Reservoir Engineering

Sector

Sectoring in Oil & Gas: Demystifying the Term Beyond Simple Division

In the oil and gas industry, the term "sector" carries a distinct meaning beyond its general use as a subdivision or category. While commonly used in other fields to describe sociological, economic, or political divisions, or even data storage sections on a computer disk, within oil and gas, "sector" refers to a specific, technical concept.

Sectoring in Oil & Gas

In this context, "sectoring" refers to the division of a wellbore into distinct sections for various purposes. These sectors can be vertical or horizontal, and their creation is achieved by strategically placing perforations in the well casing.

Why Sector a Wellbore?

Sectoring serves several crucial objectives in oil and gas production:

  • Optimized Production: Each sector can be independently controlled, allowing producers to isolate specific zones within the reservoir. This enables them to optimize production by selectively pumping from the most productive areas and potentially diverting flow from less productive zones.
  • Reservoir Management: By isolating zones, operators can monitor and manage individual reservoir compartments. This facilitates understanding fluid flow patterns, identifying potential issues like water or gas coning, and implementing strategies for efficient production.
  • Enhanced Recovery Techniques: Sectoring can be used to support enhanced oil recovery (EOR) techniques, such as waterflooding or gas injection. By isolating specific zones, operators can direct these techniques more effectively and maximize their impact.
  • Well Integrity: Sectoring can help mitigate risks associated with well integrity. If a problem arises in one sector, the others remain unaffected, minimizing downtime and production losses.

Examples of Sectoring Techniques

There are various methods employed for sectoring in oil and gas:

  • Casing Perforations: This involves strategically drilling holes in the well casing to connect different sections of the wellbore with the reservoir.
  • Gravel Packing: Gravel packs are used to prevent formation sand from entering the wellbore, ensuring long-term productivity. They can be placed in specific sectors to optimize production from different zones.
  • Slanting: In horizontal wells, sectoring is achieved by drilling multiple "laterals" at different angles within the reservoir, enabling selective production from different zones.

The Importance of Understanding Sectoring

Understanding sectoring in the oil and gas industry is critical for anyone involved in production, reservoir management, and well integrity. This technical concept plays a vital role in optimizing production, managing reservoirs effectively, and ensuring safe and efficient operations.

As the oil and gas industry evolves, sectoring techniques will continue to play a crucial role in navigating complex reservoir challenges and maximizing resource extraction.


Test Your Knowledge

Quiz: Sectoring in Oil & Gas

Instructions: Choose the best answer for each question.

1. What is the primary purpose of sectoring in oil and gas? a) To divide the wellbore into different sections for storage. b) To isolate and control production from specific zones within a reservoir. c) To enhance the aesthetic appeal of the wellhead. d) To prevent the formation of gas hydrates.

Answer

b) To isolate and control production from specific zones within a reservoir.

2. How are sectors typically created in a wellbore? a) By drilling horizontal tunnels within the reservoir. b) By using specialized pumps to separate fluids. c) By strategically placing perforations in the well casing. d) By injecting chemicals to alter the reservoir properties.

Answer

c) By strategically placing perforations in the well casing.

3. Which of these is NOT a benefit of sectoring? a) Optimized production. b) Improved reservoir management. c) Reduced wellbore pressure. d) Enhanced oil recovery techniques.

Answer

c) Reduced wellbore pressure.

4. What is gravel packing used for in sectoring? a) To increase the flow rate of oil. b) To prevent formation sand from entering the wellbore. c) To create a barrier between different sectors. d) To reduce the risk of wellbore collapse.

Answer

b) To prevent formation sand from entering the wellbore.

5. Why is understanding sectoring important in the oil and gas industry? a) It helps identify potential problems within the reservoir. b) It enables operators to optimize production and manage reservoirs effectively. c) It minimizes environmental impact of oil and gas extraction. d) Both A and B.

Answer

d) Both A and B.

Exercise: Sectoring Scenario

Scenario: An oil well has been producing for several years, but production has declined recently. The reservoir is known to have multiple zones with varying productivity. The operator suspects water coning is occurring in one of the lower zones, impacting overall production.

Task: Explain how sectoring could be used to address this situation. What are the potential benefits of using sectoring in this case? What specific techniques could be employed?

Exercice Correction

Sectoring could be used to isolate the lower zone experiencing water coning, allowing the operator to address the issue without impacting production from other zones. This isolation would prevent water from flowing into the wellbore and reduce the overall water cut. **Potential benefits:** * **Increased oil production:** By isolating the water-producing zone, production from the remaining zones can be optimized, potentially increasing overall output. * **Improved reservoir management:** The operator can monitor and control the water coning issue in the isolated zone, potentially implementing strategies like water injection to manage the water influx. * **Extended well life:** By reducing water production, the well's lifespan could be extended, minimizing downtime and operational costs. **Techniques:** * **Perforation of the well casing:** Specific perforations could be created to isolate the lower zone, allowing for individual control. * **Gravel packing:** A gravel pack could be installed in the lower zone to prevent water and sand from entering the wellbore. * **Slanting:** In case of a horizontal well, drilling a new lateral in a higher productive zone could provide additional production while isolating the water-coning area. By implementing these techniques, the operator can effectively address the water coning issue, enhance reservoir management, and ultimately optimize production from the well.


Books

  • Reservoir Engineering Handbook by Tarek Ahmed (This comprehensive handbook provides a deep dive into various aspects of reservoir engineering, including sectoring and production optimization.)
  • Well Completion Design: Fundamentals and Applications by Paul A. M. Bastiaanssen (This book covers various well completion techniques, including sectoring, perforation design, and gravel packing.)
  • Petroleum Engineering: Principles and Practice by Maurice J. Economides and John E. Nolte (This classic text covers fundamental principles of petroleum engineering, including the role of sectoring in wellbore management.)

Articles

  • "The Fundamentals of Gravel Packing" by SPE (This article from the Society of Petroleum Engineers delves into gravel packing techniques and their applications in sectoring and production optimization.)
  • "Horizontal Well Completion Optimization" by SPE (This article examines optimizing horizontal well completions, including the use of sectoring to enhance production from different zones.)
  • "Wellbore Integrity: The Role of Sectoring" by Energy Technology magazine (This article explores the importance of sectoring for well integrity, mitigating risks, and ensuring efficient production.)

Online Resources

  • Society of Petroleum Engineers (SPE): SPE's website offers a vast library of articles, technical papers, and resources related to all aspects of petroleum engineering, including sectoring.
  • Schlumberger: Schlumberger, a major oilfield service provider, has extensive online resources, including technical documents and case studies on well completion and sectoring techniques.
  • Halliburton: Similar to Schlumberger, Halliburton offers online resources on well completion, sectoring, and related technologies.
  • Oil & Gas Journal: This industry publication often features articles on sectoring, well completion, and reservoir management.
  • Google Scholar: Use Google Scholar to search for academic research articles on "sectoring," "well completion," "reservoir management," and related keywords.

Search Tips

  • Use specific keywords: Use terms like "sectoring oil and gas," "well completion sectoring," "gravel packing sectoring," "horizontal well sectoring," "reservoir management sectoring."
  • Combine keywords: Use Boolean operators ("AND," "OR," "NOT") to refine your search. For example, "sectoring AND gravel packing."
  • Search for specific publications: Specify a publication name like "SPE," "Oil & Gas Journal," or "Energy Technology."
  • Include filetype: Search for PDF files using "filetype:pdf" to find articles and technical documents.

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