This article focuses on carbon dioxide flooding and surfactant binary (ternary) flooding technologies in tertiary oil recovery and shale oil extraction, and systematically introduces real liquid droplets ® （RealDrop ®/ TrueDrop ®） High temperature and high pressure interface chemical analysis system. Elaborate on its research and development background and functional characteristics, analyze the technical advantages of each functional module, explore the driving role of the system in overcoming measurement difficulties, optimizing production process parameters, and other related technological developments, and demonstrate its technical value and application prospects in the field of interface chemistry research in petroleum extraction.
Real droplets ® High temperature and high pressure interface chemical analysis system; Tertiary oil recovery; Shale oil extraction; CO2 flooding; Surfactant binary (ternary) flooding; Interface chemical measurement; Petroleum extraction technology
Oil still holds an important position in the global energy structure. With the development of the economy and the growth of energy demand, conventional petroleum resources are facing problems such as declining reserves and increasing difficulty in extraction. To ensure energy supply, tertiary oil recovery technology and shale oil extraction technology have become the focus of the petroleum industry.
Triple oil recovery technology involves injecting chemical substances, heat, or gas into the reservoir to alter the physical and chemical properties of oil, gas, water, and rock, in order to improve recovery efficiency; Shale oil extraction obtains oil from unconventional reservoirs, breaking the dependence of traditional extraction on conventional reservoirs. Among these two technologies, carbon dioxide flooding and surfactant binary (ternary) flooding have become key means to improve oil recovery due to their advantages. The in-depth research and application of these technologies rely on precise measurement and analysis of interfacial chemical properties under high temperature and high pressure conditions. Real droplets ® The high-temperature and high-pressure interface chemical analysis system has emerged, providing support for the research of interface chemistry in petroleum extraction with advanced technology and diverse functions, and promoting the development of related technologies.
The tertiary oil recovery technology has formed a rich technical system through long-term research and practice. Among them, chemical flooding is the core, covering types such as polymer flooding, polymer/surfactant binary composite flooding, surfactant/polymer/alkali ternary composite flooding, viscoelastic particle/polymer/surfactant heterogeneous composite flooding, etc.
China has made significant achievements in the field of chemical flooding technology for tertiary oil recovery. Taking Daqing Oilfield as an example, by injecting chemical agents such as surfactants and polymers, the flowability and interfacial properties of reservoir fluids are improved. On the basis of secondary oil recovery, the recovery rate is increased by 14 to 20 percentage points, and the cumulative production exceeds 300 million tons. For 21 consecutive years, the annual production has maintained over 10 million tons, demonstrating the potential of tertiary oil recovery technology in stable production in old oilfields. According to the characteristics of different reservoirs, Henan Oilfield has tackled key problems and formed technologies such as microemulsion flooding and viscosity reducing compound flooding. In the first five months of this year, 56000 tons of oil was increased through the three production technology, which has extended the reservoir development cycle.
Shale oil, as an unconventional oil and gas resource, has made breakthroughs in extraction technology in recent years. New technologies such as pre fracturing with carbon dioxide, uniform fracturing with dense cutting, waterless fracturing, and high-pressure fracturing with enhanced vertical fractures have emerged. Technologies such as overall three-dimensional mining of blocks, early energy replenishment of shale oil, and carbon dioxide injection/displacement to improve recovery rates have shown potential for application.
China attaches great importance to shale oil development and has established shale oil demonstration areas such as Jimsar in Xinjiang Oilfield, Gulong Continental in Daqing Oilfield, and Shengli Jiyang. In 2023, China's shale oil production will exceed 4 million tons; In 2024, the cumulative production of Jimsar Demonstration Zone in Xinjiang exceeded 1 million tons, with a daily output of over 4000 tons, reflecting China's technological strength in the field of shale oil extraction.
Carbon dioxide oil displacement technology utilizes the high solubility of carbon dioxide in oil and water. After injection into the reservoir, it causes the volume of crude oil to expand and viscosity to decrease, reducing the interfacial tension between oil and water and improving the fluidity of crude oil. Compared with other oil displacement technologies, this technology has the advantages of wide applicability, lower oil displacement cost, and significant improvement in oil recovery rate.
Globally, carbon dioxide flooding projects are widely used, with nearly 80 projects currently being implemented. The United States is a country with a large number of projects, injecting approximately 20-30 million tons of carbon dioxide into oil reservoirs annually. China is also promoting related technologies, such as the million ton CCUS demonstration project between Shengli Oilfield and Qilu Petrochemical, which is expected to increase oil production by 3 million tons and reduce carbon dioxide emissions by about 1 million tons annually in 15 years. In shale oil extraction, the liquid carbon dioxide dry sand fracturing technology reduces reservoir damage with the characteristics of no water phase, no residue, and fast backflow. Carbon dioxide injection and flooding, as an early energy replenishment method, can improve shale oil recovery if multiple rounds of injection and flooding are achieved.
Surfactant binary (ternary) flooding technology is an important chemical flooding method in tertiary oil recovery. By adding surfactants, polymers and other chemical agents to the injected water, the properties of the displacement fluid and the interface properties with crude oil and rock are changed to increase crude oil production.
In the development of high-temperature and high salt oil reservoirs, Sinopec has achieved industrial application of chemical flooding technology after decades of research and development, forming supporting technologies for polymer flooding in high-temperature and high salt oil reservoirs, polymer/surfactant binary composite flooding technology, solid-liquid heterogeneous composite flooding technology, etc., which have played a role in increasing storage and stabilizing oil in old oil fields in the east. The performance and formulation of surfactants are key factors affecting oil displacement effectiveness, and need to be screened and optimized based on reservoir geological conditions, crude oil properties, and other factors.
With the development of tertiary oil recovery and shale oil extraction technologies, the requirements for measuring interfacial chemical properties under high temperature and high pressure conditions have increased. Traditional instruments have limitations in terms of functionality, accuracy, and applicability, such as decreased measurement accuracy under high temperature and pressure, large measurement errors for low or ultra-low interfacial tension, and inability to meet the requirements of complex reservoir conditions.
To solve these problems, real droplets ® The development of a high-temperature and high-pressure interface chemical analysis system has been launched. The system aims to provide advanced, accurate, and multifunctional measurement tools for researchers and engineers, promote research on interface chemistry in petroleum extraction, assist in optimizing and innovating extraction technology, improve recovery rates, and ensure energy security. It has scientific significance and practical application value.
Real droplets ® The system has the ability to accurately measure various interface chemical parameters under high temperature conditions of 70MPa pressure and 210 degrees Celsius. It integrates functions such as high temperature and high pressure contact angle measuring instrument, interface tension meter, rotating droplet interface tension meter, interface rheometer, etc. It also supports the mechanical platinum plate method and platinum ring method for testing the dynamic and static surface tension of surfactants. One instrument can complete common interface chemistry tests, improve experimental efficiency, enhance data correlation and reliability.
The system adopts advanced design concepts, such as high-precision temperature and pressure control technology, which can stably maintain the experimental environment; Advanced sensors and data processing algorithms ensure accurate and real-time measurement data. These characteristics make the system suitable for different types of reservoir research and development scenarios of production technology.
Real droplets ® In the chamber of the contact angle measuring instrument, the sample stage has the functions of lifting and X-axis movement. The sample stage lifting can accurately complete the liquid transfer operation in high temperature and high pressure environments, avoiding liquid splashing and positional deviation; The X-axis movement takes into account the non-uniformity of rock surface properties and can measure contact angles at different positions on the rock surface, providing detailed data for studying the micro interface interaction laws of oil reservoirs.
The high-pressure injection pump system has oscillation drop operation and independent temperature control functions. The oscillation drop operation can simulate the dynamic changes of fluids during reservoir exploitation and obtain interface rheological coefficient data. The independent temperature control range of the infusion pump system is room temperature -220 degrees Celsius, with an accuracy of 0.02 degrees below 100 degrees and 0.1 degrees above 100 degrees. It can accurately adjust the temperature of the injected liquid and simulate complex reservoir temperature conditions.
This instrument uses Asha ® The Young Laplace equation fitting method of technology has significant advantages compared to traditional methods. Traditional methods, due to the linear calibration technique in dimensionless processing, can only test droplets with Bond numbers in the range of 0.4-0.8. Exceeding this range can easily lead to deviation in contact angle calculation. And Asha ® The technology is based on first principles and breaks through the limitations of droplet measurement range, enabling full range droplet contour measurement and providing accurate data for studying complex reservoir interface interactions.
Real droplets ® The rotating droplet interfacial tension meter can achieve ultra-low interfacial tension testing at a pressure of 70MPa and a high temperature of 210 degrees Celsius, simulating the actual working conditions of oil reservoirs. In surfactant flooding, researchers can use this instrument to study the reduction effect of different surfactants on oil-water interfacial tension under high temperature and high pressure conditions, compare the reduction amplitude, speed and other parameters of interfacial tension of different formulations, and screen suitable surfactant formulations for specific oil reservoirs. In addition, the instrument has dynamic pressurization and dynamic injection functions, which can simulate the changes in reservoir pressure and fluid properties during actual production, and automatically configure surfactant formulations through preset injection programs.
In carbon dioxide oil displacement technology, real liquid droplets ® The interface rheometer adopts the hanging drop method, constrained stopping drop method, and VoidLock technology to solve the problem of liquid droplets climbing on the needle in traditional instruments. The instrument calculates the interfacial tension value by capturing changes in droplet morphology, which is suitable for measuring low or ultra-low interfacial tension in carbon dioxide flooding. Researchers can analyze the changes in interfacial tension under different conditions, study the solubility characteristics of carbon dioxide in crude oil and its impact on crude oil properties, and optimize the parameters of carbon dioxide flooding technology.
Real droplets ® The platinum plate dynamic surface/interface tension function and platinum ring static surface tension testing function equipped in the system provide multidimensional measurement methods for surfactant research. The dynamic surface tension function adopts Asha ® The platinum plate method of technology, with a response time of 2-5ms, can test the equilibrium surface tension value and capture the adsorption kinetics of surfactant molecules. The instrument can be optionally equipped with a bubble pressure method module to compare data and improve measurement accuracy. The static surface tension testing function of platinum ring provides stable data for evaluating the surface properties of surfactants in equilibrium state, which is used for screening surfactant formulations.
Real droplets in carbon dioxide flooding ® The system solves the problem of difficulty in droplet formation caused by the large density difference between crude oil and carbon dioxide in traditional rotating droplet interfacial tensiometers through methods such as suspended droplet method and constrained stopping droplet method. For the problem of difficulty in droplet formation of ordinary needles under low or ultra-low interfacial tension, the system's VoidLock technology enhances droplet stability through surface treatment and fluid control techniques. Asha adopted by the system ® Technology can comprehensively measure the contact angle and interfacial tension of various types of droplets, helping researchers optimize process parameters such as carbon dioxide injection concentration and speed.
Real droplets in high-temperature and high salt oil reservoirs ® The system can simulate the environment and measure parameters such as dynamic and static surface tension, interfacial tension, and contact angle of surfactant solutions, helping researchers understand the mechanism of action of surfactants under complex conditions. In the screening of surfactant formulations, the system can conduct simulation experiments on different formulations, compare parameters such as the decrease in interfacial tension, and screen for efficient formulations. In addition, the system can simulate different injection methods and sequences to determine the optimal injection plan for actual mining.
Real droplets ® The high-temperature and high-pressure interface chemical analysis system is an advanced instrument developed for carbon dioxide flooding and surfactant binary (ternary) flooding technology in tertiary oil recovery and shale oil extraction. It solves the problems of traditional instruments in measuring high temperature, high pressure, low or ultra-low interfacial tension through innovative design and technology, providing accurate data for interface chemistry research in petroleum extraction.
This system has promoted the development of carbon dioxide flooding and surfactant binary (ternary) flooding technologies, helping researchers optimize process parameters and formulations and improve recovery rates. With the increasing demand in the oil extraction industry, real liquid droplets ® The system is expected to continue promoting research and technological breakthroughs in interface chemistry, providing technical support for energy supply and sustainable development of the petroleum industry, and continuously improving and upgrading in technological progress.
