and each comparative example was tested, and the results are shown in Table 1.

Table 1 Data of each example

Figure 2 shows the effect of the final oil-water phase obtained by the comparative example and the present invention through three different treatment methods. The left side is the effect of the final oil-water phase after the treatment of Comparative Example 1, the middle is the effect of the final oil-water phase after the treatment of Comparative Example 3, and the right side is the effect of the final oil-water phase after the treatment of Example 6 of the present invention. It can be seen from Figure 2 that the oil phase is separated into layers after treatment with different dispersants and then passed through the oil phase after centrifugation. It can be found that in the comparative example, the deoiling effect is poor and the dispersion and stratification effect is not obvious, which seriously affects the The efficiency of deoiling, but after being treated with the dispersant of the present invention, the third group of effects obtained through a series of treatments has been significantly improved, the deoiling efficiency is high, and the dispersion effect is obvious. The oil method has a good effect on the deoiling of shale gas oil-based drill cuttings.

Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should Various changes may be made in details without departing from the scope of the invention as defined by the claims.

Claims (10)

1. The dispersing agent for removing oil from shale gas-oil-based drill cuttings is characterized by comprising the following raw materials in parts by mass: 10-40 parts of inorganic base, 0.01-2 parts of organic base, 0.01-2 parts of surfactant, 0.01-0.5 part of defoaming agent and 5-30 parts of sodium hexametaphosphate.

2. The shale gas-oil-based drilling cutting oil removing dispersant according to claim 1, wherein the dispersant raw material comprises the following components in parts by weight: 15-35 parts of inorganic base, 0.05-2 parts of organic base, 0.5-2 parts of surfactant, 0.1-0.5 part of defoaming agent and 10-25 parts of sodium hexametaphosphate.

3. The shale gas-oil-based drilling cutting oil removing dispersant according to claim 1, wherein the dispersant raw material comprises the following components in parts by weight: 30 parts of inorganic base, 2 parts of organic base, 2 parts of surfactant, 0.4 part of defoaming agent and 25 parts of sodium hexametaphosphate.

4. The shale gas oil-based drill cuttings dispersant for oil removal according to any one of claims 1 to 3, wherein the inorganic base is any one of sodium carbonate and sodium hydroxide; the organic base is any one of triethylamine, triethylene diamine and tetramethyl ethylene diamine; the surfactant is a mixture of cationic surfactant and nonionic surfactant; the defoaming agent is tributyl phosphate.

5. The dispersing agent for removing oil from shale gas-oil-based drill cuttings according to claim 4, wherein the mass ratio of the cationic surfactant to the nonionic surfactant in the surfactant is 1: 1-3.

6. Use of a dispersant according to any one of claims 1 to 5 for the treatment of oil removal from oil-based drill cuttings.

7. The use of claim 6 wherein the oil-based drill cuttings are added to the dispersion, stirred at room temperature and allowed to stratify.

8. Use according to claim 7, wherein the stirring speed is between 150rpm and 450rpm and the stirring time is between 40 and 90 min.

9. The use according to claim 6 or 7, wherein the volume ratio of the oil-based drill cuttings to the dispersing agent is 1:1-3, and the mass fraction of the dispersing agent is 5-35%.

10. The use according to claim 6 or 7, wherein the volume ratio of the oil-based drill cuttings to the dispersant is 1:2 and the mass fraction of the dispersant is 10-20%.

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