Surfactants are molecules that have been used in various industries for decades, including in the oil and gas industry. These compounds are commonly used to alter the surface properties of liquids, allowing them to mix with other substances that they normally would not.
A surfactant when added to a liquid, increases its spreading and wetting properties. Example: dish soap is used as a surfactant, both when washing dishes and applying herbicide to plants. The origin of the word surfactants describes just that: surfactants are a contraction of Surface Active Agents.
In the oil and gas industry, surfactants play a critical role in various stages of production, including drilling, hydraulic fracturing, enhanced oil recovery, and oil spill cleanup.
In this blog post, we will delve into the importance of surfactants in the oil and gas industry. We’ll explore their role, benefits and drawbacks, types, applications, and environmental impact as well as regulations surrounding them. Additionally, sustainable alternatives to surfactants will be discussed.
Understanding oil formation geology
To better understand how surfactants can improve oil and gas production efficiency, it’s important to have a basic understanding of oil formation geology. Two key concepts in this field are porosity and permeability.
Porosity can be defined as the ability of a rock to contain fluid. Imagine two glasses filled with ice, one containing standard cubes and the other crushed ice: the former glass has higher porosity because there is more space between each cube for fluids to occupy. In this illustration, those spaces are analogous to where oil would reside in geologic formations.
The same holds true for crushed ice; however, since it’s smaller bits create less room than larger ones do, its respective porosity remains lower.
Permeability is the capacity of fluids to move through minute spaces in rock. To grasp this concept, envision two drinking straws identical in size; one with a milkshake inside and the other containing water. You’ll notice that it takes more energy to push these drinks up their individual straws than it does for water compared to a milkshake.
However, this analogy simplifies measuring permeability which requires specialized engineers as well as accounting for multiple factors.
By understanding the principles of porosity and permeability, petroleum engineers can determine the optimal methods for oil and gas production, including the use of surfactants.
Stages of oil recovery from a formation
The three stages of oil recovery from a formation are primary, secondary, and tertiary. In primary recovery, natural forces like underground pressure are used to push oil to the surface.
In secondary recovery, man-made forces like injecting water or gas into the formation are used to increase the formation pressure and get the oil moving through the pores.
Tertiary recovery is a follow-up to secondary recovery with different methods, and is typically where Enhanced Oil Recovery (EOR) comes into play. Surfactants are widely used in tertiary recovery, which includes thermal, gas injection, water or chemical flooding.
Eventually, any remaining oil becomes too difficult and expensive to produce, and the well is sealed.
Role of surfactants in oil and gas production
Surfactants are used in the oil and gas industry for various purposes, including:
- Reducing surface tension: By reducing surface tension, surfactants are highly effective in breaking down and spreading oil particles into water for improved performance.
- Enhancing oil recovery: Surfactants can exponentially boost oil recovery efficiency by decreasing the interfacial tension between oil and water, which enables swift movement of the oil through reservoir rock.
- Stabilizing emulsions: Surfactants have the ability to stabilize oil-in-water or water-in-oil emulsions, which are oftentimes encountered in the field of petroleum and natural gas production.
- Reducing friction: Surfactants can drastically reduce the friction between fluids and pipes, resulting in increased fluid flow efficiency during drilling and production processes.
Advantages and disadvantages of using surfactants
- Improved efficiency of oil recovery: Surfactants have the potential to dramatically improve oil recovery from reservoirs, thereby eliminating the need for extra drilling.
- Lowered costs: Surfactants can prove invaluable in the process of oil recovery, as they substantially cut down on both water and energy consumption.
- Improved safety: Surfactants have the potential to drastically diminish the environmental fallout caused by oil spills. These cleaning agents can be used to successfully mitigate these disasters, reducing their damaging effects on our planet.
- Potential health risks: Some surfactants are toxic to humans and can cause skin and eye irritation.
- High costs: Some surfactants can be expensive, increasing the overall cost of oil and gas production.
Types of surfactants used in the industry
There are several types of surfactants used in the oil and gas industry, including:
- Anionic surfactants: These surfactants have a negative charge and are typically used for emulsifying oil for improved production.
- Cationic surfactants: These surfactants have a positive charge and are often used to reduce surface tension.
- Nonionic surfactants: These surfactants are neutral in charge and are often used to stabilize emulsions.
- Amphoteric surfactants: These surfactants have both positive and negative charges, making them effective in breaking down oils.
Extensive literature review suggests that anionic surfactants are the preferred surfactant category for EOR especially when it comes to sandstone reservoirs. Occasionally, in specific situations, better performance has been reported after injecting cationic, non-ionic, or mixtures of both surfactants, particularly when dealing with carbonate reservoirs.
Applications of surfactants in the oil and gas industry
Surfactants in drilling fluids
Surfactants can be added to drilling fluids in order to reduce friction and maximize lubrication, enabling faster and smoother drilling operations. Not only that – they are also beneficial for stabilizing the formation of a wellbore, preserving its structure from collapse or damage.
Surfactants in hydraulic fracturing
Surfactants improve the efficacy of hydraulic fracturing through reducing surface tension, allowing for deeper penetration into rock and consequently freeing more oil and gas. Not only do surfactants contribute to greater production, but they also minimize blockages in wellbores that might otherwise impede flow.
Surfactants in Enhanced Oil Recovery (EOR)
When traditional extraction techniques have depleted oil reserves, Enhanced Oil Recovery (EOR) methods can be utilized to recover more of the oil that remains in a reservoir. In EOR processes, surfactants are used to increase the proportion of oil extracted from a reservoir and come in two forms: micellar-polymer flooding and alkaline-surfactant-polymer flooding.
Micellar-polymer flooding is a process that injects a surfactant and polymer into the reservoir. The combination of these two elements significantly lowers the surface tension of water within, allowing more efficient movement through porous rock.
Additionally, by thickening it with polymer, this liquid mixture can be transported to every corner of the reservoir.
Alkaline-surfactant-polymer flooding is a process in which a surfactant and alkali solution are blended with a polymer, then injected into the reservoir. This solution helps to neutralize any acidity that can reduce oil flow, while the surfactant reduces surface tension of water for better efficiency throughout the reservoir.
The addition of polymer also adds viscosity; thus it helps carry both solutions evenly across all parts of said area.
Surfactants in Oil Spill Cleanup
When crude oil is spilled into the ocean, it can create a substantial barrier on the surface of the water that’s difficult to eradicate. To solve this problem, surfactants are implemented and they effectively break up this protective layer into smaller droplets that can be effortlessly removed from their liquid surroundings.
By using surfactants for oil spill cleanup efforts we substantially improve our ability to clean such environments quickly and efficiently.
Nevertheless, using surfactants in oil spill cleanup can also bring some harm to our planet. These chemicals are known to be toxic to aquatic fauna and flora while disrupting the equilibrium of oceanic habitats.
Additionally, when dispersed oil is not properly contained it can sink right into the depths of the sea causing irreparable damage to its surrounding environment.
Environmental Impact of Surfactants in the Oil and Gas Industry
Effects of Surfactants on the Environment
The oil and gas industry’s use of surfactants can have disastrous consequences for the environment. Not only are these products toxic to aquatic life and capable of upsetting delicate ecosystems, but they also remain in the environment for long periods of time, leading to bioaccumulation and biomagnification through the food chain.
Regulations on Surfactant Use in the Industry
In order to minimize the adverse environmental impacts of surfactants, the Environmental Protection Agency (EPA) has established stringent regulations for their utilization in oil and gas operations. Under both the Clean Water Act and Oil Pollution Act, companies must disclose any potential spills or releases of surfactants as well as utilize best management practices that help reduce harm to our precious environment.
Sustainable Alternatives to Surfactants
The environmental impact of surfactants in the oil and gas industry is a significant problem, yet new strategies are being developed to combat it. To this end, sustainable alternatives such as plant-based or biodegradable surfactants have been created, alongside emerging technologies that reduce their necessity altogether.
Surfactants are an essential element in the oil and gas industry, utilized to raise productivity and boost the quantity of oil and gas that can be recovered from reservoirs. They’re applied utilizing various methods such as drilling fluids, hydraulic fracturing liquids, enhanced oil recovery processes, or during clean-up efforts after a spill occurs.
As the oil and gas market progresses, surfactants will remain essential to improving productivity and cutting down environmental harm. But with this comes a higher call for eco-friendly substitutions that are just as reliable.
To mitigate the detrimental effects of surfactants on our environment, businesses must exercise conscientiousness and adherence to government regulations. Furthermore, there is an urgent necessity for research leading to the development of sustainable alternatives that can replace current surfactant usage in oil and gas operations.
Selecting the correct surfactant is critical in the oil and gas industry, as various salinities of formation water, temperatures, and compositions of oil present can alter interfacial tension and wettability that ultimately affect effectiveness.
Using the wrong surfactant can lead to high adsorption on the pore surface of the rock, resulting in unnecessary waste of resources. It is important to consider rock mineralogy when selecting a surfactant. Super CatholyteⓇ from 21st Century Energy is an effective and inexpensive surfactant that poses no risk to the formation, environment, or workers.
Learn more about Super-CatholyteⓇ here.