Polyamide phenol amine resin polyether demulsifier for offshore oilfield and preparation method thereof

Abstract

The invention discloses a polyamide phenol amine resin polyether demulsifier for an offshore oilfield and a preparation method of the polyamide phenol amine resin polyether demulsifier. The preparation method comprises the following steps: firstly, carrying out condensation polymerization on an organic amine compound and a diester compound to obtain polyamide; then, polyamide, a phenolic compound and formaldehyde are subjected to a Mannich reaction, and the novel initiator of the polyamide phenol amine resin demulsifier is obtained; and finally, sequentially reacting the polyamide phenol amine resin demulsifier initiator with propylene oxide (PO) and ethylene oxide (EO) to obtain the final polyamide phenol amine resin polyether demulsifier. The demulsifier disclosed by the invention is relatively simple in preparation method and easy to industrialize, has the advantage of higher dehydration speed compared with a phenol-amine resin polyether demulsifier commonly used in an offshore oil field at present, and can better meet the increasingly-increasing rapid oil-water separation requirement of the offshore oil field.

Description

Technical Field

[0001] The invention belongs to the technical field of oilfield chemicals, and particularly relates to a polyamide phenolamine resin polyether demulsifier for offshore oilfields and a preparation method thereof. Background Art

[0002] Demulsifiers are essential chemicals in the oil production process. Due to space constraints on offshore oil production platforms, the agent's effectiveness is typically short, placing higher demands on the agent's demulsification capabilities.

[0003] Phenolamine resin-based polyether demulsifiers are widely used in crude oil demulsification. This type of demulsifier is produced by reacting a phenolamine resin (demulsifier initiator) with an epoxy compound. Depending on the phenolic compound used, commonly used phenolamine resin polyether demulsifiers include bisphenol A phenolamine resin polyether demulsifiers, nonylphenol phenolamine resin polyether demulsifiers, and phenolamine resin polyether demulsifiers substituted with other substituents. The synthesis method for this type of polyether demulsifier is to first react a phenolic compound, an organic amine, and a formaldehyde solution to produce a phenolamine resin initiator; then, the phenolamine resin initiator is reacted with propylene oxide (PO) and ethylene oxide (EO) under alkaline conditions to produce the polyether demulsifier.

[0004] However, with the continuous increase in production of offshore oil fields, the liquid production has increased rapidly, and the oil-water separation time has become shorter and shorter. Traditional phenolamine resin polyether demulsifiers are gradually unable to meet the needs of offshore oil fields for rapid oil-water separation in terms of chain length and branching degree. Summary of the Invention

[0005] The present invention is proposed to solve the problems existing in the prior art, and its purpose is to provide a polyamide phenolamine resin polyether demulsifier for offshore oil fields and a preparation method thereof.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for preparing a polyamide phenolamine resin polyether demulsifier for offshore oil fields comprises the following steps:

[0008] (I) subjecting an organic amine compound and a diester compound to a condensation polymerization reaction to obtain a polyamide;

[0009] Add the organic amine compound, diester compound and methanol to the reaction vessel in sequence, then gradually heat the solution to 65-70°C under stirring and reflux for 5-7 hours. After the reflux, gradually reduce the pressure to -0.1 MPa and perform vacuum distillation for 1 hour to remove the methanol in the solution.

[0010] The molar ratio of the organic amine compound to the diester compound is (1-1.05):1;

[0011] The added mass of the methanol is the sum of the masses of the organic amine compound and the diester compound;

[0012] The organic amine compound is polyethylene polyamine; the polyethylene polyamine is diethylene triamine, triethylene tetramine or tetraethylene pentamine.

[0013] The diester compound is any one of dimethyl malonate, dimethyl glutarate, dimethyl adipate, dimethyl sebacate, dimethyl 1,4-cyclohexanedicarboxylate or dimethyl 3,3'-thiodipropionate.

[0014] (II) a novel polyamide phenolamine resin demulsifier initiator is obtained by subjecting polyamide to a Mannich reaction with a phenolic compound and formaldehyde;

[0015] The phenolic compound is added to the reaction vessel described in step (I), and then the temperature is raised to 60° C. and 37% formaldehyde solution is added dropwise to the reaction system for 0.5 h; after the dropwise addition is completed, the reaction is carried out at 60° C. for 2 h to 4 h; after the reaction is completed, the reaction system is gradually heated to 110° C. to 120° C., and the pressure is reduced to -0.1 MPa and the reaction is continued for 1 h to remove moisture, thereby obtaining a polyamide phenolamine resin demulsifier initiator;

[0016] The phenolic compound is any one of bisphenol A, 4-methoxyphenol, 4-ethylphenol or 4-nonylphenol.

[0017] The added mass of the phenolic compound is 3% to 8% of the mass of the organic amine compound;

[0018] The molar ratio of formaldehyde to organic amine compound is 1:10;

[0019] The dropwise addition time of the formaldehyde solution is 0.5 h.

[0020] (III) reacting the novel polyamide phenol amine resin demulsifier initiator with propylene oxide and ethylene oxide in sequence to obtain the final polyamide phenol amine resin polyether demulsifier;

[0021] The novel polyamide phenolamine resin demulsifier initiator and catalyst KOH obtained in step (II) are placed in a clean, dry reactor, which is then replaced several times with high-purity nitrogen and evacuated to -0.1 MPa; the temperature is gradually increased and the evacuation is continued during stirring until the reaction system temperature reaches 100°C; when the reaction temperature approaches 130°C, propylene oxide is slowly, continuously and gradually introduced. During this process, the temperature of the reaction system should be controlled between 130°C and 140°C, and the pressure of the reaction system should not be higher than 0.4 MPa; finally, when the propylene oxide is completely reacted, that is, the pressure of the reaction system is reduced to -0.1 MPa, evacuation is carried out for 10 minutes, and then ethylene oxide is slowly, continuously and gradually introduced in the same manner, except that since ethylene oxide is more active than propylene oxide, the temperature of the reaction system should be controlled between 120°C and 130°C;

[0022] The mass ratio of the propylene oxide to the initiator is 1:59;

[0023] The amount of the catalyst KOH used is 0.35% of the sum of the mass of the initiator and propylene oxide; and 0.25% of the mass of ethylene oxide;

[0024] The mass ratio of the ethylene oxide to the propylene oxide is 1:3.

[0025] In the above technical solution, different polyamide phenolamine resin polyether demulsifiers can be obtained by using different organic amine compounds, diester compounds, phenolic compounds and different proportions of propylene oxide and ethylene oxide.

[0026] A polyamide phenolamine resin polyether demulsifier for offshore oil fields is prepared by the above method. The general structural formula of the polyamide phenolamine resin polyether demulsifier for offshore oil fields is:

[0027]

[0028] The beneficial effects of the present invention are:

[0029] The present invention provides a polyamide-phenolamine resin polyether demulsifier for offshore oil fields and a preparation method thereof. The method comprises the following steps: first, polycondensing an organic amine compound and a diester compound to obtain a polyamide; then subjecting the polyamide to a Mannich reaction with a phenolic compound and formaldehyde to obtain a novel phenolamine resin initiator (polyamide-phenolamine resin initiator); and finally, sequentially reacting the novel phenolamine resin initiator with propylene oxide (PO) and ethylene oxide (EO) to obtain the final polyamide-phenolamine resin polyether demulsifier. The demulsifier preparation method of the present invention is relatively simple and easy to industrialize. Compared with the phenolamine resin polyether demulsifiers currently commonly used in offshore oil fields, the demulsifier has the advantage of faster dehydration speed and is more suitable for rapid demulsification and dehydration treatment in offshore oil fields. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below through specific implementation methods.

[0031] Example 1

[0032] A method for preparing a polyamide phenolamine resin polyether demulsifier for offshore oil fields comprises the following steps:

[0033] (I) 76.8 g of triethylenetetramine (0.53 mol), 66.1 g of dimethyl malonate (0.50 mol), and 142.9 g of methanol were added sequentially to a reaction kettle, and then the temperature was gradually increased under stirring and refluxed for 5 h. After the reflux, the pressure was gradually reduced to -0.1 MPa and the solution was distilled under reduced pressure for 1 h to remove the methanol in the solution, thereby obtaining polyamide compound IA.

[0034] (II) 3 g of bisphenol A was added to a reactor and uniformly mixed with the polyamide compound IA. The temperature was then raised to 60° C., and 4.3 g of a 37% formaldehyde solution was added dropwise to the reactor. The reaction was carried out at 60° C. for 2 h. After the reaction was completed, the reaction system was gradually heated to 110° C. to 120° C., and the pressure was reduced to -0.1 MPa and the reaction was continued for 1 h to remove moisture from the solvent. Thus, a polyamide phenolamine resin demulsifier initiator II-A was obtained.

[0035] (III) The demulsifier initiator and catalyst KOH obtained through the above two-step reaction are placed in a clean, dry reactor, which is then replaced several times with high-purity nitrogen and evacuated to -0.1 MPa. Next, the temperature is gradually increased while stirring and the evacuation is continued until the reaction system temperature reaches 100°C. When the reaction temperature approaches 130°C, propylene oxide is slowly, continuously, and gradually introduced (the mass ratio of propylene oxide to initiator is 1:59). During this process, the reaction system temperature should be controlled between 130°C and 140°C, and the reaction system pressure should not exceed 0.4 MPa (the amount of KOH is 0.35% of the combined mass of the initiator and propylene oxide). Finally, when the propylene oxide has completely reacted, that is, the reaction system pressure has been reduced to -0.1 MPa, the reactor is evacuated for 10 minutes, and then ethylene oxide is slowly, continuously, and gradually introduced in the same manner (the mass ratio of ethylene oxide to propylene oxide is 1:3, respectively). The difference is that the temperature of the reaction system is controlled between 120° C. and 130° C., and the amount of KOH used is 0.25% of the mass of ethylene oxide.

[0036] The polyether demulsifier III-A can be obtained through the above reaction steps.

[0037] The equation for the reaction process is as follows:

[0038]

[0039] Example 2

[0040] A method for preparing a polyamide phenolamine resin polyether demulsifier for offshore oil fields comprises the following steps:

[0041] (I) 76.8 g of triethylenetetramine (0.53 mol), 80.1 g of dimethyl glutarate (0.50 mol), and 156.9 g of methanol were added sequentially to a reaction kettle, and then the temperature was gradually increased under stirring and refluxed for 5 h. After the reflux, the pressure was gradually reduced to -0.1 MPa and the solution was distilled under reduced pressure for 1 h to remove the methanol, thereby obtaining a polyamide compound IB.

[0042] (II) 3 g of bisphenol A was added to a reaction kettle and mixed uniformly with IB. The temperature was then raised to 60°C, and 4.3 g of a 37% formaldehyde solution was added dropwise to the reaction kettle. The reaction was allowed to react at 60°C for 2 h. After the reaction was complete, the reaction system was gradually heated to 110°C to 120°C, and the pressure was reduced to -0.1 MPa and the reaction was continued for 1 h to remove moisture from the solvent. This yielded polyamide-phenolamine resin demulsifier initiator II-B.

[0043] (III) The demulsifier initiator and catalyst KOH obtained through the above two-step reaction are placed in a clean, dry reactor, which is then replaced several times with high-purity nitrogen and evacuated to -0.1 MPa. Next, the temperature is gradually increased while stirring and the evacuation is continued until the reaction system temperature reaches 100°C. When the reaction temperature approaches 130°C, propylene oxide is slowly, continuously, and gradually introduced (the mass ratio of propylene oxide to initiator is 1:59). During this process, the reaction system temperature should be controlled between 130°C and 140°C, and the reaction system pressure should not exceed 0.4 MPa (the amount of KOH is 0.35% of the combined mass of the initiator and propylene oxide). Finally, when the propylene oxide has completely reacted, that is, the reaction system pressure has been reduced to -0.1 MPa, the reactor is evacuated for 10 minutes, and then ethylene oxide is slowly, continuously, and gradually introduced in the same manner (the mass ratio of ethylene oxide to propylene oxide is 1:3, respectively). The difference is that the temperature of the reaction system is controlled between 120-130°C, and the amount of KOH used is 0.25% of the mass of ethylene oxide.

[0044] The polyether demulsifier III-B can be obtained through the above reaction steps.

[0045] The equation for the reaction process is as follows:

[0046]

[0047] Example 3

[0048] A method for preparing a polyamide phenolamine resin polyether demulsifier for offshore oil fields comprises the following steps:

[0049] (I) 76.8 g of triethylenetetramine (0.53 mol), 102.1 g of dimethyl 1,4-cyclohexanediol (0.51 mol), and 178.8 g of methanol were added sequentially to a reaction kettle, and then the temperature was gradually increased under stirring and refluxed for 7 h. After the reflux, the pressure was gradually reduced to -0.1 MPa and the solution was distilled under reduced pressure for 1 h to remove the methanol, thereby obtaining a polyamide compound IC.

[0050] (II) 3 g of bisphenol A was added to a reaction kettle and mixed uniformly with IC. The temperature was then raised to 60°C, and 4.3 g of a 37% formaldehyde solution was added dropwise to the reaction kettle. After the addition was complete, the reaction was allowed to react at 60°C for 3 h. After the reaction was completed, the reaction system was gradually heated to 110°C to 120°C, and the pressure was reduced to -0.1 MPa and the reaction was continued for 1 h to remove water from the solvent, thereby obtaining a polyamide-phenolamine resin demulsifier initiator II-C.

[0051] (III) The demulsifier initiator and catalyst KOH obtained through the above two-step reaction are placed in a clean, dry reactor, which is then replaced several times with high-purity nitrogen and evacuated to -0.1 MPa. Next, the temperature is gradually increased while stirring and the evacuation is continued until the reaction system temperature reaches 100°C. When the reaction temperature approaches 130°C, propylene oxide is slowly, continuously, and gradually introduced (the mass ratio of propylene oxide to initiator is 1:59). During this process, the reaction system temperature should be controlled between 130°C and 140°C, and the reaction system pressure should not exceed 0.4 MPa (the amount of KOH is 0.35% of the combined mass of the initiator and propylene oxide). Finally, when the propylene oxide has completely reacted, that is, the reaction system pressure has been reduced to -0.1 MPa, the reactor is evacuated for 10 minutes, and then ethylene oxide is slowly, continuously, and gradually introduced in the same manner (the mass ratio of ethylene oxide to propylene oxide is 1:3, respectively). The difference is that the temperature of the reaction system is controlled between 120-130°C, and the amount of KOH used is 0.25% of the mass of ethylene oxide.

[0052] The polyether demulsifier III-C can be obtained through the above reaction steps.

[0053] The equation for the reaction process is as follows:

[0054]

[0055] Example 4

[0056] A method for preparing a polyamide phenolamine resin polyether demulsifier for offshore oil fields comprises the following steps:

[0057] (I) 99.4 g of tetraethylenepentamine (0.53 mol), 66.1 g of dimethyl malonate (0.50 mol), and 165.5 g of methanol were added sequentially to a reaction kettle, and then the temperature was gradually increased under stirring and refluxed for 6 h. After the reflux, the pressure was gradually reduced to -0.1 MPa and the solution was distilled under reduced pressure for 1 h to remove the methanol in the solution, thereby obtaining polyamide compound ID.

[0058] (II) 3 g of bisphenol A was added to a reaction kettle and mixed uniformly with ID. The temperature was then raised to 60°C, and 4.3 g of a 37% formaldehyde solution was dropwise added to the reaction kettle. After the addition was complete, the reaction was allowed to react at 60°C for 2 h. After the reaction was complete, the reaction system was gradually heated to 110°C to 120°C, and the pressure was reduced to -0.1 MPa and the reaction was continued for 1 h to remove water from the solvent, thereby obtaining a polyamide-phenolamine resin demulsifier initiator II-D.

[0059] (III) The demulsifier initiator and catalyst KOH obtained through the above two-step reaction are placed in a clean, dry reactor, which is then replaced several times with high-purity nitrogen and evacuated to -0.1 MPa. Next, the temperature is gradually increased while stirring and the evacuation is continued until the reaction system temperature reaches 100°C. When the reaction temperature approaches 130°C, propylene oxide is slowly, continuously, and gradually introduced (the mass ratio of propylene oxide to initiator is 1:59). During this process, the reaction system temperature should be controlled between 130°C and 140°C, and the reaction system pressure should not exceed 0.4 MPa (the amount of KOH is 0.35% of the combined mass of the initiator and propylene oxide). Finally, when the propylene oxide has completely reacted, that is, the reaction system pressure has been reduced to -0.1 MPa, the reactor is evacuated for 10 minutes, and then ethylene oxide is slowly, continuously, and gradually introduced in the same manner (the mass ratio of ethylene oxide to propylene oxide is 1:3, respectively). The difference is that the temperature of the reaction system is controlled between 120° C. and 130° C., and the amount of KOH used is 0.25% of the mass of ethylene oxide.

[0060] The polyether demulsifier III-D can be obtained through the above reaction steps.

[0061] The equation for the reaction process is as follows:

[0062]

[0063] Example 5

[0064] A method for preparing a polyamide phenolamine resin polyether demulsifier for offshore oil fields comprises the following steps:

[0065] (I) 76.8 g of triethylenetetramine (0.53 mol), 66.1 g of dimethyl malonate (0.50 mol), and 142.9 g of methanol were added sequentially to a reaction kettle, and then the temperature was gradually increased under stirring and refluxed for 5 h. After the reflux, the pressure was gradually reduced to -0.1 MPa and the solution was distilled under reduced pressure for 1 h to remove the methanol, thereby obtaining a polyamide compound IE.

[0066] (II) 3.3 g of 4-methoxyphenol was added to a reaction kettle and mixed uniformly with IE. The temperature was then raised to 60°C, and 4.3 g of a 37% formaldehyde solution was added dropwise to the reaction kettle. The reaction was allowed to react at 60°C for 4 h. After the reaction was complete, the reaction system was gradually heated to 110°C to 120°C, and the pressure was reduced to -0.1 MPa and the reaction was continued for 1 h to remove water from the solvent. This yielded polyamide phenolamine resin demulsifier initiator II-E.

[0067] (III) The demulsifier initiator and catalyst KOH obtained through the above two-step reaction are placed in a clean, dry reactor, which is then replaced several times with high-purity nitrogen and evacuated to -0.1 MPa. Next, the temperature is gradually increased while stirring and the evacuation is continued until the reaction system temperature reaches 100°C. When the reaction temperature approaches 130°C, propylene oxide is slowly, continuously, and gradually introduced (the mass ratio of propylene oxide to initiator is 1:59). During this process, the reaction system temperature should be controlled between 130°C and 140°C, and the reaction system pressure should not exceed 0.4 MPa (the amount of KOH is 0.35% of the combined mass of the initiator and propylene oxide). Finally, when the propylene oxide has completely reacted, that is, the reaction system pressure has been reduced to -0.1 MPa, the reactor is evacuated for 10 minutes, and then ethylene oxide is slowly, continuously, and gradually introduced in the same manner (the mass ratio of ethylene oxide to propylene oxide is 1:3, respectively). The difference is that the temperature of the reaction system is controlled between 120° C. and 130° C., and the amount of KOH used is 0.25% of the mass of ethylene oxide.

[0068] The polyether demulsifier III-E can be obtained through the above reaction steps.

[0069] The equation for the reaction process is as follows:

[0070]

[0071] Example 6

[0072] A method for preparing a polyamide phenolamine resin polyether demulsifier for offshore oil fields comprises the following steps:

[0073] (I) 76.8 g of triethylenetetramine (0.53 mol), 66.1 g of dimethyl malonate (0.50 mol), and 142.9 g of methanol were added sequentially to a reaction kettle, and then the temperature was gradually increased under stirring and refluxed for 5 h. After the reflux, the pressure was gradually reduced to -0.1 MPa and the solution was distilled under reduced pressure for 1 h to remove the methanol, thereby obtaining a polyamide compound IF.

[0074] (II) 5.8 g of 4-nonylphenol was added to a reaction kettle and mixed uniformly with IF. The temperature was then raised to 60°C, and 4.3 g of a 37% formaldehyde solution was added dropwise to the reaction kettle. The reaction was continued at 60°C for 4 h. After the reaction was completed, the reaction system was gradually heated to 110°C to 120°C, and the pressure was reduced to -0.1 MPa and the reaction was continued for 1 h to remove water from the solvent. This yielded polyamide phenolamine resin demulsifier initiator II-F.

[0075] (III) The demulsifier initiator and catalyst KOH obtained through the above two-step reaction are placed in a clean, dry reactor, which is then replaced several times with high-purity nitrogen and evacuated to -0.1 MPa. Next, the temperature is gradually increased while stirring and the evacuation is continued until the reaction system temperature reaches 100°C. When the reaction temperature approaches 130°C, propylene oxide is slowly, continuously, and gradually introduced (the mass ratio of propylene oxide to initiator is 1:59). During this process, the reaction system temperature should be controlled between 130°C and 140°C, and the reaction system pressure should not exceed 0.4 MPa (the amount of KOH is 0.35% of the combined mass of the initiator and propylene oxide). Finally, when the propylene oxide has completely reacted, that is, the reaction system pressure has been reduced to -0.1 MPa, the reactor is evacuated for 10 minutes, and then ethylene oxide is slowly, continuously, and gradually introduced in the same manner (the mass ratio of ethylene oxide to propylene oxide is 1:3, respectively). The difference is that the temperature of the reaction system is controlled between 120° C. and 130° C., and the amount of KOH used is 0.25% of the mass of ethylene oxide.

[0076] The polyether demulsifier III-F can be obtained through the above reaction steps.

[0077] The equation for the reaction process is as follows:

[0078]

[0079] The demulsification performance test of the polyamide phenolamine resin polyether demulsifier for offshore oil fields prepared in Examples 1 to 6 was carried out:

[0080] According to the "General Technical Specifications for Crude Oil Demulsifiers (SY / T 5280-2018)", the demulsification performance of the synthesized polyamide phenolamine resin polyether demulsifier was evaluated and compared with the commonly used bisphenol A phenolamine resin polyether demulsifier FP5931. The demulsification performance was evaluated using fluid produced from an oil field in the Bohai Sea. The evaluation temperature was 60°C, the dosing concentration was 100 ppm, and after 150 shakes, the dehydration rate was observed. The volume of water removed was recorded at different times (5, 10, 15, 20, 30, 45, 60, and 120 minutes). The oil-water separation interface and the quality of the separated water were also observed.

[0081] The specific steps are as follows: Separate the oil and water samples on site to obtain purified oil and water samples. Use a 5mL pipette to calibrate the scale of the dehydration tube. After preheating the purified oil in a 60°C water bath for 10 minutes, pour 300mL of purified oil and 300mL of water sample into the emulsification cup and emulsify at 10,000r / min for 10 minutes to obtain a crude oil emulsion. Pour the crude oil emulsion into a calibrated 100mL dehydration bottle and use a microsyringe to add the demulsifier sample to the dehydration tube in sequence, ensuring that the amount of demulsifier added is 100mg / L. Perform a blank control experiment without adding demulsifier. Close the dehydration tube after adding the demulsifier and mechanically oscillate it with a horizontal oscillator at a frequency of 250 times / min, an oscillation amplitude of 4cm, and an oscillation time of 5 minutes to ensure that the sample is fully oscillated and shaken. After shaking, quickly place the dehydration tube in a constant temperature water bath at 60°C, observe the dehydration speed, record the volume of water removed at different times (5, 10, 15, 20, 30, 45, 60 and 120 min), and observe the interface of oil-water separation and the water quality of the separated water.

[0082] Table 1: Crude oil demulsification and dehydration experiments

[0083]

[0084]

[0085] From the above test data, it can be seen that for the same oil sample, when bisphenol A is used as the resin initiator phenolic compound raw material, the dehydration rate of various polyamide phenolamine resin polyether demulsifiers (III-A, III-B, III-C and III-D) is better than the commonly used bisphenol A phenolamine resin polyether demulsifier FP5931.

[0086] The chemical reaction formula of the preparation method of the present invention is:

[0087] (I) polycondensing an organic amine compound and a diester compound to obtain a polyamide;

[0088]

[0089] (II) a novel polyamide phenolamine resin demulsifier initiator is obtained by subjecting polyamide to a Mannich reaction with a phenolic compound and formaldehyde;

[0090]

[0091] (III) The novel polyamide phenolamine resin demulsifier initiator is reacted with propylene oxide and ethylene oxide in sequence to obtain the final polyamide phenolamine resin polyether demulsifier.

[0092]

[0093] In the above reaction formula:

[0094] Represents diethylenetriamine, triethylenetetramine and tetraethylenepentamine; rectangle It represents the alkyl functional group; how many molecules of propylene oxide and ethylene oxide can be connected to a certain reaction site is related to many factors such as the electron cloud density of the reaction site, steric hindrance, and the amount of propylene oxide and ethylene oxide used.

[0095] The "polyamide" phenolamine resin demulsifier invented in this patent is first reacted with a diester compound and a polyethylene polyamine compound to obtain a polyamide, which is then reacted with a phenol compound to obtain a polyamide phenolamine resin initiator. The polyamide phenolamine resin polyether demulsifier synthesized using this initiator has a longer chain length and higher branching degree than traditional phenolamine resin polyether demulsifiers, making it more capable of meeting the needs of offshore oilfields for rapid oil-water separation.

[0096] The novel polyamide phenolamine resin polyether demulsifier of the present invention is prepared using organic amines, diester compounds, formaldehyde, and phenolic compounds as raw materials. A two-step reaction (polyamidation reaction and Mannchi reaction) is performed to obtain the target demulsifier initiator. The initiator is then sequentially reacted with propylene oxide and ethylene oxide to obtain the target polyether demulsifier. The demulsifier of the present invention has a simple preparation process and is easily industrialized. Furthermore, the demulsifier of the present invention has the advantage of faster dehydration speed compared to conventional phenolamine resin demulsifiers of the same type.

[0097] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing a polyamide phenolamine resin polyether demulsifier for offshore oil fields, characterized in that: The following steps are involved: (I) subjecting an organic amine compound and a diester compound to a condensation polymerization reaction to obtain a polyamide; (II) a novel polyamide phenolamine resin demulsifier initiator is obtained by subjecting polyamide to a Mannich reaction with a phenolic compound and formaldehyde; (III) The novel polyamide phenolamine resin demulsifier initiator is reacted with propylene oxide and ethylene oxide in sequence to obtain the final polyamide phenolamine resin polyether demulsifier.

2. The method for preparing a polyamide phenolamine resin polyether demulsifier for offshore oil fields according to claim 1, wherein: The organic amine compound is polyethylene polyamine.

3. The method for preparing the polyamide phenolamine resin polyether demulsifier for offshore oil fields according to claim 1, wherein: The diester compound is any one of dimethyl malonate, dimethyl glutarate, dimethyl adipate, dimethyl sebacate, dimethyl 1,4-cyclohexanedicarboxylate or dimethyl 3,3'-thiodipropionate.

4. The method for preparing the polyamide phenolamine resin polyether demulsifier for offshore oil fields according to claim 1, wherein: The phenolic compound is any one of bisphenol A, 4-methoxyphenol, 4-ethylphenol or 4-nonylphenol.

5. The method for preparing the polyamide phenolamine resin polyether demulsifier for offshore oil fields according to claim 1, wherein: The step (I) specifically comprises: adding an organic amine compound, a diester compound and methanol into a reaction container in sequence, then gradually heating and refluxing under stirring conditions, and gradually reducing the pressure after the reflux is completed and removing the methanol in the solution by vacuum distillation to obtain polyamide.

6. The method for preparing the polyamide phenolamine resin polyether demulsifier for offshore oil fields according to claim 5, wherein: The molar ratio of the organic amine compound to the diester compound is (1-1.05):1; the mass of the added methanol is the sum of the masses of the organic amine compound and the diester compound; the reflux time is 5h-7h; the pressure of the reduced pressure distillation is -0.1Mpa, and the time of the reduced pressure distillation is 1h.

7. The method for preparing the polyamide phenolamine resin polyether demulsifier for offshore oil fields according to claim 1, wherein: The step (II) specifically comprises: adding a phenolic compound to the polyamide prepared in step (I), heating to 60° C. and gradually adding dropwise a formaldehyde solution with a mass fraction of 37%, and reacting at 60° C. for 2 to 4 hours after the addition is complete; after the reaction is completed, gradually heating the reaction system to 110 to 120° C., and reducing the pressure to -0.1 MPa and continuing the reaction for 1 hour to remove moisture, thereby obtaining a polyamide phenolamine resin demulsifier initiator.

8. The method for preparing the polyamide phenolamine resin polyether demulsifier for offshore oil fields according to claim 1, wherein: The added mass of the phenolic compound is 3% to 8% of the mass of the organic amine compound; the molar ratio of the formaldehyde to the organic amine compound is 1:10; and the dropwise addition time of the formaldehyde solution is 0.5 h.

9. A polyamide phenolamine resin polyether demulsifier for offshore oil fields, characterized by: Prepared by the method according to any one of claims 1 to 8.

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