Harmless treatment method for geological drilling waste water-based drilling fluid

Abstract

The invention provides a geological drilling waste water-based drilling fluid harmless treatment method, which adopts a chemical and physical combined method to treat waste drilling fluid, and comprises the following steps: firstly, adding a composite efficient gel breaker to carry out gel breaking on the waste drilling fluid to destroy the colloid structure of the waste drilling fluid, and adding a flocculant and a coagulant aid to further flocculate and destabilize; suspended fine particles are flocculated and agglomerated into large flocculates, a decolorizing agent is added for adsorption decolorization treatment, solid-liquid separation is performed through a filter press, the separated liquid phase can reach the standard to be discharged or recycled, and the separated solid phase is harmless solid waste and can be laid in a well site or transferred and buried. According to the innocent treatment method for the geological drilling waste drilling fluid, the treated liquid phase reaches the secondary standard of Integrated Wastewater Discharge Standard, the water content of the treated solid phase is lower than 20%, the environmental protection requirement is met, and the problem that the environment is polluted by the waste drilling fluid generated in the geological drilling process can be solved.

Description

Technical Field

[0001] The invention relates to the field of geological drilling waste drilling fluid treatment, and in particular to a method for harmlessly treating geological drilling waste water-based drilling fluid. Background Art

[0002] The implementation of geological drilling projects will bring a series of impacts to the ecological environment, including disturbance, destruction or pollution of vegetation, surface cover and groundwater, and waste slurry pollution. The construction of ecological civilization and the concept of green development have put forward higher requirements for drilling projects. Improper use and disposal of drilling fluid is the main source of environmental pollution in geological exploration drilling. To achieve green exploration, it is necessary to solve the environmental pollution problem of drilling fluid from the source, construction process and post-drilling treatment.

[0003] Waste drilling fluid from geological drilling is a multiphase colloid-suspension system containing clay, various chemical treatment agents, sewage, dirty oil and rock powder. If it is not treated, discharged at will, or improperly managed and treated, it will cause immeasurable harm to the surrounding people, animals and the natural environment. The main components of waste drilling fluid that are harmful to the environment are organic hydrocarbons, inorganic salts, and certain heavy metal ions (such as mercury, cadmium, chromium, arsenic, lead), etc.

[0004] The treatment technology of waste drilling fluid in oil and gas drilling is relatively mature, but there is little research on waste drilling fluid in the field of geological drilling. With the introduction of the concept of green development and the in-depth development of ecological civilization construction, more stringent requirements have been put forward for the treatment technology of waste drilling fluid, and treatment technology methods suitable for the characteristics of waste drilling fluid in geological drilling are urgently needed. Summary of the invention

[0005] The purpose of the present invention is to provide a method for harmlessly treating waste water-based drilling fluid in geological drilling to solve the problem of environmental pollution caused by waste drilling fluid generated in the geological drilling process. The separated liquid phase meets the secondary sewage discharge standard and can also be recycled. The separated solid phase is harmless solid waste, which can be laid in the well site or transported for landfill. The method has low treatment cost and high treatment efficiency.

[0006] The harmless treatment method of waste water-based drilling fluid of the present invention adopts the following technical scheme:

[0007] A method for harmless treatment of waste water-based drilling fluid in geological drilling is composed of five parts: gel breaking and destabilization, flocculation and sedimentation, adsorption and decolorization, oxidation and degradation, and solid-liquid separation, including the following steps:

[0008] Add 10-30kg of debonding agent to each cubic meter of waste drilling fluid, stir evenly, and perform debonding and destabilization.

[0009] Add 2-10 kg of flocculant and 1-5 kg ​​of coagulant aid to the waste drilling fluid after gel breaking and destabilization to carry out flocculation and sedimentation;

[0010] Add 5-20 kg of decolorizing agent to the waste drilling fluid after flocculation and sedimentation for adsorption decolorization;

[0011] A filter press is used to separate the solid and liquid of the waste drilling fluid after adsorption and decolorization. The liquid phase meets the secondary standard of the "Comprehensive Wastewater Discharge Standard" and can be directly discharged or recycled. The solid phase is laid at the well site or transported for landfill.

[0012] Furthermore, after adsorption decolorization and before solid-liquid separation, the method further includes adding 10 to 40 kg of oxidant and 10 to 40 kg of co-oxidant to the waste drilling fluid after adsorption decolorization for oxidative degradation;

[0013] 10-50 kg of acid-base regulator is added to the waste drilling fluid after oxidation degradation to adjust the pH value.

[0014] Furthermore, the debonding agent comprises the following components in terms of weight percentage: 50% to 80% of polyaluminium sulfate, 20% to 40% of calcium chloride, and 0% to 20% of polyaluminium chloride.

[0015] Furthermore, the flocculant comprises any one or a combination of the following components in terms of weight percentage: 30% to 100% anionic polyacrylamide, 0% to 60% polyaluminium sulfate, and 0% to 60% polyaluminium chloride.

[0016] Furthermore, the coagulant aid is sodium polyacrylate.

[0017] Furthermore, the decolorizing agent comprises any one or a combination of the following components in terms of weight percentage: 50% to 100% activated carbon and 0% to 100% activated clay.

[0018] Furthermore, the oxidant comprises any one or a combination of the following compositions in terms of weight percentage: 30% to 60% hydrogen peroxide, 0% to 60% sodium hypochlorite, and 0% to 60% calcium hypochlorite.

[0019] Furthermore, the co-oxidant is ferrous chloride or ferrous sulfate.

[0020] Furthermore, the acid-base regulator is sodium hydroxide or hydrochloric acid.

[0021] Furthermore, the treated waste drilling fluid is subjected to solid-liquid separation treatment, specifically, the treated waste drilling fluid is subjected to filter pressing treatment using a filter press to obtain a liquid phase and a solid phase.

[0022] The harmless treatment method of waste water-based drilling fluid provided by the present invention has the following technical effects:

[0023] The harmless treatment technology of waste water-based drilling fluid of the present invention adopts gel breaker, flocculant, coagulant, decolorant, oxidant and acid-base regulator to cooperate with each other, with high treatment efficiency, low solid phase water content, and the separated liquid phase meets the secondary discharge standard and can be directly discharged or recycled. The present invention comprehensively treats waste water-based drilling fluid from the source of pollution, provides technical guarantee for civilized construction, reduces pollution to the environment, and has significant environmental protection, economic and social benefits. DETAILED DESCRIPTION

[0024] The technical solutions disclosed in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Furthermore, all materials used in the examples can be obtained through commercial channels.

[0026] Specifically, in the embodiment of the present invention, the degelling agent is polyaluminum sulfate, calcium chloride, polyaluminum chloride or a combination of the above substances, and the products on sale by Gongyi City Liyuan Water Treatment Materials Co., Ltd., Gongyi City Xinqi Polymer Co., Ltd. and Gongyi City Filter Material Industry Co., Ltd. are preferably used.

[0027] In the embodiment of the present invention, the flocculant is anionic polyacrylamide, polyaluminum sulfate, polyaluminum chloride or a combination of the above substances, and the products sold by Gongyi Liyuan Water Treatment Materials Co., Ltd., Gongyi Xinqi Polymer Co., Ltd. and Gongyi Filter Material Industry Co., Ltd. are preferably used.

[0028] In the embodiment of the present invention, the coagulant aid is sodium polyacrylate, and the products sold by Jinan Zhongbei Fine Chemical Co., Ltd., Shandong Delan Chemical Co., Ltd., and Shandong Muheng Biotechnology Co., Ltd. are preferably used.

[0029] In the embodiments of the present invention, the decolorizing agent is activated carbon, activated clay or a combination of the two, and the products on sale by Gongyi Filter Source Water Treatment Materials Co., Ltd., Gongyi Xinqi Polymer Co., Ltd. and Gongyi Filter Material Industry Co., Ltd. are preferably used.

[0030] In the embodiment of the present invention, the oxidant is hydrogen peroxide, sodium hypochlorite, calcium hypochlorite or a combination of the above substances, and the products on sale by Gongyi City Filter Source Water Treatment Materials Co., Ltd., Langfang City Tuodi Chemical Co., Ltd., and Langfang City Huachen Chemical Co., Ltd. are preferably used.

[0031] Example 1

[0032] Application site: a well in Enshi block, Hubei;

[0033] Sources of waste drilling fluid: waste drilling fluid generated by drilling solids control equipment vibrating screen, desilter and desander, and centrifuge;

[0034] Drilling fluid properties: Main pollution indicators are shown in Table 1;

[0035] Gel breaking: Add a gel breaker to the waste water-based drilling fluid, wherein 15 kg of polyaluminium sulfate and 5 kg of calcium chloride are added to each cubic metre of waste drilling fluid, and stir to break the gel after adding, so as to achieve gel breaking and destabilisation of the waste drilling fluid;

[0036] Flocculation: add flocculant to the waste drilling fluid after gel breaking treatment, add while stirring, wherein 5kg of anionic polyacrylamide is added to each cubic meter of waste drilling fluid, then add coagulant aid, stir evenly, wherein 2kg of sodium polyacrylate is added to each cubic meter of waste drilling fluid;

[0037] Decolorization: add decolorizer to the waste drilling fluid after gel breaking and flocculation treatment, stir evenly, and add 10kg activated carbon to every cubic meter of waste drilling fluid;

[0038] Oxidation: Add oxidant, co-oxidant and acid-base regulator to the decolorized waste drilling fluid, stir evenly, add 10kg of sodium hypochlorite and 10kg of ferrous sulfate to each cubic meter of waste drilling fluid. Specifically, the sodium hypochlorite is added by diluting it into a solution with a mass concentration of 10%, and adding it while stirring. Add 20kg of sodium hydroxide to each cubic meter of waste drilling fluid;

[0039] Solid-liquid separation: The treated waste drilling fluid is separated into solid and liquid by using a filter press with the pressure set at 0.6-0.75MPa. The separated solid phase has a moisture content of less than 15%, and the separated liquid phase can meet the secondary sewage discharge standard. The pollution index test results are shown in Table 1.

[0040] Table 1 Liquid phase water quality test results after waste drilling fluid treatment in Example 1

[0041]

[0042] Result analysis: After treatment, the waste drilling fluid meets the secondary standard of the "Comprehensive Wastewater Discharge Standard" (GB 8978-1996), can be recycled to prepare new drilling fluid, and the separated solid phase water content is less than 15%. It meets environmental protection requirements and achieves the purpose of protecting the environment, reducing costs and increasing efficiency.

[0043] Example 2

[0044] Application site: a well in Zhumadian area, Henan;

[0045] Source of waste drilling fluid: waste drilling fluid remaining on the surface after the construction is completed;

[0046] Gel breaking: Add a gel breaker to the waste water-based drilling fluid, wherein 20 kg of polyaluminium sulfate is added to each cubic metre of waste drilling fluid, and stir to break the gel after adding, so as to achieve gel breaking and destabilisation of the waste drilling fluid;

[0047] Flocculation: add flocculant to the waste drilling fluid after gel breaking treatment, add while stirring, wherein 5kg of anionic polyacrylamide is added to each cubic meter of waste drilling fluid, then add coagulant aid, stir evenly, wherein 2kg of sodium polyacrylate is added to each cubic meter of waste drilling fluid;

[0048] Decolorization: add decolorizer to the waste drilling fluid after gel breaking and flocculation treatment, stir evenly, and add 5kg activated carbon to every cubic meter of waste drilling fluid;

[0049] Solid-liquid separation: The treated waste drilling fluid is separated into solid and liquid by using a filter press with the pressure set at 0.6-0.75MPa. The separated solid phase has a moisture content of less than 15%, and the separated liquid phase can meet the secondary sewage discharge standard. The pollution index test results after treatment are shown in Table 2.

[0050] Table 2 Liquid phase water quality test results after waste drilling fluid treatment in Example 2

[0051] Appearance Chroma(times) COD value (mg / L) BOD value (mg / L) Suspended matter (mg / L) pH Colorless and transparent 16 31 8 41 7

[0052] Example 3

[0053] Application site: a well in Shaoguan area of ​​Guangdong;

[0054] Source of waste drilling fluid: waste drilling fluid remaining on the surface after the construction is completed;

[0055] Gel breaking: Add a gel breaker to the waste water-based drilling fluid, wherein 20 kg of polyaluminium sulfate is added to each cubic metre of waste drilling fluid, and stir to break the gel after adding, so as to achieve gel breaking and destabilisation of the waste drilling fluid;

[0056] Flocculation: add flocculant to the waste drilling fluid after gel breaking treatment, add while stirring, wherein 5kg of anionic polyacrylamide is added to each cubic meter of waste drilling fluid, then add coagulant aid, stir evenly, wherein 2kg of sodium polyacrylate is added to each cubic meter of waste drilling fluid;

[0057] Decolorization: add decolorizer to the waste drilling fluid after gel breaking and flocculation treatment, stir evenly, and add 10kg activated carbon to every cubic meter of waste drilling fluid;

[0058] Solid-liquid separation: The treated waste drilling fluid is separated into solid and liquid by using a filter press with the pressure set at 0.6-0.75MPa. The separated solid phase has a moisture content of less than 15%, and the separated liquid phase can meet the secondary sewage discharge standard. The pollution index test results after treatment are shown in Table 3.

[0059] Table 3 Liquid phase water quality test results after waste drilling fluid treatment in Example 3

[0060] Appearance Chroma(times) COD value (mg / L) BOD value (mg / L) Suspended matter (mg / L) pH Colorless and transparent 16 126 24 28 6

[0061] The waste drilling fluid is rendered harmless to meet environmental protection requirements, achieving the goals of protecting the environment, reducing costs and increasing efficiency.

Claims

1. A method for harmless treatment of waste water-based drilling fluid in geological drilling, characterized in that: It consists of five parts: gel breaking and destabilization, flocculation and sedimentation, adsorption and decolorization, oxidation and degradation, and solid-liquid separation, including the following steps: Add 10-30kg of debonding agent to each cubic meter of waste drilling fluid, stir evenly, and perform debonding and destabilization. Add 2-10 kg of flocculant and 1-5 kg ​​of coagulant aid to the waste drilling fluid after gel breaking and destabilization to carry out flocculation and sedimentation; Add 5-20 kg of decolorizing agent to the waste drilling fluid after flocculation and sedimentation for adsorption decolorization; A filter press is used to separate the solid and liquid of the waste drilling fluid after adsorption and decolorization. The liquid phase meets the secondary standard of the "Comprehensive Wastewater Discharge Standard" and can be directly discharged or recycled. The solid phase is laid at the well site or transported for landfill.

2. A method for harmless treatment of waste water-based drilling fluid in geological drilling according to claim 1, characterized in that: After adsorption and decolorization, and before solid-liquid separation, the method further includes adding 10 to 40 kg of oxidant and 10 to 40 kg of co-oxidant to the waste drilling fluid after adsorption and decolorization for oxidative degradation; 10-50 kg of acid-base regulator is added to the waste drilling fluid after oxidation degradation to adjust the pH value.

3. A method for harmless treatment of waste water-based drilling fluid in geological drilling according to claim 1 or 2, characterized in that: The debonding agent comprises the following components in terms of weight percentage: 50% to 80% of polyaluminium sulfate, 20% to 40% of calcium chloride and 0% to 20% of polyaluminium chloride.

4. A method for harmless treatment of waste water-based drilling fluid in geological drilling according to claim 1 or 2, characterized in that: The flocculant comprises any one or a combination of the following components in terms of weight percentage: 30% to 100% anionic polyacrylamide, 0% to 60% polyaluminium sulfate, and 0% to 60% polyaluminium chloride.

5. A method for harmless treatment of waste water-based drilling fluid in geological drilling according to claim 1 or 2, characterized in that: The coagulant aid is sodium polyacrylate.

6. A method for harmless treatment of waste water-based drilling fluid in geological drilling according to claim 1 or 2, characterized in that: The decolorizing agent comprises any one or a combination of the following components in terms of weight percentage: 50% to 100% of activated carbon and 0% to 100% of activated clay.

7. The method for harmless treatment of waste water-based drilling fluid in geological drilling according to claim 2, characterized in that: The oxidant comprises any one or a combination of the following compositions in terms of weight percentage: 30% to 60% hydrogen peroxide, 0% to 60% sodium hypochlorite, and 0% to 60% calcium hypochlorite.

8. A method for harmless treatment of waste water-based drilling fluid in geological drilling according to claim 2 or 7, characterized in that: The co-oxidant is ferrous chloride or ferrous sulfate.

9. The method for harmless treatment of waste water-based drilling fluid in geological drilling according to claim 2, characterized in that: The acid-base regulator is sodium hydroxide or hydrochloric acid.

10. The method for harmless treatment of waste water-based drilling fluid in geological drilling according to claim 1, characterized in that: The treated drilling fluid is subjected to solid-liquid separation treatment, specifically, the treated waste drilling fluid is subjected to filter pressing treatment using a filter press to obtain a liquid phase and a solid phase.

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