Low-temperature high-viscosity oil well viscosity-reducing cleanup additive as well as preparation method and use method thereof

Abstract

The invention relates to the technical field of viscosity reduction of compound surfactants, in particular to a low-temperature high-viscosity oil well viscosity-reducing discharge aiding agent and a preparation method and application of the low-temperature high-viscosity oil well viscosity-reducing discharge aiding agent. The low-temperature and high-viscosity oil well viscosity-reducing and cleanup additive is obtained by compounding an anionic surfactant, a nonionic surfactant, an alcohol solvent, a paraffin remover and water at normal temperature, and after the low-temperature and high-viscosity oil well viscosity-reducing and cleanup additive solution is in contact with high-viscosity crude oil on the surface of stratum rock for 3-5 days, a well can be opened for production. The low-temperature high-viscosity oil well viscosity-reducing discharge aiding agent can effectively overcome the influence that the temperature of a reservoir is lower than 50 DEG C, rapidly contact with thickened oil on the surface of rock, rapidly reduce the surface tension of crude oil and enable the crude oil to be stripped from the surface of the rock, nanoscale particle type oil droplets continuously gather and expand, meanwhile, the surfactant is adsorbed on a pipe wall to form a layer of agent film, and the effect of reducing the viscosity of the crude oil is achieved. Friction between crude oil and a pipe wall is effectively reduced for a long time, and shaft lifting efficiency and pipeline conveying capacity are improved.

Description

Technical Field

[0001] The invention relates to the technical field of viscosity reduction of compound surfactants, and is a viscosity reduction and drainage aid for low-temperature and high-viscosity oil wells, and a preparation method and a use method thereof. Background Art

[0002] The main methods of heavy oil reservoir recovery include thermal recovery, chemical recovery, biological recovery, viscosity reduction, dilution and electrothermal recovery. Chemical recovery is a method of increasing crude oil recovery by injecting chemical reagents into heavy oil reservoirs. Surfactant flooding and microemulsion flooding are the two most efficient chemical flooding methods. For different types of heavy oil reservoirs and geological conditions, choosing the right recovery method is crucial to improving recovery and economic benefits.

[0003] Oil displacement agent is a chemical agent used to increase oil well production. Its principle is to change the physical and chemical environment inside the oil well, reduce the adhesion and surface tension between crude oil and rock in the oil well reservoir, so that crude oil can flow more easily and improve recovery. The application of oil displacement agent can be selected according to the characteristics of the oil reservoir and the requirements of recovery. Different types of oil reservoirs may require different oil displacement agent formulations and injection methods.

[0004] Heavy oil old areas have generally entered the final stage of steam injection development. Due to serious losses in the surface pipeline network and ground leakage, environmental pollution and other reasons, some wells cannot be injected with steam normally, resulting in low production of single wells or abnormal production. Therefore, in order to screen reservoirs of different formations, types and development stages, it is necessary to develop a low-temperature and high-viscosity oil well viscosity reducer with strong applicability through the optimization of various measures to improve the development effect of oil wells and increase the recovery rate of heavy oil well cold production development blocks. Summary of the invention

[0005] The present invention provides a preparation method and application thereof, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problem of low single well production or failure of normal production due to thick oil and low temperature in existing heavy oil well cold production development blocks.

[0006] One of the technical solutions of the present invention is achieved through the following measures: a low-temperature and high-viscosity oil well viscosity reducing and drainage agent, whose raw materials include, by weight: 4 to 8 parts of diethylene glycol ether, 3 to 9 parts of ethoxylated sodium alkyl sulfate, 2 to 6 parts of alpha-olefin sulfonate, 2 to 4 parts of sodium dodecylbenzene sulfonate, 2 to 4 parts of isotridecanol, 2 parts of paraffin remover, and 85 to 67 parts of water.

[0007] The following is a further optimization and / or improvement of the above-mentioned technical solution 1: The above-mentioned low-temperature high-viscosity oil well viscosity reducing and drainage agent is prepared according to the following steps: The first step is to mix a required amount of diethylene glycol ether and water at room temperature and stir to obtain a first mixed solution; The second step is to mix the required amounts of sodium ethoxylated alkyl sulfate, α-olefin sulfonate, sodium dodecylbenzene sulfonate and isotridecanol into the first mixed solution at room temperature, and stir to obtain a second mixed solution; The third step is to add a required amount of a paraffin remover into the second mixed solution and stir evenly to obtain a viscosity reducing and drainage agent for low-temperature and high-viscosity oil wells.

[0008] In the first step, the stirring time is 10 to 30 minutes.

[0009] In the second step, the stirring time is 2 to 4 hours.

[0010] The second technical solution of the present invention is achieved by the following measures: A method for preparing a viscosity reducing and drainage agent for low-temperature and high-viscosity oil wells is carried out according to the following steps: The first step is to mix a required amount of diethylene glycol ether and water at room temperature and stir to obtain a first mixed solution; The second step is to mix the required amounts of sodium ethoxylated alkyl sulfate, α-olefin sulfonate, sodium dodecylbenzene sulfonate and isotridecanol into the first mixed solution at room temperature, and stir to obtain a second mixed solution; The third step is to add a required amount of a paraffin remover into the second mixed solution and stir evenly to obtain a viscosity reducing and drainage agent for low-temperature and high-viscosity oil wells.

[0011] The following is a further optimization and / or improvement of the second technical solution of the above invention: In the first step, the stirring time is 10 to 30 minutes.

[0012] In the second step, the stirring time is 2 to 4 hours.

[0013] The third technical solution of the present invention is achieved by the following measures: A method for using a viscosity reducing and drainage agent for low-temperature and high-viscosity oil wells is carried out according to the following steps: The first step is to close the production gate and the back pressure gate, inject 80% of the required total amount of water into the mixing tank, and then inject the corresponding proportion of low-temperature and high-viscosity oil well viscosity reducer and drainage aid. After mixing evenly, inject the remaining 20% ​​of water into the mixed solution until it is completely mixed to obtain a low-temperature and high-viscosity oil well viscosity reducer and drainage aid solution; The second step is to use a pump truck to pump the viscosity reducing and drainage agent solution of low-temperature and high-viscosity oil wells into the casing and into the formation; The third step is to start production after the viscosity reducing and drainage agent solution of the low-temperature and high-viscosity oil well has been in contact with the high-viscosity crude oil for a certain period of time.

[0014] The following is a further optimization and / or improvement of the third technical solution of the above invention: In the first step above, the concentration of the viscosity reducing and drainage agent solution for low-temperature and high-viscosity oil wells is 5% to 8%.

[0015] In the third step, the low-temperature high-viscosity oil well viscosity reducing and drainage agent solution is in contact with the crude oil for 3 to 5 days.

[0016] The viscosity reducing and drainage aid for low-temperature and high-viscosity oil wells of the present invention can effectively overcome the influence of reservoir temperature below 50°C, quickly contact with the heavy oil on the rock surface, form a layer of agent film, effectively reduce the friction between the crude oil and the pipe wall for a long time, improve the wellbore lifting efficiency and the pipeline transportation capacity, and achieve the purpose of reducing viscosity and increasing production. DETAILED DESCRIPTION

[0017] The present invention is not limited by the following embodiments, and the specific implementation method can be determined according to the technical scheme of the present invention and the actual situation. Unless otherwise specified, the solutions in the present invention are all aqueous solutions in which the solvent is water. The normal temperature and room temperature in the present invention generally refer to a temperature of 15°C to 25°C, and are generally defined as 25°C.

[0018] The present invention will be further described below in conjunction with embodiments: Embodiment 1: The viscosity reducing and drainage aid for low-temperature and high-viscosity oil wells, the raw materials include, by weight: 4 to 8 parts of diethylene glycol ether, 3 to 9 parts of sodium ethoxylated alkyl sulfate, 2 to 6 parts of alpha-olefin sulfonate, 2 to 4 parts of sodium dodecylbenzene sulfonate, 2 to 4 parts of isotridecanol, 2 parts of paraffin remover, and 85 to 67 parts of water.

[0019] In the present invention, ethoxylated sodium alkyl sulfate, α-olefin sulfonate, sodium dodecylbenzene sulfonate are anionic surfactants, and isotridecanol is a nonionic surfactant. Ethoxylated sodium alkyl sulfate is the main component, which can withstand low temperatures of 10°C to 50°C and can still exert its activity in cold production and viscosity reduction oil wells; since each component in the raw material has different forms such as solid, liquid, and paste, diethylene glycol ether with strong solubility is used as a solvent, and because of its high melting point (-6.5°C), it has a certain antifreeze effect.

[0020] The paraffin remover used in the present invention is a paraffin remover of model KRQ-1 produced and sold by Karamay Xinkeao Petroleum and Natural Gas Technology Co., Ltd., and its main components are mixed benzene, 2% ethanol and diammonium phosphate. At low temperatures, the wax crystals dispersed in the crude oil gather on the pipe wall to form a large area of ​​solid wax, and this paraffin remover can effectively solve this problem.

[0021] Example 2: The viscosity reducing and drainage aid for low-temperature and high-viscosity oil wells is prepared according to the following steps: The first step is to mix a required amount of diethylene glycol ether and water at room temperature and stir to obtain a first mixed solution; The second step is to mix the required amounts of sodium ethoxylated alkyl sulfate, α-olefin sulfonate, sodium dodecylbenzene sulfonate and isotridecanol into the first mixed solution at room temperature, and stir to obtain a second mixed solution; The third step is to add a required amount of a paraffin remover into the second mixed solution and stir evenly to obtain a viscosity reducing and drainage agent for low-temperature and high-viscosity oil wells.

[0022] The above method can be further optimized and / or improved according to actual needs: Embodiment 3: As an optimization of the above embodiment, in the first step, the stirring time is 10 minutes to 30 minutes.

[0023] Embodiment 4: As an optimization of the above embodiment, in the second step, the stirring time is 2 hours to 4 hours.

[0024] Example 5: The preparation method of the low-temperature high-viscosity oil well viscosity reducing and drainage agent is carried out according to the following steps: The first step is to mix a required amount of diethylene glycol ether and water at room temperature and stir to obtain a first mixed solution; The second step is to mix the required amounts of sodium ethoxylated alkyl sulfate, α-olefin sulfonate, sodium dodecylbenzene sulfonate and isotridecanol into the first mixed solution at room temperature, and stir to obtain a second mixed solution; The third step is to add a required amount of a paraffin remover into the second mixed solution and stir evenly to obtain a viscosity reducing and drainage agent for low-temperature and high-viscosity oil wells.

[0025] The above method can be further optimized and / or improved according to actual needs: Embodiment 6: In the first step, the stirring time is 10 minutes to 30 minutes.

[0026] Embodiment 7: In the second step, the stirring time is 2 hours to 4 hours.

[0027] Example 8: A method for using a viscosity reducing and drainage agent for low-temperature and high-viscosity oil wells, characterized in that the method is carried out according to the following steps: The first step is to close the production gate and the back pressure gate, inject 80% of the required total amount of water into the mixing tank, and then inject the corresponding proportion of low-temperature and high-viscosity oil well viscosity reducer and drainage aid. After mixing evenly, inject the remaining 20% ​​of water into the mixed solution until it is completely mixed to obtain a low-temperature and high-viscosity oil well viscosity reducer and drainage aid solution; The second step is to use a pump truck to pump the viscosity reducing and drainage agent solution of low-temperature and high-viscosity oil wells into the casing and into the formation; The third step is to start production after the viscosity reducing and drainage agent solution of the low-temperature and high-viscosity oil well has been in contact with the high-viscosity crude oil for a required period of time.

[0028] The above method can be further optimized and / or improved according to actual needs: Example 9: In the first step, the concentration of the viscosity reducing and drainage agent solution for low-temperature and high-viscosity oil wells is 5% to 8%.

[0029] Example 10: In the third step, the low-temperature high-viscosity oil well viscosity reducing and drainage agent solution is in contact with the crude oil for 3 to 5 days.

[0030] As needed, according to the different viscosities of crude oil in reservoir formations, the contact time between the viscosity reducing and drainage agent solution of low-temperature and high-viscosity oil wells and the crude oil is formulated. Usually, the contact time for low-viscosity crude oil with a viscosity ranging from 100 mPa·s to 5000 mPa·s is set to 3 days, and the contact time for high-viscosity crude oil with a viscosity ranging from 50,000 mPa·s to 200,000 mPa·s is set to 5 days.

[0031] Example 11: The viscosity reducing and drainage aid for low-temperature and high-viscosity oil wells is prepared by the following method: First, 4 parts of diethylene glycol ether are mixed with 85 parts of water at room temperature and stirred for 10 to 30 minutes; then, 3 parts of sodium ethoxylated alkyl sulfate, 2 parts of α-olefin sulfonate, 2 parts of sodium dodecylbenzene sulfonate and 2 parts of isotridecanol are added, and the mixture is mixed and stirred for 4 hours at room temperature; finally, 2 parts of paraffin remover are added and stirred evenly to obtain a low-temperature and high-viscosity oil well viscosity reducer and drainage agent.

[0032] Example 12: The low-temperature high-viscosity oil well viscosity reducing and drainage agent is prepared according to the following method: First, 8 parts of diethylene glycol ether are mixed with 67 parts of water at room temperature and stirred for 10 to 30 minutes; then, 9 parts of sodium ethoxylated alkyl sulfate, 6 parts of α-olefin sulfonate, 4 parts of sodium dodecylbenzene sulfonate and 4 parts of isotridecanol are added, mixed and stirred for 3 hours at room temperature; finally, 2 parts of paraffin remover are added and stirred evenly to obtain a low-temperature and high-viscosity oil well viscosity reducer and drainage agent.

[0033] According to Q / XKA 242-2021 SY / T 7329-2016 "Alkyl Sulfonates as Viscosity Reducers for Oil Production" and KXDQ-10 "Determination Method for Organic Chlorine Content in Oilfield Chemicals", CJ / T 221-2005 "Inspection Method for Sludge in Municipal Wastewater Treatment Plants" and HJ 702-2014 "Determination of Mercury, Arsenic, Selenium, Bismuth and Antimony in Solid Waste by Microwave Digestion / Atomic Fluorescence Spectrometry", the system dispersibility, initial apparent viscosity, system stability dehydration reduction value, organic chlorine content and metal content of the low-temperature and high-viscosity oil well viscosity reducer obtained in Examples 11 to 12 were analyzed and tested. The test results are shown in Table 1. It can be seen from Table 1 that within the process parameter range specified in the present application, the system dispersibility, initial apparent viscosity, system stability dehydration reduction value, organic chlorine content, cyanide and metal content of the obtained low-temperature and high-viscosity oil well viscosity reducer all meet the standard requirements.

[0034] Example 13: The viscosity reducing and drainage agent for low-temperature and high-viscosity oil wells is put into use according to the following method: First, close the production gate and back pressure gate, and use a mixing tank to prepare a low-temperature and high-viscosity oil well viscosity reducer and drainage agent solution of the required concentration; then, use a pump truck to pump it into the casing and into the formation; finally, the low-temperature and high-viscosity oil well viscosity reducer and drainage agent solution is in contact with the high-viscosity crude oil on the surface of the formation rock for 3 days before the well can be started for production.

[0035] Alkaline surfactants can effectively reduce the surface tension of oil and water, approaching neutral wetting, and achieve the purpose of squeezing liquid to reduce viscosity and increase production.

[0036] Example 14: The difference from Example 13 is that the contact time between the viscosity reducing and drainage aid solution of low-temperature and high-viscosity oil wells and the high-viscosity crude oil on the surface of the formation rock is 4 days.

[0037] Example 15: The difference from Example 13 is that the contact time between the low-temperature high-viscosity oil well viscosity reducing and drainage agent solution and the high-viscosity crude oil on the surface of the formation rock is 5 days.

[0038] Comparative Example 1: The difference from Example 15 is that the low-temperature high-viscosity oil well viscosity reducing and drainage agent solution is not injected into the high-viscosity crude oil on the surface of the formation rock.

[0039] The crude oil production data obtained in Examples 13 to 15 and the crude oil production data in Comparative Example 1 were tested and analyzed, and the results are shown in Table 2. It can be seen from Table 2 that within the process parameter range specified in the present application, the viscosity of the obtained crude oil is significantly reduced, the oil-water surface tension is significantly reduced, and the crude oil yield is greatly increased.

[0040] In summary, the preparation method of the present invention is simple and easy to implement. The obtained viscosity reducing and drainage aid for low-temperature and high-viscosity oil wells can not only effectively overcome the influence of reservoir temperature below 50°C, quickly contact with the heavy oil on the rock surface, and improve the wellbore lifting efficiency and pipeline transportation capacity, but also the degradation rate of the viscosity reducing and drainage aid for low-temperature and high-viscosity oil wells is greater than 90%, is non-toxic, and does not cause pollution to the environment. It is a clean and environmentally friendly viscosity reducing and drainage agent, and is suitable for marginal oil wells that are not in the steam injection pipeline network, low-yield wells with insufficient steam injection, and cold production development blocks of heavy oil wells with high crude oil viscosity.

[0041] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A viscosity reducing and drainage agent for low-temperature and high-viscosity oil wells, characterized in that The raw materials include, by weight: 4 to 8 parts of diethylene glycol ether, 3 to 9 parts of sodium ethoxylated alkyl sulfate, 2 to 6 parts of alpha-olefin sulfonate, 2 to 4 parts of sodium dodecylbenzene sulfonate, 2 to 4 parts of isotridecanol, 2 parts of paraffin remover, and 85 to 67 parts of water.

2. The low-temperature high-viscosity oil well viscosity reducing and drainage agent according to claim 1, characterized in that Prepared according to the following steps: The first step is to mix a required amount of diethylene glycol ether and water at room temperature and stir to obtain a first mixed solution; The second step is to mix the required amounts of sodium ethoxylated alkyl sulfate, α-olefin sulfonate, sodium dodecylbenzene sulfonate and isotridecanol into the first mixed solution at room temperature, and stir to obtain a second mixed solution; The third step is to add a required amount of a paraffin remover into the second mixed solution and stir evenly to obtain a viscosity reducing and drainage agent for low-temperature and high-viscosity oil wells.

3. The low-temperature high-viscosity oil well viscosity reducing and drainage agent according to claim 2, characterized in that In the first step, the stirring time is 10 minutes to 30 minutes.

4. The low-temperature high-viscosity oil well viscosity reducing and drainage aid according to claim 2 or 3, characterized in that In the second step, the stirring time is 2 to 4 hours.

5. A method for preparing a viscosity reducing and drainage agent for low-temperature and high-viscosity oil wells according to any one of claims 1 to 4, characterized in that Follow the steps below: The first step is to mix a required amount of diethylene glycol ether and water at room temperature and stir to obtain a first mixed solution; The second step is to mix the required amounts of sodium ethoxylated alkyl sulfate, α-olefin sulfonate, sodium dodecylbenzene sulfonate and isotridecanol into the first mixed solution at room temperature, and stir to obtain a second mixed solution; The third step is to add a required amount of a paraffin remover into the second mixed solution and stir evenly to obtain a viscosity reducing and drainage agent for low-temperature and high-viscosity oil wells.

6. The method for preparing the viscosity reducing and drainage agent for low-temperature and high-viscosity oil wells according to claim 5, characterized in that In the first step, the stirring time is 10 minutes to 30 minutes.

7. The method for preparing the viscosity reducing and drainage agent for low-temperature and high-viscosity oil wells according to claim 5 or 6, characterized in that In the second step, the stirring time is 2 to 4 hours.

8. A method for using the viscosity reducing and drainage aid for low-temperature and high-viscosity oil wells according to any one of claims 1 to 4, characterized in that Follow the steps below: The first step is to close the production gate and the back pressure gate, inject 80% of the required total amount of water into the mixing tank, and then inject the corresponding proportion of low-temperature and high-viscosity oil well viscosity reducer and drainage aid. After mixing evenly, inject the remaining 20% ​​of water into the mixed solution until it is completely mixed to obtain a low-temperature and high-viscosity oil well viscosity reducer and drainage aid solution; The second step is to use a pump truck to pump the viscosity reducing and drainage agent solution of low-temperature and high-viscosity oil wells into the casing and into the formation; The third step is to start production after the viscosity reducing and drainage agent solution of the low-temperature and high-viscosity oil well has been in contact with the high-viscosity crude oil for a required period of time.

9. The method for using the viscosity reducing and drainage aid for low-temperature and high-viscosity oil wells according to claim 8, characterized in that In the first step, the concentration of the viscosity reducing and drainage agent solution for low-temperature and high-viscosity oil wells is prepared at 5% to 8%.

10. The method for using the viscosity reducing and drainage aid agent for low-temperature and high-viscosity oil wells according to claim 8 or 9, characterized in that In the third step, the low-temperature and high-viscosity oil well viscosity reducing and drainage agent solution is in contact with the crude oil for 3 to 5 days.

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