Drilling & Well Completion

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.


Test Your Knowledge

Degassing Quiz:

Instructions: Choose the best answer for each question.

1. What is the primary purpose of degassing drilling fluids?

a) To increase the density of the drilling fluid. b) To remove unwanted gas from the drilling fluid. c) To add chemicals to the drilling fluid. d) To prevent the formation of emulsions.

Answer

b) To remove unwanted gas from the drilling fluid.

2. Which of the following is NOT a benefit of degassing drilling fluids?

a) Improved drilling efficiency. b) Enhanced hole cleaning. c) Reduced risk of blowouts. d) Increased viscosity of the drilling fluid.

Answer

d) Increased viscosity of the drilling fluid.

3. Which degassing method utilizes centrifugal force to separate gas bubbles?

a) Vacuum Degassing b) Flash Degassing c) Centrifugal Degassing d) Chemical Degassing

Answer

c) Centrifugal Degassing

4. Which type of degasser is typically used for removing dissolved gases like methane and nitrogen?

a) Vacuum Degasser b) Flash Degasser c) Centrifugal Degasser d) Chemical Degasser

Answer

a) Vacuum Degasser

5. What is a key consideration when choosing the right degassing method?

a) The type of drilling fluid being used. b) The operational requirements. c) The type of gas being removed. d) All of the above.

Answer

d) All of the above.

Degassing Exercise:

Scenario: You are working on a drilling rig and are experiencing issues with gas bubbles in the drilling fluid. The drilling operation is becoming inefficient, and there is a risk of wellbore instability.

Task:

  1. Identify the potential causes of gas bubbles in the drilling fluid.
  2. Describe the different degassing methods that could be used to address the situation.
  3. Explain the advantages and disadvantages of each method in this specific scenario.
  4. Recommend the most suitable degassing method for this situation and justify your choice.

Exercice Correction

**1. Potential Causes of Gas Bubbles:** * **Gas influx from the formation:** Gas from the reservoir may be entering the wellbore, leading to gas bubbles in the drilling fluid. * **Gas dissolved in the drilling fluid:** Gas may have dissolved into the drilling fluid during mixing or transportation. * **Gas released from drilling fluid components:** Some drilling fluid additives can release gas under certain conditions. **2. Degassing Methods:** * **Vacuum Degassing:** This method is effective for removing dissolved gases but might not be suitable if the gas influx is significant. * **Flash Degassing:** This method can rapidly reduce the pressure and release gas bubbles, but it may not be effective for removing dissolved gases. * **Centrifugal Degassing:** This method is efficient for removing larger gas bubbles, but it may not be effective for removing dissolved gases or handling high gas influx. * **Chemical Degassing:** This method could be combined with other methods to promote the release of dissolved gases. **3. Advantages and Disadvantages:** * **Vacuum Degassing:** Advantages - effective for dissolved gases. Disadvantages - may not be effective for large gas influx. * **Flash Degassing:** Advantages - fast and efficient for large gas bubbles. Disadvantages - may not be effective for dissolved gases. * **Centrifugal Degassing:** Advantages - good for large gas bubbles. Disadvantages - may not be effective for dissolved gases or high gas influx. * **Chemical Degassing:** Advantages - can be combined with other methods to promote gas release. Disadvantages - may not be suitable for all drilling fluids. **4. Recommended Method:** * **Consider a combination of methods:** A combination of Vacuum Degassing and Flash Degassing might be most suitable for this situation. Vacuum Degassing can address the dissolved gas issue, and Flash Degassing can handle the influx of gas bubbles. * **Consult with drilling engineers:** For a specific solution, consulting with drilling engineers is essential to assess the situation and choose the most appropriate degassing method and equipment.


Books

  • Drilling Engineering: This classic textbook covers all aspects of drilling, including fluid mechanics, wellbore stability, and drilling fluids. It discusses the importance of degassing in detail.
  • Reservoir Engineering Handbook: This comprehensive handbook features a section on drilling and completion, including the use of drilling fluids and degassing methods.
  • Petroleum Engineering Handbook: Another extensive handbook that includes chapters on drilling and completion, with discussions on the role of degassing in drilling operations.

Articles

  • "Degassing of Drilling Fluids: A Review" by (Author Name): This article provides an overview of various degassing methods, their applications, and limitations.
  • "The Impact of Degassing on Drilling Efficiency and Safety" by (Author Name): This article explores the benefits of degassing and its impact on drilling performance and safety.
  • "Recent Advances in Degassing Technologies for Drilling Fluids" by (Author Name): This article discusses the latest advancements in degassing techniques, including new equipment and methodologies.
  • "Case Studies on Degassing in Difficult Drilling Environments" by (Author Name): This article presents real-world examples of how degassing has successfully tackled challenging drilling situations.

Online Resources

  • Society of Petroleum Engineers (SPE): This professional organization offers a vast library of technical papers and presentations on drilling and completion, including those related to degassing. Search the SPE website using keywords like "degassing," "drilling fluids," or "wellbore stability."
  • Oil and Gas Journal: This industry publication features articles on various aspects of the oil and gas industry, including drilling and completion. Check their archives for articles on degassing.
  • Schlumberger: This major oilfield services company offers a wealth of information on their website about drilling technologies, including degassing solutions and equipment.
  • Halliburton: Another leading oilfield services company with resources on drilling and completion, including degassing techniques and products.
  • Baker Hughes: This company also provides information on degassing technologies and services for the oil and gas industry.

Search Tips

  • Use specific keywords, such as "degassing drilling fluids," "vacuum degassing," "flash degassing," or "centrifugal degassing."
  • Combine keywords with relevant terms like "oil and gas," "drilling," or "well completion."
  • Use quotation marks around specific phrases to search for exact matches, e.g., "degassing methods in drilling."
  • Include specific industry names like "Schlumberger degassing equipment" or "Halliburton degassing solutions."
  • Utilize Google Scholar for academic articles and research papers.

Techniques

Similar Terms
Oil & Gas Processing
  • Degasser Degassing in Oil & Gas: Keepi…
Most Viewed

Comments


No Comments
POST COMMENT
captcha
Back