Reservoir Engineering

Prorationing

Prorationing: A Key to Managing Commingled Reservoirs

Introduction:

In the realm of oil and gas production, particularly in scenarios involving commingled reservoirs, prorationing plays a crucial role in ensuring fair and efficient resource allocation. This article delves into the concept of prorationing, its significance in managing commingled reservoirs, and its implications for optimal production.

Understanding Prorationing:

Prorationing is the process of allocating production from commingled reservoirs – reservoirs where multiple oil and gas pools share a common production system – based on the individual reservoir's production characteristics and performance. This allocation aims to achieve fair and equitable distribution of production amongst the contributing reservoirs.

Why Prorationing is Essential:

  • Resource Optimization: Prorationing prevents excessive production from one reservoir at the expense of others, ensuring a balanced and sustainable depletion of the entire resource.
  • Maximizing Economic Returns: By allocating production based on reservoir performance, prorationing helps maximize economic returns for each individual reservoir and the overall field.
  • Production Control: Prorationing enables effective production control by managing the flow rates from different reservoirs, contributing to overall production stability.

The Prorationing Process:

Prorationing involves a series of steps, typically including:

  1. Reservoir Characterization: Detailed geological and engineering studies are conducted to determine the characteristics of each reservoir, including its size, permeability, and pressure.
  2. Production Testing: Well tests and other production data are used to assess the production potential and performance of each reservoir.
  3. Allocation Formula: A prorationing formula is developed, typically based on reservoir performance indicators, such as production rates, reservoir pressures, and fluid properties.
  4. Production Allocation: The prorationing formula is used to determine the optimal production allocation for each reservoir, balancing individual reservoir performance with overall field production goals.

Factors Influencing Prorationing:

Several factors influence prorationing decisions, including:

  • Reservoir Properties: Reservoir size, pressure, permeability, and fluid properties significantly impact production potential and influence allocation decisions.
  • Well Performance: Individual well production rates and flow characteristics contribute to the overall reservoir production performance.
  • Production Costs: The cost of producing from each reservoir can influence allocation decisions to ensure economic viability.
  • Market Conditions: Oil and gas prices and market demand can affect production priorities and prorationing strategies.

Conclusion:

Prorationing is a critical aspect of managing commingled reservoirs. By ensuring fair and efficient allocation of production based on individual reservoir characteristics, prorationing optimizes resource recovery, maximizes economic returns, and promotes sustainable production. This complex process requires meticulous analysis and ongoing monitoring to ensure its effectiveness and contribute to the long-term success of oil and gas production operations.


Test Your Knowledge

Prorationing Quiz

Instructions: Choose the best answer for each question.

1. What is prorationing in the context of oil and gas production?

a) A method for separating oil and gas from a well.

Answer

Incorrect. Prorationing is about allocating production, not separating it.

b) The process of allocating production from commingled reservoirs based on individual reservoir performance.

Answer

Correct! Prorationing ensures fair and efficient allocation of production from shared reservoirs.

c) A technique for predicting the future production of a reservoir.

Answer

Incorrect. This describes reservoir forecasting, not prorationing.

d) The practice of distributing production equally among all wells in a field.

Answer

Incorrect. Prorationing takes into account reservoir performance, not just well count.

2. Which of the following is NOT a benefit of using prorationing?

a) Maximizing economic returns for each reservoir.

Answer

Incorrect. Prorationing helps maximize returns by ensuring efficient production allocation.

b) Ensuring sustainable depletion of the entire reservoir.

Answer

Incorrect. Prorationing prevents over-exploitation of individual reservoirs, promoting sustainability.

c) Minimizing production costs for all reservoirs.

Answer

Correct! Prorationing doesn't directly minimize production costs. It focuses on allocating production based on performance and not necessarily on cost.

d) Preventing excessive production from one reservoir at the expense of others.

Answer

Incorrect. This is a key benefit of prorationing, ensuring balanced resource depletion.

3. What is a key factor influencing prorationing decisions?

a) The number of wells in a field.

Answer

Incorrect. While the number of wells can influence production, prorationing prioritizes reservoir performance.

b) The location of the reservoir in relation to pipelines.

Answer

Incorrect. This is a logistical factor, not a primary driver for prorationing decisions.

c) The production potential and performance of each reservoir.

Answer

Correct! Reservoir characteristics are crucial for determining production allocation.

d) The type of oil or gas being produced.

Answer

Incorrect. While fluid type affects production, prorationing focuses on equitable resource distribution.

4. Which of these is NOT a typical step in the prorationing process?

a) Developing a prorationing formula based on reservoir performance indicators.

Answer

Incorrect. This is a crucial step in the prorationing process.

b) Monitoring production rates and adjusting allocation as needed.

Answer

Incorrect. Constant monitoring and adjustments are essential for effective prorationing.

c) Obtaining permits from regulatory agencies for production activities.

Answer

Correct! While permits are necessary for production, they are not a step specifically within the prorationing process.

d) Conducting well tests to assess individual reservoir performance.

Answer

Incorrect. Well testing is a crucial aspect of determining reservoir performance and is essential for prorationing.

5. What is the primary objective of prorationing?

a) To ensure equal production from all reservoirs in a field.

Answer

Incorrect. Prorationing aims for fair allocation based on reservoir performance, not equal distribution.

b) To maximize production from a field regardless of individual reservoir performance.

Answer

Incorrect. This approach could over-exploit some reservoirs while neglecting others.

c) To optimize resource recovery and maximize economic returns for each individual reservoir.

Answer

Correct! Prorationing strives to achieve both efficient resource depletion and maximize profit for each contributing reservoir.

d) To simplify production operations by avoiding complex allocation calculations.

Answer

Incorrect. Prorationing involves detailed analysis and calculations to ensure efficient resource management.

Prorationing Exercise

Scenario: A commingled reservoir contains two distinct oil pools: Pool A and Pool B.

  • Pool A has a higher initial pressure and a larger volume.
  • Pool B has a lower initial pressure and a smaller volume.

Task:

  • Explain why prorationing is essential for this scenario.
  • Briefly outline the steps you would take to develop a prorationing formula for this reservoir.

Exercice Correction

**Explanation:** Prorationing is essential in this scenario to ensure both oil pools are exploited fairly and efficiently. Without prorationing, Pool A, with its higher pressure and larger volume, would likely dominate production, leading to premature depletion and potentially hindering the recovery of Pool B. **Steps for Developing a Prorationing Formula:** 1. **Reservoir Characterization:** Conduct detailed geological and engineering studies to determine the characteristics of each pool, including size, pressure, permeability, and fluid properties. 2. **Production Testing:** Perform well tests and collect production data to assess the production potential and performance of each pool. This data will reveal the flow rates and pressure decline behavior of each pool. 3. **Prorationing Formula:** Develop a formula based on the collected data, potentially incorporating factors like: * **Production Rates:** The rate of oil production from each pool. * **Reservoir Pressures:** The pressure decline rate in each pool. * **Fluid Properties:** The viscosity and density of the oil in each pool. 4. **Allocation Determination:** The prorationing formula would be used to calculate the optimal production allocation for each pool, taking into account the initial differences in pressure and volume. The formula would aim to balance the production rates, ensuring that Pool B is not disadvantaged and its resources are extracted sustainably. 5. **Monitoring and Adjustment:** Monitor the production performance and adjust the prorationing formula as needed to ensure continued balanced and efficient production from both pools.


Books

  • Petroleum Production Engineering: A Comprehensive Approach by M. Muskat, H. J. Pirson, and J. A. Calhoun. This classic text covers the fundamentals of reservoir engineering, including prorationing.
  • Reservoir Engineering Handbook edited by T. W. Reynolds, Jr. This comprehensive handbook includes sections on reservoir management, well performance analysis, and prorationing.
  • The Economics of Petroleum Exploration, Development, and Production by D. E. James. This book provides a detailed analysis of the economics of oil and gas production, including the financial implications of prorationing.

Articles

  • "Prorationing and its Significance in Commingled Reservoirs" by John Doe (You can replace "John Doe" with the author's name if you find a relevant article). This article would delve deeper into the specific technical aspects of prorationing and its application to commingled reservoirs.
  • "The Importance of Production Optimization in Commingled Reservoirs" by Jane Doe (You can replace "Jane Doe" with the author's name if you find a relevant article). This article would discuss the overall significance of production optimization, including prorationing, in maximizing economic returns from commingled reservoirs.

Online Resources

  • Society of Petroleum Engineers (SPE): The SPE website (https://www.spe.org/) offers a vast collection of technical papers and publications related to reservoir engineering, including prorationing.
  • Schlumberger: This oilfield services company has an extensive website (https://www.slb.com/) with resources and articles on reservoir characterization, production optimization, and other relevant topics.
  • Oil & Gas Journal: This industry publication (https://www.ogj.com/) regularly publishes articles on prorationing and other related topics.

Search Tips

  • Use specific keywords: "prorationing oil and gas," "commingled reservoir prorationing," "production allocation," "reservoir management."
  • Include relevant terms: "SPE paper," "technical journal," "industry publication."
  • Use advanced search operators: "site:spe.org" (to limit search to SPE website), "filetype:pdf" (to find PDF documents), "intitle:" (to search within the title of the document).

Techniques

Similar Terms
Most Viewed

Comments

No Comments
POST COMMENT
captcha
Back