Deep purification method for water-based drilling pressure filtrate

Abstract

The invention relates to the technical field of oil field drilling waste treatment, in particular to a water-based drilling pressure filtrate deep purification method which comprises the following steps: feeding water-based drilling pressure filtrate into a fixed bed reactor for destabilization enzymolysis; the added immobilized compound enzyme is prepared by adsorbing a compound enzyme preparation onto a porous solid-phase carrier and incubating in a tetraethyl orthosilicate solution; feeding into a coalescence reactor for decoloration, hardness removal and filtration; the added modified adsorption coalescence agent is obtained by carrying out shake culture on carboxymethyl chitosan in a microbial liquid; and finally, feeding into an electrochemical bioreactor for decoloration and hardness removal so as to realize recycling and pulp preparation. The added microbial activator is prepared by compounding a carbon source, a nitrogen source, a phosphorus source and molasses fermentation liquor. The method provided by the invention solves the problems of high purification difficulty of the press filtrate and low recycling rate of the press filtrate caused by the gel breaker.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield drilling filtrate treatment, and in particular to a method for deep purification of water-based drilling filtrate. Background Art

[0002] In the process of crude oil extraction, a large amount of drilling solid and liquid waste is usually generated. The composition of these wastes is complex, generally containing drill cuttings, clay, weighting materials, petroleum, inorganic salts, organic salts, drilling fluid additives, etc., which makes these wastes difficult to handle, and improper disposal can easily cause serious impacts on the environment.

[0003] At present, drilling solid and liquid waste is mainly treated by plate and frame filter press process. The specific process is: first, the drilling solid and liquid waste is collected into the waste collection tank through the solid control system, and after reaching the preset amount, it is transferred to the filter press gel breaking tank for treatment; a gel breaker is added to the filter press gel breaking tank for gel breaking treatment; then a liquid supply pump is used to inject the completely debonded solid-liquid mixture into the plate and frame filter press for solid-liquid separation, and filter cake and filtrate are produced after separation. However, the filtrate after plate and frame filtration still contains a large amount of organic matter and high-valent ions, which will have a huge impact on the reuse and slurry preparation of the filtrate.

[0004] The analysis of the filtrate showed that the reason why the filtrate reuse is difficult is mainly because a degelling agent must be added during the drilling fluid degelling process to degel. As a result, a large amount of A1 remains in the filtrate produced after degelling. 3+ , Fe 2+ , Fe 3+ , Ca 2+ Mg 2+ , Cl- ions, cationic surfactants and water-soluble polymers. Limited by on-site operating conditions, it is difficult to achieve on-site purification of filtrate using conventional purification methods, such as chemical oxidation, flocculation, and filtration processes. Most of the waste filtrate cannot be recycled and reused to prepare drilling fluid; the resource reuse rate of waste filtrate is less than 10%. In addition, the water-based drilling filtrate system also contains highly difficult-to-degrade water-soluble substances, high chroma, high hardness, and high salt. The disposal cost is high, and the relevant indicators cannot fully meet the sewage discharge standards. Summary of the invention

[0005] In order to solve the problems of great difficulty in purifying filtrate caused by debonding agents and low resource recovery rate of filtrate, the purpose of the present invention is to provide a method for deep purification of water-based drilling filtrate.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows.

[0007] The present invention provides a method for deep purification of water-based drilling filtrate, comprising the following steps:

[0008] The water-based drilling filtrate is sent to a fixed bed reactor for destabilization enzymolysis; the fixed bed reactor is filled with an immobilized complex enzyme;

[0009] The water-based drilling filtrate after destabilization and enzymatic hydrolysis is sent to a polymerization reactor, and a modified adsorption polymerization agent is added to decolorize it; then an alkaline agent is added to remove hardness, and then filtered;

[0010] The separated filtrate is sent to an electrochemical bioreactor, and a microbial activator is added to the electrochemical bioreactor to decolorize and remove hardness, so as to realize the reuse of pulp;

[0011] The immobilized complex enzyme is prepared by adsorbing the complex enzyme preparation onto a porous solid phase carrier and incubating it in a tetraethyl orthosilicate solution; the complex enzyme preparation is prepared by combining the complex enzyme, a glycolipid protective agent, a salt-tolerant bacterium, and an additive;

[0012] The modified adsorption polymerizing agent is obtained by oscillating and culturing carboxymethyl chitosan in a microbial culture solution; the total number of viable bacteria in the microbial culture solution is 5×10 9 cfu / g~10×10 9 cfu / g; the microorganism in the microbial solution is at least one of Bacillus, denitrifying bacteria, lactic acid bacteria, and yeast;

[0013] The microbial activator is prepared by compounding a carbon source, a nitrogen source, a phosphorus source and molasses fermentation liquid, wherein the mass ratio of the carbon source, the nitrogen source, the phosphorus source and the molasses fermentation liquid is 1:0.2-0.5:0.1-0.2:2-4.

[0014] Preferably, the tetraethyl orthosilicate solution is obtained by dispersing tetraethyl orthosilicate in a phosphate buffer solution; the concentration of the tetraethyl orthosilicate solution is 8-10 mmol / L.

[0015] Preferably, the pH of the phosphate buffer solution is 4-7, preferably 5-7.

[0016] Preferably, the mass ratio of the complex enzyme preparation to the porous solid phase carrier is 0.2:1;

[0017] The mass ratio of the complex enzyme preparation to the tetraethyl orthosilicate solution is 0.2:1000.

[0018] Preferably, the material of the porous solid phase carrier is at least one of pumice, silicon oxide, aluminum oxide, and zirconium oxide. Preferably, the particle size of the porous solid phase carrier is 35 to 500 μm.

[0019] Preferably, the mass ratio of the complex enzyme, glycolipid protective agent, salt-tolerant bacteria and additive is 1-10:0.5-3:0.5-3:0.1-1.

[0020] Preferably, the complex enzyme is a mixture of at least two of acid protease, amylase, pectinase, cellulase, laccase, catalase, lipase, and hydrolase;

[0021] The glycolipid protective agent is at least one of rhamnolipid, sophorolipid and trehalolipid;

[0022] The salt-tolerant bacteria are at least one of nitrifying bacteria, Bacillus subtilis, and photosynthetic bacteria;

[0023] The additive is at least one of vitamin C, carbonic acid amide, monocrystalline glucose powder, ammonium sulfate, ammonium chloride, and ammonium molybdate.

[0024] Preferably, the modified adsorption and aggregation agent is prepared by the following method:

[0025] The sterilized carboxymethyl chitosan is added to the microbial liquid, cultured under shaking at 25° C. to 30° C. for 4 to 6 days, and then vacuum-freeze-dried to obtain the product.

[0026] Preferably, the mass ratio of the carboxymethyl chitosan to the microbial culture liquid is 0.01-0.04:2.

[0027] Preferably, the carbon source is any one of glucose, sucrose and corn starch;

[0028] The molasses fermentation liquid is obtained by fermenting molasses, and the dry basis content of the molasses fermentation liquid is ≥50%;

[0029] The nitrogen source is any one of peptone, ammonium chloride, ammonium sulfate, and yeast powder;

[0030] The phosphorus source is any one of dipotassium hydrogen phosphate, potassium dihydrogen phosphate, and diammonium hydrogen phosphate.

[0031] Preferably, the electrochemical bioreactor has an anode chamber, in which anode plates are vertically arranged, and the anode chamber is filled with conductive oxidizing fillers; electroactive microorganisms grow on both the anode plates and the conductive oxidizing fillers; the electroactive microorganisms are Geobacter or anaerobic ammonia-oxidizing bacteria.

[0032] Preferably, the fixed bed reactor is provided with an aeration pipe along the flow direction of the water-based drilling filtrate; an aeration head is arranged on the aeration pipe, and the aeration direction of the aeration head is opposite to the flow direction of the water-based drilling filtrate. The aeration direction of the aeration head forms an angle α with the flow direction of the water-based drilling filtrate; the value range of the angle α is 30-80°.

[0033] Preferably, the plurality of aeration pipes are connected to an oxygen pipeline or an air pipeline for providing oxygen. The plurality of aeration pipes are arranged in parallel in a fixed bed reactor, and aeration areas with different oxygen concentrations can be alternately formed in the fixed bed reactor through an equidistant arrangement, such as aeration areas with high and low concentrations alternately arranged.

[0034] Beneficial effects of the present invention:

[0035] 1. The present invention introduces immobilized complex enzymes into water-based drilling filtrate, and utilizes the combination of complex enzyme preparations and carriers to efficiently remove water-soluble colloids, polymers and other difficult-to-resolve macromolecular substances in the filtrate, thereby solving the technical problem of the influence of high-molecular organic matter in the filtrate on the return drilling fluid. After passing through the bio-enzyme fixed bed reactor, most of the polymers in the filtrate are broken and decomposed to form unstable medium and small molecules; in the polymerization reactor, efficient adsorption and agglomeration are achieved by adding modified adsorption polymerization agents, thereby achieving efficient organic matter removal.

[0036] 2. The present invention can rapidly decompose some water-soluble polymer materials in the filtrate through the interaction of the efficient degradation enzyme and glycolipid protective agent in the composite enzyme preparation, efficiently degrade the toxic components in the filtrate, and ensure the rapid reproduction of salt-tolerant bacteria, thereby achieving deep degradation of organic matter in the filtrate.

[0037] 3. The present invention uses a modified adsorbent to electrically neutralize anionic groups in wastewater pollutant molecules to form an easily removable substance. At the same time, the huge surface area generated by the hydrolysis of the modified adsorbent plays a network bridging role, and achieves water flocculation and purification by capturing and adsorbing flocculant particles.

[0038] 4. The present invention combines the advantages of biological and chemical methods through biological coupling chemical process, and has the advantages of simple process, convenient operation, low cost, etc. It is suitable for promotion in the deep disposal of mud filtrate in Changqing Oilfield, and is of great significance for the deep disposal of drilling mud filtrate and the resource utilization of mud well site. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A flowchart of a method for deep purification of water-based drilling filtrate provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0042] At present, drilling solid and liquid waste is mainly treated by filter pressing through plate and frame filter pressing process. However, the filtrate after plate and frame filtration still contains a large amount of organic matter and high-valent ions, which will have a great impact on the reuse and slurry preparation of the filtrate.

[0043] Through the analysis of oilfield water-based drilling filtrate, it can be seen that there are many types of water-based drilling fluid systems, especially sulfonated drilling fluid systems and brine drilling fluid systems, which have the characteristics of high difficult to degrade water-soluble COD, high chroma, high hardness, and high salt. Local treatment plants need to adopt advanced oxidation, electrodialysis, chemical hardness removal, membrane separation, evaporation crystallization and other processes to meet the sewage "GB8978-1996" discharge standards and difficult to degrade organic wastewater deep treatment "GB / T39308-2020" process control conditions, but the site disposal cost is high, and local areas often do not accept and treat high COD and high salinity drilling filtrate fluids, resulting in large well site inventories, high storage safety and environmental risks, and serious impact on normal drilling operations.

[0044] The drilling fluid degelling process must be done by adding degelling agents. Due to the addition of degelling agents, a large amount of Al2O3 remains in the filter press waste liquid after degelling. 3+ , Fe 2+ , Fe 3+ , Ca 2+ Due to the limitations of on-site operating conditions, it is difficult to purify the filter press liquid on-site using conventional chemical oxidation, flocculation and filtration processes due to the high-valent metal ions and cationic surfactants and water-soluble rigid and difficult-to-degrade polymers in the drilling fluid system. Most of the filter press waste liquid cannot be recycled and reused to prepare drilling fluid; the resource reuse rate of filter press waste liquid is less than 10%.

[0045] The reasons why the filter press fluid is difficult to reuse are as follows: First, during the degumming process, water-soluble polymer surfactants such as carboxymethyl cellulose, starch, polyacrylamide copolymers, humic acid, phenolic resins, and cationic organic matter in drilling additives seep out from the filter cloth. The residual substances of these drilling additives have a certain viscosity. During the mud degumming process, the performance of these water-soluble substances themselves fails, but they affect the performance of the newly added drilling additives in the secondary slurry, which has a great impact on the re-mixing of the filter press fluid; second, the drilling fluid has good stability, especially in the completion stage, a large amount of lime needs to be added to the drilling fluid for degumming, resulting in high hardness of the filter press fluid, in which calcium ions reach 10,000 mg / L, and calcium ions will interact with drilling additives and affect the rheological properties of the drilling fluid; third, during the degumming process, the aluminum-based degumming agent causes a certain concentration of trivalent aluminum ions in the filter press fluid. Aluminum ions have strong positive charge. On the one hand, they can passivate sodium-based bentonite and affect bentonite slurrying. On the other hand, aluminum ions are easy to cross-link with polymer drilling additives, resulting in a decrease in mud performance.

[0046] Through the above analysis, it can be seen that the key point of deep purification and reuse of water-based drilling filtrate in oilfields is to solve the influence of interference factors of filtrate such as high molecular polymers, surfactants, cationic organic matter, and high-valent ions on the reuse and preparation of filtrate, and to improve the reuse rate of filtrate. In summary, the factors affecting the deep purification and reuse of water-based drilling filtrate in oilfields are mainly the removal of organic matter and calcium and magnesium ions in the filtrate. If the removal efficiency of organic matter is not good, it will also affect the hardness removal effect of the filtrate. Therefore, the removal of organic matter in the filtrate is the most important factor affecting the deep purification and reuse of water-based drilling filtrate in oilfields.

[0047] At present, through searching the literature, the known methods for removing organic matter from water-based drilling filtrate in oil fields are mainly concentrated on the oxidation process, which is to pre-treat the filtrate by oxidation to facilitate subsequent biochemical treatment. However, the mud filtrate is reused near the wellhead, lacks fixed hazardous chemical storage facilities, and occupies a large area. Considering the site safety and site operation conditions, the oxidation process cannot meet the requirements. In addition, the commonly used oxidation processes include Fenton reagent oxidation process, iron-carbon micro-electrolysis process, electrocatalytic oxidation process, and ozone catalytic oxidation process. However, the Fenton reagent oxidation process has the problems of large amount of reagent, high cost, long reaction time, and low oxidation capacity. In addition, hazardous chemicals such as sulfuric acid and hydrogen peroxide need to be added on site, which poses certain safety hazards. In the iron-carbon micro-electrolysis process, the iron-carbon filler is easy to compact, the amount of reagent is large, and sulfuric acid is also needed to adjust the pH value, and hazardous chemicals such as hydrogen peroxide need to be added. The electrocatalytic oxidation process is suitable for the chain breaking, gel breaking and viscosity reduction of organic matter in wastewater that is difficult to biodegrade or difficult to be oxidized by general chemical oxidation. However, the electrocatalytic oxidation process is not suitable for treating low-concentration polluted organic matter. For low-concentration organic matter, the electrocatalytic oxidation treatment efficiency is low, the power consumption is high, and it is easy to scale. Moreover, it is often necessary to add conductive salts to increase the conductivity of the wastewater to ensure the smooth progress of the electrocatalytic oxidation reaction. Therefore, the scope of application and cost-effectiveness of the electrocatalytic oxidation technology should still be paid attention to in practical applications. The disadvantage of the ozone catalytic oxidation process is that it is easy to scale, and the high calcium and magnesium in the filtrate affect the oxidation efficiency.

[0048] Based on the above analysis, the present invention aims to develop a water-based drilling filtrate deep purification method to replace the conventional oxidation process, achieve efficient removal of water-soluble organic polymers in the mud filtrate, and ensure efficient reuse of the drilling filtrate.

[0049] The inventive principle of the present invention is to introduce a composite enzyme preparation into the drilling filtrate, utilize the catalytic degradation of biological enzymes and the efficient adsorption characteristics of the active agent enzyme carrier to efficiently remove the difficult-to-resolve macromolecular substances such as water-soluble colloids and polymers in the filtrate, and solve the technical problem of the influence of high-molecular organic matter in the filtrate on the return of drilling fluid. After passing through the biological enzyme fixed bed reactor, most of the polymers in the filtrate are broken down by chain breaking to form unstable medium-molecular and small-molecular substances; in the polymerization reactor, efficient adsorption and agglomeration are achieved by adding modified adsorption polymerization agents, achieving efficient organic matter removal effects; and then through the electrochemical bioreactor, the pollutants in the filtrate are further removed, providing a basis for the efficient reuse of the filtrate. For the specific process flow, see Figure 1 .

[0050] The composite enzyme preparation described in the present invention is mainly composed of cellulose degrading enzyme, lignin degrading enzyme, glycolipid protective agent, salt-tolerant bacteria and additives. Through the interaction between the high-efficiency degrading enzyme and the glycolipid protective agent, part of the water-soluble polymer materials in the filtrate can be quickly decomposed, the toxic components in the filtrate can be efficiently degraded, and the rapid reproduction of salt-tolerant bacteria can be ensured to achieve deep degradation of organic matter in the filtrate.

[0051] The fixed bed reactor is an aerated fixed bed reactor with repeated coupling of aerobic immobilized complex enzyme preparations. It contains multiple mineral components as carriers, providing a good skeleton for the immobilized complex enzymes. It has a good porous structure and a specific surface area of ​​2000m 2 / g, can efficiently adsorb water-soluble and difficult-to-degrade organic macromolecules, and promote the efficient reaction between enzyme preparations and organic macromolecules. Under a constant dissolved oxygen content, it can perform acidic hydrolysis and ring-opening on macromolecules such as benzene ring structures in the press filtrate, and achieve efficient degradation of water-soluble macromolecules that are difficult to degrade in the press filtrate. Compared with conventional oxidation processes, it does not require the addition of hazardous chemicals such as sulfuric acid and oxidants, and the reaction environment is mild, safe and environmentally friendly. The fixed bed reactor has a good removal effect on organic matter, and its strong impact resistance can meet on-site applications.

[0052] Modified adsorption polymerizer belongs to the category of natural polysaccharide polymer adsorbents. It neutralizes the anionic groups in the wastewater pollutant molecules to form substances that are easy to remove. At the same time, it uses the huge surface area generated by its hydrolysis to play a network bridging role, and achieves water flocculation and purification by capturing and adsorbing flocculant particles. In water treatment technology, it has the effects of decolorization, adsorption, and flocculation for the filtrate of the trisulfone system and the composite salt system. It has good water solubility, is insensitive to pH, has stable properties, and has a good water purification effect.

[0053] The structure of the electrochemical bioreactor is an existing structure. For example, the embodiment of the present invention adopts a bioelectrochemical reactor with application number 202211100429.9. The electrochemical bioreactor is separated by an insulating diaphragm to form an anode chamber and a cathode chamber, and the anode chamber is filled with a conductive oxidizing filler; preferably, the conductive oxidizing filler is activated carbon with a particle size of 0.2 μm to 0.8 μm. The anode chamber has a vertically arranged anode plate, and the first anode chamber and the second anode chamber are formed by the anode plate; the cathode chamber is filled with a conductive reducing filler, preferably, the conductive reducing filler is a carbon-based material modified by nickel oxide, which is an existing conductive reducing filler. The bottom of the insulating diaphragm has a permeable diaphragm to facilitate the liquid in the anode chamber to enter the cathode chamber through the permeable diaphragm. The material of the permeable diaphragm can be selected from insulating materials such as non-woven fabrics; the material of the insulating diaphragm can be selected from insulating materials such as plastic plates. The cathode chamber has a vertically arranged cathode plate, and the first cathode chamber and the second cathode chamber are formed by the cathode plate. When in use, the separated filtrate enters the first anode chamber from the liquid inlet, and then overflows to the second anode chamber through the anode plate; then enters the first cathode chamber through the water-permeable diaphragm at the bottom of the insulating partition, and then overflows to the second cathode chamber through the cathode plate. Of course, in a preferred embodiment of the present invention, there are multiple anode chambers and cathode chambers, which are arranged side by side in sequence and connected to each other, so that the liquid treated in the cathode chamber enters the next group of anode chambers and cathode chambers again to achieve the decolorization and hardness removal effect.

[0054] The present invention combines the advantages of biological and chemical methods through biological coupling chemical process, and has the advantages of simple process, convenient operation, low cost, etc. It is suitable for promotion in the deep disposal of mud filtrate in Changqing Oilfield, and is of great significance for the deep disposal of drilling mud filtrate and the resource utilization of mud well site.

[0055] The present invention is mainly aimed at deep purification of water-based drilling filtrate after plate-frame filter pressing. The deep purification method of water-based drilling filtrate of the present invention is specifically described below through specific embodiments. The methods described in the following embodiments are conventional methods unless otherwise specified; the reagents and materials, unless otherwise specified, can all be purchased on the market.

[0056] In the following embodiments, the water-based drilling fluid is a sol suspension mixed system with water as the dispersion medium and clay such as bentonite, a weighting agent and various chemical treatment agents as the dispersed phase.

[0057] Salt water drilling fluid refers to drilling fluid with a NaCl content exceeding 1wt% or a Cl- content of about 5000mg / L.

[0058] Completion drilling fluid is a general term for the working fluid used in the completion process of oil and gas wells.

[0059] A polymer well section refers to a well section that uses drilling fluid containing polymer additives; polymer well sections generally appear in various formations where the rheology and stability of the drilling fluid need to be improved, especially when it is necessary to control the drilling fluid loss and increase the drilling fluid viscosity.

[0060] The salt water system well section refers to the well section where the drilling fluid contains a certain concentration of salt when encountering saline formations during the drilling process, among which the salt is mainly sodium chloride.

[0061] In the following examples of the present invention, the various bacterial agents described are all purchased from the market. Nitrifying bacteria and Bacillus subtilis, Cangzhou Zhongxin Biotechnology Co., Ltd.

[0062] In the following embodiments of the present invention, amylase is α-amylase, 20,000 U / g; cellulase, 100,000 U / g; hydrolase is a mixture of xylanase and protease in equal mass ratio; xylanase, 100,000 U / g; protease is neutral protease, 50,000 U / g, item number 478; catalase, 100,000 U / g; lipase; 100,000 U / g, item number 0069; pectinase, 50,000 U / g, item number 061, all from Suzhou Zhuoxin Biotechnology Co., Ltd. Laccase, Wenzhou Shoucheng Chemical Technology Co., Ltd., molecular weight 151.2, item number 021.

[0063] In the following embodiments of the present invention, the tetraethyl orthosilicate solution is obtained by dispersing tetraethyl orthosilicate in a phosphate buffer solution; the concentration of the tetraethyl orthosilicate solution is 8-10 mmol / L; and the pH of the phosphate buffer solution is 6.5.

[0064] In the following embodiments of the present invention, the porous solid phase carrier is pumice, the particle size of the pumice is 35-100 μm, the porosity of the pumice is 80.87%, and the pores > 2 μm in the pumice account for 82.39% of the total pores.

[0065] In the following examples of the present invention, carboxymethyl chitosan is from Rewell Biotech, with a molecular weight of 543.5.

[0066] In the following embodiments of the present invention, molasses fermentation liquid, referred to as CMS, is a concentrated fermentation liquid of sugarcane molasses prepared by a fermentation process using sugarcane molasses as the main raw material, and mainly contains bacterial biological protein and biochemical fulvic acid, with a dry basis content of about 50wt%.

[0067] In the following examples of the present invention, the anaerobic ammonia oxidizing bacteria, Weifang Fanxing Biotechnology Co., Ltd., has an effective viable count of 2×10 9 Pieces / g, item number 001.

[0068] In the following embodiments of the present invention, the salt-tolerant bacteria are at least one of nitrifying bacteria, Bacillus subtilis, and photosynthetic bacteria; the nitrifying bacteria, Shandong Xinzhuoyuan Biotechnology Co., Ltd., product number 20200810, the effective viable count is 2×10 10 Bacillus subtilis, Shandong Xinzhuoyuan Biotechnology Co., Ltd., catalog number 20230115, effective viable count 2×10 10 / g; photosynthetic bacteria are Rhodopseudomonas palustris, Shandong Xinzhuoyuan Biotechnology Co., Ltd., catalog number 20230712, effective viable count is 1×10 10 Pieces / g.

[0069] In the following embodiments of the present invention, the microorganisms in the microbial solution are at least one of Bacillus, denitrifying bacteria, lactic acid bacteria, and yeast; the total number of viable bacteria in the microbial solution is 5×10 9 cfu / g~10×10 9 cfu / g. The Bacillus genus is Bacillus subtilis, Shandong Xinzhuoyuan Biotechnology Co., Ltd., product number 20230115, and the effective viable count is 2×10 10 / g; denitrifying bacteria are Achromobacter denitrificans, Shanghai Yiyan Biotechnology Co., Ltd., item number EY-J963899; lactic acid bacteria are Lactobacillus lactis, Shaanxi Benhe Bioengineering Co., Ltd., item number TR-5987569, and the effective viable count is 1×10 10 cfu / g; yeast, Shaanxi Benhe Bioengineering Co., Ltd., effective viable count is 1×10 10 cfu / g.

[0070] In the following examples of the present invention, trehalose lipid, molecular weight 342.3, Tongchuan Boliante Chemical Co., Ltd.; sophorolipid, molecular weight 688.8, Xi'an Kangnuo Chemical Co., Ltd. Sucrose, molecular weight 342.3, Jiangxi Ruiweier Biotechnology Co., Ltd. Corn starch, Wuhan Lanabai Pharmaceutical Chemical Co., Ltd., item number llb-1160. Peptone, molecular weight 244.3, Shandong Changsheng Environmental Protection Technology Development Co., Ltd., CAS: 73049-73-7. Yeast powder, molecular weight: 179.14, Wuhan Jiyesheng Chemical Co., Ltd., CAS: 119-44-8.

[0071] Example 1

[0072] like Figure 1A method for deep purification of water-based drilling filtrate includes a destabilization and enzymolysis process, a primary decolorization and hardness removal process, and a secondary decolorization and hardness removal process. The destabilization and enzymolysis process is carried out in a fixed bed reactor, and the fixed bed reactor is filled with an immobilized complex enzyme; the primary decolorization and hardness removal process is carried out in a polymerization reactor, and a modified adsorption polymerization agent is added during the reaction to decolorize, and then an alkaline reagent is added to remove hardness; the secondary decolorization and hardness removal process is carried out in an electrochemical bioreactor, and a microbial activator is added during the reaction to decolorize and remove hardness.

[0073] The immobilized composite enzyme is obtained by adsorbing the composite enzyme preparation onto pumice and incubating it in a 10mmol / L tetraethyl orthosilicate solution at 37°C for 24h. The mass ratio of the composite enzyme preparation to pumice and tetraethyl orthosilicate solution is 0.2:1:1000. Among them, the composite enzyme preparation is prepared by mixing the composite enzyme, glycolipid protective agent, salt-tolerant bacteria, and additives in a mass ratio of 5:1:1:0.3. The composite enzyme is a mixture of amylase, cellulase, and hydrolase in equal mass ratios; among them, amylase is used to degrade starch components and is α-amylase; cellulase is used to degrade cellulose components in drilling fluid; hydrolases include glycosidic bond hydrolases and peptide bond hydrolases, and are mixed in equal mass ratios, wherein the glycosidic bond hydrolase is xylanase, and the peptide bond hydrolase is a protease, which is used to hydrolyze polysaccharide components and protein components. The glycolipid protective agent is trehalose lipid. The salt-tolerant bacteria are nitrifying bacteria. The additive is a mixture of carbonic acid amide, monocrystalline glucose powder and ammonium sulfate, and the mixing mass ratio is 1:1:1.

[0074] The modified adsorption polymerizer is obtained by oscillating carboxymethyl chitosan in a microbial culture solution; the mass ratio of carboxymethyl chitosan to the microbial culture solution is 0.02:2; the total number of viable bacteria in the microbial culture solution is 5×10 9 cfu / g; the microorganisms in the microbial solution are a mixture of Bacillus, denitrifying bacteria, lactic acid bacteria and yeast in equal mass ratios.

[0075] The microbial activator is prepared by mixing a carbon source, a nitrogen source, a phosphorus source and molasses fermentation liquid in a mass ratio of 1:0.3:0.1:3. The carbon source is glucose; the nitrogen source is ammonium chloride; and the phosphorus source is dipotassium hydrogen phosphate.

[0076] The specific method includes the following steps:

[0077] Step 1, destabilization and enzymatic hydrolysis process: This process is mainly carried out in a fixed bed reactor.

[0078] The water-based drilling filtrate after plate and frame filtration is sent to a fixed bed reactor for destabilization enzymolysis, and the reaction time is 48 hours. Among them, the fixed bed reactor is provided with an aeration pipe along the flow direction of the water-based drilling filtrate; an aeration head is arranged on the aeration pipe, and the aeration direction of the aeration head is opposite to the flow direction of the water-based drilling filtrate. Among them, the aeration direction of the aeration head is at an angle α with the flow direction of the water-based drilling filtrate; the value range of the angle α is 45°. Multiple aeration pipes are connected to oxygen pipelines or air pipelines to provide oxygen. Multiple aeration pipes are arranged in parallel in the fixed bed reactor, and different oxygen concentration aeration areas can be alternately formed in the fixed bed reactor through an equidistant arrangement, such as aeration zones with high-low concentrations alternately arranged, with a high concentration of oxygen content at 45% and a low concentration of oxygen content at 10%. The fixed bed reactor is filled with immobilized complex enzyme, and the filling amount of the immobilized complex enzyme is 10% of the total volume of the water-based drilling filtrate in the fixed bed reactor.

[0079] Step 2, primary decolorization and hardness removal process: This process is carried out in a polymerization reactor.

[0080] The water-based drilling filtrate after destabilization and enzymatic hydrolysis is sent to a polymerization reactor, and a modified adsorption polymerization agent is added to decolorize. Then, a 25wt% sodium carbonate aqueous solution is added to the polymerization reactor to remove hardness for 24 hours, and a 20wt% sodium hydroxide aqueous solution is added to the filtrate obtained by filtration to remove hardness for another 24 hours. The filtrate obtained by filtration is sent to an electrochemical bioreactor.

[0081] Step 3, secondary decolorization and hardness removal process: This process is carried out in an electrochemical bioreactor.

[0082] Add microbial activator to the electrochemical bioreactor, the amount of microbial activator added is 10% of the total volume of the filtrate in the electrochemical bioreactor, and perform decolorization and hardness removal for 48 hours. After filtration, a deeply purified water-based drilling filtrate is obtained to achieve reuse for slurry preparation.

[0083] The electrochemical bioreactor has an anode chamber, in which anode plates are arranged vertically and filled with conductive oxidizing fillers; electroactive microorganisms grow on the anode plates and the conductive oxidizing fillers; the electroactive microorganisms are anaerobic ammonia oxidizing bacteria, and the effective viable bacteria count is 2×10 9 Pieces / g.

[0084] Example 2

[0085] like Figure 1A method for deep purification of water-based drilling filtrate includes a destabilization and enzymolysis process, a primary decolorization and hardness removal process, and a secondary decolorization and hardness removal process. The destabilization and enzymolysis process is carried out in a fixed bed reactor, and the fixed bed reactor is filled with an immobilized complex enzyme; the primary decolorization and hardness removal process is carried out in a polymerization reactor, and a modified adsorption polymerization agent is added during the reaction to decolorize, and then an alkaline reagent is added to remove hardness; the secondary decolorization and hardness removal process is carried out in an electrochemical bioreactor, and a microbial activator is added during the reaction to decolorize and remove hardness.

[0086] The immobilized composite enzyme is obtained by adsorbing the composite enzyme preparation onto pumice and incubating it at 37°C for 24 hours in an 8mmol / L tetraethyl orthosilicate solution. The mass ratio of the composite enzyme preparation to pumice and tetraethyl orthosilicate solution is 0.2:1:1000. Among them, the composite enzyme preparation is prepared by mixing the composite enzyme, glycolipid protective agent, salt-tolerant bacteria, and additives in a mass ratio of 1:0.5:0.5:0.1. The composite enzyme is a mixture of amylase, cellulase, catalase, and lipase in equal mass ratios; among them, amylase is used to degrade starch components; cellulase is used to degrade cellulose components in drilling fluid; lipase can act on the ester bond of triglycerides to degrade triglycerides into diglycerides, monoglycerides, glycerol, and fatty acids. The hydrolase includes glycosidic bond hydrolase and peptide bond hydrolase, and they are mixed in equal mass ratios, among which the glycosidic bond hydrolase is xylanase and the peptide bond hydrolase is protease, which is used to hydrolyze polysaccharide components and protein components. The glycolipid protective agent is a mixture of sophorolipids and trehalolipids in an equal mass ratio. The salt-tolerant bacteria are nitrifying bacteria and Bacillus subtilis. The additive is a mixture of vitamin C, carbonic acid amide, monocrystalline glucose powder and ammonium sulfate in a mass ratio of 1:1:1:1.

[0087] The modified adsorption polymerizer is obtained by oscillating carboxymethyl chitosan in a microbial culture solution; the mass ratio of carboxymethyl chitosan to the microbial culture solution is 0.01:2; the total number of viable bacteria in the microbial culture solution is 8×10 9 cfu / g; the microorganisms in the microbial solution are a mixture of Bacillus, denitrifying bacteria, lactic acid bacteria and yeast in equal mass ratios.

[0088] The microbial activator is prepared by mixing a carbon source, a nitrogen source, a phosphorus source and molasses fermentation liquid in a mass ratio of 1:0.2:0.1:2. The carbon source is glucose; the nitrogen source is ammonium chloride; and the phosphorus source is dipotassium hydrogen phosphate.

[0089] The specific method includes the following steps:

[0090] Step 1, destabilization and enzymatic hydrolysis process: This process is mainly carried out in a fixed bed reactor.

[0091] The water-based drilling filtrate after plate and frame filtration is sent to a fixed bed reactor for destabilization enzymolysis, and the reaction time is 48 hours. Among them, the fixed bed reactor is provided with an aeration pipe along the flow direction of the water-based drilling filtrate; an aeration head is arranged on the aeration pipe, and the aeration direction of the aeration head is opposite to the flow direction of the water-based drilling filtrate. Among them, the aeration direction of the aeration head is at an angle α with the flow direction of the water-based drilling filtrate; the value range of the angle α is 30°. Multiple aeration pipes are connected to oxygen pipelines or air pipelines to provide oxygen. Multiple aeration pipes are arranged in parallel in the fixed bed reactor, and different oxygen concentration aeration areas can be alternately formed in the fixed bed reactor through an equidistant arrangement, such as aeration zones with high-low concentrations alternately arranged, with a high concentration of oxygen content at 45% and a low concentration of oxygen content at 10%. The fixed bed reactor is filled with immobilized complex enzyme, and the filling amount of the immobilized complex enzyme is 10% of the total volume of the water-based drilling filtrate in the fixed bed reactor.

[0092] Step 2, primary decolorization and hardness removal process: This process is carried out in a polymerization reactor.

[0093] The water-based drilling filtrate after destabilization and enzymatic hydrolysis is sent to a polymerization reactor, and a modified adsorption polymerization agent is added to decolorize. Then, a 25wt% sodium carbonate aqueous solution is added to the polymerization reactor to remove hardness for 24 hours. A 20wt% sodium hydroxide aqueous solution is added to the filtrate obtained by the first filtration to remove hardness for 24 hours. The filtrate obtained by the second filtration is sent to an electrochemical bioreactor.

[0094] Step 3, secondary decolorization and hardness removal process: This process is carried out in an electrochemical bioreactor. A microbial activator is added to the electrochemical bioreactor, and the amount of the microbial activator added is 10% of the total volume of the filtrate in the electrochemical bioreactor, and the decolorization and hardness removal are carried out for 48 hours. After filtration, a deeply purified water-based drilling filtrate is obtained to achieve reuse for slurry preparation.

[0095] The electrochemical bioreactor has an anode chamber, in which anode plates are arranged vertically and filled with conductive oxidizing fillers; electroactive microorganisms grow on the anode plates and the conductive oxidizing fillers; the electroactive microorganisms are anaerobic ammonia oxidizing bacteria, and the effective viable bacteria count is 2×10 9 Pieces / g.

[0096] Example 3

[0097] like Figure 1A method for deep purification of water-based drilling filtrate includes a destabilization and enzymolysis process, a primary decolorization and hardness removal process, and a secondary decolorization and hardness removal process. The destabilization and enzymolysis process is carried out in a fixed bed reactor, and the fixed bed reactor is filled with an immobilized complex enzyme; the primary decolorization and hardness removal process is carried out in a polymerization reactor, and a modified adsorption polymerization agent is added during the reaction to decolorize, and then an alkaline reagent is added to remove hardness; the secondary decolorization and hardness removal process is carried out in an electrochemical bioreactor, and a microbial activator is added during the reaction to decolorize and remove hardness.

[0098] The immobilized composite enzyme is obtained by adsorbing the composite enzyme preparation onto pumice and incubating it at 37°C for 24 hours in a 10mmol / L tetraethyl orthosilicate solution. The mass ratio of the composite enzyme preparation to pumice and tetraethyl orthosilicate solution is 0.2:1:1000. Among them, the composite enzyme preparation is prepared by mixing the composite enzyme, glycolipid protective agent, salt-tolerant bacteria, and additives in a mass ratio of 10:3:3:1. The composite enzyme is a mixture of amylase, pectinase, cellulase, laccase, catalase, lipase, and hydrolase in equal mass ratios; among them, amylase is used to degrade starch components; cellulase is used to degrade cellulose components in drilling fluid; hydrolases include glycosidic bond hydrolases and peptide bond hydrolases, and are mixed in equal mass ratios, wherein the glycosidic bond hydrolase is xylanase, and the peptide bond hydrolase is a protease, which is used to hydrolyze polysaccharide components and protein components. The glycolipid protective agent is trehalose lipid. The salt-tolerant bacteria are nitrifying bacteria. The additive is a mixture of carbonic acid amide, monocrystalline glucose powder and ammonium sulfate, and the mixing mass ratio is 1:1:1.

[0099] The modified adsorption polymerizer is obtained by oscillating carboxymethyl chitosan in a microbial culture solution; the mass ratio of carboxymethyl chitosan to the microbial culture solution is 0.04:2; the total number of viable bacteria in the microbial culture solution is 10×10 9 cfu / g; the microorganisms in the microbial solution are a mixture of Bacillus, denitrifying bacteria, lactic acid bacteria and yeast in equal mass ratios.

[0100] The microbial activator is prepared by mixing a carbon source, a nitrogen source, a phosphorus source and molasses fermentation liquid in a mass ratio of 1:0.5:0.2:4. The carbon source is glucose; the nitrogen source is ammonium chloride; and the phosphorus source is dipotassium hydrogen phosphate.

[0101] The specific method includes the following steps:

[0102] Step 1, destabilization and enzymatic hydrolysis process: This process is mainly carried out in a fixed bed reactor.

[0103] The water-based drilling filtrate after plate and frame filtration is sent to a fixed bed reactor for destabilization enzymolysis, and the reaction time is 48 hours. Among them, the fixed bed reactor is provided with an aeration pipe along the flow direction of the water-based drilling filtrate; an aeration head is arranged on the aeration pipe, and the aeration direction of the aeration head is opposite to the flow direction of the water-based drilling filtrate. Among them, the aeration direction of the aeration head is at an angle α with the flow direction of the water-based drilling filtrate; the value range of the angle α is 80°. Multiple aeration pipes are connected to oxygen pipelines or air pipelines to provide oxygen. Multiple aeration pipes are arranged in parallel in the fixed bed reactor, and different oxygen concentration aeration areas can be alternately formed in the fixed bed reactor through an equidistant arrangement, such as aeration zones with high-low concentrations alternately arranged, with a high concentration of oxygen content at 45% and a low concentration of oxygen content at 10%. The fixed bed reactor is filled with immobilized complex enzyme, and the filling amount of the immobilized complex enzyme is 10% of the total volume of the water-based drilling filtrate in the fixed bed reactor.

[0104] Step 2, primary decolorization and hardness removal process: This process is carried out in a polymerization reactor.

[0105] The water-based drilling filtrate after destabilization and enzymatic hydrolysis is sent to a polymerization reactor, and a modified adsorption polymerization agent is added to decolorize. Then, a 25wt% sodium carbonate aqueous solution is added to the polymerization reactor to remove hardness for 24 hours. A 20wt% sodium hydroxide aqueous solution is added to the filtrate obtained by the first filtration to remove hardness for 24 hours. The filtrate obtained by the second filtration is sent to an electrochemical bioreactor.

[0106] Step 3, secondary decolorization and hardness removal process: This process is carried out in an electrochemical bioreactor.

[0107] Add microbial activator to the electrochemical bioreactor, the amount of microbial activator added is 10% of the total volume of the filtrate in the electrochemical bioreactor, and perform decolorization and hardness removal for 48 hours. After filtration, a deeply purified water-based drilling filtrate is obtained to achieve reuse for slurry preparation.

[0108] The electrochemical bioreactor has an anode chamber, in which anode plates are arranged vertically and filled with conductive oxidizing fillers; electroactive microorganisms grow on the anode plates and the conductive oxidizing fillers; the electroactive microorganisms are anaerobic ammonia oxidizing bacteria, and the effective viable bacteria count is 2×10 9 Pieces / g.

[0109] The press filtrate of the brine system after the conversion was treated according to the method of Example 1, and the basic water quality parameters of the water samples before treatment, the water samples obtained in each treatment step, and the water samples after treatment were tested. The basic water quality parameters include pH value, TDS, color, turbidity, SS, Ca 2+ Mg 2+, COD, Cl-, etc. The specific testing standards are shown in Table 1. The focus is on evaluating the changes in the rheological properties of the return drilling fluid and the medium-pressure water loss performance, providing guiding indicators for the slurry preparation technology for the reuse of filtrate and optimizing the mud return.

[0110] Table 1 Filtrate water quality testing indicators and standards

[0111]

[0112] The water quality test results of the filtrate of the salt water system after the system conversion are shown in Table 2. The filtrate of the salt water system after the system conversion is referred to as filtrate.

[0113] Table 2 Water quality test results of the filtrate of the brine system after the conversion system

[0114]

[0115] Note: The water sample of produced water is used as blank control; the water sample of filtrate is the filtrate of brine system after the system is transferred; the water sample obtained by fixed bed reactor is the primary re-allocation water sample after treatment by fixed bed reactor; the water sample obtained by electrochemical bioreactor is the tertiary re-allocation water sample after treatment by electrochemical bioreactor.

[0116] It can be seen from the results in Table 2 that after the brine system filtrate is treated by the method of Example 1 of the present invention, various parameters of water quality are reduced to varying degrees, meeting the requirements for reuse and slurry preparation.

[0117] The completion drilling hydraulic filtrate was treated according to the method of Example 2, and basic water quality parameters were tested for the water samples before treatment, the water samples obtained in each treatment step, and the water samples after treatment. Basic water quality parameters include pH value, TDS, color, turbidity, SS, Ca 2+ Mg 2+ 、COD、Cl - The specific testing standards are shown in Table 1. The focus is on evaluating the changes in the rheological properties of the return drilling fluid and the medium-pressure water loss performance, providing guiding indicators for the slurry preparation technology for the reuse of filtrate and optimizing the mud return.

[0118] The water quality test results of the completion drilling hydraulic filtrate are shown in Table 3.

[0119] Table 3 Water quality test results of completion drilling hydraulic filtrate

[0120]

[0121] Note: The water sample of produced water is used as blank control; the water sample of filtrate is the hydraulic filtrate of completion drilling; the water sample obtained by fixed bed reactor is the primary re-allocation water sample after treatment by fixed bed reactor; the water sample obtained by electrochemical bioreactor is the tertiary re-allocation water sample after treatment by electrochemical bioreactor.

[0122] From the results in Table 3, it can be seen that after the completion drilling hydraulic filtrate is treated according to the method of Example 2, various parameters of water quality are reduced to varying degrees, meeting the requirements for reuse and slurry preparation.

[0123] The completion drilling hydraulic filtrate was treated according to the method of Example 3, and basic water quality parameters were tested for the water samples before treatment, the water samples obtained in each treatment step, and the water samples after treatment. Basic water quality parameters include pH value, TDS, color, turbidity, SS, Ca 2+ Mg 2+ 、COD、Cl - The specific testing standards are shown in Table 1. The focus is on evaluating the changes in the rheological properties of the return drilling fluid and the medium-pressure water loss performance, providing guiding indicators for the slurry preparation technology for the reuse of filtrate and optimizing the mud return.

[0124] The test results show that after the completion drilling hydraulic filtrate is treated according to the method of Example 3, various parameters of water quality are reduced to varying degrees, meeting the requirements for reuse and slurry preparation.

[0125] The above analysis shows that the method of the embodiment of the present invention can be used for deep purification of the filtrate of the brine system after the conversion system and the completion drilling hydraulic filtrate, and the treated filtrate can meet the requirements of reuse and slurry preparation.

[0126] The filtrate of the brine system after the conversion system, referred to as the filtrate, is used to mix the filtrate with the production water, and applied to the polymer well section under the action of 0.2% anti-collapse agent and 0.2% flocculant, and the relevant experimental results are recorded, as shown in Table 4. The anti-collapse agent is mainly used to prevent the well wall from collapsing during drilling and keep the wellbore stable. The anti-collapse agent is an existing material and can be selected according to actual needs. For example, the anti-collapse agent can be selected as any one of potassium chloride, polyacrylamide, and sodium silicate. The flocculant is mainly used to improve the solid phase control of the drilling fluid and promote the aggregation of fine particles in the drilling fluid into large particles, which is convenient for subsequent solid-liquid separation. The flocculant is an existing material and can be selected according to actual needs. For example, the flocculant can be selected as at least one of ferric sulfate, ferric chloride, aluminum sulfate, alum, and polyacrylamide. The anti-collapse agent used in the embodiment of the present invention is sodium silicate, and the flocculant is a mixture of ferric sulfate, aluminum sulfate and polyacrylamide in a mass ratio of 5:5:1.

[0127] Table 4 Polymer well section slurry test

[0128]

[0129] Note: The produced water sample is used as blank control; the filtrate sample is the filtrate of the brine system after the system is transferred.

[0130] It can be seen from Table 4 that when the ratio of filtrate to produced water is 1:3, and the formula is 0.2% anti-collapse agent and 0.2% flocculant, the performance is closer to produced water.

[0131] The filtrate of the brine system after the conversion was treated according to the method of Example 1, and the water samples before treatment, the water samples obtained in each treatment step, and the water samples after treatment were applied to the brine system well section under the action of 0.2% anti-collapse agent and 0.2% flocculant, and the relevant experimental results were recorded, as shown in Table 5.

[0132] Table 5 Slurry matching experiment of salt water system well section

[0133]

[0134] Note: The water sample of production water is used as blank control; the water sample of filtrate is the filtrate of brine system after the system is transferred; the water sample obtained by polymerization reactor is the secondary re-allocation water sample after being treated and filtered by polymerization reactor; the water sample obtained by electrochemical bioreactor is the tertiary re-allocation water sample after being treated by electrochemical bioreactor.

[0135] From the results in Table 5, it can be seen that the water samples of the filtrate of the brine system after the system conversion and the water samples of the filtrate purified by the method of Example 1 were used to carry out the slurry matching experiment of the brine system well section. The results show that the water sample of the filtrate purified by the method of Example 1 has little effect on the performance of the mud.

[0136] The above results show that the filtrate treated by the embodiment of the present invention can achieve deep purification of water-based drilling filtrate, and the purified filtrate has little effect on the performance of the mud.

[0137] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for deep purification of water-based drilling filtrate, characterized in that: The following steps are involved: The water-based drilling filtrate is sent to a fixed bed reactor for destabilization enzymolysis; the fixed bed reactor is filled with an immobilized complex enzyme; The water-based drilling filtrate after destabilization and enzymatic hydrolysis is sent to a polymerization reactor, and a modified adsorption polymerization agent is added to decolorize it; then an alkaline agent is added to remove hardness, and then filtered; The separated filtrate is sent to an electrochemical bioreactor, and a microbial activator is added to the electrochemical bioreactor to decolorize and remove hardness, so as to realize the reuse of pulp; The immobilized complex enzyme is prepared by adsorbing the complex enzyme preparation onto a porous solid phase carrier and incubating it in a tetraethyl orthosilicate solution; the complex enzyme preparation is prepared by combining the complex enzyme, a glycolipid protective agent, a salt-tolerant bacterium, and an additive; The modified adsorption polymerizing agent is obtained by oscillating and culturing carboxymethyl chitosan in a microbial culture solution; the total number of viable bacteria in the microbial culture solution is 5×10 9 cfu / g~10×10 9 cfu / g; the microorganism in the microbial solution is at least one of Bacillus, denitrifying bacteria, lactic acid bacteria, and yeast; The microbial activator is prepared by compounding a carbon source, a nitrogen source, a phosphorus source and molasses fermentation liquid, wherein the mass ratio of the carbon source, the nitrogen source, the phosphorus source and the molasses fermentation liquid is 1:0.2-0.5:0.1-0.2:2-4.

2. The method for deep purification of water-based drilling filtrate according to claim 1, characterized in that: The tetraethyl orthosilicate solution is obtained by dispersing tetraethyl orthosilicate in a phosphate buffer solution; the concentration of the tetraethyl orthosilicate solution is 8-10 mmol / L.

3. The method for deep purification of water-based drilling filtrate according to claim 2, characterized in that: The mass ratio of the complex enzyme preparation to the porous solid phase carrier is 0.2:1; The mass ratio of the complex enzyme preparation to the tetraethyl orthosilicate solution is 0.2:1000.

4. The method for deep purification of water-based drilling filtrate according to claim 3, characterized in that: The material of the porous solid phase carrier is at least one of pumice, silicon oxide, aluminum oxide and zirconium oxide.

5. The method for deep purification of water-based drilling filtrate according to claim 1, characterized in that: The mass ratio of the complex enzyme, glycolipid protective agent, salt-tolerant bacteria and additives is 1-10: 0.5-3: 0.5-3: 0.1-1.

6. The method for deep purification of water-based drilling filtrate according to claim 5, characterized in that: The complex enzyme is a mixture of at least two of acid protease, amylase, pectinase, cellulase, laccase, catalase, lipase and hydrolase; The glycolipid protective agent is at least one of rhamnolipid, sophorolipid and trehalolipid; The salt-tolerant bacteria are at least one of nitrifying bacteria, Bacillus subtilis, and photosynthetic bacteria; The additive is at least one of vitamin C, carbonic acid amide, monocrystalline glucose powder, ammonium sulfate, ammonium chloride, and ammonium molybdate.

7. The method for deep purification of water-based drilling filtrate according to claim 1, characterized in that: The modified adsorption polymerization agent is prepared by the following method: The sterilized carboxymethyl chitosan is added into the microbial bacterial liquid, cultured at 25°C to 30°C for 4 to 6 days, and then vacuum-freeze-dried to obtain the product.

8. The method for deep purification of water-based drilling filtrate according to claim 7, characterized in that: The mass ratio of the carboxymethyl chitosan to the microbial culture liquid is 0.01-0.04:

2.

9. The method for deep purification of water-based drilling filtrate according to claim 1, characterized in that: The carbon source is any one of glucose, sucrose and corn starch; The nitrogen source is any one of peptone, ammonium chloride, ammonium sulfate, and yeast powder; The phosphorus source is any one of dipotassium hydrogen phosphate, potassium dihydrogen phosphate, and diammonium hydrogen phosphate; The dry basis content of the molasses fermentation liquid is ≥40%.

10. The method for deep purification of water-based drilling filtrate according to claim 1, characterized in that: The electrochemical bioreactor has an anode chamber, in which anode plates are vertically arranged, and the anode chamber is filled with conductive oxidizing fillers; Electroactive microorganisms grow on both the anode plate and the conductive oxidizing filler; the electroactive microorganisms are anaerobic ammonia-oxidizing bacteria.

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