Core application scenarios for oilfield emulsifiers: Emulsification control solutions adapted to the entire process.

The application of emulsifiers in oilfields spans key stages such as drilling, oil production, gathering and transportation, and storage. The emulsification requirements vary significantly across different scenarios, necessitating the selection of specific emulsifier types and formulations to achieve precise control.

(I) Drilling process: Stabilizing the drilling fluid system and ensuring drilling safety

During drilling, emulsifiers are mainly used to stabilize the emulsion structure of oil-based and water-based drilling fluids, improve the drilling fluid’s sand-carrying capacity, lubricity, and anti-pollution ability, and prevent accidents such as wellbore collapse and stuck pipe.

1. Oil-based drilling fluids: Cationic and nonionic emulsion stabilizers (such as polyquaternium salts and Span-type emulsions) are used to construct stable water-in-oil emulsions, giving the drilling fluid excellent lubricity and resistance to temperature and salt, making it suitable for drilling in deep and complex formations. For example, in a deep, high-temperature oilfield (temperature 180℃), a combination of polyquaternium salts and Span-80 emulsion stabilizers was used, resulting in a 40% increase in the stability of the oil-based drilling fluid and a 35% reduction in the lubricity coefficient, successfully completing deep drilling operations.

2. Water-based drilling fluids: Adding anionic and amphoteric emulsifying stabilizers (such as petroleum sulfonates and alkyl betaines) helps stabilize tiny oil droplets in the drilling fluid, improving its anti-fouling ability and sand-carrying capacity. For example, in a loose sandstone oilfield, adding 0.5% petroleum sulfonate emulsifying stabilizer to the water-based drilling fluid increased its anti-fouling ability by 50%, and reduced the wellbore collapse rate from 30% to 8%.

(II) Oil extraction stage: Enhance emulsification to improve extraction efficiency

In the oil extraction process, emulsifiers artificially construct stable emulsions to achieve goals such as viscosity reduction of heavy oil and tertiary oil recovery and displacement, thus solving the extraction problems of low-yield and difficult-to-extract oil and gas reservoirs.

1. Heavy Oil Extraction: Anionic and nonionic emulsifying stabilizers (such as petroleum sulfonates and AEO-based emulsions) are used to convert heavy oil into oil-in-water emulsions, significantly reducing the viscosity and improving fluidity. For example, in a certain heavy oil field (heavy oil viscosity 8000 mPa·s), a petroleum sulfonate + co-emulsifier compound system was used to produce an oil-in-water emulsion, reducing the viscosity to below 300 mPa·s, and increasing the daily oil production from wells from 5 tons to 12 tons.

2. Tertiary oil recovery: In surfactant flooding and combined flooding systems, adding emulsifying stabilizers (such as alkyl betaine and petroleum sulfonates) forms stable oil-in-water emulsions, expanding the coverage of the oil displacement system and improving the efficiency of residual oil displacement. For example, a high water-cut oilfield adopted a combined flooding system of “polymer + alkali + betaine emulsifying stabilizer,” which increased crude oil recovery by 15% compared to waterflooding, breaking through the bottleneck of production increase during the high water-cut period.

3. Unconventional Oil and Gas Reservoir Development: In the development of unconventional oil and gas reservoirs such as shale gas and tight oil, nanomaterial-based, intelligently responsive emulsifiers are used to adapt to high-temperature, high-pressure, and high-salinity environments, constructing stable emulsions in fracturing fluids to improve fracturing efficiency and oil and gas production rates. For example, in a shale gas field, the use of nano-silica-modified emulsion stabilizers improved the stability of the fracturing fluid emulsion by 60%, increased fracture conductivity by 3 times, and increased daily shale gas production by 80,000 m³.

(III) Gathering, Transportation and Storage: Breaking up emulsions to ensure efficient processing

In the process of crude oil gathering, transportation and storage, emulsifiers (demulsifiers) are mainly used to break up naturally formed stable emulsions, achieve oil-water separation, reduce transportation energy consumption, and meet the requirements of subsequent refining.

1. Crude Oil Gathering and Transportation: Based on the type of crude oil emulsion, select polyether, polyamine, or compound demulsifiers and rapidly break up the emulsion by injecting into pipelines or adding to storage tanks, reducing fluid viscosity and transportation resistance. For example, in an oilfield gathering and transportation pipeline, the transportation pressure increased by 30% due to emulsion stabilization. After adding a polyether-polyamine compound demulsifier, the transportation pressure returned to normal, and energy consumption decreased by 25%.

2. Crude Oil Storage and Dehydration: Adding demulsifiers to crude oil storage tanks, combined with heating and settling processes, accelerates oil-water separation and reduces the water content of crude oil. For example, in a heavy crude oil storage tank, polyamine demulsifiers were used, reducing the dehydration time from 48 hours to 12 hours. After dehydration, the crude oil water content decreased from 20% to 0.5%, meeting the refining process requirements.