Address
304 North Cardinal St.
Dorchester Center, MA 02124
Work Hours
Monday to Friday: 7AM - 7PM
Weekend: 10AM - 5PM
Polyethylene glycol (PEG) drilling fluid is an environmentally friendly water-based drilling fluid with excellent performance. Due to its excellent lubrication performance, inhibition ability, borehole stability and environmental protection characteristics, it is suitable for various complex formation conditions and special operating environments. The following details its applicability and advantages in various application scenarios.
I. Shale formation drilling
1. Shale swelling inhibition
Shale formations are extremely water-sensitive, and are prone to collapse due to water absorption and expansion. Polyethylene glycol drilling fluids are effective in dealing with shale problems by:
- Polyethylene glycol molecules are adsorbed on the surface of the shale to form a protective film that prevents water molecules from seeping into the shale interior, thereby inhibiting shale expansion.
- When an inhibitor (e.g., KCl) is added, it works synergistically with PEG to improve inhibition.
2. Applicable well type
Polyethylene glycol drilling fluids are particularly suitable for shale gas exploitation, medium and long horizontal sections and complex well types.
3. Practical Application
- PEG drilling fluids have significantly reduced drilling complexity and increased operational efficiency in the development of shale gas fields in North America.
- The system is also widely used in shale gas development in the Sichuan Basin in China, which effectively controls the problem of borehole instability.
Second, high temperature and high pressure (HTHP) drilling
1. Temperature Stability
High-temperature and high-pressure wells have extreme temperature and pressure conditions, and conventional drilling fluids are prone to decomposition or failure. Polyethylene glycol drilling fluid has the following advantages:
- At high temperatures (up to 180°C), PEG exhibits excellent thermal stability and does not decompose easily.
- It can effectively maintain the rheology of drilling fluids and avoid thickening or gelling.
2. Stress Resistance
The polymer chains in PEG drilling fluids can work synergistically with other components to enhance the mechanical strength of the system under high pressure conditions, avoiding mud cake collapse or borehole instability.
3. Practical Application
- In deep and ultra-deep well operations, such as the Middle East and the Tarim Basin in China, PEG drilling fluids have successfully navigated formation complexity in high-temperature, high-pressure environments.
3. Deepwater drilling
1. Low temperature adaptability
The temperature in the deepwater environment is low, and the performance of traditional drilling fluids may be reduced due to low-temperature crystallization, while polyethylene glycol drilling fluids have the following advantages:
- PEG has good low-temperature fluidity and can maintain liquid uniformity, which is suitable for low-temperature operation.
- Combines with antifreeze to further extend its range of low-temperature operation.
2. Environmental Requirements
Deepwater operations have extremely high requirements for the environmental performance of drilling fluids. PEG is a non-toxic, biodegradable material that does not pollute the marine environment.
3. Well Control Safety
In deepwater operations, the risk of well control is high. PEG drilling fluids help reduce the probability of well control accidents by optimizing rheological properties and mud cake plugging effect.
4. Practical Application
- PEG drilling fluids have proven to offer significant safety and economic advantages in the development of deepwater oil and gas fields in the Gulf of Mexico and pre-salt oil fields in Brazil.
Fourth, horizontal well and extended-reach well drilling
1. Friction & Torque Control
Due to the large inclination angle of horizontal wells and extended-reach wells, the contact area between drilling tools and the borehole wall is wide, and the friction and torque problems are more serious. PEG drilling fluids exhibit excellent performance in the following areas:
- High lubricity: PEG molecules form a lubricating film on the surface of the drilling tool, significantly reducing the coefficient of friction.
- Reduced jamming: After optimizing rheological properties, PEG drilling fluid can effectively reduce the difficulty of wellbore cleaning and reduce the risk of jamming.
2. Borehole Stability
The long section of the horizontal well has a long exposure time, and the wall collapse is prone to occur. PEG drilling fluid enhances borehole stability through shale inhibition and plugging.
3. Practical Application
- In the Bakken Shale in the U.S. and in the Dagang Oilfield in China, PEG drilling fluids are widely used in long-horizontal drilling, significantly reducing drilling friction.
5. Drilling in complex formations
1. High fracture strata
The high fracture formation is prone to leakage, and it is difficult for conventional drilling fluids to form dense mud cakes. PEG drilling fluids are solved by:
- PEG molecules work synergistically with occluder to quickly close cracks.
- Low Filtration Loss: PEG reduces the volume of filtrate entering the formation, which can avoid inducing borehole instability.
2. Salt and gypsum formations
Salt rock and gypsum rock have strong solubility, and are easy to expand and fall off after contact with water. PEG drilling fluids have excellent salt resistance and low filtration performance, which can effectively prevent formation dissolution and instability.
3. Practical Application
- In the development of salt rock formations in the Middle East, PEG drilling fluid reduced the salt dissolution rate and ensured drilling safety.
Sixth, environmentally sensitive area operations
1. Environmental Regulatory Requirements
Environmentally sensitive areas (such as urban underground and drinking water protection areas) require drilling fluids to be non-toxic and degradable. PEG drilling fluids meet the following conditions with their environmental advantages:
- Non-toxic, non-polluting, no negative impact on groundwater and soil.
- Readily biodegradable, reducing environmental legacy issues.
2. Practical Application
- PEG drilling fluids protect groundwater resources in shale gas development in metropolitan areas of North America.
7. Coalbed methane and unconventional oil and gas exploitation
1. Low filtration demand
Coalbed methane wells require drilling fluids with very low filtration loss to reduce coal seam damage. PEG drilling fluid protects the coal seam through mud cake plugging and low filtration.
2. Compatibility of foam drilling fluid
PEG can be used as an additive in foam drilling fluids to enhance the stability and lubricity of foam.
3. Practical Application
- PEG drilling fluid significantly increased gas production in coalbed methane development in China’s Ordos Basin.
8. Performance optimization of downhole tools
1. Drill life extended
The excellent lubricity of PEG reduces the friction between the drill bit and the wellbore, extending the service life of the drill bit.
2. Efficiency improvement of power drilling tools
After the rheological properties of PEG drilling fluid are optimized, the resistance of drilling fluid in the wellbore can be reduced, and the output efficiency of dynamic drilling tools can be improved.
3. Practical Application
- In extended-reach wells, PEG drilling fluids significantly improve the efficiency and durability of turbine drilling tools.
9. Future application expansion
1. Deep Reservoir Development
In the future, with the technological progress of deep reservoir development, PEG drilling fluid will play a greater role in ultra-deep wells and ultra-high temperature and high pressure wells.
2. New energy field
PEG drilling fluids are expected to be used in geothermal well development and carbon capture and storage (CCS) operations, further expanding their applications.
Summary
With its excellent lubricity, inhibition, environmental protection and ability to adapt to complex formations, polyethylene glycol drilling fluid has shown strong adaptability and economy in various scenarios such as shale gas, deepwater, high temperature and high pressure wells. With the continuous advancement of oil and gas extraction technology, polyethylene glycol drilling fluids will be further optimized to provide efficient and environmentally friendly solutions for modern energy development.