Abstract
The chapter covers the topic of deep eutectic solvents (DESs) and their potential as drilling fluid additives, focusing on their use as mud rheology modifiers, shale swelling inhibitors, and hydrate inhibitors during drilling. The properties and characteristics of DES, as well as their advantages and disadvantages, are discussed in detail. The environmental benefits of DES-based drilling fluids, compatibility with other drilling fluid additives, and potential future applications are also examined. Additionally, the challenges and limitations of using DESs as a drilling fluid additive and the safety concerns associated with their use are highlighted. Overall, this chapter provides a comprehensive overview of the use of DES in drilling fluids and its potential to improve the efficiency and safety of drilling operations.
Keywords
- deep eutectic solvents
- drilling fluids
- mud rheology
- shale inhibitor
- hydrate inhibitor
1. Introduction
1.1 Overview of drilling fluids and their importance in drilling operations
Drilling fluids, also known as drilling muds, are an essential component in drilling operations. They are used to lubricate and cool the drill bit, suspend cuttings and debris, and control pressure in the wellbore. Without drilling fluids, drilling operations would be impossible to carry out, as they play a critical role in ensuring the safety and efficiency of the drilling process. Drilling fluids are composed of various components, including a base fluid, which can be water, oil, or synthetic oil, and additives such as clays, polymers, and weighting agents. The type of drilling fluid used depends on the type of well being drilled, the formation being penetrated, and the conditions of the drilling operation. The composition of the drilling fluid is carefully selected to meet the specific requirements of each drilling operation [1].
One of the most important functions of drilling fluids is to provide stability to the wellbore. As the drill bit penetrates the formation, the drilling fluids help to keep the wellbore stable, preventing the formation from collapsing in on itself. This is particularly important when drilling through unstable or unconsolidated formations, where the pressure of the drilling fluid helps to support the formation and prevent it from collapsing. Another crucial function of drilling fluids is to cool and lubricate the drill bit. Drilling generates a significant amount of heat, which can cause damage to the bit and decrease drilling efficiency. Drilling fluids help to cool the bit by circulating around it and carrying away the heat generated by the drilling process. Additionally, they also provide lubrication, reducing friction between the bit and the formation, which further enhances drilling efficiency [2, 3].
Drilling fluids also help to suspend cuttings and debris generated by the drilling process, preventing them from settling in the wellbore and interfering with drilling operations. The suspended cuttings are then transported to the surface by the drilling fluid, where they are separated from the fluid and disposed of. Furthermore, drilling fluids are used to control pressure in the wellbore, which is essential in preventing blowouts and other dangerous situations. The weight of the drilling fluid is carefully controlled to maintain a balance of pressure between the wellbore and the formation being drilled, preventing the formation fluids from entering the wellbore [4].
In conclusion, drilling fluids play a critical role in ensuring the safety and efficiency of drilling operations. They provide stability to the wellbore, cool and lubricate the drill bit, suspend cuttings and debris, and control pressure in the wellbore. The selection of the appropriate drilling fluid composition for a specific drilling operation is crucial, as it ensures that the drilling process is carried out safely and efficiently.
1.2 The need for innovation in drilling fluid design
The oil and gas industry is constantly evolving, and with it, the technology used in drilling operations. In recent years, there has been a growing need for innovation in drilling fluid design. As drilling operations become more complex, the demand for drilling fluids that can meet the specific requirements of each operation has increased. The following are some of the main reasons why innovation in drilling fluid design is crucial [5]:
Increasing complexity of drilling operations
As drilling operations become more complex, the requirements for drilling fluids have become more stringent. Today’s drilling operations involve drilling in deeper waters, at higher pressures and temperatures, and through more challenging formations. This has led to a need for drilling fluids that can perform under extreme conditions, such as high-temperature and high-pressure environments, and can provide the necessary stability and lubrication required for efficient drilling.
Environmental regulations
Environmental regulations have become increasingly strict in recent years, leading to a need for drilling fluids that are more environmentally friendly. Traditional drilling fluids contain toxic chemicals that can harm the environment and wildlife if they are released into the surrounding ecosystem. Therefore, there is a need for drilling fluids that are less toxic and biodegradable, which can reduce the impact of drilling operations on the environment.
Cost-effective solutions
Drilling fluids can account for a significant portion of the total cost of drilling operations. As such, there is a need for cost-effective solutions that can meet the specific requirements of each drilling operation. Innovations in drilling fluid design can lead to the development of more efficient and cost-effective drilling fluids, which can help reduce the overall cost of drilling operations.
Increasing demand for energy
The world’s demand for energy is increasing, and the oil and gas industry is under pressure to meet this demand. This has led to an increase in drilling operations, and as such, a need for drilling fluids that can help increase drilling efficiency. Innovations in drilling fluid design can help develop fluids that can improve drilling efficiency, reduce the time required for drilling operations, and increase the overall output of oil and gas wells.
Safety and risk management
Drilling operations can be dangerous, and safety is always a top priority. Innovations in drilling fluid design can help develop fluids that are safer to handle, reducing the risk of accidents and injuries during drilling operations. Furthermore, drilling fluids that can provide better pressure control can reduce the risk of blowouts and other dangerous situations.
1.3 Insight into some tradition drilling fluid additives
Traditional drilling fluid additives have been used in the oil and gas industry for many years to optimize drilling operations. These additives are designed to improve the physical and chemical properties of the drilling fluid, which is crucial for efficient drilling and wellbore stability. Some of the commonly used traditional drilling fluid additives include [6]:
These traditional drilling fluid additives have been used for many years and have proven to be effective in improving the properties of the drilling fluid. However, they also have some limitations and drawbacks. For example, some of these additives can be expensive and may have adverse environmental impacts. Additionally, they may not be effective in certain drilling conditions or formations. As a result, there is a growing interest in exploring alternative additives, such as deep eutectic solvents, that can provide comparable or superior performance while addressing some of these limitations.
2. Deep eutectic solvents
2.1 Definition of DES
Deep eutectic solvents (DESs) are a relatively new class of solvents that have been attracting increasing attention due to their unique properties and potential applications in various industries, including the oil and gas industry. DESs are typically formed by mixing two or more components, such as a hydrogen bond acceptor and a hydrogen bond donor, at a specific molar ratio, which results in a eutectic mixture that has a lower melting point than either of the individual components. The concept of eutectic mixtures has been known for over a century, but it was not until the early 21st century that the term ‘deep eutectic solvents’ was coined to describe these types of mixtures. The ‘deep’ part of the name refers to the fact that the melting point depression is significant and occurs at a temperature much lower than that of either of the individual components, which is not the case for traditional eutectic mixtures [7].
2.1.1 Eutectic mixtures
Eutectic mixtures are a type of mixture formed when two or more substances with different melting points are combined in certain proportions to form a new mixture that has a lower melting point than either of the individual components. The specific proportions at which the mixture will have the lowest melting point are called the eutectic point or eutectic composition. At this point, the mixture will solidify or melt at a single temperature instead of over a range of temperatures.
In the case of deep eutectic solvents (DESs), eutectic mixtures are formed between a hydrogen bond acceptor (HBA) and a hydrogen bond donor (HBD). These mixtures form a new solvent with unique properties such as low vapor pressure, low flammability, high thermal stability, and a wide range of tunable physical and chemical properties. The formation of a eutectic mixture is dependent on the molecular structure and properties of the HBA and HBD. The HBA typically has a higher melting point and stronger electron-withdrawing ability than the HBD. When combined in the correct proportions, the HBD can disrupt the lattice structure of the HBA, leading to a reduction in the melting point of the mixture. The formation of DES is a delicate balance between the strength of hydrogen bonding and the size and shape of the molecules involved. Too weak of a hydrogen bond or a mismatch in size and shape can result in a mixture that does not have the desired properties of a DES.
Overall, the formation of eutectic mixtures and subsequent development of DESs have opened up a new frontier in solvent design, with potential applications in a wide range of industries, including drilling fluid design.
2.2 Properties and characteristics of DES
Deep eutectic solvents (DESs) are a class of solvents that have been gaining increasing attention in various industries, including the oil and gas industry. Here are some of the key properties and characteristics of DES:
2.3 Utilization of DES in various fields
Deep eutectic solvents (DESs) are a type of ionic liquid that exhibit unique properties and have found diverse applications in various fields. Here are some details on the uses of DES and their mechanisms in different areas:
The mechanisms underlying the properties and behavior of DES can vary depending on the specific composition and components involved. Generally, DESs operate through a combination of hydrogen bonding, ion-dipole interactions, and coordination between the components, leading to unique solvent characteristics and enabling their diverse applications.
3. Introduction to deep eutectic solvents and their potential as drilling fluid additives
In their pioneering work, Han Jia et al. (2019) investigated the use of deep eutectic solvents (DESs) as shale inhibitors. They tested three different DES compositions: Propoanoic acid ChCl (1:1), 3-phenyl propanoic acid ChCl (1:2), and a mixture of 3-mercapto propanoic acid, Itaconic acid, and ChCl (1:1:2). Their study revealed that these DES formulations provided 68%, 58%, and 58% inhibition of bentonite swelling, respectively [22]. In a subsequent study by M.H. Rasool et al. (2021), a Glycerine:Potassium Carbonate DES (2:1) was employed in a free-style experiment using swelling shale samples. Remarkably, this DES demonstrated 87% inhibition of swelling [23]. Moreover, M.H. Rasool et al. (2022) investigated a double-action approach using a Potassium carbonate-based DES in combination with a Poly (2-ethyl-2-Oxazoline) hydroxyl-terminated polymer in drilling mud. This innovative combination resulted in a remarkable 76% inhibition of swelling [24].
Deep eutectic solvents (DESs) have shown potential as drilling fluid additives for various applications, including mud rheology modification, shale swelling inhibition, and hydrate inhibition. A detailed discussion on each aspect has been carried out below.
3.1 As a rheology modifier
Drilling mud rheology refers to the study of the flow behavior of drilling fluids. Drilling mud is a critical component of the drilling process, used to cool and lubricate the drill bit, carry drill cuttings to the surface, and maintain pressure in the wellbore. The flow properties of the drilling mud, including viscosity, yield point, gel strength, and fluid loss, are crucial to ensure efficient and safe drilling operations. Viscosity is the most fundamental property of drilling mud rheology and refers to the fluid’s resistance to flow. The viscosity of the drilling mud must be carefully controlled to prevent excessive pressure buildup, which can cause wellbore instability, lost circulation, and other drilling problems. Yield point is another important rheological property, representing the minimum stress required to initiate fluid movement. Gel strength measures the shear strength of the drilling mud, and fluid loss measures the amount of fluid that is lost to the formation during drilling operations.
Deep eutectic solvents (DESs) have shown potential as drilling fluid additives for various applications, including mud rheology modification. One of the most common components of drilling fluids is sodium bentonite, which is a clay mineral that provides viscosity and filtration control properties to the drilling fluid [25]. The interaction between DES and sodium bentonite in drilling mud can improve the rheology of the fluid and provide other benefits. The interaction between DES and sodium bentonite is believed to involve the formation of hydrogen bonds between the HBA and HBD components of DES and the hydroxyl groups of sodium bentonite. The hydrogen bonding can lead to changes in the interlayer spacing of the sodium bentonite and improve the rheological properties of the drilling mud. DES can act as both a thickener and a thinner of drilling fluids depending on the HBA and HBD components used [26].
For example, DES based on choline chloride and urea can increase the viscosity of sodium bentonite-based drilling fluids. The interaction between DES and sodium bentonite can cause an increase in the interlayer spacing of sodium bentonite, leading to an increase in the viscosity of the drilling fluid. In addition, DES can reduce the gel strength of the drilling mud, which can improve the flow properties of the fluid and reduce the risk of differential sticking. On the other hand, DES based on choline chloride and ethylene glycol can decrease the viscosity of sodium bentonite-based drilling fluids. The interaction between DES and sodium bentonite can cause a decrease in the interlayer spacing of sodium bentonite, leading to a decrease in the viscosity of the drilling fluid. This can be useful in situations where a lower-viscosity drilling fluid is required. Furthermore, DES can also improve the thermal stability of sodium bentonite-based drilling fluids. The interaction between DES and sodium bentonite can help to prevent thermal degradation of the fluid and improve the thermal stability of the fluid. However, there are still challenges that need to be addressed when using DES as drilling fluid additives, including issues related to the compatibility of DES with other drilling fluid components and the need for further research to fully understand the behavior of DES under different drilling conditions.
In conclusion, the interaction between DES and sodium bentonite in drilling mud can improve the rheology of the fluid and provide other benefits. The mechanism of DES interaction with sodium bentonite is believed to involve the formation of hydrogen bonds between the HBA and HBD components of DES and the hydroxyl groups of sodium bentonite. DES can act as both a thickener and a thinner of drilling fluids depending on the HBA and HBD components used. Further research is needed to optimize the use of DES in drilling fluids and address compatibility issues. DES can also be used as shale swelling inhibitors in drilling fluids. Shale swelling is a common issue in drilling operations, which can lead to significant challenges, including reduced drilling efficiency and wellbore instability. DESs can inhibit shale swelling by penetrating the shale formation and interacting with the clay minerals, preventing them from absorbing water and swelling. The mechanism of DES as a shale swelling inhibitor is believed to involve the disruption of the hydrogen bonding between the clay minerals and water molecules. This can prevent the swelling of the shale formation and improve the stability of the wellbore.
3.2 As a hydrate inhibitor
During deepwater drilling operations, the high-pressure and low-temperature conditions can cause the formation of gas hydrates, which are crystalline structures composed of water and gas molecules. These hydrates can cause significant problems in drilling operations, such as plugging of equipment and pipes, reducing the efficiency of the drilling process, and even leading to safety hazards. Gas hydrates form when gas molecules (typically methane, ethane, propane, and butane) are trapped within the lattice structure of water molecules, under conditions of high pressure and low temperature. In deepwater drilling, the temperature can drop below the hydrate formation temperature of the gas, and the pressure can be high enough to stabilize the hydrate structure. Once formed, these hydrates can accumulate in pipes, valves, and other equipment, reducing the flow of drilling fluid and increasing the risk of blockages.
Deep eutectic solvents (DESs) have shown potential as drilling fluid additives for various applications, including the inhibition of hydrate formation during deepwater drilling operations. DES can act as hydrate inhibitors by forming a hydrate-inhibiting film on the surface of gas hydrate crystals, which prevents further growth and agglomeration of the crystals as shown in Figure 1. The mechanism of DES inhibition of hydrate formation involves a combination of thermodynamic and kinetic effects.
The thermodynamic effect is due to the ability of DES to reduce the driving force for hydrate formation by lowering the equilibrium temperature and pressure for hydrate formation. This is because DES can dissolve in water and reduce the concentration of free water molecules, which are required for hydrate formation. As a result, the formation of hydrates is suppressed, and the stability of existing hydrate crystals is reduced. The kinetic effect is due to the ability of DES to adsorb onto the surface of hydrate crystals and form a film that prevents further growth and agglomeration of the crystals. The adsorption of DES onto the surface of hydrate crystals is believed to be facilitated by the presence of hydrogen bonding sites on the surface of the crystals. The hydrogen bonding between the HBA and HBD components of DES and the hydrogen bonding sites on the surface of hydrate crystals can lead to the formation of a stable film that inhibits further growth of the crystals.
One of the most promising DES for hydrate inhibition is based on choline chloride and urea. This DES has been shown to be effective in inhibiting hydrate formation in laboratory experiments and in field trials. In addition, this DES has the advantage of being environmentally friendly and biodegradable, which is important for reducing the environmental impact of drilling operations. However, there are still challenges that need to be addressed when using DES as hydrate inhibitors in drilling operations, including issues related to the compatibility of DES with other drilling fluid components and the need for further research to fully understand the behavior of DES under different drilling conditions.
In conclusion, DES has the potential to be effective hydrate inhibitor in deep-water drilling operations. The mechanism of DES inhibition of hydrate formation involves a combination of thermodynamic and kinetic effects, which reduce the driving force for hydrate formation and prevent further growth and agglomeration of hydrate crystals. Further research is needed to optimize the use of DES as hydrate inhibitors in drilling fluids and address compatibility issues.
3.3 As a shale inhibitor
Shale is a fine-grained sedimentary rock composed of clay minerals such as illite, kaolinite, and smectite. Shale is a common rock encountered in oil and gas drilling, and it poses several challenges to drilling operations due to its unique properties. One of the major issues with shale is its tendency to swell when exposed to water-based drilling fluids. This phenomenon is known as shale swelling, and it can result in significant problems such as stuck pipe, lost circulation, and formation damage. Shale swelling is primarily caused by the interaction between the clay minerals in shale and water-based drilling fluids. When shale is exposed to water-based drilling fluids, the clay minerals in the shale absorb water and begin to swell. This swelling can cause the shale to expand and reduce the permeability of the formation, making it difficult for the drilling fluid to circulate through the wellbore [25, 28].
Deep eutectic solvents (DESs) have shown potential as drilling fluid additives for inhibiting shale swelling during drilling operations. The mechanism of DES inhibition of shale swelling involves a combination of physical and chemical effects. The physical effect is due to the ability of DES to reduce the hydration of clay minerals in shale formations. Clay minerals have a layered structure that consists of negatively charged sheets of silica and alumina, with positively charged ions such as sodium and potassium located between the layers. When water is present, the positively charged ions interact with the negatively charged sheets, causing the layers to swell and expand. DES can interact with these positively charged ions, reducing the amount of water that can access the clay mineral layers and reducing the amount of swelling as shown in Figure 2 [7, 29]. The chemical effect is due to the ability of DES to interact with the clay minerals at a molecular level. DES can penetrate into the interlayer space of clay minerals and disrupt the interactions between the layers. This can lead to the delamination of the clay minerals, reducing their ability to swell and expand.
One of the most promising DES for shale swelling inhibition is based on choline chloride and urea. This DES has been shown to be effective in reducing shale swelling in laboratory experiments and in field trials. In addition, this DES has the advantage of being environmentally friendly and biodegradable, which is important for reducing the environmental impact of drilling operations. However, there are still challenges that need to be addressed when using DES as shale swelling inhibitors in drilling operations, including issues related to the compatibility of DES with other drilling fluid components and the need for further research to fully understand the behavior of DES under different drilling conditions [30, 31].
In conclusion, DESs have the potential to be used as drilling fluid additive for various applications, including mud rheology modification, shale swelling inhibition, and hydrate inhibition. The mechanism of DES in each application is believed to involve specific interactions with the components of the drilling fluid and the geological formations. Further research is needed to fully understand the behavior of DES under different drilling conditions and to optimize their use in drilling fluids.
3.4 Advantages and disadvantages of using DES as drilling fluid additives
Deep eutectic solvents (DESs) have gained attention as potential additives for drilling fluids due to their unique properties. However, as with any new technology, there are advantages and disadvantages to their use in drilling operations [23, 32, 33].
3.4.1 Advantages of using DES as drilling fluid additives
3.4.2 Disadvantages of using DES as drilling fluid additives
In conclusion, DESs have unique advantages as drilling fluid additives due to their environmental friendliness, high solubility, and tunable properties. However, their limited research and higher cost, as well as potential compatibility issues and increased viscosity, may limit their use in certain drilling applications. Further research is needed to fully understand the benefits and limitations of DES as drilling fluid additives.
3.5 Potential combination of DES as drilling fluid additives
There are numerous combinations of deep eutectic solvents (DESs) that have been successfully used as drilling fluid additives. Some of these include [22, 25, 34, 35]:
Overall, the use of DES as drilling fluid additive has shown great promise in improving the performance and efficiency of drilling operations. As research continues, it is likely that new combinations of DESs will be developed and tested for their potential as drilling fluid additives.
3.6 Ionic liquids vs. DES as drilling fluid additives
Ionic liquids and deep eutectic solvents (DESs) are both types of solvents that have gained attention for their potential applications in various fields, including drilling fluid additives. While both are considered “green solvents” due to their low toxicity and biodegradability, there are key differences between them. Ionic liquids (ILs) are salts that are liquid at room temperature, typically composed of large, asymmetric cations and small, inorganic anions. The ionic nature of these compounds means that they have a high degree of polarity and can dissolve a wide range of materials, including inorganic salts, polymers, and gases. However, their high cost and potential toxicity have limited their widespread use [36].
In contrast, DESs are formed through the interaction of two or more solid components, typically a hydrogen bond acceptor (HBA) and a hydrogen bond donor (HBD), that undergo a eutectic reaction to form a liquid. This results in a solvent that has a lower melting point than either of its individual components and exhibits unique properties such as high polarity, low viscosity, and tunable solubility. DES can be composed of a variety of HBAs and HBDs, allowing for a wide range of possible solvents with different properties. One of the main advantages of DESs over ILs is their lower cost, as the solid components used to form DESs are typically more readily available and less expensive than the chemicals used to produce ILs. Additionally, DESs are generally less toxic and have a lower environmental impact than ILs.
In terms of their applications as drilling fluid additives, both ILs and DESs have shown promise in improving drilling fluid properties such as viscosity, lubricity, and stability. However, DESs are considered to be more suitable for use in this field due to their lower cost, lower toxicity, and compatibility with other drilling fluid additives. In summary, while both Ils and DES are considered “green solvents” with potential applications in a variety of fields, including drilling fluid design, DESs have certain advantages over ILs in terms of cost, toxicity, and compatibility with other additives.
4. Environmental benefits of DES-based drilling fluids
Deep eutectic solvents (DESs) are an emerging class of solvents that have gained attention as potential drilling fluid additives due to their unique properties. In addition to their tunable properties and high solubility, DES-based drilling fluids also offer several environmental benefits that make them an attractive alternative to traditional drilling fluids [37].
Overall, DES-based drilling fluids offer several environmental benefits over traditional drilling fluids. By reducing the environmental impact of drilling operations, these fluids can help to protect the environment and promote sustainable drilling practices.
5. Compatibility with other drilling fluid additives
The compatibility of deep eutectic solvents (DESs) with other drilling fluid additives is an important factor in determining their overall effectiveness in drilling operations. Here we will discuss the compatibility of DES with various additives commonly used in drilling fluids, including soda ash, caustic soda, xanthan gum, barite, KCl, and cellulose starch.
In general, the compatibility of DES with other drilling fluid additives is dependent on the specific composition of the DES and the other additives used. It is important to carefully consider the concentrations and pH levels of all additives in the drilling fluid, and to test the compatibility of the DES with other additives before using it in drilling operations.
6. Challenges and future outlook
6.1 Use of DES in high-temperature and high-pressure drilling environments
Deep eutectic solvents (DESs) have shown great potential as drilling fluid additives in high-temperature and high-pressure drilling environments. These conditions are often encountered in deepwater and ultra-deepwater drilling, where temperatures and pressures can exceed 150°C and 20,000 psi, respectively. Traditional drilling fluids may not be able to withstand these extreme conditions and can break down, resulting in decreased drilling efficiency and safety hazards. One of the key advantages of using DESs in high-temperature and high-pressure drilling environments is their excellent thermal stability. DESs have been shown to remain stable at temperatures up to 200°C and pressures up to 1000 bar. This makes them ideal for use in deepwater and ultra-deepwater drilling applications, where temperatures and pressures are at their highest. DESs also have good lubricity and can reduce the coefficient of friction between the drill string and the borehole wall. This can help to reduce wear and tear on the drill string and improve drilling efficiency [38].
6.2 Cost-effectiveness of DES-based drilling fluids
Deep eutectic solvents (DESs) have gained attention as a potential alternative to conventional drilling fluid additives due to their unique properties and potential advantages. One advantage that has been explored is the cost-effectiveness of using DES-based drilling fluids. The cost-effectiveness of drilling fluids is an important factor to consider in the oil and gas industry, as the cost of drilling can be a significant expense. DES-based drilling fluids have the potential to be more cost-effective than traditional drilling fluids for several reasons.
First, DES can be synthesized from relatively inexpensive starting materials, such as choline chloride and urea. This means that the cost of producing DES can be lower than that of traditional drilling fluid additives. Additionally, DES can be used at lower concentrations than traditional additives, further reducing the cost of the fluid. DES can also potentially reduce the overall cost of drilling by improving drilling efficiency. The unique properties of DES can improve drilling performance by reducing friction between the drill bit and the formation being drilled. This can lead to faster drilling times and less wear on the drilling equipment, reducing maintenance costs.
Another potential cost-saving benefit of DES-based drilling fluids is their ability to be reused. Traditional drilling fluids can become contaminated with rock cuttings and other debris, which can render them unusable and require disposal. DES-based fluids, however, have been shown to be more stable and less prone to contamination, making them potentially reusable and reducing the need for frequent fluid changes. Overall, the cost-effectiveness of DES-based drilling fluids is a promising advantage that warrants further exploration and development. As research into the use of DES in drilling fluids continues, it is likely that more cost-saving benefits will be identified [39].
6.3 Potential future applications of DES in drilling fluid design
Deep eutectic solvents (DESs) have shown promising results as drilling fluid additives due to their ability to modify the rheology of the drilling fluid, inhibit shale swelling, and prevent hydrate formation. However, the potential applications of DES in drilling fluid design go beyond these uses.
One potential application is in enhancing the lubricity of the drilling fluid. Lubricity is a critical property for reducing friction and wears on the drill bit and the drilling equipment. DESs have been found to exhibit good lubricating properties, and their use in drilling fluid design could lead to improved drilling efficiency and reduced wear on equipment. Another potential application of DES is in enhancing the thermal stability of the drilling fluid. In high-temperature and high-pressure drilling environments, the drilling fluid is subjected to extreme conditions that can cause thermal degradation and loss of viscosity. DESs have been shown to have good thermal stability, and their incorporation into the drilling fluid could improve the fluid’s performance in such environments [39].
DESs also have the potential to act as surfactants in drilling fluids, which could enhance their ability to wet and disperse solids and improve their emulsifying properties. This could lead to improved suspension of drill cuttings and better removal of solids from the wellbore. In addition, DESs have been investigated for their potential as environmentally friendly drilling fluid additives. They are biodegradable and have low toxicity, which makes them an attractive alternative to conventional drilling fluid additives that can have harmful environmental impacts.
Overall, DESs have shown great potential as versatile and innovative drilling fluid additives with a wide range of potential applications beyond their current uses. Further research and development are needed to fully explore their capabilities and optimize their performance in drilling operations [40].
6.4 Challenges and limitations
Despite their potential benefits, there are still several challenges and limitations associated with the use of deep eutectic solvents (DESs) as drilling fluid additives. Some of the major challenges are discussed below:
In conclusion, while DESs offer many potential benefits as drilling fluid additives, there are still several challenges and limitations that need to be addressed before they can be widely adopted in the drilling industry. Further research is needed to better understand their behavior and optimize their use under various drilling conditions.
7. Conclusion
In conclusion, deep eutectic solvents (DESs) are a promising alternative to traditional drilling fluid additives due to their unique properties and potential benefits. They can serve as mud rheology modifiers, shale swelling inhibitors, and hydrate inhibitors during drilling operations. DES can improve the rheological properties of drilling mud by interacting with sodium bentonite, which increases the stability of the fluid and prevents solids from settling. DES can also inhibit hydrate formation during deep-water drilling by disrupting the formation of hydrate crystals. Furthermore, they can act as shale swelling inhibitors by coating the shale surface and preventing the absorption of water.
However, there are some limitations and challenges associated with the use of DES as drilling fluid additives, including their high cost and potential environmental impact. Compatibility issues with certain drilling formations and other additives must also be considered. Health and safety concerns should also be taken into account when handling DES. Despite these challenges, DES has shown potential in improving the efficiency and effectiveness of drilling operations. Further research is needed to explore the potential of DES-based drilling fluids in high-temperature and high-pressure drilling environments, as well as their compatibility with a wider range of drilling formations and additives. As the oil and gas industry continues to evolve and adapt to new environmental and regulatory requirements, DES may prove to be a valuable tool for sustainable and effective drilling fluid design.
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Acknowledgments
The authors would like to thank YUTP grant 015LC0-326 for providing the support.
References
- 1.
Hao Y. Research and application of anti-leakage drilling fluid. Bulgarian Chemical Communications. 2016; 48 :215-221 - 2.
Kårstad E, Aadnøy BS. Density behavior of drilling fluids during high pressure high temperature drilling operations. In: IADC/SPE Asia Pacific Drilling Technology. Kualalumpur, Malaysia. OnePetro; 1998 - 3.
Ravi A. Experimental Assessment of Water Based Drilling Fluids in High Pressure and High Temperature Conditions. Doha, Qatar: Texas A & M University; 2012 - 4.
Wójcik M, Kostowski W. Environmental risk assessment for exploration and extraction processes of unconventional hydrocarbon deposits of shale gas and tight gas: Pomeranian and Carpathian region case study as largest onshore oilfields. Journal of Earth Science. 2020; 31 (1):215-222 - 5.
Wang C-Q et al. Human carcinogenic risk analysis and utilization of shale gas water-based drilling cuttings in road materials. Environmental Science and Pollution Research. 2023; 30 (5):12741-12768 - 6.
Ali I, Ahmad M, Ganat T. Biopolymeric formulations for filtrate control applications in water-based drilling muds: A review. Journal of Petroleum Science and Engineering. 2022; 210 :110021 - 7.
Smith EL, Abbott AP, Ryder KS. Deep eutectic solvents (DESs) and their applications. Chemical Reviews. 2014; 114 (21):11060-11082 - 8.
Chang XX et al. A review on the properties and applications of chitosan, cellulose and deep eutectic solvent in green chemistry. Journal of Industrial and Engineering Chemistry. 2021; 104 :362-380 - 9.
Durand E, Lecomte J, Villeneuve P. From green chemistry to nature: The versatile role of low transition temperature mixtures. Biochimie. 2016; 120 :119-123 - 10.
Calvo-Flores FG, Mingorance-Sánchez C. Deep eutectic solvents and multicomponent reactions: Two convergent items to green chemistry strategies. ChemistryOpen. 2021; 10 (8):815-829 - 11.
Li X, Row KH. Development of deep eutectic solvents applied in extraction and separation. Journal of Separation Science. 2016; 39 (18):3505-3520 - 12.
Huang J, Guo X, Xu T, Fan L, Zhou X, Wu S. Ionic deep eutectic solvents for the extraction and separation of natural products. Journal of Chromatography A. 2019; 1598 :1-19 - 13.
Yucui H, Congfei Y, Weize W. Deep eutectic solvents: Green solvents for separation applications. Acta Physico-Chimica Sinica. 2018; 34 (8):873-885 - 14.
Abbott AP. Deep eutectic solvents and their application in electrochemistry. Current Opinion in Green and Sustainable Chemistry. 2022; 36 :100649 - 15.
Nkuku CA, LeSuer RJ. Electrochemistry in deep eutectic solvents. The Journal of Physical Chemistry B. 2007; 111 (46):13271-13277 - 16.
Xu P, Zheng G-W, Zong M-H, Li N, Lou W-Y. Recent progress on deep eutectic solvents in biocatalysis. Bioresources and Bioprocessing. 2017; 4 :1-18 - 17.
Pätzold M, Siebenhaller S, Kara S, Liese A, Syldatk C, Holtmann D. Deep eutectic solvents as efficient solvents in biocatalysis. Trends in Biotechnology. 2019; 37 (9):943-959 - 18.
Emami S, Shayanfar A. Deep eutectic solvents for pharmaceutical formulation and drug delivery applications. Pharmaceutical Development and Technology. 2020; 25 (7):779-796 - 19.
Pedro SN, Freire CS, Silvestre AJ, Freire MG. Deep eutectic solvents and pharmaceuticals. Encyclopedia. 2021; 1 (3):942-963 - 20.
Nahar Y, Thickett SC. Greener, faster, stronger: The benefits of deep eutectic solvents in polymer and materials science. Polymers. 2021; 13 (3):447 - 21.
Ge X, Gu C, Wang X, Tu J. Deep eutectic solvents (DESs)-derived advanced functional materials for energy and environmental applications: Challenges, opportunities, and future vision. Journal of Materials Chemistry A. 2017; 5 (18):8209-8229 - 22.
Jia H et al. Investigation of inhibition mechanism of three deep eutectic solvents as potential shale inhibitors in water-based drilling fluids. Fuel. 2019; 244 :403-411 - 23.
Rasool MH, Zamir A, Elraies KA, Ahmad M, Ayoub M, Abbas MA. Potassium carbonate based deep eutectic solvent (DES) as a potential drilling fluid additive in deep water drilling applications. Petroleum Science and Technology. 2021; 39 (15-16):612-631 - 24.
Rasool MH, Ahmad M, Abbas MA. A double action PD (polymer-deep eutectic solvent) based shale inhibitor in drilling mud. Journal of Advanced Research in Fluid Mechanics and Thermal Sciences. 2022; 99 (1):149-157 - 25.
Ma J, Pang S, Zhou W, Xia B, An Y. Novel deep eutectic solvents for stabilizing clay and inhibiting shale hydration. Energy & Fuels. 2021; 35 (9):7833-7843 - 26.
Ma J, Pang S, An Y. Deep eutectic solvents for enhancing the rheological behavior of polymers and clays in polymeric water-based drilling fluids. Energy & Fuels. 2023; 37 (6):4391-4400 - 27.
Rasool MH, Zamir A, Elraies KA, Ahmad M, Ayoub M, Abbas MA. A deep eutectic solvent based novel drilling mud with modified rheology for hydrates inhibition in deep water drilling. Journal of Petroleum Science and Engineering. 2022; 211 :110151 - 28.
Jia H et al. Study of a gemini surface active ionic liquid 1, 2-bis (3-hexylimidazolium-1-yl) ethane bromide as a high performance shale inhibitor and inhibition mechanism. Journal of Molecular Liquids. 2020; 301 :112401 - 29.
Beg M, Haider MB, Thakur NK, Husein M, Sharma S, Kumar R. Clay-water interaction inhibition using amine and glycol-based deep eutectic solvents for efficient drilling of shale formations. Journal of Molecular Liquids. 2021; 340 :117134. DOI: 10.1016/j.molliq.2021.117134 - 30.
Jia H et al. Investigation of anionic group effects on the shale inhibition performance of fatty acid-based ionic liquids and their inhibition mechanism. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2022; 636 :128135 - 31.
Sivabalan V, Sahith JK, Lal B. Deep eutectic solvents as the new norm for oil and gas industry: A mini review. In: Third International Conference on Separation Technology 2020 (ICoST 2020). Amsterdam, Netherlands: Atlantis Press; 2020. pp. 119-124 - 32.
Rasool MH, Ahmad M, Ayoub M, Zamir A, Abbas MA. A review of the usage of deep eutectic solvents as shale inhibitors in drilling mud. Journal of Molecular Liquids. 2022; 361 :119673 - 33.
Rasool MH, Ahmad M, Ayoub M, Abbas MA. A novel ascorbic acid based natural deep eutectic solvent as a drilling mud additive for shale stabilization. PRO. 2023; 11 (4):1135 - 34.
Sultana K, Rahman MT, Habib K, Das L. Recent advances in deep eutectic solvents as shale swelling inhibitors: A comprehensive review. ACS Omega. 2022; 7 (33):28723-28755 - 35.
Muhammad MHR. Deep Eutectic Solvent Based Novel Drilling Mud with Improved Rheological and Filtration Behaviour. Bandar Seri Iskander, Malaysia: Universiti Teknologi PETRONAS; 2021 - 36.
Sanati A, Malayeri MR, Busse O, Weigand JJ. Utilization of ionic liquids and deep eutectic solvents in oil operations: Progress and challenges. Journal of Molecular Liquids. 2022; 361 :119641 - 37.
Bai J et al. Investigation of the mechanism and effect of citric acid-based deep eutectic solvents inhibiting hydration and expansion of gas shale clay minerals. Energy & Fuels. 2023; 37 (4):2750-2758 - 38.
Padinhattath SP, Chenthamara B, Gardas RL. Ionic liquids as alternative solvents for energy conservation and environmental engineering. Acta Innovations. 2021; 38 :62-79 - 39.
Ma J, Xu J, Pang S, Zhou W, Xia B, An Y. Novel environmentally friendly lubricants for drilling fluids applied in shale formation. Energy & Fuels. 2021; 35 (9):8153-8162 - 40.
Beg M, Kesarwani H, Sharma S, Saxena A. Impact of low-molecular-weight poly (4-styrenesulfonic acid-co-maleic acid) sodium salt on filtration and rheological parameters of nanoparticles-enhanced drilling fluid. Journal of Vinyl and Additive Technology. 2022; 28 (1):125-139