Well drilling and reservoir transformation waste liquid treatment system

Abstract

The invention discloses a well drilling and reservoir transformation waste liquid treatment system, and relates to the technical field of waste liquid treatment. The micro-electrolytic oxidation system is used for adjusting the pH value of the waste liquid subjected to oil removal treatment and carrying out electrolytic oxidation; the pH adjusting system is used for carrying out secondary adjusting treatment on the pH value of the waste liquid subjected to electrolytic oxidation; the ion removal system is used for carrying out ion removal treatment on the waste liquid subjected to secondary pH value regulation treatment; the coagulation and inclined plate sedimentation system is used for carrying out coagulation and flocculation treatment and sedimentation on the waste liquid subjected to ion removal treatment, and carrying out solid-liquid separation; the waste liquid after solid-liquid separation is subjected to multi-stage filtration through the multi-stage filtration system and the water quality neutralization system and then is subjected to third-time pH value regulation treatment, so that the waste liquid reaches the emission standard. Through multiple systems, the waste liquid treatment effect is improved, and the treatment cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of waste liquid treatment, and more particularly to a drilling and reservoir transformation waste liquid treatment system. Background Art

[0002] Globally, oil and gas exploration and production activities generate a large amount of drilling and reservoir reconstruction waste fluids every year. If these waste fluids are not properly treated, they will directly threaten surface water and groundwater resources, and further have a serious impact on the ecological environment and human health.

[0003] Drilling and reservoir reconstruction waste liquid contains a variety of harmful substances, including but not limited to heavy metals, organic matter, suspended solids and harmful chemicals. Due to the large variety of pollutants in the waste liquid and the changeable water quality, the treatment of waste liquid becomes complicated. Although a variety of technologies have been applied to waste liquid treatment, such as physical methods, chemical methods, biological methods, etc., although the physical method can separate the oil and water in the waste liquid, it cannot effectively reduce the viscosity of the waste liquid and the total hardness of the waste liquid. The chemical method has certain advantages in reducing the viscosity of the waste liquid and the COD content, but the chemical method is prone to secondary pollution. Some chemical treatment methods may only be effective for specific types of pollutants, and have poor effects on other types of pollutants, which limits its scope of application. The biological method is more effective in treating waste liquid, but the operating conditions of this method are relatively harsh and it is difficult to use on site.

[0004] Therefore, how to improve the waste liquid treatment effect and reduce the treatment cost is an urgent problem that technicians in this field need to solve. Summary of the invention

[0005] In view of this, the present invention provides a drilling and reservoir transformation waste liquid treatment system, which is composed of an oil removal system, a micro-electrolysis oxidation system, a pH adjustment system, an ion removal system, a coagulation and inclined plate sedimentation system, a multi-stage filtration system and a water quality neutralization system. At the same time, an advanced algorithm is designed to predict the effluent viscosity of the wastewater according to different process parameters. By evaluating the impact of different process parameters on wastewater treatment, the flexibility of the process is enhanced, the treatment efficiency is improved, and the dosage of the micro-electrolysis oxidation system is reduced, thereby reducing the treatment cost.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A drilling and reservoir transformation waste liquid treatment system comprises: an oil removal system, a micro-electrolysis oxidation system, a pH adjustment system, an ion removal system, a coagulation and inclined plate sedimentation system, a multi-stage filtration system and a water quality neutralization system connected in sequence, wherein the oil removal system removes oil from the waste liquid; the micro-electrolysis oxidation system adjusts the pH value of the waste liquid after the oil removal treatment and performs electrolytic oxidation; the pH adjustment system performs a secondary pH adjustment treatment on the waste liquid after the electrolytic oxidation; the ion removal system performs ion removal treatment on the waste liquid after the secondary pH value adjustment treatment; the coagulation and inclined plate sedimentation system performs coagulation and flocculation treatment and sedimentation on the waste liquid after the ion removal treatment, and performs solid-liquid separation; the waste liquid after the solid-liquid separation is subjected to multi-stage filtration by the multi-stage filtration system and the water quality neutralization system, and then undergoes a tertiary pH adjustment treatment to make it meet the discharge standard.

[0008] Preferably, the oil removal system is composed of a coalescing oil remover, and the oil content in the waste liquid after being treated by the coalescing oil remover is 0 to 50 mg / L.

[0009] Preferably, in the micro-electrolysis oxidation system, the waste liquid after oil removal treatment enters the micro-electrolysis oxidation system from the bottom by overflow, the pH value is adjusted by adding a pH regulator, electrolytic oxidation is carried out by the micro-electrolysis material, and aeration is performed to promote the oxidation reaction; wherein, the micro-electrolysis reaction time is 40 to 100 minutes; the pH value of the waste liquid is adjusted to 3 to 4; the porosity of the micro-electrolysis material is 60 to 80%; 40 to 160 kg of micro-electrolysis material is added to each cubic meter of waste liquid; the ratio of aeration volume to waste liquid is 6:1 to 12:1; and the viscosity of the waste liquid is 1 to 8 mPa·s.

[0010] Preferably, 300-1000 mg / L of alkaline solvent is added to the pH adjustment system to maintain the pH of the waste liquid at 8-9; an aeration device is provided in the pH adjustment system, and the aeration device is kept running while adding sodium hydroxide; the ratio of aeration volume to waste liquid is 6:1-12:1; and the aeration time is within 20-40 minutes.

[0011] Preferably, in the ion removal system, the waste liquid enters the ion removal system from the bottom by overflow, and the amount of ion remover added is 1000-3500 mg / L; the ion remover is a composite agent, composed of agent A, agent B, and auxiliary agents, including agent A: 1-10% sodium sulfate, 1-5% aluminum sulfate, 1-5% potassium carbonate; agent B: 20-50% sodium carbonate; auxiliary agent: 20-30% bentonite; the ion removal system is provided with a stirring paddle, and the speed of the stirring motor is 100-400 r / min; the residence time of the waste liquid in the ion removal system is 20-40 min.

[0012] Preferably, the coagulation and inclined plate sedimentation system includes a coagulation tank and an inclined plate sedimentation tank. The waste liquid after ion removal treatment enters the coagulation tank from the bottom in an overflow manner. The coagulation tank is divided into two chambers, A and B. The waste liquid enters chamber A from the bottom in an overflow manner. 300-1000 mg / L of PAC is added to chamber A. A stirring paddle is provided in chamber A. The speed of the stirring motor is 300-600 r / min. The residence time of the waste liquid in chamber A is 10-20 m; the waste liquid enters chamber B from the bottom in an overflow manner. 10-40 mg / L of PAM is added to chamber B. A stirring paddle is provided in chamber B. The speed of the stirring motor is 100-240 r / min. The residence time of the waste liquid in chamber B is 10-20 min. The waste liquid after coagulation enters the inclined plate sedimentation tank in an overflow manner for sludge sedimentation. The residence time of the waste liquid in the inclined plate sedimentation tank is 60-150 min.

[0013] Preferably, in the multi-stage filtration system, the waste liquid overflowing from the coagulation and inclined plate sedimentation system is pressurized by a pump and then enters the multi-stage filtration system. The multi-stage filtration system is composed of anthracite, glass fiber, and polyester fiber from top to bottom; the waste liquid stays in the multi-stage filtration system for 30 to 60 minutes.

[0014] Preferably, in the water neutralization system, the waste liquid treated by the multi-stage filtration system enters the water neutralization system in an overflow manner, a stirring paddle is provided in the water neutralization system, and the speed of the stirring motor is 100 to 400 r / min; the pH adjuster is citric acid, and the addition amount thereof is 1000 to 2300 mg / L; the treated waste liquid exits the system in an overflow or pump-pressurized manner.

[0015] Preferably, the effluent viscosity of the waste liquid is predicted by a preset algorithm in the micro-electrolysis oxidation system, specifically including establishing a training set with pH, ​​micro-electrolysis material dosage, reaction time, aeration volume and waste liquid viscosity as training samples; wherein pH, micro-electrolysis material dosage, reaction time and aeration volume are inputs, and waste liquid viscosity is output; and adjusting the usage of the input parameters of the micro-electrolysis oxidation system based on the predicted effluent viscosity.

[0016] It can be seen from the above technical scheme that compared with the prior art, the present invention discloses a drilling and reservoir transformation waste liquid treatment system, which optimizes the key reaction parameters of iron-carbon micro-electrolysis in micro-electrolysis, including the dosage of micro-electrolysis materials, the pH of the reaction, the aeration volume and the reaction duration, thereby ensuring that the drilling and reservoir transformation waste liquid is efficiently treated while also optimizing the utilization efficiency of the raw materials, avoiding problems such as water color reversal, and the present invention is characterized by economy and high efficiency, and achieves dual optimization of cost-effectiveness and treatment efficiency; by adding ion control agents, the total hardness and high-valent ion content of the wastewater are effectively reduced, and the treated wastewater can be reinjected or reused, reducing the pollution of the wastewater to the environment, which is beneficial to improving the wastewater treatment efficiency and reducing the difficulty of subsequent treatment; through the supporting advanced algorithm, the effect of wastewater treatment can be predicted according to different process parameters, and by predicting the influence of different process parameters on the wastewater treatment effect, the flexibility of the process is improved, the treatment efficiency is improved, and the amount of reagents used is reduced, thereby saving treatment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0018] Figure 1 A schematic diagram of the structure provided by the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in 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.

[0020] The embodiment of the present invention discloses a drilling and reservoir transformation waste liquid treatment system, such as Figure 1As shown, it includes: an oil removal system, a micro-electrolysis oxidation system, a pH adjustment system, an ion removal system, a coagulation and inclined plate sedimentation system, a multi-stage filtration system and a water quality neutralization system connected in sequence, the oil removal system removes oil from the waste liquid; the micro-electrolysis oxidation system adjusts the pH value of the waste liquid after the oil removal treatment and electrolytically oxidizes it; the pH adjustment system performs a secondary pH adjustment treatment on the waste liquid after the electrolytic oxidation; the ion removal system performs ion removal treatment on the waste liquid after the secondary pH adjustment treatment; the coagulation and inclined plate sedimentation system performs coagulation and flocculation treatment and sedimentation on the waste liquid after the ion removal treatment, and performs solid-liquid separation; the waste liquid after solid-liquid separation is multi-stage filtered through a multi-stage filtration system and a water quality neutralization system, and then undergoes a tertiary pH adjustment treatment to make it meet the emission standards.

[0021] Among them, oil removal system: First, the wastewater enters the oil removal system, and the oil in the wastewater is removed by the coalescence oil remover. Micro-electrolysis oxidation system: Then, the wastewater enters the micro-electrolysis oxidation system, and the wastewater is treated by micro-electrolysis materials and pH adjustment. pH adjustment system: Then, the wastewater enters the pH adjustment system, and the pH value of the wastewater is adjusted by adding alkali solution. Ion removal system: The next step is the ion removal system, which removes ions from the wastewater by adding an ion controller. Coagulation tank: The wastewater then enters the coagulation tank, and the wastewater is further treated by adding coagulants and flocculants. Inclined plate sedimentation tank: After the wastewater treated with coagulation and flocculation enters the inclined plate sedimentation tank, the larger flocs slide to the bottom along the surface of the inclined plate under the action of gravity, thereby achieving solid-liquid separation, and the purified water is discharged from the top. Multi-stage filtration system: The wastewater then enters the multi-stage filtration system, and the wastewater is further purified by multi-stage filters. Water neutralization system: Wastewater enters the water neutralization system, and pH adjusters are added to neutralize the pH value of the wastewater to meet the discharge standards.

[0022] In a specific embodiment, the oil removal system is composed of a coalescing oil remover, and the oil content in the waste liquid after being treated by the coalescing oil remover is 0 to 50 mg / L.

[0023] In a specific embodiment, in a micro-electrolysis oxidation system, waste liquid after oil removal treatment enters the micro-electrolysis oxidation system from the bottom by overflow, the pH value is adjusted by adding a pH regulator, electrolytic oxidation is carried out by a micro-electrolysis material, and aeration is performed to promote the oxidation reaction; wherein, the micro-electrolysis reaction time is 40 to 100 minutes; the pH value of the waste liquid is adjusted to 3 to 4; the porosity of the micro-electrolysis material is 60 to 80%; 40 to 160 kg of micro-electrolysis material is added to each cubic meter of waste liquid; the ratio of aeration volume to waste liquid is 6:1 to 12:1; and the viscosity of the waste liquid is 1 to 8 mPa·s.

[0024] In a specific embodiment, 300-1000 mg / L of alkaline solvent is added to the pH adjustment system to maintain the pH of the waste liquid at 8-9; an aeration device is provided in the pH adjustment system, and the aeration device is kept running while adding sodium hydroxide; the ratio of aeration volume to waste liquid is 6:1-12:1; and the aeration time is within 20-40 minutes.

[0025] In a specific embodiment, the pH of the wastewater will rise to a certain extent after passing through the micro-electrolysis oxidation system, and the pH of the wastewater is maintained at 8-9 by adding 300-1000 mg / L of sodium hydroxide. During the pH adjustment process, aeration promotes Fe 2+ The oxidation can effectively avoid the problem of water discoloration and improve the pH adjustment efficiency. Continuous aeration can prevent pollutants from depositing on the surface of iron filings and prevent them from hardening, thus maintaining the activity and reaction efficiency of the iron filings.

[0026] In a specific embodiment, in the ion removal system, the waste liquid enters the ion removal system from the bottom by overflow, and the amount of ion remover added is 1000-3500 mg / L; the ion remover is a composite agent, which is composed of agent A, agent B, and auxiliary agent, including agent A sodium sulfate 1-10%, aluminum sulfate 1-5%, potassium carbonate 1-5%; agent B sodium carbonate 20-50%; auxiliary bentonite 20-30%; the ion removal system is provided with a stirring paddle, and the speed of the stirring motor is 100-400 r / min; the residence time of the waste liquid in the ion removal system is 20-40 min. The total hardness (calculated as calcium carbonate) of the wastewater treated by the ion removal system is less than 300 mg / L.

[0027] In a specific embodiment, the coagulation and inclined plate sedimentation system includes a coagulation tank and an inclined plate sedimentation tank. The waste liquid after ion removal treatment enters the coagulation tank from the bottom in an overflow manner. The coagulation tank is divided into two chambers, A and B. The waste liquid enters chamber A from the bottom in an overflow manner. 300-1000 mg / L of PAC is added to chamber A. A stirring paddle is provided in chamber A. The stirring motor speed is 300-600 r / min. The residence time of the waste liquid in chamber A is 10-20 m; the waste liquid enters chamber B from the bottom in an overflow manner. 10-40 mg / L of PAM is added to chamber B. A stirring paddle is provided in chamber B. The stirring motor speed is 100-240 r / min. The residence time of the waste liquid in chamber B is 10-20 min. The waste liquid after coagulation enters the inclined plate sedimentation tank in an overflow manner for sludge sedimentation. The residence time of the waste liquid in the inclined plate sedimentation tank is 60-150 min.

[0028] In a specific embodiment, in a multi-stage filtration system, the waste liquid overflowing from the coagulation and inclined plate sedimentation system is pressurized by a pump and enters the multi-stage filtration system. The multi-stage filtration system is anthracite, glass fiber, and polyester fiber from top to bottom; the waste liquid stays in the multi-stage filtration system for 30 to 60 minutes.

[0029] In a specific embodiment, in a water neutralization system, waste liquid treated by a multi-stage filtration system enters the water neutralization system in an overflow manner, a stirring paddle is provided in the water neutralization system, and the speed of the stirring motor is 100 to 400 r / min; the pH adjuster is citric acid, and the amount thereof is 1000 to 2300 mg / L; the treated waste liquid exits the system in an overflow or pump-pressurized manner, and the treated wastewater can be reinjected or used to prepare drilling and fracturing fluids.

[0030] In a specific embodiment, the effluent viscosity of the waste liquid is predicted by a preset algorithm in the micro-electrolysis oxidation system, specifically including establishing a training set with pH, ​​micro-electrolysis material dosage, reaction time, aeration volume and waste liquid viscosity as training samples; wherein pH, micro-electrolysis material dosage, reaction time, aeration volume are inputs, and waste liquid viscosity is output; and the usage of the input parameters of the micro-electrolysis oxidation system is adjusted based on the predicted effluent viscosity.

[0031] The preset algorithm can predict the effluent viscosity of wastewater according to different process parameters. By predicting the impact of different process parameters on the wastewater treatment effect, it can improve the flexibility of the process, improve the treatment efficiency, reduce the use of chemicals, and thus save treatment costs.

[0032] The algorithm converts the nonlinear problem in low-dimensional space into a linear problem in high-dimensional space through the kernel function, and converts the problem into a quadratic convex programming problem by seeking the optimal regression hyperplane. Finally, the low-dimensional nonlinear problem is solved by obtaining the global optimal solution of the quadratic convex programming problem.

[0033] Furthermore, suppose that the given training sample is a set of m samples in n+1 dimensional space T = {(x1, y1), (x2, y2), …, (x i ,y i ),…,(x m ,y m )},x i ∈R n is the input vector, y i ∈R is the output value.

[0034] Furthermore, this algorithm is used to find a suitable regression function f(x).

[0035] Furthermore, the regression function formula is established as follows:

[0036] f(x)= ωg(x)+ b (1)

[0037] Further, x is the input vector; g() is the mapping function; ω is the weight vector; and b is the threshold.

[0038] Furthermore, the regression prediction problem is transformed into an optimization problem for solving quadratic programming, and the formula is:

[0039]

[0040] Furthermore, where: ε is the insensitive function; c is the penalty factor; ξ i and i * is the slack variable.

[0041] Furthermore, the kernel function is used to map the above optimization problem into a high-dimensional space, and the dual problem of this problem is obtained, and the formula is:

[0042]

[0043] Furthermore, L is the objective function, α i , β i is the Lagrange multiplier of the i-th training sample, α j , β j is the Lagrange multiplier of the jth training sample; K(x i , x j ) is the kernel function.

[0044] Furthermore, K() generally adopts a radial basis kernel function, and its basic form is shown in formula (4):

[0045]

[0046] Furthermore, γ is a regularization parameter.

[0047] Furthermore, by solving this dual problem, we can get the final regression function, which is:

[0048]

[0049] Furthermore, n m is the number of vectors, α i and is the Lagrange multiplier; b* is the threshold.

[0050] Based on the above algorithm, the viscosity of the effluent from this process can be predicted.

[0051] In specific embodiment 1, the drilling and reservoir reconstruction waste fluid in this embodiment is taken from a joint station.

[0052] Step 1: The wastewater is pressurized by a pump and enters the coalescing deoiler from the bottom. After being treated by the coalescing deoiler, the oil content in the wastewater is 9 mg / L.

[0053] Step 2: After the wastewater passes through the oil removal system, it flows out of the coalescing oil remover by overflow and enters the micro-electrolysis oxidation system from the bottom. The micro-electrolysis reaction time is 60 minutes.

[0054] Furthermore, after treatment with a pH regulator, the pH of the wastewater in the micro-electrolysis oxidation system was ensured to be 4; the porosity of the micro-electrolysis material was 66%; 120 kg of micro-electrolysis material was added to each cubic meter of waste liquid; the ratio of aeration volume to waste water was (10:1); and the viscosity of the waste liquid was 1.83 mPa·s.

[0055] Step three: After passing through the micro-electrolytic oxidation system, the pH of the wastewater will rise to a certain extent, and the pH of the wastewater is maintained at around 8 by adding 600 mg / L of sodium hydroxide.

[0056] Furthermore, an aeration device is provided in the pH adjustment system, and the aeration device is kept running while sodium hydroxide is added; the ratio of aeration volume to wastewater is 10:1; and the aeration time is 20 minutes.

[0057] Step 4: the wastewater treated by the pH adjustment system enters the ion removal system from the bottom by overflow, and an ion remover is added to the system.

[0058] Furthermore, the amount of the ion remover added is 1342 mg / L; the ion remover is a composite agent, which is composed of agent A, agent B, and an auxiliary agent, and is composed of the following components in mass percentage:

[0059] Agent A: 10% sodium sulfate, 5% aluminum sulfate, 5% potassium carbonate; Agent B: 50% sodium carbonate; Additive: 30% bentonite; The ion removal system is equipped with a stirring paddle, and the speed of the stirring motor is 300r / min; The total hardness (in terms of calcium carbonate) of the wastewater after treatment by the ion removal system is 180mg / L; The residence time of the wastewater in the ion removal system is 20min.

[0060] Step 5: The wastewater after ion treatment flows into the coagulation tank from the bottom in an overflow manner.

[0061] Furthermore, the coagulation tank can be divided into two chambers, A and B. The wastewater enters chamber A from the bottom in an overflow manner, wherein 1000 mg / L of PAC is added to chamber A; chamber A is provided with a stirring paddle, and the speed of the stirring motor is 500 r / min; the residence time of the wastewater in chamber A is 10 min; the wastewater enters chamber B from the bottom in an overflow manner, wherein chamber B is provided with a stirring paddle, and the speed of the stirring motor is 100 r / min; the residence time of the wastewater in chamber B is 15 min; the coagulated wastewater enters the inclined plate sedimentation tank by overflow; the residence time of the wastewater in the inclined plate sedimentation tank is 90 min; the sludge at the bottom of the inclined plate sedimentation tank is regularly transported for reduction treatment.

[0062] Step six, the wastewater overflowing from the coagulation and inclined plate sedimentation system is pressurized by a pump and then enters the multi-stage filtration system.

[0063] Furthermore, the multi-stage filtration system is composed of three-level filter materials of anthracite, glass fiber, and polyester fiber; the residence time of wastewater in the multi-stage filtration system is 40 minutes.

[0064] Step 7, water neutralization system: The wastewater treated by the multi-stage filtration system enters the water neutralization system in the form of overflow.

[0065] Furthermore, a stirring paddle is provided in the water neutralization system, and the speed of the stirring motor is 200r / min; the pH adjuster is citric acid, and the addition amount is 1600mg / L; the treated wastewater is discharged from the system by overflow or pump pressure, and the treated wastewater can be reinjected or used to prepare drilling and fracturing fluids.

[0066] Example 2

[0067] The drilling and reservoir reconstruction waste liquid in this embodiment is taken from a joint station. Unlike Example 1, the waste water in Example 2 is taken from waste liquids of different systems in different well sites. In this embodiment, a treatment system for drilling and reservoir reconstruction waste liquid includes an oil removal system, a micro-electrolysis oxidation system, a pH adjustment system, an ion removal system, a coagulation and inclined plate sedimentation system, a multi-stage filtration system, and a water quality neutralization system.

[0068] Step 1: The wastewater is pressurized by a pump and enters the coalescing deoiler from the bottom. After being treated by the coalescing deoiler, the oil content in the wastewater is 13 mg / L.

[0069] Step 2: After the wastewater passes through the oil removal system, it flows out of the coalescing oil remover by overflow and enters the micro-electrolysis oxidation system from the bottom. The micro-electrolysis reaction time is 60 minutes.

[0070] Furthermore, after treatment with a pH regulator, the pH of the wastewater in the micro-electrolysis oxidation system was ensured to be 4; the porosity of the micro-electrolysis material was 66%; 120 kg of micro-electrolysis material was added to each cubic meter of waste liquid; the ratio of aeration volume to waste water was (10:1); and the viscosity of the waste liquid was 2.67 mPa·s.

[0071] Step three: After passing through the micro-electrolytic oxidation system, the pH of the wastewater will rise to a certain extent, and the pH of the wastewater is maintained at around 8 by adding 600 mg / L of sodium hydroxide.

[0072] Furthermore, an aeration device is provided in the pH adjustment system, and the aeration device is kept running while sodium hydroxide is added; the ratio of aeration volume to wastewater is 10:1; and the aeration time is 20 minutes.

[0073] Step 4: the wastewater treated by the pH adjustment system enters the ion removal system from the bottom by overflow, and an ion remover is added to the system.

[0074] Furthermore, the amount of the ion remover added is 3436 mg / L; the ion remover is a composite agent, which is composed of agent A, agent B, and an auxiliary agent, and is composed of the following components in mass percentage:

[0075] Agent A: 10% sodium sulfate, 5% aluminum sulfate, 5% potassium carbonate;

[0076] Agent B: sodium carbonate 50%;

[0077] Additives: bentonite 30%.

[0078] Furthermore, the ion removal system is provided with a stirring paddle, and the rotation speed of the stirring motor is 300r / min; the total hardness (calculated as calcium carbonate) of the wastewater after being treated by the ion removal system is 300mg / L; the residence time of the wastewater in the ion removal system is 20min.

[0079] Step 5: The wastewater after ion treatment flows into the coagulation tank from the bottom in an overflow manner.

[0080] Furthermore, the coagulation tank can be divided into two chambers, A and B, and the wastewater flows from the bottom into chamber A in an overflow manner. 700 mg / L of PAC is added to chamber A.

[0081] Furthermore, a stirring paddle is provided in chamber A, and the speed of the stirring motor is 500r / min; the residence time of the wastewater in chamber A is 10min; the wastewater enters chamber B from the bottom in an overflow manner, wherein 20mg / L PAM is added to chamber B; a stirring paddle is provided in chamber B, and the speed of the stirring motor is 100r / min; the residence time of the wastewater in chamber B is 15min; the coagulated wastewater enters the inclined plate sedimentation tank by overflow; the residence time of the wastewater in the inclined plate sedimentation tank is 90min; the sludge at the bottom of the inclined plate sedimentation tank is regularly transported for reduction treatment.

[0082] Step six, the wastewater overflowing from the coagulation and inclined plate sedimentation system is pressurized by a pump and then enters the multi-stage filtration system.

[0083] Furthermore, the multi-stage filtration system is composed of three-level filter materials of anthracite, glass fiber, and polyester fiber; the residence time of wastewater in the multi-stage filtration system is 40 minutes.

[0084] Step 7, water neutralization system: The wastewater treated by the multi-stage filtration system enters the water neutralization system in the form of overflow.

[0085] Furthermore, a stirring paddle is provided in the water neutralization system, and the speed of the stirring motor is 200r / min; the pH adjuster is citric acid, and the addition amount is 1600mg / L; the treated wastewater is discharged from the system by overflow or pump pressure, and the treated wastewater can be reinjected or used to prepare drilling and fracturing fluids.

[0086] Table 1 Data comparison table

[0087]

[0088] As can be seen from Table 1, after the process, the wastewater treatment of the two embodiments has a COD removal rate of more than 90%. The viscosity of the wastewater also decreases significantly, the total hardness is less than or equal to 300 mg / L, and the turbidity of the wastewater after treatment is less than 20 NTU, which shows that the wastewater treatment of the two embodiments has achieved significant results.

[0089] Example 3

[0090] For the waste liquid in Example 2, the input vectors of the model are optimized according to the supporting algorithm for the micro-electrolysis oxidation system, namely pH, amount of micro-electrolysis material added, reaction time, and aeration volume, and the output is the wastewater viscosity.

[0091] In the first step, the dimension of the input data matrix X is m×4, where m is the number of samples.

[0092] Furthermore, the input matrix is:

[0093]

[0094] In the second step, the expression under the model assumption is:

[0095]

[0096] in, is the objective function, and ω is the weight vector.

[0097] In the third step, the processing of the upper and lower bound errors is:

[0098]

[0099] The fourth step is to optimize the solution of the dual problem, that is, to solve equation (2) and equation (3) by i and i * Taking the derivative and setting it to zero gives:

[0100]

[0101] Furthermore, based on formula (10), the final regression function is obtained:

[0102]

[0103] The corresponding prediction model was constructed according to formulas (6) to (11), and the model was used for regression prediction using MATLAB software. When the micro-electrolysis reaction time was 60 min, the pH value of the wastewater was 4, 120 kg of micro-electrolysis material was added to each cubic meter of wastewater, and the ratio of aeration volume to wastewater was 10:1, the predicted viscosity was 1.46 mPa·s, and the actual viscosity after treatment was 1.48 mPa·s with a relative error of only 1.35%, which proved that the model had high accuracy, improved process flexibility, improved treatment efficiency, reduced the amount of reagents used, and thus saved treatment costs.

[0104] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0105] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A drilling and reservoir reconstruction waste liquid treatment system, characterized in that: include: The oil removal system, micro-electrolysis oxidation system, pH adjustment system, ion removal system, coagulation and inclined plate sedimentation system, multi-stage filtration system and water neutralization system are connected in sequence. The oil removal system removes oil from the waste liquid; the micro-electrolysis oxidation system adjusts the pH value of the waste liquid after the oil removal treatment and performs electrolytic oxidation; the pH adjustment system performs secondary pH adjustment on the waste liquid after electrolytic oxidation; the ion removal system performs ion removal on the waste liquid after the secondary pH adjustment treatment; The coagulation and inclined plate sedimentation system performs coagulation and flocculation treatment and sedimentation on the waste liquid after ion removal treatment to perform solid-liquid separation; the waste liquid after solid-liquid separation is subjected to multi-stage filtration through the multi-stage filtration system and the water quality neutralization system and then undergoes three pH value adjustment treatments to meet the discharge standards.

2. A drilling and reservoir reconstruction waste liquid treatment system according to claim 1, characterized in that: The oil removal system is composed of a coalescing oil remover, and the oil content in the waste liquid after being treated by the coalescing oil remover is 0-50 mg / L.

3. A drilling and reservoir reconstruction waste liquid treatment system according to claim 1, characterized in that: In the micro-electrolysis oxidation system, the waste liquid after oil removal enters the micro-electrolysis oxidation system from the bottom by overflow, the pH value is adjusted by adding a pH regulator, electrolytic oxidation is carried out by the micro-electrolysis material, and aeration is performed to promote the oxidation reaction; wherein, the micro-electrolysis reaction time is 40 to 100 minutes; the pH value of the waste liquid is adjusted to 3 to 4; the porosity of the micro-electrolysis material is 60 to 80%; 40 to 160 kg of micro-electrolysis material is added to each cubic meter of waste liquid; the ratio of aeration volume to waste liquid is 6:1 to 12:1; and the viscosity of the waste liquid is 1 to 8 mPa·s.

4. A drilling and reservoir reconstruction waste liquid treatment system according to claim 1, characterized in that: 300-1000 mg / L of alkaline solvent is added to the pH regulating system to maintain the pH of the waste liquid at 8-9; an aeration device is provided in the pH regulating system, and the aeration device is kept running while sodium hydroxide is added; the ratio of aeration volume to waste liquid is 6:1-12:1; and the aeration time is within 20-40 minutes.

5. A drilling and reservoir reconstruction waste liquid treatment system according to claim 1, characterized in that: In the ion removal system, waste liquid enters the ion removal system from the bottom by overflow, and the amount of ion remover added is 1000-3500 mg / L; the ion remover is a composite agent, which is composed of agent A, agent B, and auxiliary agent, including agent A sodium sulfate 1-10%, aluminum sulfate 1-5%, potassium carbonate 1-5%; agent B sodium carbonate 20-50%; auxiliary bentonite 20-30%; the ion removal system is provided with a stirring paddle, and the speed of the stirring motor is 100-400 r / min; the residence time of the waste liquid in the ion removal system is 20-40 minutes.

6. A drilling and reservoir reconstruction waste liquid treatment system according to claim 1, characterized in that: The coagulation and inclined plate sedimentation system comprises a coagulation tank and an inclined plate sedimentation tank. The waste liquid after ion removal treatment enters the coagulation tank from the bottom in an overflow manner. The coagulation tank is divided into two chambers, A and B. The waste liquid enters the A chamber from the bottom in an overflow manner. 300-1000 mg / L of PAC is added to the A chamber. A stirring paddle is provided in the A chamber. The stirring motor speed is 300-600 r / min. The residence time of the waste liquid in the A chamber is 10-20 m; the waste liquid enters the B chamber from the bottom in an overflow manner. 10-40 mg / L of PAM is added to the B chamber. A stirring paddle is provided in the B chamber. The stirring motor speed is 100-240 r / min. The residence time of the waste liquid in the B chamber is 10-20 min. The waste liquid after coagulation enters the inclined plate sedimentation tank in an overflow manner for sludge sedimentation. The residence time of the waste liquid in the inclined plate sedimentation tank is 60-150 min.

7. A drilling and reservoir reconstruction waste liquid treatment system according to claim 1, characterized in that: In the multi-stage filtration system, the waste liquid overflowing from the coagulation and inclined plate sedimentation system enters the multi-stage filtration system after being pressurized by a pump. The multi-stage filtration system is composed of anthracite, glass fiber, and polyester fiber from top to bottom. The waste liquid stays in the multi-stage filtration system for 30 to 60 minutes.

8. A drilling and reservoir reconstruction waste liquid treatment system according to claim 1, characterized in that: In the water neutralization system, the waste liquid treated by the multi-stage filtration system enters the water neutralization system in an overflow manner. A stirring paddle is provided in the water neutralization system, and the speed of the stirring motor is 100-400r / min; the pH regulator is citric acid, and the addition amount thereof is 1000-2300mg / L; the treated waste liquid exits the system in an overflow or pump-pressurized manner.

9. A drilling and reservoir reconstruction waste liquid treatment system according to claim 3, characterized in that: The micro-electrolysis oxidation system predicts the effluent viscosity of the waste liquid through a preset algorithm, specifically including using pH, micro-electrolysis material dosage, reaction time, aeration volume and waste liquid viscosity as training samples to establish a training set; wherein pH, micro-electrolysis material dosage, reaction time, aeration volume are inputs, and waste liquid viscosity is output; and the usage of the input parameters of the micro-electrolysis oxidation system is adjusted based on the predicted effluent viscosity.

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