A method and system for treating waste liquid of polysulfone drilling fluid cuttings

Abstract

The present invention provides a method and system for treating waste rock cuttings from polysulfonated drilling fluid. The method for treating waste rock cuttings from polysulfonated drilling fluid comprises: adding rock cuttings to water and stirring evenly, adding a non-ionic gel-breaking flocculant aqueous solution and stirring evenly, performing a first filter press to obtain a first filter press liquid; adjusting the pH value of the first filter press liquid to 4-6, adding a cationic gel-breaking flocculant aqueous solution and stirring evenly, performing a second filter press to obtain a second filter press liquid; adding a chelating agent to the second filter press liquid and stirring evenly, performing a third filter press to obtain a third filter press liquid. The beneficial effects of the present invention include: the cationic gel-breaking flocculant and the non-ionic gel-breaking flocculant reduce the content of high-valent metal ions in the filter press liquid, and reduce the influence of the reuse of the filter press liquid on the performance of the drilling fluid system; the chelating agent reduces the mineralization of the filter press liquid and increases the reuse rate of the filter press liquid.

Description

Technical Field

[0001] The invention belongs to the technical field of drilling cuttings processing, and in particular, relates to a method and a system for processing polysulfone drilling fluid cuttings waste liquid. Background Art

[0002] With the introduction of the new environmental protection law and the improvement of environmental protection requirements, oilfield exploration and development requires that drilling must be carried out to prevent drilling cuttings from falling to the ground. At present, the main technology for the treatment of drilling cuttings from falling to the ground in Sichuan Qing is to mix and break the cuttings and then filter them for solid-liquid separation. The waste liquid generated by polysulfone drilling fluid cuttings needs to be transported to the sewage treatment plant for treatment. In the high-grit area, Sichuan Qing Drilling produces an average of more than 1,000 cubic meters of cuttings waste liquid per well, and as the unit price of sewage treatment increases year by year, the cost of harmless treatment of cuttings waste liquid is getting higher and higher.

[0003] At present, non-ground treatment stages are often used at home and abroad to treat water-based cuttings harmlessly. Through solid-liquid separation equipment, electrochemical adsorption and other principles, the solid phase is removed, the liquid phase is recovered, and the solid phase is prepared into a mud cake. After solid-liquid separation, the water treatment unit undergoes filtration, osmosis and other processes. However, on the one hand, the drilling site needs to add water treatment equipment, which increases the treatment cost and equipment operation risk. On the other hand, the polysulfone drilling fluid has strong colloid stability and poor gel breaking and flocculation effect.

[0004] The Chinese patent with publication number CN102295401A discloses a harmless treatment method for deep well polysulfonated drilling fluid waste mud, and the invention comprises the following steps: (1) composite consolidation: taking a certain volume of deep well polysulfonated drilling fluid waste mud, adding a composite curing agent, stirring evenly for curing treatment; (2) oxidation: adding an oxidant to the solid waste after the consolidation treatment in step (1) for stirring; (3) adjustment: adding an adjusting agent to the solid waste after the oxidation treatment in step (2) to adjust the pH of the solid waste to neutral. The invention has a high cost for curing the polysulfonated drilling fluid cuttings, resulting in cost waste and poor economic efficiency in industrial application. Summary of the invention

[0005] The purpose of the present invention is to solve at least one of the above-mentioned deficiencies in the prior art. For example, one of the purposes of the present invention is to provide a method for treating waste rock cuttings from polysulfonated drilling fluid. Another purpose of the present invention is to provide a system for treating waste rock cuttings from polysulfonated drilling fluid.

[0006] In order to achieve the above-mentioned purpose, one aspect of the present invention provides a method for treating polysulfonated drilling fluid waste cuttings, which comprises the following steps: adding cuttings to water and stirring evenly, adding a non-ionic gel breaker flocculant aqueous solution and stirring evenly, performing a first filter press to obtain a first filtrate; adjusting the pH value of the first filtrate to 4-6, adding a cationic gel breaker flocculant aqueous solution and stirring evenly, performing a second filter press to obtain a second filtrate; adding a chelating agent to the second filtrate and stirring evenly, performing a third filter press to obtain a third filtrate.

[0007] In an exemplary embodiment of the present invention, in the step of adjusting the pH value of the first filtrate to 4-6, the pH value can be adjusted by using a hydrochloric acid solution, and the concentration of the hydrochloric acid solution can be 10-15%.

[0008] In an exemplary embodiment of the present invention, the rock cuttings are 100 m 3 The addition amount of the remaining components can be 500-1000 kg of water, 100-200 kg of non-ionic gel-breaking flocculant aqueous solution, 1000-2000 kg of cationic gel-breaking flocculant aqueous solution, and 100-200 kg of chelating agent.

[0009] In an exemplary embodiment of the present invention, the concentration of the non-ionic gel-breaking flocculant aqueous solution may be 0.3-0.5%, and the concentration of the cationic gel-breaking flocculant aqueous solution may be 30-50%.

[0010] In an exemplary embodiment of the present invention, the non-ionic gel breaker flocculant aqueous solution may include one or more of a non-ionic polyacrylamide aqueous solution, a polyethylene oxide aqueous solution, and a polyvinyl alcohol aqueous solution.

[0011] In an exemplary embodiment of the present invention, the cationic gel breaker flocculant aqueous solution may include one or more of a polyethyleneimine aqueous solution, a dimethyldiallylammonium chloride acrylamide copolymer aqueous solution, and a dimethylaminoethyl acrylate methyl chloride copolymer aqueous solution.

[0012] In an exemplary embodiment of the present invention, the chelating agent may include one or more of polycarboxylates, polyepoxysuccinates, and inorganic phosphates.

[0013] In an exemplary embodiment of the present invention, the treatment method also includes using the third filter press liquid to prepare drilling fluid, and the step of preparing the drilling fluid may include: adding bentonite, potassium polyacrylamide and polymer cellulose to water for hydration and dispersion, and after the molecular chain of the polymer is fully extended, adding the third filter press liquid, and mixing to obtain the drilling fluid.

[0014] In an exemplary embodiment of the present invention, 5% bentonite, 1.0% to 2.0% potassium polyacrylamide, and 3.0% to 5.0% polymer cellulose are added to the mixture of the third filtrate and water in a volume ratio of 70:30 to 30:70.

[0015] Another aspect of the present invention provides a system for treating waste rock cuttings from polysulfone drilling fluid, the system comprising a rock cuttings collection tank, a first delivery pump, an acid-resistant pump, a pH value adjustment unit, a non-ionic gel-breaking flocculant aqueous solution supply unit, a cationic gel-breaking flocculant aqueous solution supply unit, a chelating agent supply unit, a drilling fluid circulation tank, a plate and frame filter press, a second delivery pump, a third delivery pump and a fourth delivery pump, wherein the cationic gel-breaking flocculant aqueous solution supply unit is used to provide a cationic gel-breaking flocculant aqueous solution; the non-ionic gel-breaking flocculant aqueous solution supply unit is used to provide a non-ionic gel-breaking flocculant aqueous solution; the rock cuttings The collecting tank has a containing cavity for collecting and containing rock cuttings, and the rock cutting collecting tank includes a stirring unit; the delivery pump connects the non-ionic gel-breaking flocculant aqueous solution supply unit with the rock cutting collecting tank, and is used to pump the non-ionic gel-breaking flocculant aqueous solution into the rock cutting collecting tank; the plate and frame filter press has a filtration function, and the inlet of the plate and frame filter press is connected to the outlet of the rock cutting collecting tank through the second delivery pump, the first outlet of the plate and frame filter press is connected to the inlet of the rock cutting collecting tank through the third delivery pump, and the second outlet of the plate and frame filter press is connected to the inlet of the drilling fluid circulation tank through the fourth delivery pump. The invention is configured to perform a first pressure filtration on the mixed liquid fed into the cuttings collection tank for the first time, and re-pump the first pressure filtrate obtained by the pressure filtration into the cuttings collection tank; perform a second pressure filtration on the mixed liquid fed into the cuttings collection tank for the second time, and re-pump the second pressure filtrate obtained by the pressure filtration into the cuttings collection tank; perform a third pressure filtration on the mixed liquid fed into the cuttings collection tank for the third time; the chelating agent supply unit is used to add a chelating agent to the second pressure filtrate; the pH value adjusting unit is configured to adjust the pH value of the mixed liquid in the cuttings collection tank to 4-6 after the first pressure filtrate is re-pumped into the cuttings collection tank; the acid-resistant pump is connected to the positive The ionic gel breaker flocculant aqueous solution supply unit and the cuttings collection tank are configured to pump the cationic gel breaker flocculant supplied by the cationic gel breaker flocculant aqueous solution supply unit into the cuttings collection tank after the pH value is adjusted to 4-6 by the pH value adjustment unit; the hydration dispersion unit sequentially adds water, bentonite, potassium salt of polyacrylamide and polymer cellulose to the drilling fluid circulation tank for hydration and dispersion; the fourth delivery pump is connected between the plate and frame filter press and the drilling fluid circulation tank, and is used to pump the third filtrate obtained by filtration into the drilling fluid circulation tank after the molecular chains of the polymer are fully stretched to obtain recovered drilling fluid.

[0016] Compared with the prior art, the beneficial effects of the present invention may include:

[0017] 1) Two polymer-based flocculants, cationic flocculants and non-ionic flocculants, are used to replace traditional inorganic salt-based flocculants. While meeting the on-site flocculant breaking and flocculation effect, the content of high-valent metal ions in the filtrate is greatly reduced, and the impact of the filtrate reuse on the performance of the drilling fluid system is reduced.

[0018] 2) A chelating agent is preferably used to treat waste water-based drilling hydraulic filtrate. The chelating agent has good chelating effect and high temperature stability, and can chelate high-valent metal ions in the filtrate, further reduce the mineralization of the filtrate, and improve the reuse rate of the filtrate.

[0019] 3) The process of the present invention is simple and does not require the addition of additional equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other objects and / or features of the present invention will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0021] Figure 1 A schematic diagram of a system for treating waste cuttings of polysulfone drilling fluid according to an exemplary embodiment of the present invention is shown.

[0022] Figure 2 A flow chart showing a method for treating waste cuttings of polysulfone drilling fluid according to an exemplary embodiment of the present invention.

[0023] The following are the descriptions of the reference numerals:

[0024] 1. Cuttings collection tank, 2. First delivery pump, 3. Acid-resistant pump, 4. pH value adjustment unit, 5. Non-ionic gel-breaking flocculant aqueous solution supply unit, 6. Cationic gel-breaking flocculant aqueous solution supply unit, 7. Chelating agent supply unit, 8. Drilling fluid circulation tank, 9. Plate and frame filter press, 10. Second delivery pump, 11. Third delivery pump, 12. Fourth delivery pump, 13. Hydration dispersion unit. DETAILED DESCRIPTION

[0025] Hereinafter, the polysulfone drilling fluid cuttings waste liquid treatment and treatment system of the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments.

[0026] In order to solve the environmental and cost pressures brought by polysulfonated drilling fluid cuttings waste liquid and promote the green exploration and development of oil and gas resources, the present invention provides a method for treating and recycling polysulfonated drilling fluid cuttings waste liquid. The method uses the treated polysulfonated drilling fluid cuttings waste liquid to prepare drilling fluid, which greatly improves the reuse rate of polysulfonated drilling fluid waste liquid and reduces the treatment cost of polysulfonated drilling fluid cuttings waste liquid.

[0027] First Exemplary Embodiment

[0028] In the first exemplary embodiment of the present invention, a method for treating waste rock cuttings from a polysulfonated drilling fluid is provided, and the method for treating waste rock cuttings from a polysulfonated drilling fluid comprises the following steps: adding the rock cuttings to water and stirring evenly, adding an aqueous solution of a non-ionic gel breaker and flocculant and stirring evenly, performing a first filter press to obtain a first filtrate; adjusting the pH value of the first filtrate to 4 to 6, adding an aqueous solution of a cationic gel breaker and flocculant and stirring evenly, performing a second filter press to obtain a second filtrate; adding a chelating agent to the second filtrate and stirring evenly, performing a third filter press to obtain a third filtrate.

[0029] In an exemplary embodiment of the present invention, in the step of adjusting the pH value of the first filtrate to 4-6, the pH value can be adjusted by using a hydrochloric acid solution, and the concentration of the hydrochloric acid solution can be 10-15%.

[0030] Optionally, the first pH value of the filtrate is adjusted to 4-6 because when the pH value is alkaline, the colloid of the filtrate is difficult to destroy, and the subsequent addition of a cationic gel-breaking flocculant aqueous solution has a poor effect. When the pH value is further adjusted to an acidic state, the colloid of the filtrate is destroyed, and the subsequent addition of a cationic gel-breaking flocculant aqueous solution significantly improves the water yield.

[0031] In an exemplary embodiment of the present invention, the cuttings are measured at 10 m 3 The addition amount of the remaining components can be 50-100 kg of water, 10-20 kg of non-ionic gel-breaking flocculant aqueous solution, 100-200 kg of cationic gel-breaking flocculant aqueous solution, and 10-20 kg of chelating agent.

[0032] That is, the rock cuttings are 100m 3 The addition amount of the remaining components can be 500-1000 kg of water, 100-200 kg of non-ionic gel-breaking flocculant aqueous solution, 1000-2000 kg of cationic gel-breaking flocculant aqueous solution, and 100-200 kg of chelating agent.

[0033] In an exemplary embodiment of the present invention, the concentration of the non-ionic gel-breaking flocculant aqueous solution may be 0.3-0.5%, and the concentration of the cationic gel-breaking flocculant aqueous solution may be 30-50%.

[0034] Optionally, the concentration of the nonionic gel-breaking flocculant aqueous solution is 0.3-0.5%, and the addition range is 0.1%-0.2%, the concentration of the cationic gel-breaking flocculant aqueous solution is 30-50%, and the addition range is 1%-2%, and the addition range of the chelating agent is 0.1%-0.2%. Among them, the addition amount of the nonionic gel-breaking flocculant aqueous solution refers to 100-200kg of the nonionic gel-breaking flocculant aqueous solution accounting for 100m 3The volume mass ratio of the cuttings is 1000-2000 kg of the cationic gel-breaking flocculant aqueous solution per 100 m 3 The volume-to-mass ratio of rock cuttings is 100-200 kg of chelating agent per 100 m 3 Volume to mass ratio of cuttings.

[0035] In an exemplary embodiment of the present invention, the non-ionic gel breaker flocculant aqueous solution may include one or more of a non-ionic polyacrylamide aqueous solution, a polyethylene oxide aqueous solution, and a polyvinyl alcohol aqueous solution.

[0036] In an exemplary embodiment of the present invention, the cationic degelling flocculant may include one or more of a polyethyleneimine aqueous solution, a dimethyldiallylammonium chloride acrylamide copolymer aqueous solution, and a dimethylaminoethyl acrylate methyl chloride copolymer aqueous solution.

[0037] In an exemplary embodiment of the present invention, the chelating agent may include one or more of polycarboxylates, polyepoxysuccinates, and inorganic phosphates.

[0038] According to an exemplary embodiment of the present invention, the above-mentioned polysulfonated drilling fluid cuttings waste liquid treatment steps and the types and amounts of each treatment agent therein are the key points of the present invention to solve the treatment of polysulfonated drilling fluid cuttings waste liquid.

[0039] Second Exemplary Embodiment

[0040] In a second exemplary embodiment of the present invention, a method for treating polysulfone drilling fluid cuttings waste liquid is provided, the treatment method also includes using the third filter press liquid to prepare drilling fluid, and the step of preparing the drilling fluid may include: adding bentonite, potassium polyacrylamide and polymer cellulose to water for hydration and dispersion, adding the third filter press liquid after the molecular chain of the polymer is fully extended, and mixing to obtain the drilling fluid.

[0041] In an exemplary embodiment of the present invention, 5% bentonite, 1.0% to 2.0% potassium polyacrylamide, and 3.0% to 5.0% polymer cellulose are added to a mixture of the third press filtrate and water in a volume ratio of 70:30 to 30:70.

[0042] Among them, the English name of potassium polyacrylamide is KPAM, and the English name of polymer cellulose is PAC-LV.

[0043] According to an exemplary embodiment of the present invention, the drilling fluid may be prepared by processing and recycling the waste cuttings of the polysulfone drilling fluid.

[0044] Third Exemplary Embodiment

[0045] In an exemplary embodiment of the present invention, a system for treating waste cuttings of polysulfone drilling fluid is provided, such as Figure 1 As shown, it includes a cuttings collection tank 1, a first delivery pump 2, an acid-resistant pump 3, a pH value adjustment unit 4, a non-ionic gel breaker flocculant aqueous solution supply unit 5, a cationic gel breaker flocculant aqueous solution supply unit 6, a chelating agent supply unit 7, a drilling fluid circulation tank 8, a plate and frame filter press 9, a second delivery pump 10, a third delivery pump 11, a fourth delivery pump 12 and a hydration dispersion unit 13.

[0046] Among them, the cationic gel-breaking flocculant aqueous solution supply unit 6, the nonionic gel-breaking flocculant aqueous solution supply unit 5, the chelating agent supply unit 7 and the hydration dispersion unit 13 are used to add various treatment agents. For example, the cationic gel-breaking flocculant aqueous solution supply unit 6 is used to provide a cationic gel-breaking flocculant aqueous solution. The nonionic gel-breaking flocculant aqueous solution supply unit 5 is used to provide a nonionic gel-breaking flocculant aqueous solution. The chelating agent supply unit 7 is used to provide a chelating agent. The hydration dispersion unit 13 is used to add water, bentonite, potassium polyacrylamide and polymer cellulose to the drilling fluid circulation tank 8 for hydration dispersion.

[0047] The cuttings collecting tank 1 has a containing cavity for collecting and containing cuttings, and the cuttings collecting tank comprises a stirring unit for stirring and mixing the solution therein uniformly.

[0048] The first delivery pump 2 is connected to the non-ionic gel-breaking flocculant aqueous solution supply unit and the cuttings collection tank, and is used to pump the non-ionic gel-breaking flocculant aqueous solution into the cuttings collection tank.

[0049] The acid-resistant pump connects the cationic gel-breaking flocculant aqueous solution supply unit and the rock cuttings collection tank, and is used for pumping the cationic gel-breaking flocculant supplied by the cationic gel-breaking flocculant aqueous solution supply unit into the rock cuttings collection tank.

[0050] The plate-frame filter press 9 has a filter pressing function, the inlet of the plate-frame filter press is connected to the outlet of the cuttings collection tank through the second delivery pump, the first outlet of the plate-frame filter press is connected to the inlet of the cuttings collection tank through the third delivery pump, and the second outlet of the plate-frame filter press is connected to the inlet of the drilling fluid circulation tank through the fourth delivery pump. The first outlet and the second outlet of the plate-frame filter press can be set separately or in common.

[0051] The plate and frame filter press can perform multiple filtrations, for example, three times. In this embodiment, the plate and frame filter press can be configured to perform a first filtration on the mixed liquid fed into the cuttings collection tank for the first time, and re-pump the first filtrate obtained by filtration into the cuttings collection tank; perform a second filtration on the mixed liquid fed into the cuttings collection tank for the second time, and re-pump the second filtrate obtained by filtration into the cuttings collection tank; perform a third filtration on the mixed liquid fed into the cuttings collection tank for the third time, and pump the third filtrate obtained by filtration into the drilling fluid circulation tank.

[0052] The drilling fluid circulation tank 8 is used to receive the filtrate obtained by the plate and frame filter press and to recycle and prepare the drilling fluid.

[0053] The pH value adjusting unit 4 is used to adjust the pH. In this embodiment, the pH value adjusting unit can be configured to adjust the pH value of the mixed liquid in the cuttings collection tank to 4-6 after the first filtrate is re-pumped into the cuttings collection tank.

[0054] The acid-resistant pump 3 connects the cationic gel-breaking flocculant aqueous solution supply unit and the cuttings collection tank, and is configured to pump the cationic gel-breaking flocculant supplied by the cationic gel-breaking flocculant aqueous solution supply unit into the cuttings collection tank after the pH value adjustment unit adjusts the pH value to 4 to 6. The fourth delivery pump is connected between the plate-frame filter press and the drilling fluid circulation tank, and is used to pump the third filtrate obtained by filtration into the drilling fluid circulation tank after the molecular chains of the polymer are fully stretched, so as to obtain recovered drilling fluid.

[0055] Among them, the acid-resistant pump is used to pump dilute hydrochloric acid. Using a general pump for pumping may corrode the pump components and cause damage to the pump.

[0056] Among them, the cuttings collection tank is used to collect cuttings at the drilling site. The cuttings collection tank has a matching agitator. The advantage of using the cuttings collection tank directly is that there is no need to add additional on-site equipment. The effect is that after dilution with water, the viscosity and colloid strength of the cuttings themselves are weakened, which is convenient for subsequent pumping and breaking. The drilling fluid circulation tank is used to prepare drilling fluid at the drilling site. The advantage is that no additional on-site equipment is required. The delivery pump is a pumping equipment at the drilling site. Using a delivery pump to pump drugs is easy to operate and does not require additional equipment.

[0057] Fourth Exemplary Embodiment

[0058] In an embodiment, the polysulfone drilling fluid cuttings waste liquid treatment system of the third exemplary embodiment is used to treat the polysulfone drilling fluid cuttings waste liquid, such as Figure 2As shown, the treatment process includes: adding water to the rock cuttings in the rock cuttings collection tank and stirring evenly, pumping the non-ionic gel-breaking flocculant aqueous solution into the rock cuttings collection tank through a delivery pump and stirring evenly, pumping into a plate-frame filter press, performing the first filter pressing, and obtaining the first filter press liquid; pumping the first filter press liquid back into the rock cuttings collection tank, adding hydrochloric acid solution using an acid-resistant pump, and adjusting the pH value to 4-6, wherein the concentration of the hydrochloric acid solution can be 10-15%. Pumping in the cationic gel-breaking flocculant aqueous solution using an acid-resistant pump and stirring evenly, performing the second filter pressing, and obtaining the second filter press liquid; adding a chelating agent to the second filter press liquid and stirring evenly, performing the third filter pressing, and obtaining the third filter press liquid; adding water to the drilling fluid circulation tank, adding bentonite, potassium salt of polyacrylamide and polymer cellulose to the water for hydration and dispersion, and after the molecular chain of the polymer is fully stretched, pumping the third filter press liquid into the drilling fluid circulation tank, and mixing to obtain the drilling fluid.

[0059] In order to better understand the above exemplary embodiments of the present invention, the method for treating polysulfone drilling fluid cuttings waste liquid is described below with reference to specific examples.

[0060] Example 1

[0061] The present example is a method for treating waste rock cuttings from polysulfone drilling fluid, and the method comprises the following steps:

[0062] (1) Select a 20m 3 Cuttings collection tank, collect 10m in the collection tank 3 Cuttings: add 100 kg of water to the cuttings and stir evenly, add 15 kg of 0.5% non-ionic polyacrylamide aqueous solution and stir evenly, perform the first filter press, and obtain the first filtrate.

[0063] (2) 15% hydrochloric acid was added to the first filtrate to adjust the pH value to 4.1, 200 kg of 50% polyethyleneimine aqueous solution was added and stirred evenly, and a second filtration was performed to obtain a second filtrate.

[0064] (3) Add 20 kg of polycarboxylate to the second filtrate and stir evenly, and perform a third filtrate to obtain a third filtrate.

[0065] Example 2

[0066] The present example is a method for treating waste rock cuttings from polysulfone drilling fluid, and the method comprises the following steps:

[0067] (1) Select a 20m 3 Cuttings collection tank, collect 10m in the collection tank 3Cuttings, add 50kg of water to the cuttings in the cuttings collection tank and stir evenly, pump 10kg of 0.5% polyethylene oxide aqueous solution into the cuttings collection tank through a delivery pump and stir evenly, pump it into the plate and frame filter press, perform the first filtration, and obtain the first filtrate.

[0068] (2) The first filtrate is pumped back into the cuttings collection tank, and a 15% hydrochloric acid solution is added using an acid-resistant pump, and the pH value is adjusted to 5. A 100 kg, 50% concentration of dimethyldiallylammonium chloride acrylamide copolymer aqueous solution is pumped in using an acid-resistant pump and stirred evenly, and a second filtration is performed to obtain a second filtrate.

[0069] (3) Add 10 kg of polyepoxysuccinate chelating agent to the second filtrate and stir evenly, and perform a third filtration to obtain a third filtrate.

[0070] Example 3

[0071] The present example is a method for treating waste rock cuttings from polysulfone drilling fluid, and the method comprises the following steps:

[0072] (1) Select a 20m 3 Cuttings collection tank, collect 10m in the collection tank 3 Cuttings: add 100 kg of water to the cuttings and stir evenly; add 20 kg of 0.5% polyvinyl alcohol aqueous solution and stir evenly; perform the first filter press to obtain the first filtrate.

[0073] (2) 15% hydrochloric acid was added to the first filtrate to adjust the pH value to 6, 200 kg of 50% aqueous solution of ethyl acrylate dimethylamine methyl chloride copolymer was added and stirred evenly, and a second filtration was performed to obtain a second filtrate.

[0074] (3) Add 10 kg of an inorganic phosphate chelating agent to the second filtrate and stir evenly, and perform a third filtration to obtain a third filtrate.

[0075] Example 4

[0076] The present example provides a method and system for treating waste rock cuttings from polysulfone drilling fluid, and the method and system for treating waste rock cuttings from polysulfone drilling fluid include the following steps:

[0077] (1) Select a 20m 3 Cuttings collection tank, collect 10m in the collection tank 3 Cuttings: add 100 kg of water to the cuttings and stir evenly, add 10 kg of 0.5% non-ionic polyacrylamide aqueous solution and stir evenly, perform the first filter press, and obtain the first filtrate.

[0078] (2) 15% hydrochloric acid was added to the first filtrate to adjust the pH value to 4, 100 kg of 50% polyethyleneimine aqueous solution was added and stirred evenly, and a second filtration was performed to obtain a second filtrate.

[0079] (3) Add 15 kg of a polycarboxylate chelating agent to the second filtrate and stir evenly, and perform a third filtration to obtain a third filtrate.

[0080] (4) Add 6m3 of drilling fluid to the drilling fluid circulation tank. 3 Water, add 5% bentonite, 1% potassium polyacrylamide and 3% polymer cellulose to the water for hydration and dispersion. After the molecular chain of the polymer is fully extended, add 14m 3 The filtrate is filtered for the third time and mixed to obtain drilling fluid.

[0081] Example 5

[0082] The present example provides a method and system for treating waste rock cuttings from polysulfone drilling fluid, and the method and system for treating waste rock cuttings from polysulfone drilling fluid include the following steps:

[0083] (1) Select a 20m 3 Cuttings collection tank, collect 10m in the collection tank 3 Cuttings, add 50kg of water to the cuttings in the cuttings collection tank and stir evenly, pump 10kg of 0.5% polyethylene oxide aqueous solution into the cuttings collection tank through a delivery pump and stir evenly, pump it into the plate and frame filter press, perform the first filtration, and obtain the first filtrate.

[0084] (2) The first filtrate is pumped back into the cuttings collection tank, and a 15% hydrochloric acid solution is added using an acid-resistant pump, and the pH value is adjusted to 5. 100 kg of a 50% aqueous solution of dimethyldiallylammonium chloride acrylamide copolymer is pumped in using an acid-resistant pump and stirred evenly, and a second filtration is performed to obtain a second filtrate.

[0085] (3) Add 15 kg of polyepoxysuccinate chelating agent to the second filtrate and stir evenly, and perform a third filtration to obtain a third filtrate.

[0086] (4) Add 10m3 of drilling fluid to the drilling fluid circulation tank. 3 Water, add 5% bentonite, 1% potassium polyacrylamide and 3% polymer cellulose to the water for hydration and dispersion. After the molecular chain of the polymer is fully extended, add 10m 3 The filtrate is filtered for the third time and mixed to obtain drilling fluid.

[0087] Example 6

[0088] The present example provides a method and system for treating waste rock cuttings from polysulfone drilling fluid, and the method and system for treating waste rock cuttings from polysulfone drilling fluid include the following steps:

[0089] (1) Select a 20m 3 Cuttings collection tank, collect 10m in the collection tank 3 Cuttings, add 100 kg of water to the cuttings and stir evenly, add 10 kg of 0.5% polyvinyl alcohol aqueous solution and stir evenly, perform the first filter press, and obtain the first filtrate.

[0090] (2) 15% hydrochloric acid was added to the first filtrate to adjust the pH value to 6, 100 kg of 50% aqueous solution of ethyl acrylate dimethylamine methyl chloride copolymer was added and stirred evenly, and a second filtration was performed to obtain a second filtrate.

[0091] (3) Add 15 kg of an inorganic phosphate chelating agent to the second filtrate and stir evenly, and perform a third filtration to obtain a third filtrate.

[0092] (4) Add 14m3 of water to the drilling fluid circulation tank. 3 Water, add 5% bentonite, 1% potassium polyacrylamide and 3% polymer cellulose to the water for hydration and dispersion. After the molecular chain of the polymer is fully extended, add 6m 3 The filtrate is filtered for the third time and mixed to obtain drilling fluid.

[0093] Comparative Examples 1-5

[0094] Take 1000 mL of rock cuttings, add different amounts of polyvinyl alcohol aqueous solution with a concentration of 0.5% and an addition range of 0.1% to 0.5%, and test the water yield of the polysulfone drilling fluid rock cuttings slurry after stirring for 30 minutes.

[0095] Table 1

[0096]

[0097]

[0098] As shown in Table 1, the water yield is the largest when the amount of polyvinyl alcohol aqueous solution added is 0.2%. The water yield does not increase significantly as the percentage of polyvinyl alcohol aqueous solution in the base liquid continues to increase. Therefore, the addition range is 0.1% to 0.2%.

[0099] Comparative Examples 6-12

[0100] (1) Select a 20m 3 Cuttings collection tank, collect 10m in the collection tank 3Cuttings, add 100kg of water to the cuttings in the cuttings collection tank and stir evenly, pump 10kg of 0.5% polyvinyl alcohol aqueous solution into the cuttings collection tank through a delivery pump and stir evenly, pump it into the plate and frame filter press, perform the first filtration, and obtain the first filtrate.

[0101] (2) 1000 mL of the first filtrate was taken and adjusted to different pH values. A 1% aqueous solution of dimethyldiallylammonium chloride acrylamide copolymer was added to the first filtrate at different pH values ​​to test the water yield of the first filtrate at different pH values.

[0102] Table 2

[0103] Serial number pH Water output rate / % Comparative Example 6 10 37 Comparative Example 7 9 37 Comparative Example 8 8 38 Comparative Example 9 7 40 Comparative Example 10 6 65 Comparative Example 11 5 68 Comparative Example 12 4 68

[0104] As shown in Table 2, when the pH value is alkaline, the colloid of the filtrate is difficult to destroy, and the addition of a cationic gel breaker flocculant aqueous solution has little effect. When the pH value is further adjusted to acidic, the colloid of the filtrate is destroyed. After adding a dimethyldiallylammonium chloride acrylamide copolymer aqueous solution, the water yield is significantly improved. Therefore, the pH value of the primary filtrate needs to be adjusted to 5.

[0105] Comparative Examples 13-17

[0106] (1) Select a 20m 3 Cuttings collection tank, collect 10m in the collection tank 3 Cuttings, add 100kg of water to the cuttings in the cuttings collection tank and stir evenly, pump 10kg of 0.5% polyvinyl alcohol aqueous solution into the cuttings collection tank through a delivery pump and stir evenly, pump it into the plate and frame filter press, perform the first filtration, and obtain the first filtrate.

[0107] (2) Take 1000 mL of the first filtrate, adjust the pH value of the first filtrate to 5, add 50% dimethyldiallylammonium chloride acrylamide copolymer in an amount ranging from 1 to 5%, stir for 30 minutes, and then test the water yield of the first filtrate.

[0108] Table 3

[0109]

[0110] As shown in Table 3, the water yield is the largest when the percentage of dimethyldiallyl ammonium chloride acrylamide copolymer in the base liquid is 2%. Continuing to increase the content of dimethyldiallyl ammonium chloride acrylamide copolymer, the water yield has no significant increase, so the addition range is 1% to 2%.

[0111] Comparative Examples 18-23

[0112] (1) Select a 20m3 Cuttings collection tank, collect 10m in the collection tank 3 Cuttings: add 100 kg of water to the cuttings and stir evenly, add 10 kg of 0.5% non-ionic polyacrylamide aqueous solution and stir evenly, perform the first filter press, and obtain the first filtrate.

[0113] (2) The first filtrate is pumped back into the cuttings collection tank, 15% hydrochloric acid solution is added using an acid-resistant pump, the pH value is adjusted to 4-6, 100 kg of 50% polyethyleneimine aqueous solution is pumped in using an acid-resistant pump and stirred evenly, and a second filtration is performed to obtain a second filtrate.

[0114] (3) Take 1000 mL of the second filtrate, add polyepoxy succinate in an amount ranging from 0.1 to 0.5, stir for 30 minutes, and then test the water yield of the second filtrate.

[0115] Table 4

[0116]

[0117]

[0118] As shown in Table 4, the total hardness decreases significantly after the addition of polyepoxy succinates. When the addition amount of polyepoxy succinates is 0.1% to 0.2%, the total hardness is less than 200 mg / L, which meets the requirements for drilling fluid preparation ("Related Requirements for Preparation Water in PetroChina Drilling Fluid Technical Specifications SY / T 7377-2017")

[0119] Comparative Examples 24-32

[0120] Table 5

[0121]

[0122] Table 5 is a performance comparison table of drilling fluids prepared with different base fluids. The performance of the filtrate treated with this technical solution is closest to that of the drilling fluid prepared with clean water, which meets the needs of on-site construction.

[0123] Although the present invention has been described above by combining with exemplary embodiments, it will be apparent to those skilled in the art that various modifications and changes may be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined in the claims.

Claims

1. A method for treating polysulfone drilling fluid cuttings waste liquid, characterized in that: The polysulfone drilling fluid cuttings waste liquid treatment method comprises the following steps: Add rock cuttings to water and stir evenly, add non-ionic gel breaker flocculant aqueous solution and stir evenly, perform the first filter press, and obtain the first filtrate; The pH value of the first filtrate is adjusted to 4-6, and a cationic gel-breaking flocculant aqueous solution is added and stirred evenly, and a second filtration is performed to obtain a second filtrate; Add a chelating agent to the second filtrate and stir evenly, perform a third filtration to obtain a third filtrate. The non-ionic gel breaker flocculant aqueous solution includes one or more of a non-ionic polyacrylamide aqueous solution, a polyethylene oxide aqueous solution, and a polyvinyl alcohol aqueous solution; The cationic gel breaker flocculant aqueous solution includes one or more of polyethyleneimine aqueous solution, dimethyldiallylammonium chloride acrylamide copolymer aqueous solution, and dimethylaminoethyl acrylate methyl chloride copolymer aqueous solution; The chelating agent includes one or more of polycarboxylates, polyepoxysuccinates, and inorganic phosphates.

2. The method for treating polysulfone drilling fluid cuttings waste liquid according to claim 1, characterized in that: In the step of adjusting the pH value of the first filtrate to 4-6, a hydrochloric acid solution is used to adjust the pH value, and the concentration of the hydrochloric acid solution is 10-15%.

3. The method for treating polysulfone drilling fluid cuttings waste liquid according to claim 1, characterized in that: The rock cuttings are measured at 100m 3 The addition amount of the remaining components is 500-1000kg water, 100-200kg non-ionic gel breaker flocculant aqueous solution, 1000-2000kg cationic gel breaker flocculant aqueous solution, and 100-200kg chelating agent.

4. The method for treating polysulfone drilling fluid cuttings waste liquid according to claim 3, characterized in that: The concentration of the non-ionic gel-breaking flocculant aqueous solution is 0.3-0.5%, and the concentration of the cationic gel-breaking flocculant aqueous solution is 30-50%.

5. The method for treating polysulfone drilling fluid cuttings waste liquid according to any one of claims 1 to 4, characterized in that: The treatment method further comprises using the third filtrate to prepare drilling fluid, and the steps of preparing the drilling fluid include: Bentonite, potassium polyacrylamide and polymer cellulose are added to water for hydration and dispersion. After the molecular chain of the polymer is fully extended, the third filter press liquid is added and mixed to obtain the drilling fluid.

6. The method for treating waste cuttings of polysulfone drilling fluid according to claim 5, characterized in that: 5% bentonite, 1.0% to 2.0% potassium polyacrylamide, and 3.0% to 5.0% polymer cellulose are added to a mixture of the third press filtrate and water in a volume ratio of 70:30 to 30:

70.

7. A system for treating waste liquid of polysulfone drilling fluid cuttings, characterized in that: The treatment system includes a cuttings collection tank, a first delivery pump, an acid-resistant pump, a pH value adjustment unit, a non-ionic gel-breaking flocculant aqueous solution supply unit, a cationic gel-breaking flocculant aqueous solution supply unit, a chelating agent supply unit, a drilling fluid circulation tank, a plate and frame filter press, a second delivery pump, a third delivery pump, a hydration dispersion unit, and a fourth delivery pump, wherein: The cationic gel-breaking flocculant aqueous solution supply unit is used to provide a cationic gel-breaking flocculant aqueous solution; The non-ionic gel-breaking flocculant aqueous solution supply unit is used to provide a non-ionic gel-breaking flocculant aqueous solution; The rock cuttings collection tank has a receiving chamber for collecting and receiving rock cuttings, and the rock cuttings collection tank includes a stirring unit; The first delivery pump is connected to the non-ionic gel breaker flocculant aqueous solution supply unit and the rock cuttings collection tank, and is used to pump the non-ionic gel breaker flocculant aqueous solution into the rock cuttings collection tank; The plate and frame filter press has a filter pressing function, the inlet of the plate and frame filter press is connected to the outlet of the cuttings collection tank through a second delivery pump, the first outlet of the plate and frame filter press is connected to the inlet of the cuttings collection tank through a third delivery pump, and the second outlet of the plate and frame filter press is connected to the inlet of the drilling fluid circulation tank through a fourth delivery pump. The plate and frame filter press is configured to perform a first filter pressing on the mixed liquid fed into the cuttings collection tank for the first time, and re-pump the first filter press liquid obtained by the filter pressing into the cuttings collection tank; perform a second filter pressing on the mixed liquid fed into the cuttings collection tank for the second time, and re-pump the second filter press liquid obtained by the filter pressing into the cuttings collection tank; and perform a third filter pressing on the mixed liquid fed into the cuttings collection tank for the third time; The chelating agent supply unit is used to add the chelating agent to the second press filtrate; The pH value adjusting unit is configured to adjust the pH value of the mixed liquid in the cuttings collection tank to 4-6 after the first filtrate is re-pumped into the cuttings collection tank; The acid-resistant pump is connected to the cationic gel-breaking flocculant aqueous solution supply unit and the rock cuttings collection tank, and is configured to pump the cationic gel-breaking flocculant supplied by the cationic gel-breaking flocculant aqueous solution supply unit into the rock cuttings collection tank after the pH value adjustment unit adjusts the pH value to 4 to 6; The hydration and dispersion unit sequentially adds water, bentonite, potassium salt of polyacrylamide and polymer cellulose to the drilling fluid circulation tank for hydration and dispersion; The fourth delivery pump is connected between the plate-frame filter press and the drilling fluid circulation tank, and is used to pump the third filtrate obtained by filtration into the drilling fluid circulation tank after the molecular chains of the polymer are fully stretched, so as to obtain the recovered drilling fluid; The non-ionic gel breaker flocculant aqueous solution includes one or more of a non-ionic polyacrylamide aqueous solution, a polyethylene oxide aqueous solution, and a polyvinyl alcohol aqueous solution; The cationic gel breaker flocculant aqueous solution includes one or more of polyethyleneimine aqueous solution, dimethyldiallylammonium chloride acrylamide copolymer aqueous solution, and dimethylaminoethyl acrylate methyl chloride copolymer aqueous solution; The chelating agent includes one or more of polycarboxylates, polyepoxysuccinates, and inorganic phosphates.

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