2.3 Problems with Reservoir Protection Drilling Fluid Technology

Despite the good research and application of temporary plugging reservoir protection drilling fluid technology, liquid casing oil and gas reservoir protection drilling fluid technology, and soil free water-based/synthetic based drilling fluid technology, there are still a series of problems and challenges.① The current technology performs well in certain types of reservoirs, but may not be effective in other types of reservoirs. The selection and implementation of technology need to be customized according to specific reservoir characteristics and drilling conditions, which increases the complexity and application difficulty of the technology.② Various additives and materials used in reservoir protection drilling fluid technology may lose their effectiveness or undergo performance changes in high temperature, high pressure, and corrosive environments, leading to reservoir damage or decreased drilling fluid performance. The stability of materials is also a concern during long-term storage and transportation.③ Real time monitoring of the performance of reservoir protection drilling fluid and reservoir damage during the drilling process is crucial for optimizing drilling operations. In addition, due to the complexity and uncertainty of the reservoir, even with real-time monitoring, it may be difficult to detect problems and make adjustments in a timely and accurate manner. This may result in unnecessary damage to the reservoir or a decrease in drilling efficiency.

2.4 Problems with Leak Prevention and Sealing Techniques for Drilling Fluid

Drilling fluid leak prevention and plugging technology plays a crucial role in oil and gas exploration and development. However, despite the existence of various leak prevention and plugging technologies, there are still a series of problems and challenges in practical applications.① Technical selection and geological compatibility. The physical and chemical properties of different strata vary greatly, including porosity, permeability, rock type, and fracture development. Due to the complexity and diversity of geological formations, different leak prevention and plugging techniques may only be applicable to specific geological conditions.② Performance of sealing materials. Currently used bridging materials, gel materials, curable materials, etc. may have poor performance under the action of high temperature, high pressure or corrosive fluids in the formation. The physical properties such as particle size distribution, density, viscosity, etc. of the plugging material need to be matched with the geological characteristics to achieve effective plugging.③ The complexity and timeliness of leak plugging operations. When a well leak occurs, it is necessary to quickly diagnose and take measures to prevent further deterioration. However, due to the complexity and uncertainty of the drilling environment, quickly and accurately determining the location, type, and scale of leaks is a challenging task.④ Environmental and safety impacts. Some leak proof and plugging materials may cause pollution to the environment, such as heavy metals, toxic chemicals, etc. Strict environmental measures need to be taken when using these materials. At the same time, the problem of well leakage itself and improper leak prevention and plugging operations may cause safety risks, such as wellbore collapse, blowouts, etc.

3.Development Prospects of Deep and Ultra Deep Drilling Fluid Technology

3.1 Development Prospects of High-temperature and High Salinity Water-based Drilling Fluid Technology

① Improve high-temperature stability. In order to solve the problems of thermal degradation and phase separation of drilling fluids under high temperature conditions, future high-temperature resistant water-based drilling fluid technologies should focus on improving high-temperature stability. By developing new high-temperature stabilizers, antioxidants, etc., the thermal stability of polymers and other additives in drilling fluids can be enhanced, reducing the risk of thermal degradation.

② Improve rheological performance control. In order to better control the rheological properties of drilling fluids in high-temperature environments, future technologies need to focus on improving rheological control methods. By introducing new flow regulators and viscosity control agents, precise control of drilling fluid viscosity can be achieved, avoiding the impact of high or low viscosity on drilling efficiency and wellbore stability.

③ Strengthen the control of filtration loss. In order to solve the problem of increased filtration loss of drilling fluid under high temperature conditions, future high-temperature resistant water-based drilling fluid technologies need to strengthen filtration loss control. By developing new types of fluid loss reducers and filter cake enhancers, the filtration loss of drilling fluids can be reduced, the quality of filter cakes can be improved, the stability of wellbore walls can be maintained, and the risk of reservoir damage can be reduced.

④ Improve compatibility with geological formations. In order to improve the compatibility between high-temperature resistant water-based drilling fluids and formations, future technologies should focus on selecting drilling fluid systems and additives that match the characteristics of the formations. By conducting in-depth research on the mineral and fluid characteristics in the formation, the chemical composition and properties of the drilling fluid can be adjusted in a targeted manner to reduce the risk of reactions with the formation.

⑤ Promote intelligent and green development. With the advancement of technology and the improvement of environmental awareness, future high-temperature resistant water-based drilling fluid technology will develop towards intelligence and greenness. By introducing advanced sensors and monitoring technologies, real-time monitoring of the performance of drilling fluid and formation changes is achieved, providing data support for optimizing drilling fluid formulations and adjusting process parameters.

3.2 Development Prospects of High-temperature Resistant Oil-based/Synthetic based Drilling Fluid Technology

① Improve high-temperature stability and rheological properties. The future high-temperature resistant oil-based/synthetic based drilling fluid technology needs to focus on developing more efficient high-temperature stabilizers and flow regulators. These additives will be able to maintain the chemical and physical stability of drilling fluids in high-temperature environments and effectively regulate their rheology to ensure drilling efficiency and wellbore cleanliness.

② Improve emulsion stability and demulsification effect. In the future, attention should be paid to the research and development of high-performance emulsifiers and demulsifiers. These new emulsifiers need to have stronger emulsifying ability and higher thermal stability to maintain the emulsifying stability of drilling fluids at high temperatures. At the same time, demulsifiers need to have higher demulsification efficiency and lower environmental impact.

③ Enhance compatibility with geological formations and cement slurry. In the future, more attention should be paid to the selection and optimization of additives. By conducting in-depth research on the reaction mechanism between drilling fluid and formation minerals and fluids, appropriate additives are selected to reduce the risk of reaction with the formation. At the same time, optimize the compatibility between drilling fluid and cement slurry to ensure the quality of cementing operations and wellbore stability.

④ Improve environmental protection and safety. In terms of environmental protection, future high-temperature resistant oil-based/synthetic based drilling fluid technologies need to focus on developing low toxicity and easily degradable environmentally friendly additives to reduce the risk of environmental pollution. At the same time, optimize the drilling fluid formula and process parameters to reduce the generation and discharge of waste. In terms of safety, strengthen the research on the safety performance of drilling fluids in high-temperature environments to prevent the generation of toxic or flammable gases.

3.3 Development Prospects of Reservoir Protection Drilling Fluid Technology

① Improve technological adaptability. Future reservoir protection drilling fluid technology should pay more attention to improving adaptability to meet the challenges of different types of reservoirs. By conducting in-depth research on the physical and chemical properties of reservoirs, such as porosity, permeability, rock type, and sensitivity, more targeted drilling fluid formulations and treatment methods can be developed. In addition, advanced simulation and emulation techniques are utilized to predict and optimize the performance of drilling fluids under various reservoir conditions, thereby improving the adaptability and effectiveness of the technology.

② Improve material performance and stability. Future reservoir protection drilling fluid technology should focus on developing new high-performance additives and materials. These new materials will have higher resistance to high temperature, high pressure, and corrosion, and can maintain stable performance in harsh environments. Meanwhile, by optimizing the molecular structure and surface properties of the material, the risk of adverse reactions with fluids or rocks in the reservoir can be reduced.

③ Strengthen real-time monitoring and adjustment capabilities. The future reservoir protection drilling fluid technology should further improve real-time monitoring technology, enhance sensor accuracy and data transmission speed. By introducing advanced sensor networks and artificial intelligence algorithms, real-time monitoring, analysis, and prediction of drilling fluid performance and reservoir damage can be achieved.

3.4 Development Prospects of Drilling Fluid Leak Prevention and Plugging Technology

① Integrate and enhance intelligent technology. By introducing advanced technologies such as artificial intelligence, big data analysis, and machine learning, real-time acquisition, processing, and analysis of formation data can be achieved, thereby more accurately identifying formation characteristics, predicting well leakage risks, and providing scientific basis for selecting appropriate leak prevention and plugging technologies. In addition, intelligent technology can also be applied to real-time monitoring and diagnosis during the drilling process, helping operators quickly determine the location, type, and scale of leaks, and improving the timeliness and accuracy of leak plugging operations

② Develop and apply high-performance leak sealing materials. The future drilling fluid leak prevention and plugging technology will focus on developing high-performance plugging materials. These new materials will have higher resistance to high temperature, high pressure, corrosion, and shear to cope with extreme conditions in geological formations. Meanwhile, by optimizing the physical properties such as particle size distribution, density, and viscosity of the material, as well as introducing special chemical functional groups, the matching degree between the plugging material and the formation characteristics can be improved, achieving more effective plugging.

③ Explore diversified leak prevention techniques and methods. The future drilling fluid leak prevention and plugging technology should pay more attention to the exploration of diversified leak prevention techniques and methods, and study new leak prevention principles and technologies, such as nano material leak prevention, microbial leak prevention, chemical reaction leak prevention, etc. These new technologies and methods will provide more options and possibilities for solving well leakage problems in complex formations and extreme conditions.

④ Enhance awareness of environmental protection and safety production. Future drilling fluid leak prevention and plugging technologies should pay more attention to environmental protection and safe production. When developing and applying new technologies, full consideration should be given to their impact on the environment, and environmentally friendly materials and processes should be prioritized. At the same time, strengthen the construction of risk assessment and early warning mechanisms for well leakage, timely discover and deal with potential safety hazards, and ensure the safe operation of drilling operations.

4.Conclusions

Deep and ultra deep drilling fluid technology is one of the key technologies in the field of oil and gas exploration and development, facing many challenges and scientific problems. These challenges include stability issues in extreme environments such as high temperature, high pressure, and high stress, adaptability issues in complex formation environments, and uncertainty brought about by the interaction between drilling fluid and formation.In terms of high-temperature resistant water-based drilling fluid technology, although various high-temperature resistant water-based drilling fluid technologies have been developed, they still face problems such as insufficient high-temperature stability, difficulty in controlling rheological properties and filtration loss, and insufficient compatibility with the formation in practical applications.The future high-temperature resistant water-based drilling fluid technology will strive to enhance high-temperature stability, improve rheological properties, strengthen filtration control, and improve compatibility with the formation.In the field of high-temperature resistant oil-based/synthetic drilling fluid technology, there are still issues related to high-temperature stability and rheology, emulsion stability and demulsification treatment, compatibility with formations and cement slurries, as well as environmental protection and safety. In the future, further research and development are needed in high-temperature stabilizers and flow regulators, emulsifiers and demulsifiers, as well as environmentally friendly additives with low toxicity and easy degradation, and related supporting technologies.

In terms of reservoir protection drilling fluid technology, it is necessary to focus on technological adaptability, material performance and stability, real-time monitoring and adjustment, and strive for the research and development of new high-performance additives and materials to improve the adaptability and effectiveness of technology. By introducing advanced sensor networks and artificial intelligence algorithms, real-time monitoring technology can be further improved and strengthened.In terms of drilling fluid leak prevention and plugging technology, although there are currently various leak prevention and plugging technologies, there are still many problems in terms of technology selection and formation compatibility, plugging material performance, plugging operation complexity and timeliness, as well as environmental and safety impacts.The future drilling fluid leak prevention and plugging technology will pay more attention to the integration and application of intelligent technology, the research and application of high-performance plugging materials, the exploration of diversified plugging technologies and methods, and the improvement of environmental protection and safety production awareness.

Overall, although some progress has been made in deep and ultra deep drilling fluid technology both domestically and internationally, there are still many key issues that need to be addressed. In the future, deep and ultra deep drilling fluid technology should develop towards high-performance, intelligent, and environmentally friendly directions, utilizing advanced technologies such as artificial intelligence and big data to achieve intelligent control of the drilling process, improve drilling efficiency, and increase oil and gas production. Through these efforts, we believe that in the future, greater breakthroughs and progress will be made in deep and ultra deep drilling fluid technology.