Degasser

Degassing: A Vital Step in Drilling & Well Completion

In the demanding world of oil and gas exploration, efficiency and safety are paramount. One vital tool in this complex process is the degasser, a piece of equipment designed to remove unwanted gas from drilling fluids. These fluids, essential for drilling operations, can accumulate gas during various stages, impacting performance and potentially leading to safety hazards.

Why Degassing Matters

• Improved Drilling Efficiency: Gas bubbles in drilling fluids reduce their density, leading to a loss of hydrostatic pressure. This can cause wellbore instability, blowouts, and even uncontrollable gas flow. Degassing ensures the fluid maintains its weight and pressure, leading to a more controlled and efficient drilling process.
• Enhanced Hole Cleaning: Gas bubbles interfere with the ability of the drilling fluid to transport cuttings to the surface. Degassing eliminates these bubbles, allowing the fluid to effectively clean the wellbore and prevent complications like stuck drill pipe.
• Safety and Environmental Protection: Degassing reduces the risk of gas release into the atmosphere, promoting safer working conditions and minimizing environmental impacts. It also prevents the formation of gas pockets in the wellbore, which could potentially lead to explosions or uncontrolled pressure release.

Common Degassing Methods

There are several methods employed in degassing drilling fluids, each tailored to specific applications:

• Vacuum Degassing: This method uses a vacuum to reduce the pressure in the drilling fluid, forcing the dissolved gases to escape. It's widely used for removing dissolved gas like methane, nitrogen, and carbon dioxide.
• Flash Degassing: This method involves rapidly reducing the pressure of the drilling fluid, causing the gas to come out of solution. It's particularly effective for removing gas that is already in the form of bubbles.
• Centrifugal Degassing: This method utilizes centrifugal force to separate gas bubbles from the drilling fluid. This is particularly beneficial for removing larger gas bubbles that are difficult to remove through other methods.
• Chemical Degassing: In some cases, chemicals are added to the drilling fluid to promote the release of dissolved gases. This method is often used in conjunction with other degassing methods.

Degasser Equipment

Degassing equipment can range from simple, portable units to complex, automated systems. Some common types include:

• Vacuum Degassers: These units typically consist of a vacuum chamber, a separator vessel, and a pump. The drilling fluid is passed through the chamber where the vacuum draws out the dissolved gas.
• Flash Degassers: These units are designed to quickly reduce the pressure of the drilling fluid, causing the gas to release. They typically use a series of nozzles or orifices to achieve this.
• Centrifugal Degassers: These units employ a rotating drum or impeller to separate gas bubbles from the drilling fluid. They are often used in combination with other degassing methods.

Conclusion

Degassing is a crucial step in drilling and well completion operations. By removing unwanted gas from drilling fluids, degassing equipment improves efficiency, safety, and environmental protection. Choosing the right degassing method and equipment depends on the specific characteristics of the drilling fluid and the operational requirements. Understanding the principles and technologies involved in degassing enables drilling professionals to optimize well operations and achieve successful outcomes.