Search

CN-122010210-A - Deep purification and circulation treatment process for tertiary oil recovery produced water

CN122010210ACN 122010210 ACN122010210 ACN 122010210ACN-122010210-A

Abstract

The invention relates to a deep purification and circulation treatment process of tertiary oil recovery produced water, which belongs to the technical field of petroleum exploitation and comprises the following steps: step one: preprocessing and regulating the entering tertiary oil recovery produced water to obtain preprocessed water; step two: constructing a depth adsorption filtration system; step three: performing an in-situ regeneration cycle routine based on the differential pressure feedback; the pretreatment water is introduced into a filtering unit filled with a bionic amphiphilic anti-fouling modified filter material, contact filtering operation is performed, the hydrophobic cavity of the mono (methacryloyloxy) -beta-cyclodextrin ester grafted on the surface of the filter material is utilized in the scheme, the surfactant in the water body is physically enveloped, the process can effectively destroy the interfacial film of emulsion, micro oil drops are induced to coalesce and be intercepted, and a layer of compact hydration barrier is formed on the surface of the filter material through hydration of the zwitterionic groups of the sulfobetaine methacrylate.

Inventors

  • SHI YAN
  • LIU ZHEQIN

Assignees

  • 西安方汇石油工程有限公司

Dates

Publication Date
20260512
Application Date
20260414

Claims (8)

  1. 1. A deep purification circulation treatment process of tertiary oil recovery produced water is characterized by comprising the following steps of firstly carrying out pretreatment regulation and control on the entering tertiary oil recovery produced water to obtain pretreated water, secondly constructing a deep adsorption filtration system, thirdly executing an in-situ regeneration circulation program based on pressure difference feedback, introducing the pretreated water into a filtration unit filled with a bionic amphiphilic anti-fouling modified filter material, and executing contact filtration operation, wherein the bionic amphiphilic anti-fouling modified filter material is prepared based on a ternary functional copolymer coating grafted on the surface of a walnut shell substrate, and the ternary functional copolymer is formed by copolymerizing sulfobetaine methacrylate, dopamine methacrylamide and mono (methacryloyloxy) -beta-cyclodextrin ester.
  2. 2. The advanced purification cycle treatment process of tertiary oil recovery produced water according to claim 1 is characterized by comprising the specific steps of A1, introducing produced water into a settling tank for gravity settling to remove floating oil and large-particle suspended matters, A2, performing gradient heating control on a water body through a heat exchange device, adjusting the water temperature to 35-60 ℃ to reduce the viscosity of the water body and enhance Brownian motion, and obtaining pretreated water containing polymer and emulsified oil.
  3. 3. The process for deep purification of tertiary oil recovery produced water according to claim 1, wherein the specific parameters of the contact filtration operation in the second step are as follows, the filtration rate of the filtration unit is set to be The hydrophobic cavity of beta-cyclodextrin in the mono (methacryloyloxy) -beta-cyclodextrin ester grafted on the surface of the filter material is used for physically enveloping the hydrophobic end of the surfactant in the water body, destroying the emulsion interface film, inducing the coalescence of micro oil drops and intercepting oil and suspended matters through the filter material layer.
  4. 4. The process for deeply purifying and recycling the tertiary oil recovery produced water according to claim 1 is characterized by comprising the specific steps of step B1, monitoring differential pressure data of an inlet and an outlet of a filtering unit in real time, wherein the specific step of executing an in-situ regeneration and recycling program based on differential pressure feedback in step three is as follows Step B2, when When the filter material layer reaches the sewage receiving threshold, automatically blocking water inflow and starting a back flushing instruction, wherein the step B3 is to introduce the air-water ratio as The gas-water mixed fluid is subjected to back flushing, the attached oily sludge is stripped by utilizing the underwater super-oleophobic characteristic of the surface of the filter material, water is recovered after back flushing is finished, and the next treatment cycle is carried out.
  5. 5. The advanced purification and cyclic treatment process of tertiary oil recovery produced water according to claim 2, wherein the preparation method of the amphiphilic anti-fouling modified filter material comprises the following steps: Step C1, performing substrate activation treatment on natural walnut shell particles, removing surface impurities and exposing active sites to obtain activated walnut shells; Step C2, synthesizing the ternary functional copolymer; And C3, constructing a bionic coating, immersing the activated walnut shells into a buffer solution containing a ternary functional copolymer, performing oxidation self-polymerization assembly and surface grafting, and performing aftertreatment to obtain the bionic amphiphilic anti-fouling modified filter material.
  6. 6. The deep purification cycle treatment process of tertiary oil recovery produced water according to claim 5 is characterized in that the specific operation of the substrate activation treatment in the step C1 is that walnut shell particles with the particle size of 0.5 mm-1.2 mm are selected and immersed in an NaOH aqueous solution with the mass fraction of 4% -6%, mechanical stirring and cleaning are carried out at room temperature to remove surface pectin and grease, deionized water is used for washing to be neutral after cleaning, and constant-temperature drying is carried out in a drying box.
  7. 7. The process for deeply purifying and recycling tertiary oil recovery produced water according to claim 5, wherein the step C2 of synthesizing the ternary functional copolymer comprises the following specific operations of preparing reaction monomers in step D1 and setting the molar ratio of the monomers in step D2 to be And step D3, dissolving the monomer in a mixed solvent of ethanol and water, adding azo diisobutylamidine hydrochloride accounting for 0.8-1.2% of the total mass of the monomer as an initiator, and step D4, introducing nitrogen to deoxidize, carrying out constant-temperature stirring reaction for 5-7 hours at 55-65 ℃, and carrying out dialysis purification and freeze drying after the reaction to obtain the ternary functional copolymer powder.
  8. 8. The deep purification cycle treatment process of tertiary oil recovery produced water according to claim 5 is characterized in that the specific operation of constructing a bionic coating in the step C3 is that in the step E1, a ternary functional copolymer solution with the concentration of 1.5 mg/mL-2.5 mg/mL is prepared, a Tris-HCl buffer solution with the pH value of 8.0-9.0 is adopted as a solvent, in the step E2, activated walnut shells obtained in the step C1 are put into the solution, mechanical stirring is carried out under the condition of continuously introducing air, the reaction time is 12-24 hours, and a functional hydrogel coating grows on the surfaces of the walnut shells in situ.

Description

Deep purification and circulation treatment process for tertiary oil recovery produced water Technical Field The invention relates to the field of petroleum exploitation, in particular to a deep purification and circulation treatment process of tertiary oil recovery produced water. Background In the field of oil exploitation, particularly in the tertiary oil recovery process, the wide application of chemical oil displacement technology leads to extremely complex components of produced water, and at present, the treatment of the produced water mainly depends on the traditional processes of physical sedimentation, coarse granulation, conventional medium filtration and the like; In the actual operation process, the prior art faces serious challenges, as the produced water contains high-concentration polyacrylamide and other polymers, the viscosity of the water body is obviously increased, so that the stability of micro oil drops in the water is extremely strong, and the conventional filter medium is difficult to effectively capture and separate the micro oil drops; When the prior filtering technology is used for treating polymer-containing sewage, the surface of a filter material is extremely easy to generate serious irreversible pollution. Under the actual working condition, the polymer and oil drops often generate a co-adsorption phenomenon to form extremely-viscous polymer-containing oil sludge which is firmly wrapped on the surface of the filter material, the phenomenon directly causes rapid rising of the filtering resistance in extremely short time and abnormal shortening of the running period, when the back flushing operation is carried out, the traditional flushing means often cannot thoroughly strip the attached oil sludge due to the extremely strong binding force between the filter material and pollutants, so that the flux recovery rate of the filter material is continuously reduced, and the inside of the filter layer often has obvious hardening phenomenon and even deep blockage caused along with the running time, so that the whole treatment unit is finally forced to frequently stop to replace the filter material, thereby seriously affecting the production continuity and obviously improving the running maintenance cost. In addition, the prior art lacks flexible regulation means when dealing with water quality fluctuation of different emulsification degrees and polymer concentrations, and when the content of surfactant in inflow water is higher, an emulsion interfacial film is extremely difficult to damage, so that a large number of micro oil drops penetrate a filter layer to make the purification effect extremely unstable, and the problem of poor adaptability to complex water quality caused by single function of the surface of a filter material becomes a bottleneck for restricting deep purification and recycling of tertiary oil recovery produced water. The above information disclosed in the above background section is only for enhancement of understanding of the background of the disclosure and therefore it may include information that does not form the prior art that is already known to those of ordinary skill in the art. Disclosure of Invention The invention aims to provide a deep purification and circulation treatment process of tertiary oil recovery produced water, which aims to solve the problems in the background technology. The technical scheme includes that the method comprises the steps of firstly, preprocessing and regulating and controlling incoming tertiary oil recovery produced water to obtain preprocessed water, secondly, constructing a deep adsorption filtration system, thirdly, executing an in-situ regeneration circulation program based on pressure difference feedback, introducing the preprocessed water into a filtration unit filled with a bionic amphiphilic anti-fouling modified filter material, and executing contact filtration operation, wherein the bionic amphiphilic anti-fouling modified filter material is prepared based on a walnut shell substrate surface grafted ternary functional copolymer coating, and the ternary functional copolymer is formed by copolymerizing sulfobetaine methacrylate, dopamine methacrylamide and mono (methacryloyloxy) -beta-cyclodextrin ester. The method comprises the following specific steps of carrying out pretreatment regulation and control on the entering tertiary oil recovery produced water, namely, a step A1 of introducing the produced water into a settling tank for gravity settling to remove floating oil and large-particle suspended matters, and a step A2 of carrying out gradient heating control on a water body through a heat exchange device, and regulating the water temperature to 35-60 ℃ so as to reduce the viscosity of the water body and enhance Brownian motion, thus obtaining pretreated water containing polymer and emulsified oil. Preferably, the specific parameters of the contact filtration operation in the second step are as follows, the filtrat