Barrel

Understanding Barrels: A Guide to Oilfield Measurement

The term "barrel" is ubiquitous in the oil and gas industry, but its meaning can be surprisingly complex. While it's commonly associated with the familiar 55-gallon drum, in oilfield operations, "barrel" refers to a specific volume used for measuring crude oil and other liquid hydrocarbons.

Here's a breakdown of the different types of barrels used in the oil industry:

1. Oilfield Measurement Barrel:

Definition: The standard unit for measuring oil and gas production. It is defined as 42 US gallons, which equates to 5.615 cubic feet (ft³) or 158.987 liters.
Conversion: 6.28 barrels are equal to 1 cubic meter (m³).

2. Reservoir Barrels:

Definition: Refer to the volume of oil in the reservoir, before it is extracted. This includes the volume of dissolved gas.
Key Feature: Reservoir barrels undergo shrinkage when the dissolved gas escapes during extraction. This shrinkage is measured by the reservoir volume factor (RVF).

3. Stock Tank Barrels:

Definition: Refer to the volume of oil measured after the gas has escaped and the oil has settled in a stock tank.
Importance: Stock tank barrels are the basis for oil production reporting and royalty calculations.

Understanding the Differences:

Reservoir barrels vs. Stock Tank barrels: Reservoir barrels are larger than stock tank barrels due to the dissolved gas. The difference is expressed by the RVF, which is the ratio of reservoir barrels to stock tank barrels.
RVF: A high RVF indicates a significant amount of gas dissolved in the oil, leading to greater shrinkage. This means that the actual volume of oil produced will be less than the volume measured in the reservoir.

The Importance of Accurate Measurement:

Understanding the different types of barrels is essential for accurately assessing oil reserves, managing production, and calculating royalty payments. Incorrect barrel conversions can lead to substantial financial implications, particularly for large-scale oil and gas operations.

Conclusion:

While the term "barrel" may seem simple at first glance, the nuances of oilfield measurement require careful consideration. Understanding the differences between reservoir, stock tank, and oilfield measurement barrels is crucial for anyone involved in the oil and gas industry, ensuring accurate reporting and efficient management of resources.

Test Your Knowledge

Quiz: Understanding Barrels in the Oilfield

Instructions: Choose the best answer for each question.

1. What is the standard definition of an "oilfield measurement barrel" in terms of US gallons?

a) 42 gallons b) 55 gallons c) 100 gallons d) 159 gallons

Answer

a) 42 gallons

2. Which type of barrel refers to the volume of oil measured after the dissolved gas has escaped?

a) Oilfield Measurement Barrel b) Reservoir Barrel c) Stock Tank Barrel d) All of the above

Answer

c) Stock Tank Barrel

3. What does the term "RVF" stand for?

a) Reservoir Volume Factor b) Royalties Value Factor c) Refining Value Factor d) Residual Volume Factor

Answer

a) Reservoir Volume Factor

4. How many oilfield measurement barrels are equivalent to 1 cubic meter?

a) 1.59 barrels b) 6.28 barrels c) 10.45 barrels d) 15.89 barrels

Answer

b) 6.28 barrels

5. Why is understanding the difference between reservoir and stock tank barrels crucial in the oil and gas industry?

a) For accurate oil production reporting and royalty calculations b) For determining the market value of crude oil c) For optimizing drilling operations d) All of the above

Answer

d) All of the above

Exercise: Calculating Oil Production

Scenario:

An oil well produces 1,000 reservoir barrels of oil. The reservoir volume factor (RVF) for this well is 1.2.

Task:

Calculate the number of stock tank barrels of oil produced.
Explain why the number of stock tank barrels is different from the number of reservoir barrels.

Exercice Correction

**1. Calculation:**

Stock Tank Barrels = Reservoir Barrels / RVF

Stock Tank Barrels = 1,000 barrels / 1.2

Stock Tank Barrels = 833.33 barrels (approximately)

**2. Explanation:**

The number of stock tank barrels is less than the number of reservoir barrels because the dissolved gas in the oil escapes during extraction and processing. The RVF accounts for this shrinkage, indicating that for every 1.2 reservoir barrels, only 1 stock tank barrel is produced.

Books

Petroleum Engineering Handbook: This comprehensive handbook covers various aspects of oil and gas engineering, including oilfield measurements and the different types of barrels. You can find chapters dedicated to reservoir engineering, production engineering, and well testing, which delve into the concepts of reservoir barrels, stock tank barrels, and oilfield measurement barrels.
Oil and Gas Production Operations: This book provides a practical guide to the operations involved in oil and gas production, including well testing, fluid handling, and production measurement. It will help you understand the practical applications of different barrel types and the conversion processes.
Fundamentals of Petroleum Engineering: This textbook offers a comprehensive introduction to petroleum engineering, including basic concepts of reservoir fluid properties, production techniques, and measurement practices.

Articles

"Understanding Oil Measurement Units: A Guide to Barrels, Cubic Feet, and Gallons" by [Author's Name] - Search for articles with this title or similar ones on websites of industry associations like the American Petroleum Institute (API), SPE (Society of Petroleum Engineers), or online publications like Oil & Gas Journal.
"Reservoir Volume Factor (RVF): A Key Parameter in Oil and Gas Production" by [Author's Name] - Look for articles that discuss the concept of RVF and its importance in oil production.
"Oil and Gas Measurement Standards: A Global Perspective" by [Author's Name] - Find articles that explain the different standards for oil and gas measurement used in various parts of the world.

Online Resources

American Petroleum Institute (API): API is a leading organization in the oil and gas industry, offering standards and guidance for measurement practices. Visit their website for technical publications, industry standards, and resources on oilfield measurement.
Society of Petroleum Engineers (SPE): SPE is a professional society for petroleum engineers. Their website provides access to technical papers, conference proceedings, and educational materials related to oil and gas production and measurement.
Oil & Gas Journal: This industry publication offers articles, news, and technical insights on oil and gas production and measurement.
Wikipedia: Wikipedia is a good starting point for basic definitions and an overview of oilfield measurements. Search for terms like "oilfield measurement barrel," "reservoir volume factor," "stock tank oil," and "oil production."

Search Tips

Use specific keywords: Use terms like "oilfield measurement," "barrel conversion," "reservoir barrels," "stock tank barrels," "RVF," and "API oilfield measurement standard" to refine your search.
Include relevant industry terms: Combine your search terms with industry-specific jargon like "oil production," "well testing," "fluid handling," and "royalty calculations."
Use quotation marks: Use quotation marks to search for specific phrases, like "oilfield measurement barrel" or "reservoir volume factor," to ensure you find relevant results.
Combine keywords: Combine different keywords to explore related topics, for example, "oil production and RVF," or "stock tank barrels and royalty calculations."