Table of Contents

Proved and Probable Reserves

The 30-Second Summary

What is Proved and Probable Reserves? A Plain English Definition

Imagine you're not an investor, but an apple farmer. Your entire business—your wealth—is tied to the apples you can harvest and sell. How would you count your apples? You wouldn't just wave a hand at your entire property and say, “I have a million apples.” You'd be more precise, because your livelihood depends on it. This is exactly what Proved and Probable Reserves do for companies that extract resources like oil, natural gas, gold, or copper. They are a system for taking inventory of what's still in the ground, but with crucial layers of certainty. Let's walk through your apple orchard:

In short, Proved and Probable Reserves are an attempt to answer the most fundamental question for a resource company: “What do we actually own, and how sure are we that we can turn it into cash?”

“Risk comes from not knowing what you're doing.” - Warren Buffett

This quote is the essence of why understanding reserves is critical. Focusing on Proved reserves is how you know what you're doing; getting lured by Possible reserves is often how you court risk.

Why It Matters to a Value Investor

For a value investor, the distinction between Proved and Probable isn't just academic—it's the entire game. Our philosophy is built on buying businesses for less than their conservative intrinsic_value. In the resource sector, that value is overwhelmingly derived from the company's reserves.

The Bedrock of Value, Not the Sands of Speculation

A company like Coca-Cola has brand value, distribution networks, and secret formulas. An oil and gas company has… oil and gas in the ground. That's it. The value of the entire enterprise is the present value of the future cash flows it can generate from pulling those resources out and selling them. This is where the reserve categories become your most powerful tool:

Ultimately, by focusing on what is proved, you are investing. By paying for what is merely probable or possible, you are speculating.

How to Apply It in Practice

You don't need to be a geologist to use reserve data to make smarter investment decisions. You just need to know where to look and what questions to ask.

The Method: From Report to Insight

  1. Step 1: Locate the Data. The most reliable information is found in a company's Annual Report (Form 10-K for U.S. companies). Look for a section on “Reserves” or “Supplementary Information on Oil and Gas Producing Activities.” Investor presentations are also useful but always cross-reference with the official filings.
  2. Step 2: Distinguish 1P, 2P, and 3P. The company will report its reserves in barrels of oil (bbl), or thousands of cubic feet of natural gas (Mcf). They will be broken down by category (Proved, Probable, Possible) and geography. Your primary focus should be on the Proved (1P) figures.
  3. Step 3: Analyze Key Performance Indicators (KPIs). Looking at the total reserve number isn't enough. You need context. Three key metrics will give you that context:
    • Reserve Replacement Ratio (RRR): This measures the amount of new reserves a company adds in a year relative to what it produces. An RRR of 100% means it replaced every barrel it pumped. A value investor looks for companies that consistently maintain an RRR above 100% through drilling or smart acquisitions, not just from commodity price increases. This demonstrates sustainability.

`RRR = (Reserves Added in Year / Reserves Produced in Year) * 100%`

`RLI = (Total Proved Reserves / Annual Production)`

Interpreting the Result

The numbers tell a story. A company with a high percentage of Proved reserves, a consistent RRR above 100%, low F&D costs, and a long reserve life is a durable, well-run business. It's a robust farming operation. Conversely, a company with stagnant Proved reserves, a low RRR, and a management team that constantly points to its “exciting” Possible reserves is often a sign of a business struggling to replace its core assets. It's a farm that is harvesting more than it's planting. This is a red flag. Always trust the audited Proved numbers over the promotional PowerPoint slides.

A Practical Example

Let's compare two fictional oil producers, “Bedrock Oil Co.” and “Wildcatter Exploration Inc.” Both have the same market capitalization. Which one would a value investor prefer?

Metric Bedrock Oil Co. (The Value Play) Wildcatter Exploration Inc. (The Speculative Play)
Total Reported Reserves 120 million barrels of oil equivalent (BOE) 150 million BOE
Reserve Breakdown Proved (1P): 100 million BOE (83%) Probable: 20 million BOE | Proved (1P): 50 million BOE (33%) Probable & Possible: 100 million BOE
Reserve Replacement (RRR) 115% (consistently) 75% (declining)
F&D Cost per Barrel $12 $25
Reserve Life Index (RLI) 12 years 6 years
Management Tone “Our focus is on disciplined capital allocation and low-cost development of our proved assets.” “We have world-class potential in the XYZ basin that could hold billions of barrels!”

The Value Investor's Analysis: At first glance, Wildcatter Exploration seems to have more reserves (150M vs 120M BOE). But a value investor immediately sees the flashing red lights.

The choice is clear. A value investor buys Bedrock Oil, confident in the assets they can see and measure, and lets the speculators gamble on Wildcatter.

Advantages and Limitations

Strengths

Weaknesses & Common Pitfalls

1)
The infamous Bre-X Minerals scandal of the 1990s, where a massive gold deposit turned out to be a complete fraud, is a stark reminder that reserve reports can be manipulated.