Possible Reserves

Unlocking Potential: Understanding "Possible Reserves" in Drilling & Well Completion

In the world of oil and gas exploration, understanding the potential of a reservoir is crucial. While "proved reserves" represent the highly likely and commercially viable oil or gas that can be extracted, the concept of "possible reserves" delves into a realm of greater uncertainty.

Possible reserves are those unproved reserves that, based on geological and engineering data, are considered less likely to be recoverable than "probable reserves." They represent a lower probability of being extracted but still hold potential value.

The "10% Probability Rule"

A key factor in defining possible reserves is the "10% probability rule." When probabilistic methods are used to estimate reserves, there should be at least a 10% probability that the quantities actually recovered will equal or exceed the sum of estimated proved, probable, and possible reserves. This rule emphasizes the inherent uncertainty associated with possible reserves, signifying a lower confidence level compared to proved and probable reserves.

What Makes a "Possible Reserve"?

Possible reserves can arise from various scenarios, each representing a different level of uncertainty:

• Beyond the Probable: Reserves that may exist beyond areas classified as probable based on geological interpretations. These areas might hold potential, but the data available is not sufficient to classify them as probable.
• Potentially Productive Formations: Formations identified through logs and core analysis that appear to be petroleum-bearing but may not be productive at commercially viable rates. Further exploration and testing are required to determine their feasibility.
• Infill Drilling Uncertainty: Incremental reserves attributed to infill drilling, where technical uncertainties exist regarding their recovery potential.
• Improved Recovery Methods: Reserves attributed to enhanced recovery methods where a project or pilot is planned but not yet operational. The uncertainty here stems from the feasibility of the technology and the reservoir's characteristics.
• Structurally Lower Areas: Reserves in areas separated from the proved area by faulting, where geological interpretation suggests the subject area is structurally lower. This indicates potential, but further assessment is needed to determine connectivity and recovery feasibility.

P3: A Short-Hand for Potential

Possible reserves are often referred to as P3 in the Society of Petroleum Engineers (SPE) terminology. This designation helps streamline communication and emphasizes their status as a less certain but still potentially valuable resource.

Understanding the Value of "Possible Reserves"

While possible reserves carry a higher risk than proved or probable reserves, they play a significant role in strategic planning for oil and gas companies. They represent potential that can be unlocked through further exploration, technological advancements, and optimized recovery methods. By understanding the potential of possible reserves, companies can make informed decisions regarding future investments, resource allocation, and overall development strategies.

In conclusion, possible reserves are a crucial element in evaluating the full potential of an oil or gas field. They offer a glimpse into the less certain but still valuable resources that may be unlocked through further exploration and advancements in technology. Understanding the nuances of possible reserves allows for more informed decision-making, contributing to a sustainable and prosperous future in the oil and gas industry.