Restoration soil prepared from gas field water-based drilling waste and preparation method and application thereof

Abstract

The invention discloses remediation soil prepared from gas field water-based drilling waste and a preparation method and application of the remediation soil. The preparation method comprises the steps that solid phases in the gas field water-based drilling waste are sieved; mixing the sieved solid-phase waste with liquid-phase waste in the gas field water-based drilling waste to obtain a mixed raw material; mixing the soil with the mixed raw materials to obtain mixed soil; and adding charcoal, urea, mineral source humic acid and desulfurized gypsum into the mixed soil to obtain the remediated soil. The method is simple in process and convenient to operate, beneficial substances in the drilling waste can be fully utilized, remediated soil rich in nutrition is obtained and can be used for planting plants, and meanwhile resource utilization of the water-based drilling waste is promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of comprehensive utilization of waste gas water-based drilling wastes, and relates to a repair soil prepared by utilizing gas field water-based drilling wastes, and a preparation method and application thereof. Background Art

[0002] Water-based drilling waste mainly includes drilling mud, rock cuttings and various additives. Studies have found that the drilling fluid additives used in the drilling process contain a large amount of organic matter such as humic acid, starch, sawdust, etc., which can improve soil fertility; bentonite, carboxymethyl cellulose, and polyacrylamide are good soil water retainers and improvers; bentonite can improve the physical and chemical properties of the soil. Since bentonite has a high water absorption rate, applying it to the soil can increase the number and stability of aggregates, which is beneficial to increasing soil fertility and crop growth. At the same time, bentonite has high adsorption and ion exchange properties, and has a good repair effect on heavy metal-contaminated soil and saline-alkali land; polyacrylamide is a good water retainer that can reduce soil erosion and improve soil structure; inorganic salts (KCl and NaOH) are added to the drilling fluid, and KCl can be used as a potassium fertilizer to improve soil fertility and crop quality. Therefore, the soil utilization of abandoned water-based drilling waste has received widespread attention. Some existing patents involve methods for soil utilization of waste water-based drilling waste, such as the patent "A process for producing sand-control and water-retaining agent using water-based drilling cuttings", patent number CN113135799A, which is characterized in that the sand-control and water-retaining agent for saline-alkali sandy land is formed by screening the drilling cuttings, adjusting the pH, fermenting and adding some additives, the first fermentation and maturation are carried out at 15°C to 60°C, the second fermentation and maturation are carried out at 15°C to 40°C, and fermentation bacteria must be added, which has high requirements on the on-site environment, complex processes and high costs; the patent "A soil treatment composition for waste water-based drilling fluid and its application", patent number CN106508163, is characterized in that coal, solid waste slag phosphogypsum, powder and the like are mixed and added to the drilling fluid, stirred and allowed to stand, and tall fescue plants can be planted after the water content is less than 15%. The fertility of the repaired soil obtained by this scheme is limited, so the types of crops that can be planted are limited. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides a remediation soil prepared using gas field water-based drilling waste, and a preparation method and application thereof, thereby solving the technical problems in the prior art of using water-based drilling waste to prepare remediation soil, that is, the preparation process is complicated, the requirements on the preparation environment are high, and the fertility of the obtained remediation soil is limited.

[0004] The present invention is achieved through the following technical solutions:

[0005] A method for preparing soil restoration using gas field water-based drilling waste comprises the following steps:

[0006] S1: Screening the solid phase in the water-based drilling waste of the gas field;

[0007] S2: mixing the sieved solid waste with liquid waste in gas field water-based drilling waste to obtain a mixed raw material;

[0008] S3: mixing the soil with the mixed raw material to obtain mixed soil;

[0009] S4: adding biochar, urea, mineral humic acid and desulfurized gypsum to the mixed soil to obtain the repaired soil.

[0010] Preferably, after screening in step S1, solid waste with a particle diameter not greater than 2 mm is obtained.

[0011] Preferably, in step S1, the solid waste larger than 2 mm is pulverized and then sieved again.

[0012] Preferably, in step S2, the mixing mass ratio of the filtered waste to the liquid waste in the gas field water-based drilling waste is (2-3):1.

[0013] Preferably, in step S3, the mixing mass ratio of the soil to the mixed raw materials is (3-4):1.

[0014] Preferably, in terms of percentage by mass of the mixed soil, the amount of biochar added is 3% to 5%, the amount of urea added is 0.01% to 0.03%, the amount of mineral humic acid added is 0.4% to 0.6%, and the amount of desulfurized gypsum added is 1% to 2%.

[0015] Preferably, the particle size of the biochar is not greater than 0.02 mm; the nitrogen content in the urea is 44% to 46%; the number of effective live bacteria in the mineral humic acid is not less than 500 million / g, and the mass fraction of humic acid is not less than 50%; the content of CaSO4 in the desulfurized gypsum is not less than 74%.

[0016] Preferably, the soil comprises loess soil or sandy loess soil.

[0017] A method for preparing remediation soil using gas field water-based drilling waste is prepared by the above method.

[0018] The above-mentioned one kind utilizes gas field water-based drilling waste to prepare repair soil and uses it in plant cultivation.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] A method for preparing soil restoration using gas field water-based drilling waste, wherein solid waste and liquid waste in the gas field water-based drilling waste are treated separately, the solid waste is sieved so that it can be well mixed with soil to obtain mixed soil with uniform particles, and in addition, biochar, urea, mineral humic acid and desulfurized gypsum are added to the mixed soil, wherein the biochar can significantly reduce the soil bulk density, increase the soil saturated water conductivity, and increase the porous structure, and is mainly used to deal with the characteristics of viscous mud and fine particles; urea is used to adjust the soil C / N, and the C / N will affect the conversion and mineralization of humus in the soil speed, affecting the growth of microorganisms, and further affecting the absorption of nitrogen by plants; humic acid can improve the soil aggregate structure, facilitate the reproduction of soil microorganisms, and enhance the soil chelating ability. Its strong chelating ability can enrich the heavy metals in the soil and reduce the damage of harmful substances to plants; desulfurized gypsum can use the calcium ions in the gypsum to exchange the sodium ions in the saline-alkali soil, reduce the pH of the soil, and improve the alkalinity of the soil. This method is simple in process and easy to operate. It can make full use of the beneficial substances in the drilling waste to obtain nutrient-rich repaired soil, which can be used for planting plants. At the same time, it also promotes the resource utilization of water-based drilling waste.

[0021] Furthermore, after sieving in step S1, solid waste with a particle diameter not greater than 2 mm is obtained, which can be effectively mixed with soil to obtain uniform mixed soil.

[0022] Furthermore, in step S1, the solid waste with a size larger than 2 mm is crushed and then sieved, thereby effectively achieving sufficient treatment of the solid waste.

[0023] Furthermore, in step S2, when the filtered waste is mixed with the mud, the mass ratio is (2-3):1, which can effectively control the nutrient content in the repaired soil.

[0024] Furthermore, in step S3, when the soil and the mixed raw material are mixed, the mass ratio is (3-4):1, which can make the properties of the mixed soil stable and the nutrient content moderate.

[0025] Furthermore, in terms of percentage by mass of the mixed soil, the amount of biochar added is 3% to 5%, the amount of urea added is 0.01% to 0.03%, the amount of mineral humic acid added is 0.4% to 0.6%, and the amount of desulfurized gypsum added is 1% to 2%, so that the nutrients in the repaired soil are moderate and balanced.

[0026] Furthermore, the particle size of biochar is not greater than 0.02 mm; the nitrogen content in urea is 44% to 46%; the number of effective live bacteria in mineral humic acid is not less than 500 million / g, and the mass fraction of humic acid is not less than 50%; the content of CaSO4 in desulfurized gypsum is not less than 74%, which can effectively meet the demand for nutrients in soil repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 A schematic diagram of a process for preparing soil restoration using gas field water-based drilling waste in the present invention; DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0030] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0031] Herein, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0032] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0033] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0034] like Figure 1 As shown, the present invention provides a method for preparing soil restoration using gas field water-based drilling waste, comprising the following steps:

[0035] S1: The solid phase in the gas field water-based drilling waste is screened, wherein the solid phase waste with a particle diameter not greater than 2 mm is obtained after screening, and the solid phase waste with a particle diameter greater than 2 mm is crushed and screened again.

[0036] S2: Mixing the screened solid waste with the liquid waste in the gas field water-based drilling waste to obtain a mixed raw material, wherein the mixed mass ratio of the filtered waste to the liquid waste in the gas field water-based drilling waste is (2-3):1.

[0037] S3: Mixing the soil with the mixed raw material to obtain mixed soil, wherein the mixing mass ratio of the soil to the mixed raw material is (3-4): 1. The soil includes loess soil or sandy loess, and is sieved to 2 mm before use.

[0038] S4: Adding biochar, urea, mineral humic acid and desulfurized gypsum to the mixed soil to obtain the remediated soil, wherein, in terms of the mass percentage of the mixed soil, the added amount of biochar is 3% to 5%, the added amount of urea is 0.01% to 0.03%, the added amount of mineral humic acid is 0.4% to 0.6%, and the added amount of desulfurized gypsum is 1% to 2%; wherein the biochar is obtained by low-temperature thermal cracking of crop straw, and the particle size of the biochar is not greater than 0.02 mm; the nitrogen content in the urea is 44% to 46%; the number of effective live bacteria in the mineral humic acid is not less than 500 million / g, and the mass fraction of humic acid is not less than 50%; the content of CaSO4 in the desulfurized gypsum is not less than 74%.

[0039] A method for preparing soil restoration using gas field water-based drilling waste, wherein solid waste and liquid waste in the gas field water-based drilling waste are treated separately, the solid waste is screened so that it can be well mixed with soil to obtain mixed soil with uniform particles, and in addition, biochar, urea, mineral humic acid and desulfurized gypsum are added to the mixed soil, wherein the biochar can significantly reduce the soil bulk density, increase the soil saturated water conductivity, and increase the porous structure, and is mainly used to deal with the characteristics of viscous mud and fine particles; urea is used to adjust the soil C / N, and the C / N will affect the conversion of humus and mineral in the soil The speed of chemical reaction affects the growth of microorganisms, and then affects the absorption of nitrogen by plants; humic acid can improve the soil aggregate structure, facilitate the reproduction of soil microorganisms, and strengthen the soil chelating ability. Its strong chelating ability can enrich heavy metals in the soil and reduce the damage of harmful substances to plants; desulfurized gypsum can use calcium ions in gypsum to exchange sodium ions in saline-alkali soil, reduce the pH of the soil, and improve the alkalinity of the soil. This method has simple process and convenient operation. It can make full use of the beneficial substances in drilling waste to obtain nutrient-rich repaired soil, and also promote the resource utilization of water-based drilling waste. The repaired soil obtained by this method meets the requirements of the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (Trial)" (GB 15618-2018), can be used for planting plants, promotes the resource utilization of water-based drilling waste, conforms to the concept of green environmental protection and sustainable development, protects and improves the mining environment, and has high social benefits.

[0040] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0041] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0042] Example 1

[0043] The abandoned water-based rock cuttings at the gas field site were crushed and sieved at 2 mm. The sieved rock cuttings and mud were mixed in a mass ratio of 3:1 to form a mixed raw material. After sieving 2 mm of loess soil, it was mixed with the mixed raw material in a mass ratio of 4:1 to form a mixed soil. 5% biochar, 0.02% urea, 0.5% mineral humic acid and 2% desulfurized gypsum were added to the mixed soil to form a repaired soil. The sheep grass seedlings were planted in the repaired soil. During the planting period, the soil moisture content was maintained at 50-70%. After 2 weeks of growth, the plant height, fresh weight and dry weight of the plants were observed and recorded, and the soil was taken for monitoring. The results are shown in Table 1.

[0044] Comparative Example 1

[0045] The Leymus chinensis seedlings were directly planted in loess soil. After growing for 2 weeks, the plant height, fresh weight and dry weight were observed and recorded, and the soil was taken for monitoring. The results are shown in Table 1.

[0046] Table 1 Monitoring results of Leymus chinensis seedlings after 2 weeks of growth in Example 1 and Comparative Example 1

[0047]

[0048] Example 2

[0049] The abandoned water-based rock cuttings at the gas field site were crushed and sieved at 2 mm. The sieved rock cuttings and mud were mixed in a mass ratio of 2:1 to form a mixed raw material. After sieving the sandy loess at 2 mm, it was mixed with the mixed raw material in a mass ratio of 3:1 to form a mixed soil. 3% biochar, 0.03% urea, 0.6% mineral humic acid and 1% desulfurized gypsum were added to the mixed soil to form a repaired soil. The sheep grass seedlings were planted in the repaired soil. During the planting period, the soil moisture content was maintained at 50-70%. After 2 weeks of growth, the plant height, fresh weight and dry weight of the plants were observed and recorded, and the soil was taken for monitoring. The results are shown in Table 2.

[0050] Comparative Example 2

[0051] The Leymus chinensis seedlings were directly planted in sandy loess. After growing for 2 weeks, the plant height, fresh weight and dry weight were observed and recorded, and the soil was taken for monitoring. The results are shown in Table 2.

[0052] Table 2 Monitoring results of Leymus chinensis seedlings after 2 weeks of growth in Example 2 and Comparative Example 2

[0053]

[0054] Among them, the risk screening values ​​in the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (Trial)" (GB 15618-2018) are as shown in Table 3. The risk screening value refers to the value at which the pollutant content in the agricultural land soil is equal to or lower than this value, and the risk to the quality and safety of agricultural products, crop growth or soil ecological environment is low and can generally be ignored. It can be seen that the content of heavy metals in the repaired soil obtained by the technical solution of the present invention is lower than the limit value in the national standard, meeting the requirements of the national standard.

[0055] Table 3 Screening values ​​for soil pollution risk in agricultural land

[0056]

[0057]

[0058] Example 3

[0059] The abandoned water-based rock cuttings at the gas field site were crushed and sieved at 2 mm. The sieved rock cuttings and mud were mixed at a mass ratio of 2.7:1 to form a mixed raw material. After sieving the loess soil at 2 mm, it was mixed with the mixed raw material at a mass ratio of 3.8:1 to form a mixed soil. 4% biochar, 0.015% urea, 0.4% mineral humic acid and 1.7% desulfurized gypsum were added to the mixed soil to form a repaired soil, and the sheep grass seedlings were planted in the repaired soil. During the planting period, the soil moisture content was maintained at 50-70%. After 2 weeks of growth, the plant height, fresh weight and dry weight were increased, and the contents of chromium, arsenic, lead, mercury and cadmium met the requirements of GB15618-2018.

[0060] Example 4

[0061] The abandoned water-based rock cuttings at the gas field site were crushed and sieved at 2 mm. The sieved rock cuttings and mud were mixed in a mass ratio of 2.2:1 to form a mixed raw material. After sieving the sandy loess at 2 mm, it was mixed with the mixed raw material in a mass ratio of 3.3:1 to form a mixed soil. 3.5% biochar, 0.025% urea, 0.55% mineral humic acid and 1.2% desulfurized gypsum were added to the mixed soil to form a repaired soil, and the sheep grass seedlings were planted in the repaired soil. During the planting period, the soil moisture content was maintained at 50-70%. After 2 weeks of growth, the plant height, fresh weight and dry weight were increased, and the contents of chromium, arsenic, lead, mercury and cadmium met the requirements of GB15618-2018.

[0062] Example 5

[0063] The repaired soil prepared by the technical solution of the present invention can also be used to grow plants such as alfalfa and beet, and their growth conditions are shown in Table 4.

[0064] Table 4 Growth trends of alfalfa and beet planted in the remediated soil prepared in Example 1 of the present invention

[0065]

[0066] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing soil restoration using gas field water-based drilling waste, characterized in that: The following steps are involved: S1: Screening the solid phase in the water-based drilling waste of the gas field; S2: mixing the sieved solid waste with liquid waste in gas field water-based drilling waste to obtain a mixed raw material; S3: mixing the soil with the mixed raw material to obtain mixed soil; S4: adding biochar, urea, mineral humic acid and desulfurized gypsum to the mixed soil to obtain the repaired soil.

2. A method for preparing soil restoration using gas field water-based drilling waste according to claim 1, characterized in that: After sieving in step S1, solid waste with a particle diameter not greater than 2 mm is obtained.

3. The method for preparing soil restoration using gas field water-based drilling waste according to claim 1, characterized in that: In the step S1, the solid waste with a size larger than 2 mm is crushed and then sieved again.

4. The method for preparing soil restoration using gas field water-based drilling waste according to claim 1, characterized in that: In the step S2, the mixed mass ratio of the filtered waste to the liquid phase waste in the gas field water-based drilling waste is (2-3):

1.

5. The method for preparing soil restoration using gas field water-based drilling waste according to claim 1, characterized in that: In step S3, the mixing mass ratio of the soil to the mixed raw material is (3-4):

1.

6. The method for preparing soil restoration using gas field water-based drilling waste according to claim 4, characterized in that: Calculated by mass percentage of the mixed soil, the added amount of biochar is 3% to 5%, the added amount of urea is 0.01% to 0.03%, the added amount of mineral humic acid is 0.4% to 0.6%, and the added amount of desulfurized gypsum is 1% to 2%.

7. The method for preparing soil restoration using gas field water-based drilling waste according to claim 4, characterized in that: The particle size of the biochar is not greater than 0.02 mm; the nitrogen content in the urea is 44% to 46%; the number of effective live bacteria in the mineral humic acid is not less than 500 million / g, and the mass fraction of humic acid is not less than 50%; the content of CaSO4 in the desulfurized gypsum is not less than 74%.

8. The method for preparing soil restoration using gas field water-based drilling waste according to claim 1, characterized in that: The soil includes loess soil or sandy loess soil.

9. A remediation soil prepared using gas field water-based drilling waste, characterized in that: It is prepared by the method according to any one of claims 1 to 8.

10. Use of the remediation soil prepared from gas field water-based drilling waste as claimed in claim 9 in plant cultivation.

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