阅读说明：本技术 一种以天然气钻井废弃物为原料的路基填料及其制备方法 (Roadbed filling material taking natural gas drilling waste as raw material and preparation method thereof ) 是由 周长波 赵传铭 方刚 宋海林 韩桂梅 宋海鑫 党春阁 李子秀 郭亚静 于 2020-04-30 设计创作，主要内容包括：本发明涉及天然气钻井废弃物的资源化利用,具体公开了一种以天然气钻井废弃物为原料的路基填料及其制备方法。通过对钻井泥浆的分类管控,针对不同井段的泥浆进行化学改良、破胶处理和焚烧处理,并筛选改良剂、优化焚烧工艺,利用处理后的无害化固体废弃物制备具有建材性能的路基填料,使钻井废弃物得到了充分的资源化应用,可产生良好的社会效益与经济效益。(The invention relates to resource utilization of natural gas drilling waste, and particularly discloses a roadbed filler taking natural gas drilling waste as a raw material and a preparation method thereof. Through the classification control of the drilling mud, the chemical improvement, gel breaking treatment and incineration treatment are carried out on the mud in different well sections, the modifying agent is screened, the incineration process is optimized, and the treated harmless solid waste is utilized to prepare the roadbed filler with the building material performance, so that the drilling waste is fully recycled and applied, and good social benefit and economic benefit can be generated.)

1. A method for preparing roadbed filling by taking natural gas drilling waste as a raw material is characterized by comprising the following steps:

(1) classifying the drilling mud to obtain first mud and second mud; the first type of mud is drilling mud on the upper parts of the first drilling and the second drilling; the second type of mud is drilling mud for the lower part of the second drilling and the third drilling;

wherein the upper part of the second drilling is 650-2750 m of the drilled well; the lower part of the second drilling is 2750-3500 m of the drilled well;

(2) mixing the first type of slurry obtained in the step (1) with a gel breaker and a modifier for gel breaking treatment, and then performing filter pressing treatment to obtain first type of solid waste;

(3) mixing the second type of slurry obtained in the step (1) with a gel breaker for gel breaking treatment, and then performing filter pressing treatment to obtain second type of solid waste; then carrying out incineration treatment on the second type of solid waste to obtain an incineration product;

(4) and (3) mixing the first type of solid waste obtained in the step (2) and the incineration product obtained in the step (3) to obtain the roadbed filler.

2. The method of claim 1, wherein the modifying agent is calcium sulfate, ferric sulfate, or ferrous sulfate.

3. The method according to claim 2, wherein in the step (2), the modifying agent is ferrous sulfate, and the amount of the modifying agent is 0.3-0.6% of the mass of the first type of slurry; the dosage of the gel breaker is 1.0-1.4% of the mass of the first type of slurry;

or the modifying agent is calcium sulfate, and the using amount of the modifying agent is 5-9% of the mass of the first type of slurry; the dosage of the gel breaker is 1.5-2.0% of the mass of the first type of slurry;

or the modifying agent is ferric sulfate, and the using amount of the modifying agent is 0.125-1% of the mass of the first type of slurry; the dosage of the gel breaker is 1.5-2.0% of the mass of the first type of mud.

4. The method according to claim 1, wherein in the step (3), the temperature for burning the second type of solid waste is 880-920 ℃, and the burning time is 20-30 minutes.

5. The method of claim 4, wherein in step (3), the amount of the gel breaker is 2.5-5% of the mass of the second type of mud.

6. The method according to any one of claims 1 to 5, wherein in the step (4), the first type solid waste obtained in the step (2) and the incineration product obtained in the step (3) are respectively sieved to obtain materials with the particle size of not more than 100mm, and then the materials are mixed according to the mass ratio of not less than 1: 1.

7. The method of claim 6, wherein the first type of solid waste has a moisture content of no greater than 5%.

8. The method of claim 6, wherein the second type of solid waste has a moisture content of no greater than 4%.

9. A roadbed filler, which is prepared according to the method of any one of claims 1 to 8.

Technical Field

The invention relates to resource utilization of natural gas drilling waste, in particular to a roadbed filling material taking the natural gas drilling waste as a raw material and a preparation method thereof.

Background

With the development of times and the progress of mankind, people have increasingly increased consumption of fossil energy, and the main components of the fossil energy are petroleum and natural gas. The petroleum and natural gas are mainly obtained by drilling, but the petroleum and natural gas exploration and drilling process generates a large amount of drilling waste, including drilling cuttings, drilling mud and the like, and becomes one of the main pollution sources of the petroleum and natural gas industry. Due to engineering requirements, the natural gas drilling mud is added with chemical additives and mixed with substances such as water, bentonite and the like, so that indexes such as petroleum hydrocarbon, chroma, pH and the like are high. In recent two years, the use of water-based mud and composite-based mud by drilling crews is increasing, and the cost increase and the environmental pollution problem are also becoming more serious. In order to protect the environment around the well production, the waste needs to be treated, and the influence of the waste on the environment is reduced.

The natural gas exploitation process comprises a first-time drilling (first-time drilling) well section, a second-time drilling (second-time drilling) upper well section, a second-time drilling (second-time drilling) lower part and a third-time drilling (third-time drilling) well section, wherein the drilling fluid systems used in the three well sections are different. The first opening adopts common bentonite slurry, namely, the bentonite slurry is prepared by adding clear water into bentonite powder to hydrate and disperse, the second opening is provided with an upper well section and uses a clear water polymer drilling fluid system, the types of added additives are less, the additives are mainly polyacrylamide polymers, and the second opening is provided with a lower part and a third opening stage and uses a polysulfonate/potassium-based polysulfonate drilling fluid system.

In the current natural gas exploitation industry, waste mud generated in three drilling stages of an oil and gas field is generally collected while drilling by a mud non-landing operation team, then uniformly mixed and stored in a waste centralized treatment plant, and then subjected to gel breaking treatment and filter pressing, so that the obtained solid wastes are general industrial second-class wastes, the later-stage resource utilization difficulty and the treatment capacity are high, and the treatment cost is high.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to provide a roadbed filling material taking natural gas drilling waste as a raw material and a preparation method thereof.

In order to realize the purpose of the invention, the technical scheme of the invention is as follows:

in a first aspect, the invention provides a method for preparing roadbed filling by using natural gas drilling waste as a raw material, which comprises the following steps:

(1) classifying drilling mud (the drilling mud is a mixture of drilling debris and waste drilling fluid) to obtain first mud and second mud; the first type of mud is drilling mud on the upper parts of the first drilling and the second drilling; the second type of mud is drilling mud for the lower part of the second drilling and the third drilling;

wherein the upper part of the second drilling is 650-2750 m of the drilled well; the lower part of the second drilling is 2750-3500 m of the drilled well;

(2) mixing the first type of slurry obtained in the step (1) with a gel breaker and a modifier for gel breaking treatment, and then performing filter pressing treatment to obtain first type of solid waste;

(3) mixing the second type of slurry obtained in the step (1) with a gel breaker for gel breaking treatment, and then performing filter pressing treatment to obtain second type of solid waste; then carrying out incineration treatment on the second type of solid waste to obtain an incineration product;

(4) and (3) mixing the first type of solid waste obtained in the step (2) and the incineration product obtained in the step (3) to obtain the roadbed filler.

Further, the modifying agent is calcium sulfate, ferric sulfate or ferrous sulfate.

The type and source of the gel breaker are not particularly limited in the invention, and a commercially available gel breaker well known to those skilled in the art can be adopted, and one or more of polyaluminium chloride, sodium hypochlorite and hydrogen peroxide are preferred. The gel breaking treatment is preferably carried out in a gel breaking tank.

Furthermore, the following three preferable schemes are obtained by screening the components and the dosage of the modifier and the dosage of the gel breaker through a multi-factor comparison experiment:

(1) the modifier is ferrous sulfate, and the dosage of the modifier is 0.3 to 0.6 percent of the mass of the first type of slurry; the dosage of the gel breaker is 1.0-1.4% of the mass of the first type of slurry;

(2) the modifier is calcium sulfate, and the using amount of the modifier is 5-9% of the mass of the first type of slurry; the dosage of the gel breaker is 1.5-2.0% of the mass of the first type of slurry;

(3) the modifier is ferric sulfate, and the dosage of the modifier is 0.125-1% of the mass of the first type of slurry; the dosage of the gel breaker is 1.5-2.0% of the mass of the first type of mud.

On the basis of comprehensively considering the dosage of the gel breaker and the modifier and the price cost, the optimal scheme is to select ferrous sulfate as the modifier.

Furthermore, after comparative tests on the temperature and time of incineration treatment of the second type of solid waste, the invention has the best effect when the incineration temperature is about 900 ℃ and the incineration is carried out for 20-30 minutes. The concrete embodiment is as follows: the solid waste after incineration is kept stand and precipitated, no floating oil exists in the water in the beaker, and the water sample is clear; and (3) detecting the solid waste leachate after incineration, wherein the pH value is lower than 9, and the petroleum hydrocarbon removal rate in the solid waste after incineration exceeds 98%, so that the harmless treatment of the drilling solid waste can be realized.

Therefore, in the step (3), the temperature for burning the second type solid waste is preferably 880 to 920 ℃ and the burning time is preferably 20 to 30 minutes.

Furthermore, the drilling mud is classified, collected and treated, so that the dosage of the gel breaker is reduced, and therefore in the step (3), the dosage of the gel breaker is only 2.5-5% of the mass of the second type of mud.

Further, in the step (4), the first type of solid waste obtained in the step (2) and the incineration product obtained in the step (3) are respectively screened to obtain materials with the particle size not larger than 100mm, and then the materials are mixed according to the mass ratio not smaller than 1:1, namely the dosage of the first type of solid waste is larger than that of the incineration product.

Preferably, the water content of the first type of solid waste is not more than 5%.

Preferably, the water content of the second type solid waste is not more than 4%.

In a second aspect, the present invention provides a roadbed filler, which is prepared according to the method.

The roadbed filling includes but is not limited to first-level, second-level, third-level and fourth-level highway roadbed soil and highway roadbed.

The raw materials or reagents involved in the invention are all common commercial products, and the operations involved are all routine operations in the field unless otherwise specified.

The above-described preferred conditions may be combined with each other to obtain a specific embodiment, in accordance with common knowledge in the art.

The invention has the beneficial effects that:

firstly, the invention classifies the drilling mud, according to the difference of mud systems obtained at different well sections in the drilling process, the drilling waste is divided into two types of waste generated at the upper parts of the first and second drilling and waste generated at the lower parts of the second and third drilling according to the drilling process for collection treatment, the generation amount of drilling solid waste containing toxic and harmful pollutants is reduced from the source, the treatment difficulty is reduced, the dosage of gel breaking agent is reduced, and further the problem that the addition of a large amount of agent causes greater difficulty in standard treatment of rear end pressure filtrate is avoided, and the equipment investment and the treatment cost are increased; meanwhile, the solid waste is prevented from being mixed into the second-class solid waste of the common industry, and the treatment cost is reduced. Experimental results show that compared with the traditional method, the method for classifying and treating the drilling mud reduces the dosage of the gel breaker by 50%, and the solid waste obtained after pH adjustment is general industrial solid waste, so that the treatment cost is reduced.

Secondly, the invention respectively carries out gel breaking improvement and gel breaking incineration on the slurry of different well sections, screens better modifying agent and incineration process, and utilizes the obtained harmless solid waste to prepare the roadbed filling with building material performance, so that the drilling waste is fully recycled, and good social benefit and economic benefit can be generated.

Detailed Description

The invention provides a method for preparing roadbed filling by taking drilling mud as a raw material, which comprises the following steps:

(1) classifying the drilling mud to obtain first mud and second mud; the first type of mud is drilling mud on the upper parts of the first drilling and the second drilling; the second type of mud is drilling mud for the lower part of the second drilling and the third drilling;

wherein the upper part of the second drilling is 650-2750 m of the drilled well; the lower part of the second drilling is 2750-3500 m of the drilled well;

(2) mixing the first type of slurry obtained in the step (1) with a gel breaker and a modifier for gel breaking treatment, then performing filter pressing treatment to obtain first type of solid waste, and controlling the water content to be not more than 5%;

(3) mixing the second type of slurry obtained in the step (1) with a gel breaker for gel breaking treatment, and then performing filter pressing treatment to obtain second type of solid waste; then carrying out incineration treatment on the second type of solid waste to obtain an incineration product with the water content not more than 4%;

(4) and (3) mixing the first solid waste obtained in the step (2) and the incineration product obtained in the step (3) according to a ratio not less than 1:1 (for example, 3:1, 2:1, 1:1 and the like) to obtain the roadbed filler.

The method comprises the steps of classifying drilling mud to obtain first mud and second mud; the first type of mud is drilling mud at the upper parts of the first drilling and the second drilling; the second type of mud is drilling mud for the second drilling of the lower part and the third drilling of the lower part. According to the invention, according to different drilling fluid systems used in different well sections in the drilling process, the generated mud has larger component difference, different performance and index requirements and larger pollution characteristic difference, the mud is classified to obtain different types of solid wastes, the generation amount of drilling solid wastes containing toxic and harmful pollutants is reduced from the source, and the treatment difficulty is reduced.

The first drilling mud is not particularly limited in the present invention, and the first drilling mud may be collected according to a well drilling process known to those skilled in the art. In the invention, the drilling fluid for the first drilling is preferably common bentonite slurry, and the common bentonite slurry is formed by adding bentonite powder into clear water for hydration and dispersion.

In the invention, the upper part of the second drilling is preferably 650-2750 m of the drilled well. In the invention, the drilling fluid at the upper part of the second drilling is preferably a clear water polymer drilling fluid system, and the added additives are few in types and mainly comprise polyacrylamide polymers.

In the present invention, the properties of the drilling mud obtained in the upper part of the first and second drilling operations are preferably: the color is earthy yellow or earthy gray, TDS<2500mg/L, conductivity<4600s, density 1.05-1.15 mg/cm³The pH value is above 9.0. In the invention, the drilling mud obtained from the upper parts of the first drilling and the second drilling has similar pollution characteristics, and can be classified and treated with other mud, so that the use of a gel breaker can be reduced.

In the invention, the lower part of the second drilling is preferably 2750-3500 m of the drilled well. In the invention, the drilling fluid for the second drilling and the third drilling is preferably a polysulfonate/potassium-based polysulfonate drilling fluid system. In the present invention, the properties of the drilling mud for the second and third drilling of the lower and third drilling of the drill string are preferably: the color is brown or dark brown, TDS>4000mg/L, conductivity>5600s, density of 1.2-1.35 mg/cm³. In the invention, the drilling mud of the second drilling lower part and the third drilling has similar pollution characteristics, and the use of the gel breaker can be reduced by classifying and processing the drilling mud with other mud.

TABLE 1 summary of drilling mud property indices for different intervals

If in practical application, when the mud is difficult to be classified according to the drilling times, the mud can be classified according to the characteristics of the mud at different well sections, for example, the mud is firstly distinguished through the mud color, and the mud is directly classified with obvious color difference; if the color difference is not obvious, testing the TDS of the slurry, and directly classifying the slurry with the TDS difference value of more than 1500 mg/L; if the difference value of the TDS is less than 1500mg/L, testing the conductivity of the slurry, and directly classifying if the conductivity difference value is more than 1000 s; if the conductivity difference is <1000, the density of the mud is tested and classified according to density range.

After the first type of mud and the second type of mud are obtained, the first type of mud and the second type of mud are subjected to gel breaking treatment in sequence respectively to obtain first type of solid waste and second type of solid waste respectively.

The invention preferably performs classified temporary storage after the first type of mud and the second type of mud are obtained, and then performs gel breaking treatment. The temporary storage device is not specially limited, and the two types of mud can be temporarily stored respectively by adopting the temporary storage device well known by the technical personnel in the field. In the present invention, the first type of slurry and the second type of slurry are preferably temporarily stored in different slurry temporary storage tanks.

In the invention, the dosage of the gel breaker for gel breaking treatment of the first type of slurry is 1-2%; the dosage of the gel breaker for gel breaking treatment of the second type of slurry is 2.5-5%.

In the invention, solid-liquid separation is also included after the gel breaking treatment; the solid-liquid separation is preferably pressure filtration. The operation of the filter pressing is not particularly limited in the invention, and the technical scheme of the filter pressing known to those skilled in the art can be adopted. In the present invention, the press filtration is preferably carried out in a filter press.

In the invention, the first type of mud is subjected to gel breaking treatment and solid-liquid separation to obtain a first filter pressing liquid and first type of solid waste; and performing gel breaking treatment and solid-liquid separation on the second type of slurry to obtain a second filter pressing liquid and second solid waste. And the first pressure filtrate and the second pressure filtrate generated after pressure filtration can be respectively recycled.

Further, aiming at the gel breaking treatment of the first type of slurry, the first type of slurry is mixed with a gel breaker and a modifier, and the gel breaking treatment and the filter pressing are sequentially carried out to obtain the first type of solid waste. In the present invention, the first type of mud includes drilling mud obtained from the upper part of the first (first) and second (second) drilling. According to the invention, through analyzing the pollution characteristics of drilling waste generated in the first-opening and second-opening well sections, the pollution indexes are determined that only the pH value reaches over 9.0 and exceeds the limit value requirement of common industrial solid waste, and the waste is distinguished and treated.

In the invention, the upper part of the second drilling is preferably a part 650-2750 m of the natural gas drilling well. In the invention, more NaOH and Na are added into the drilling fluid system at the upper parts of the first and second drilling₂CO₃In the link of non-falling and filter-pressing of the slurry at the rear end, a certain amount of CaO and cement are added to promote gel breaking and plate stripping, so that the pH value of the drilling waste leachate exceeds the standard range of 6-9, and the drilling waste has the characteristic of poor physicochemical property.

In the present invention, the water content of the first type slurry is 60% or more. In the invention, the water in the first type of mud can dissolve the modifying agent, which is beneficial to the full play of the modifying agent.

In the invention, the modifier is calcium sulfate, ferric sulfate or ferrous sulfate.

The mass ratio of the calcium sulfate to the first type mud is preferably 5-9%, more preferably 6-8%, and most preferably 7%. In the invention, when the modifying agent is calcium sulfate, the mass ratio of the gel breaker to the first mud is preferably 1.5-2.0%, more preferably 1.6-1.9%, and most preferably 1.8%. In the invention, the hydrolysis of the calcium sulfate can neutralize alkali in the first mud, so that the pH value of the solid waste is in a standard reuse range.

The mass ratio of the ferric sulfate to the first type mud is preferably0.125 to 1%, more preferably 0.25 to 0.75%, most preferably 0.5%. In the invention, when the modifying agent is ferric sulfate, the mass ratio of the gel breaker to the first mud is preferably 1.5-2.0%, more preferably 1.5-1.8%, and most preferably 1.6%. In the invention, the ferric sulfate is a composite iron-containing material with stronger activity, and releases H while generating iron hydroxide by hydrolysis in water⁺The alkali in the first type of mud can be neutralized, so that the pH value of the solid waste is in a standard reuse range.

The mass ratio of the ferrous sulfate to the first type mud is preferably 0.3-0.6%, and more preferably 0.4-0.5%. In the invention, when the modifying agent is ferrous sulfate, the mass ratio of the gel breaker to the first mud is preferably 1.0-1.4%, more preferably 1.0-1.2%, and most preferably 1.1%. In the invention, the ferrous sulfate is a composite iron-containing material with strong activity, and releases H while generating iron hydroxide by hydrolysis in water⁺The alkali in the first type of mud can be neutralized, so that the pH value of the solid waste is in a standard reuse range; in addition, the ferrous sulfate is low in price and cost, has a certain gel breaking effect and a certain water treatment catalysis effect, and can be used together with the gel breaker, so that the dosage of the gel breaker can be reduced, and the cost is further reduced.

The type of the gel breaker is not particularly limited in the present invention, and a gel breaker for gel breaking treatment of drilling mud known to those skilled in the art may be used. In the present invention, the breaker preferably comprises one or more of polyaluminium chloride, sodium hypochlorite and hydrogen peroxide. The gel breaking treatment is preferably carried out in a gel breaking tank.

The operation of mixing the first type of mud with the gel breaker and the modifier is not particularly limited, and the technical scheme of mixing materials, which is well known to those skilled in the art, can be adopted.

Further, burning the second type solid waste subjected to gel breaking treatment of the second type slurry at 880-920 ℃ for 20-30 minutes, standing and precipitating the burned solid waste, and obtaining a clear water sample without floating oils in water in a beaker; and (3) detecting the solid waste leachate after incineration, wherein the pH value is lower than 9, and the petroleum hydrocarbon removal rate in the solid waste after incineration exceeds 98%, so that the harmless treatment of the drilling solid waste can be realized.

Further, the first type of solid waste obtained after gel breaking treatment and filter pressing treatment and the second type of solid waste obtained after gel breaking treatment, filter pressing treatment and incineration treatment are respectively sieved to obtain materials with the particle size not larger than 100mm, and the materials are mixed according to the mass ratio not smaller than 1:1 to obtain the roadbed filler taking the drilling waste as the raw material.

Preferably, the water content of the first type of solid waste is not more than 5%.

Preferably, the water content of the second type solid waste is not more than 4%.

Preferred embodiments of the present invention will be described in detail with reference to the following examples. It is to be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the present invention. Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the spirit and scope of this invention.

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified.

Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.